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RegRag1977
10-13-2010, 11:36 AM
Hi guys,

I just wanted to know if there was a major technical difference between the D22 and the D27, apart from the bubble canopy and the different propeller?

I also wanted to know how many bubble canopy P47 there was compared to the Razorbacks. Were bubble canopy (and new prop equipped) present in large numbers or were they a minority (late 44 until the end).

Thanks http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

ytareh
10-13-2010, 12:33 PM
Get yerself a copy of IL2 Compare online !It tells me that (surprisingly) the 22 is a little (15kmh)faster ABOVE 8500m but 30kmh slower at all other alts .The 27 turns and climbs better again except its slightly slower in a climb above 8250m.Of course while youre not going to get a better combat flight sim the 'real life' figures dont always compare perfectly with in game ones ...

JtD
10-13-2010, 12:44 PM
The D-22 and the D-27 had the same propeller.

Besides the bubble top canopy, the biggest difference were the tank capacities for fuel and ADI.

Also the engine got cleared for a higher boost as the bubble tops appeared, but this should not be a difference since earlier versions could also use this higher boost.

In game, the story is different with the D-27 simply using an engine with more power down low (higher boost modelled).

The bubble tops would be more numerous by late 1944 than the razorbacks.

JG53Frankyboy
10-13-2010, 02:35 PM
a long time wish of mine is that the ingame D-22 and D-27 would get the same performance (at least almost....), means D-22 should perform like the D-27

so that their only difference would be the cockpit - and could fly together, as in real.

there would still be the D-10....

RegRag1977
10-13-2010, 03:02 PM
Thank You guys,

i'm discovering the Tbolts, so i cannot really talk about their respective performances in game (not to talk about real world where i am even more ignorant http://forums.ubi.com/images/smilies/53.gif ...)

If i understood clearly, D-22 and D-27 are exactly the same aircraft, the only difference being the canopy (the Razorback definitely having the most beautiful one http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif) .

BTW JTD what is the ADI thing you mentionned? And according to you which one of the two is closer to the real thing, from what i understood you seem to consider the D-27 a bit "overmodelled" down low?

Buzzsaw-
10-13-2010, 03:22 PM
Salute

The boost levels and weight of the aircraft are the main differences. Wing area was the same.

The D10 was 13,500 lbs normal loaded (full fuel and ammo, no bombs/rockets/droptanks) It was equipped with the Pratt and Whitney R-2800-63 engine. It came standard with Water injection which allowed the use of 56 inches of boost. Water injection capability was added to the earlier R-2800-21 engine beginning with the D-4-RA and D-5-RE P-47 production blocks. Provision was made for the mounting of 15-gallon tank carrying a water-alcohol mixture to the bulkhead just aft of the engine. A line from this tank was plumbed directly into the fuel intake. When injected into the combustion chamber, the water checked a dangerous rise in cylinder head temperature while manifold pressure was boosted. For brief instants, a 15-percent increase in engine power could be obtained, giving a maximum war emergency power of 2300 hp. In the D-5-RE, D-6-RE, and D-10-RE (D-4-RA, production blocks, the pilot manually controlled the water flow of the injector, but the injection procedure was automatically- controlled on the D-11-RE (D-11-RA) and subsequent blocks. This happened when the throttle was pushed forward into its last half-inch of travel.

The D22 was slightly heavier than the D10, it had the 'universal wing' which allowed pods mounted underwing which allowed it to take the long range dual 108 gallon drop tanks or bombs, which the D10 could not carry. Its belly shackle mounts were also strengthened. The pods were first introduced on the P-47D-15 model. The D22 used the R-2800-59 engine, which also had Water injection and also ran 56 inches of boost and 2300 hp from the factory. The D22 also had standard a larger (13- foot diameter) paddle-bladed propeller (either a Hamilton Standard Hydromatic 24E50-65 or a Curtiss Electric C542S) to make full use of the additional power provided by water injection. It added 400 feet per minute to the climb rate. Unfortunately, the game D22 does not show the performance gain realized by the paddle blade addition. All earlier models of the P-47D were retroactively fitted with the Paddle blade props in late December '43 and early January '44.

The D27 was 14,600 lbs normal loaded, also used the R-2800-59 engine, but experience in Europe had shown this engine could be easily boosted to 64 inchs when using 100/130 octane and Water injection, which gave 2535 hp and this had become standardized in Production models beginning with the D25. Earlier P-47D models, (including the D22) equipped with either the R-2800-21 with Water injection, R-2800-59, or R-2800-63 were officially cleared to use 66 inches of boost with 100/130 operationally by January of 1944. The other major difference between the D27 and the D22 was obviously the bubble canopy, but it also had an 83-gallon auxiliary fuel tank fitted internally, which added extra weight.

The final game model, the P-47D (late) is simply a D-27 running 70 inches of boost and Water injection with 100/150 octane fuel. This gave approx. 2700 hp. This was cleared officially for operations by July of 1944.

The game should really have modelled additional versions of the P-47, unfortunately not even the various modders have done this even though it would not require graphics changes.

Missing models

1) D10 using 64-65 inches boost and paddle blade prop.

2) D10 using 70 inches boost with 100/130 octane and paddle blade (this would be the best performing P-47, with low weight/high horsepower, better handling properties of the Razor back without underwing pods) Robert Johnson, the 2nd highest scoring P-47 pilot flew a P-47D-5 named 'Lucky' similar to a D10, which was upgraded with water injection. His crew chief modded it to allow 70 inches boost, and according to Johnson, this was the best P-47 he flew in Europe. It was destroyed by another pilot who borrowed it for a mission Johnson missed. According to Johnson and other pilots, 70 inches of boost was not a problem with 100/130 octane. This level of boost was commonly used for the P-47's based on the continent, even though 100/130 octane fuel was the only variety available to the 9th AAF Groups there.

Picture of Johnson's D5:

http://www.littlefriends.co.uk/gallery/56g/lucky.jpg

3) D22 with 64-65 inches of boost and Paddle blade prop

4) D22 with 70 inches of boost using 150 octane and Paddle blade (Razorback P-47's were still the most numerous version of the aircraft right up to September of 1944, after the introduction of 100/150 octane and clearance for 70 inchs of boost in the 8th AAF)

BillSwagger
10-13-2010, 05:51 PM
It would be cool to have more models but to include retrofitted early D models would be a bit redundant. The advent of ADI was not well understood even when put into use in '43, and even then the PW-R2800 components had to be engineered to handle higher boost settings. The likelihood of a pilot flying a D-10 or earlier with more than a standard output would not be surprising, but it wouldn't be until newer technology was shipped in on the newer models, where said retrofitting could occur. So i ask, why include the retrofitted model when the later model would have similar performance?
The loaded weights have more to do with the fuel increase than actual mass added to the airframe. In game its conceivable that both airplanes would perform pretty closely.

BTW, the P-47D-30 was the most widely produced variant, but you would have to look to see if those numbers are more than the total number of razor backs produced. There are about 20 production blocks of Razorbacks, and only 7 production blocks of bubble tops if you include the M model.

The D-27 and D-22 were not the same plane.
The D-27 had a higher fuel capacity making it heavier, however it was also cleared for higher boost. The issue of ADI is not only a matter of power output but also a heat reduction method.
The main handicap of early Ds was that they overheated in extended climbs, meaning that full power could not be used for more than a couple minutes at a time, lowering the climb rate. I've previously thought it was a power to weight issue, but it had more to do with heat. ADI and better cowling improved cooling to allow for longer extended climbs such that by the time the D-30s were out, climbs at higher power could be achieved all the way up to 40,000ft taking about 20 minutes.

The exact outputs for different models are difficult to pin down because of the variations in boost pressure and the use of higher octane fuel:
P-47C - the first D variants = 2000hp
P-47D-5 - P-47D-23 = 2000hp - 2300hp
P-47D-25 - P-47D-30 = 2300hp - 2500hp
Late D-30 and D-40 = 2500hp - 2800hp

These figures don't include field modifications that might be able to produce similar outputs in earlier variants.
I would still argue that some of these numbers are understated only because the R-2800 being engineered at the factory was pushing much higher boost pressures with outputs exceeding 3500hp for 100 hours. It was both marveled and somewhat held back because of fear the technology would be devastating if it fell into enemy hands. I have not seen what the max boost pressure of the turbo system for a P-47 was but outputs achieved at the PW plant reached 150".
It would be no surprise to me if field mods allowed higher performance but i don't think this sim should take such obscurities like that into consideration.


Bill

RegRag1977
10-14-2010, 03:51 AM
Originally posted by Buzzsaw-:
Salute

The boost levels and weight of the aircraft are the main differences. Wing area was the same.

The D10 was 13,500 lbs normal loaded (full fuel and ammo, no bombs/rockets/droptanks) It was equipped with the Pratt and Whitney R-2800-63 engine. It came standard with Water injection which allowed the use of 52 inches of boost. Water injection capability was added to the earlier R-2800-21 engine beginning with the D-4-RA and D-5-RE P-47 production blocks. Provision was made for the mounting of 15-gallon tank carrying a water-alcohol mixture to the bulkhead just aft of the engine. A line from this tank was plumbed directly into the fuel intake. When injected into the combustion chamber, the water checked a dangerous rise in cylinder head temperature while manifold pressure was boosted. For brief instants, a 15-percent increase in engine power could be obtained, giving a maximum war emergency power of 2300 hp. In the D-5-RE, D-6-RE, and D-10-RE (D-4-RA, production blocks, the pilot manually controlled the water flow of the injector, but the injection procedure was automatically- controlled on the D-11-RE (D-11-RA) and subsequent blocks. This happened when the throttle was pushed forward into its last half-inch of travel.

The D22 was slightly heavier than the D10, it had the 'universal wing' which allowed pods mounted underwing which allowed it to take the long range dual 108 gallon drop tanks or bombs, which the D10 could not carry. Its belly shackle mounts were also strengthened. The pods were first introduced on the P-47D-15 model. The D22 used the R-2800-59 engine, which also had Water injection and also ran 52 inches of boost and 2300 hp from the factory. The D22 also had standard a larger (13- foot diameter) paddle-bladed propeller (either a Hamilton Standard Hydromatic 24E50-65 or a Curtiss Electric C542S) to make full use of the additional power provided by water injection. It added 400 feet per minute to the climb rate. Unfortunately, the game D22 does not show the performance gain realized by the paddle blade addition. All earlier models of the P-47D were retroactively fitted with the Paddle blade props in late December '43 and early January '44.

The D27 was 14,600 lbs normal loaded, also used the R-2800-59 engine, but experience in Europe had shown this engine could be easily boosted to 64 inchs when using 100/130 octane and Water injection, which gave 2535 hp and this had become standardized in Production models beginning with the D25. Earlier P-47D models, (including the D22) equipped with either the R-2800-21 with Water injection, R-2800-59, or R-2800-63 were officially cleared to use 64 inches of boost with 100/130 operationally by January of 1944. The other major difference between the D27 and the D22 was obviously the bubble canopy, but it also had an 83-gallon auxiliary fuel tank fitted internally, which added extra weight.

The final game model, the P-47D (late) is simply a D-27 running 70 inches of boost and Water injection with 100/150 octane fuel. This gave approx. 2700 hp. This was cleared officially for operations by July of 1944.

The game should really have modelled additional versions of the P-47, unfortunately not even the various modders have done this even though it would not require graphics changes.

Missing models

1) D10 using 64 inches boost and paddle blade prop.

2) D10 using 70 inches boost with 100/130 octane and paddle blade (this would be the best performing P-47, with low weight/high horsepower, better handling properties of the Razor back without underwing pods) Robert Johnson, the 2nd highest scoring P-47 pilot flew a P-47D-5 named 'Lucky' similar to a D10, which was upgraded with water injection. His crew chief modded it to allow 70 inches boost, and according to Johnson, this was the best P-47 he flew in Europe. It was destroyed by another pilot who borrowed it for a mission Johnson missed. According to Johnson and other pilots, 70 inches of boost was not a problem with 100/130 octane. This level of boost was commonly used for the P-47's based on the continent, even though 100/130 octane fuel was the only variety available to the 9th AAF Groups there.

Picture of Johnson's D5:

http://www.littlefriends.co.uk/gallery/56g/lucky.jpg

3) D22 with 64 inches of boost and Paddle blade prop

4) D22 with 70 inches of boost using 150 octane and Paddle blade (Razorback P-47's were still the most numerous version of the aircraft right up to September of 1944, after the introduction of 100/150 octane and clearance for 70 inchs of boost in the 8th AAF)

Salute,

Thank you for all the informations (and pic!) you posted,it is much appreciated http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Very interesting indeed http://forums.ubi.com/images/smilies/25.gif

RegRag1977
10-14-2010, 04:15 AM
Originally posted by BillSwagger:
It would be cool to have more models but to include retrofitted early D models would be a bit redundant. The advent of ADI was not well understood even when put into use in '43, and even then the PW-R2800 components had to be engineered to handle higher boost settings. The likelihood of a pilot flying a D-10 or earlier with more than a standard output would not be surprising, but it wouldn't be until newer technology was shipped in on the newer models, where said retrofitting could occur. So i ask, why include the retrofitted model when the later model would have similar performance?
The loaded weights have more to do with the fuel increase than actual mass added to the airframe. In game its conceivable that both airplanes would perform pretty closely.

BTW, the P-47D-30 was the most widely produced variant, but you would have to look to see if those numbers are more than the total number of razor backs produced. There are about 20 production blocks of Razorbacks, and only 7 production blocks of bubble tops if you include the M model.

The D-27 and D-22 were not the same plane.
The D-27 had a higher fuel capacity making it heavier, however it was also cleared for higher boost. The issue of ADI is not only a matter of power output but also a heat reduction method.
The main handicap of early Ds was that they overheated in extended climbs, meaning that full power could not be used for more than a couple minutes at a time, lowering the climb rate. I've previously thought it was a power to weight issue, but it had more to do with heat. ADI and better cowling improved cooling to allow for longer extended climbs such that by the time the D-30s were out, climbs at higher power could be achieved all the way up to 40,000ft taking about 20 minutes.

The exact outputs for different models are difficult to pin down because of the variations in boost pressure and the use of higher octane fuel:
P-47C - the first D variants = 2000hp
P-47D-5 - P-47D-23 = 2000hp - 2300hp
P-47D-25 - P-47D-30 = 2300hp - 2500hp
Late D-30 and D-40 = 2500hp - 2800hp

These figures don't include field modifications that might be able to produce similar outputs in earlier variants.
I would still argue that some of these numbers are understated only because the R-2800 being engineered at the factory was pushing much higher boost pressures with outputs exceeding 3500hp for 100 hours. It was both marveled and somewhat held back because of fear the technology would be devastating if it fell into enemy hands. I have not seen what the max boost pressure of the turbo system for a P-47 was but outputs achieved at the PW plant reached 150".
It would be no surprise to me if field mods allowed higher performance but i don't think this sim should take such obscurities like that into consideration.


Bill


Thank You Bill,

A lot of info in you post too! I have now a lot to digest!

Now i'm starting to ask myself why i did wait so long to start having interest in this bird...

Even though this community is often called UBIzoo (and for good reasons sometime); when one have a question to ask about an aircraft one can always count on it to get good infos http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

TY guys!

Wildnoob
10-14-2010, 10:20 AM
One time I read here the roll rate of the P-47 is wrong.

If this is truth maybe TD could fix this isn't?

Buzzsaw-
10-14-2010, 01:49 PM
Originally posted by Wildnoob:
One time I read here the roll rate of the P-47 is wrong.

If this is truth maybe TD could fix this isn't?

This was an issue way back when IL-2 Forgotten Skies was the hot new item.

But after much data provided by myself and others, (and much disinformation from certain Axis fanatics), the roll rate of the razorback was changed, then after further information came forward, the rollrate of all P-47's was changed. At high speeds, the P-47 now displays one of the best rollrates of any IL-2 1946 aircraft. They can stay with 190's as they were able to historically. (they also have excellent elevator response at high speed)

With the exception of the D22's not being modeled with paddleblades, the P-47's as modeled by Oleg now actually are one of the more accurate aircraft in the game. The only other thing which the standard game has incorrectly is the position of the gunsight for the Razorbacks, it's too low, (similar to the 190's) but this has been corrected in the modded versions.

At higher altitudes, 6000+, the P-47D bubbletop's are some of the best aircraft available in the game, replicating the historical aircraft's ability to dominate the 109's and 190's at those altitudes.

Still it would be nice to see the Razorback models get their historical level of performance.

BillSwagger
10-14-2010, 04:28 PM
maybe its apples to apples, but i've always thought the P-47's in game rolled too well at lower speeds, and not good enough at higher speeds. Peek roll performance was achieved above 300IAS at something like 80 degrees per second.
It has a lot to do with altitude, but i notice 109s roll with better velocity at these speeds, and that is not accurate.
Actually roll should be more similar to the P-51s modeling, IMO, but giving the edge to the P-51 at lower speeds and the edge to the P-47 at higher speeds.

Kwiatos
10-23-2010, 12:13 PM
Unfortunately you are not right that P-47s in Il2 have accurate FM and performacne.

Makinig some research and comparing Il2 P-47 to RL data i found that mostly all P-47 in game have too good climb rate and some are too fast at the deck. LAte models - P-47 D-27 and D-27 late have also too low take off weight ( the same like early models which is wrong) and turn too good comparing to early version.

Other hand P-47s had way too slow roll rate at high speeds and wobbling nose after any movement.

These things required a serious fix.

I made such changes and in new UP patch there will be new FM's for all P-47 which would be more close to RL data and flight characteritic - the same way like new P-51 and other plane in UP.

Buzzsaw-
10-23-2010, 02:44 PM
Hello Kwiatos

Thanks for your work on the various aircraft flight models which you have done.

However, while I do appreciate that, before you start to degrade the performance of the game's P-47's, please be aware of a number of things.

If you are basing the performance of the P-47 on U.S. factory figures, remember that the aircraft used in the European Theater were tuned to higher boost than the factory aircraft in the United States, even when using only 100/130 octane.

Additionally, all the Razorback P-47's were either equipped with paddleblade propellors or retroactively fitted with them. The early models, similar to the D-10 were fitted with these props in late December '43, early January '44. These aircraft continued in service right through the summer of 1944 and the types without pylons were the most common right up to April.

See this paddleblade performance test done with D-10:

http://www.wwiiaircraftperformance.org/p-47/p-47d-75035-fig2.jpg

This shows a climb of 3600 fpm at ground level. And remember this test was at only 56 inch boost. These aircraft were all cleared for 66 inches boost in May which would give even better performance. You can see the test which cleared them here which involved a Pratt and Whitney R-2800-63 engine, the same type which the D-10 was equipped with:

http://www.wwiiaircraftperformance.org/150grade/p-47-66inch.jpg

Degrading these aircraft to factory boost performance, without paddle blade props is inaccurate.

Additionally, all models of P-47 were cleared to use 70 inches boost in June of '44 with 100/150 octane fuel:

http://www.wwiiaircraftperform...-progress-report.pdf (http://www.wwiiaircraftperformance.org/p-47/24june44-progress-report.pdf)

What is really needed, as I have mentioned in my previous posts, is several new models representing the performance of aircraft used in Europe.

And to those who say that 'field mods' should not be allowed, then I say, why then is there a 190A-5 with 1.65ata boost? This aircraft never came from the factory with this setting, it was only retroactively allowed to use a higher boost.

Aircraft should be represented at the performance level which they achieved in operational use.

Again, thanks for your work on aircraft.

Cheers Buzzsaw

JtD
10-23-2010, 03:20 PM
This shows a climb of 3600 fpm at ground level. And remember this test was at only 56 inch boost.

http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

Tested at 64 inch boost. If you want to make a case, try facts. And when you do, don't forget to mention that is was done at 13300lbs.

K_Freddie
10-23-2010, 03:41 PM
Originally posted by RegRag1977:
Now i'm starting to ask myself why i did wait so long to start having interest in this bird...

Everyone thinks that the 'sexy' a/c are the winners, but soon are they to realise that sexy = parachute/death.

It's the 'ugly' beasts that keep you alive http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

ROXunreal
10-23-2010, 04:04 PM
I have a question regarding the early thunderbolts: is there any worse cockpit for a monowing single seater in the game?

M_Gunz
10-23-2010, 04:32 PM
Originally posted by JtD:
The D-22 and the D-27 had the same propeller.

Besides the bubble top canopy, the biggest difference were the tank capacities for fuel and ADI.

Also the engine got cleared for a higher boost as the bubble tops appeared, but this should not be a difference since earlier versions could also use this higher boost.

In game, the story is different with the D-27 simply using an engine with more power down low (higher boost modelled).

The bubble tops would be more numerous by late 1944 than the razorbacks.

And IL2 models are to represent certain planes as they were in certain times. Later clearance or change makes no difference.

Perhaps with a different game engine some or all things like different prop or internal workings could have been covered. It is there for weapons, ammo, fuel and loadout but not all software is made to anticipate every possibility.

JtD
10-23-2010, 10:44 PM
Originally posted by M_Gunz:

And IL2 models are to represent certain planes as they were in certain times. Later clearance or change makes no difference.

The things designated P-47 D-10, D-22 and D-27 do not represent a P-47 D-10, D-22 or D-27.

M_Gunz
10-24-2010, 02:07 AM
Either they do to the dev team or they are possibly the result of sloppy work or outcome of FM shortcuts and limited time getting tweaks done.

I try to say that a D-22 is -supposed- to be a D-22 at some stage but not a later time just as our 190A-4 is from some period Russian Front. Our Spit VB is mislabeled, supposed to be Aug 42 not 1941 but there again someone will point out the speed and climb together are neither.

It's no good to say prop and boost were later changed with reference to these models unless the model is from after the change. I don't expect more than a certain closeness that I do not define anyway and I have been thrilled to get as good as IL2 has been even with the known warts.

BillSwagger
10-24-2010, 02:16 AM
You can nickle and dime the P-47 but I really don't think they are that far off.
A lot of people don't realize that the Razorback also had B and C production blocks before the Ds arrived. The main improvements of the D were automatic boost control, and better cowling for cooling. These two improvements alone would make for an easier ride aside from higher engine outputs.
I think the game does a fair job and gives a variety of choices to use for a map. If you look at specs and performance they seem to combine different performance traits rather than being clearly representative of one type. For example, the D-10 climbs well but is slower than historical tests show. You might find that the P-47D-27 is actual more or less spot on with historical climb rates but its top speed should be that of the late, while the late has a climb closer to that of the P-47M but is nowhere fast enough to represent that plane.
If someone wants to fine tune them, that would be great. Maybe you could also fix the roll and dive accleration considering it takes the better part of 20,000ft to reach terminal velocity when test indicate it only took about 10k. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif
I actually think thats the bigger flaw than whats been mentioned because most of the level speed and climb projections always seem to be with in reason, ie that 10% margin. But if you have a plane that takes twice as much altitude to build up the speed that it should, then it probably seems like it zooms too well because it doesn't gain the speed that it should from a shallow dive. If it did, its zoom might be more proportionate to its actual weight. If that makes sense.


Bill

M_Gunz
10-24-2010, 05:38 AM
Just asking: Same start speed and dive angle as that dive test used Bill?
Also do they say in the test results what the end speed is or use the word terminal? I don't trust IL2 terminal speeds.

BillSwagger
10-24-2010, 03:18 PM
yes, you can look at that or even look into the dive tests that Curtis performed with their propellers.

Terminal is a term i used to mean as fast as the plane could go which is about 600mph TAS (+/- 20mph) dependent on altitude and atmospheric conditions.

I should avoid any embellishments on my part, my only point being that the plane accelerated faster in a dive, particularly in shallower dives. It further adds to my point about the zoom climb. My guess would be that most people who complain about the P-47 would be in the area of climb. You might consider that has something to do with it.


Bill

Gaston444
10-24-2010, 04:33 PM
The important thing to remember about the earlier needle-tip Razorbacks is that the Germans tested a captured one they had(underpowered) and concluded that it out-turned the Me-109G in all circumstances: "The P-47D out-turns our Bf-109" Source: "On Special Missions. KG 200".

It didn't turn nearly as well to the right however.

The fact that the German-captured Razorback's power was below specs probably helped it in sustained turns, as might have done the inferior wing-depressing pull of the needle-tip prop... Later Bubbletop and paddle-blade P-47s were not that good in sustained flat turns however, especially since they were usually loaded with more power, and thus much more slowly out-turned the Me-109G and Ks (but still did: See ANY combat account on the TV show "Dogfights": the "Boddenplatte" episode for instance (the last 15 minutes), or anywhere else for that matter)...

Later Paddle-blade Bubbletops were pretty hopeless in sustained flat turns against the FW-190A-8s, but the earlier Needle-tip Razorbacks were roughly competitive against A-6s until the A-8 appeared.

Sorry for the inadvertant injection of actual reality in a sim forum...

Gaston

RegRag1977
10-25-2010, 03:23 AM
Originally posted by Gaston444:
The important thing to remember about the earlier needle-tip Razorbacks is that the Germans tested a captured one they had(underpowered) and concluded that it out-turned the Me-109G in all circumstances: "The P-47D out-turns our Bf-109" Source: "On Special Missions. KG 200".

It didn't turn nearly as well to the right however.

The fact that the German-captured Razorback's power was below specs probably helped it in sustained turns, as might have done the inferior wing-depressing pull of the needle-tip prop... Later Bubbletop and paddle-blade P-47s were not that good in sustained flat turns however, especially since they were usually loaded with more power, and thus much more slowly out-turned the Me-109G and Ks (but still did: See ANY combat account on the TV show "Dogfights": the "Boddenplatte" episode for instance (the last 15 minutes), or anywhere else for that matter)...

Later Paddle-blade Bubbletops were pretty hopeless in sustained flat turns against the FW-190A-8s, but the earlier Needle-tip Razorbacks were roughly competitive against A-6s until the A-8 appeared.

Sorry for the inadvertant injection of actual reality in a sim forum...

Gaston

Hi Gaston,

I guess that even the very same aircraft tested at different altitudes against the same opponent gives different conclusions:

perhaps the first captured underpowered P47 you're talking about was tested against an Me109 at very high altitude where combat generally occured in ETO (P47 was then in its high alt, escort role), and the second one more powerfull with paddle prop and all, was "tested" when flown versus real US pilots during Bodenplatte which was a very low altitude operation (late war P47 were at these times often used as Fighter-bombers), where one of the best 190A, the A8, really shines.

So these differences you mention may not be as important as you seem to believe? We cannot jump to conclusion with these examples only, at least this is my humble opinion.

RegRag1977
10-25-2010, 07:53 AM
Originally posted by BillSwagger:
yes, you can look at that or even look into the dive tests that Curtis performed with their propellers.

Terminal is a term i used to mean as fast as the plane could go which is about 600mph TAS (+/- 20mph) dependent on altitude and atmospheric conditions.

I should avoid any embellishments on my part, my only point being that the plane accelerated faster in a dive, particularly in shallower dives. It further adds to my point about the zoom climb. My guess would be that most people who complain about the P-47 would be in the area of climb. You might consider that has something to do with it.


Bill


Anyone tried to reproduce the final part of this P47 training movie where the half roll is treated (min. 17:14) ?

PS http://forums.ubi.com/images/smilies/10.gif Bill, I precise that I'm a total newb with the P47, but i think you're on the right path, it seems to me ( but i may be wrong, and i definitely need far more training with the Tbolt) that the P47 doesn't take speed quickly enough in dives, and that it climbs too well at low alt (especially late marks).

http://www.youtube.com/watch?v=_NWaHlnI_LQ

Gaston444
10-25-2010, 11:19 AM
Originally posted by RegRag1977:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Gaston444:
The important thing to remember about the earlier needle-tip Razorbacks is that the Germans tested a captured one they had(underpowered) and concluded that it out-turned the Me-109G in all circumstances: "The P-47D out-turns our Bf-109" Source: "On Special Missions. KG 200".

It didn't turn nearly as well to the right however.

The fact that the German-captured Razorback's power was below specs probably helped it in sustained turns, as might have done the inferior wing-depressing pull of the needle-tip prop... Later Bubbletop and paddle-blade P-47s were not that good in sustained flat turns however, especially since they were usually loaded with more power, and thus much more slowly out-turned the Me-109G and Ks (but still did: See ANY combat account on the TV show "Dogfights": the "Boddenplatte" episode for instance (the last 15 minutes), or anywhere else for that matter)...

Later Paddle-blade Bubbletops were pretty hopeless in sustained flat turns against the FW-190A-8s, but the earlier Needle-tip Razorbacks were roughly competitive against A-6s until the A-8 appeared.

Sorry for the inadvertant injection of actual reality in a sim forum...

Gaston

Hi Gaston,

I guess that even the very same aircraft tested at different altitudes against the same opponent gives different conclusions:

perhaps the first captured underpowered P47 you're talking about was tested against an Me109 at very high altitude where combat generally occured in ETO (P47 was then in its high alt, escort role), and the second one more powerfull with paddle prop and all, was "tested" when flown versus real US pilots during Bodenplatte which was a very low altitude operation (late war P47 were at these times often used as Fighter-bombers), where one of the best 190A, the A8, really shines.

So these differences you mention may not be as important as you seem to believe? We cannot jump to conclusion with these examples only, at least this is my humble opinion. </div></BLOCKQUOTE>

-I have read on this subject for the last 15 years to create my boardgame variant;

http://forums.ubi.com/eve/foru...031083708#5031083708 (http://forums.ubi.com/eve/forums/a/tpc/f/4811054957/m/5031083708?r=5031083708#5031083708)

and despite a few US comparative tests that find the P-47 roughly equal or inferior to the Merlin P-51 in sustained turns (which I think is bunk), I would say thousands of combat accounts abundantly demonstrates that the Me-109G is utterly hopeless in sustained turns against the P-47 at any altitude, except in right turns. (The Me-109G can carve a tighter RADIUS unsustained turn, but the source of its very mediocre sustained flat-turning performance is I think in turn-induced drag in prolonged turns, though at very low speeds(downthrottled to an "optimal" speed around 160 MPH(!!!) according to Fin ace Karhila), it can again turn so tightly that its inferior turn speed is compensated for, to some extent, by the tightness of the sustained turn radius). Note also that the Me-109G should turn marginally better than the FW-190A at any speed above 250 MPH.

My game is probably inaccurate for the P-47D entry in that the below 250 MPH sustained turn performance is shown as symmetrical, and that the narrow needle-tip prop is inferior to the broad paddle-blade prop for sustained turns, but if downthrottling is used on the P-47D the issue is unclear (you never hear of the P-47D downthrottling in sustained turns. I don't know why)...

Tests of the P-47D vs the FW-190A found an increase in competitiveness in sustained turns near the ground for the P-47D (say below 5000 feet), and I also failed to depict this correctly if the improvement is on the P-47D's side, which I think it might not be...:

http://www.ww2aircraft.net/for...-38-p-51-a-5551.html (http://www.ww2aircraft.net/forum/flight-test-data/p-47-vs-fw-190-spitfire-p-38-p-51-a-5551.html)



I suspect however that the decrease (to rough parity) of the FW-190A's sustained turning ability near the ground comes from the lack of FW-190A's downthrottling in US/British tests, because the FW-190A's engine below 4000 ft. has a large surge of power which is detrimental to sustained turning if you keep full power as non-frontline test pilots always do...

My opinion of the P-47D as a sustained turn fighter is in part derived from having read all 600 P-47 AND 700 P-51 combat accounts visible at Mike Williams "WWII Aircraft Performance site", so it is not an opinion formed quickly: It took me over twelve years to put aside simulation-based dogma and how entirely wrong almost all of it is...:

http://www.wwiiaircraftperform...counter-reports.html (http://www.wwiiaircraftperformance.org/p-47/p-47-encounter-reports.html)


This is where I found several specific accounts that confirm the use of downthrottling to better sustain low-speed turns, such as this:

http://www.spitfireperformance...hanseman-24may44.jpg (http://www.spitfireperformance.com/mustang/combat-reports/339-hanseman-24may44.jpg)

Which tactic is also confirmed on the Me-109G by Fin ace Karhila and on the FW-190A-8 as well... This fairly widespread tactic demonstrates that the entire calculated predictive method used by simulations for WWII fighters is mostly false and incapable of predicting ANY outcome... Modern calculations cannot even predict where the 6 G "Corner Speed" really is on any of these WWII fighters: The math says around 2.44 times Stall apeed, around 250 MPH for the P-51D Mustang. Actual 1989 test by the "Society of Experimental Test Pilots"?: 320 MPH!!!!! Ugh... Not even close...

Kurt Tank mentions 7 Gs for the FW-190A at 400 MPH: You can bet that is the 7G "Corner Speed" speed too, very consistent with the 1989 tests (but the Gs here are likely partly nose-up tail-down deceleration on a loose curve due to the FW-190A's dirt-poor high-speed handling)...

I think this unexpetedly high "Corner Speed" in most WWII fighters is due to the depressing effects of the prop's above-wing traction at high power pressing down on the wing's lift (not noticeable on lower-power and high-wing Cessnas I would think), requiring more speed and airflow for the wing's lift to finally beat the prop's disc load. (The prop disc's load has a downward push on the wings because pulling on the stick puts it increasingly high compared to its previous already high position vs the wings, using the actual trajectory as the reference line: No such effect on jets...)

This shows you just how little is known about the actual handling of these old fighters...

And these opinions were not arrived at quickly, believe me...

Gaston

P.S. Another interesting thing found in those combat accounts is that the P-51's gun jamming problems in hard turns were never really solved, and are endemic even on the D model, and almost inevitable on the B/C variants... P-47? Non-existent...

G.

JtD
10-25-2010, 11:44 AM
http://forums.ubi.com/images/smilies/88.gif

BillSwagger
10-25-2010, 03:16 PM
Originally posted by RegRag1977:
and that it climbs too well at low alt (especially late marks).


The data reveals that later model P-47s were excellent climbers in a fighter configuration.
There is also zoom data that compares the ability of the N and D variants. Something like 1400ft to 5000ft in 20 seconds, while the N made it to 8000ft before a normal climb was resumed. These aren't direct quotes because i haven't looked at the zoom data in several months.
I only ask how consistent the zoom performance was over the range of altitude, and most stories, descriptions, combat reports and other data seems to suggest the P-47 had a fairly consistent zoom due to the consistent output of the engine over the range of altitude.

There are usually disparities in the data depending on which country did the testing. Much of the inconsistency is answered by the fact that different fighters flew at various cruising speeds and as such, their peek performance gap is usually based in relation to their cruising speed. Unless someone knows otherwise, its generally perceived that USAAF fighters had higher cruising speeds and their acceleration from those speeds was superior to German aircraft, however if the planes were tested from a slower start speed, its generally revealed that the German aircraft had better initial acceleration.

M_Gunz
10-25-2010, 10:26 PM
Bill you can put a late model 190A or 190D to the same test and check its cruise speed at FTH, not exactly shabby nor was the Do335 or any 109K I know of and that is just from the prop fighters as a 262 accelerates beyond top speed of any USAAF fighter.

There are usually disparities in the data depending on which country did the testing.

Why I get sticky about test conditions is that when gamers play at 'testing' even more disparities get introduced. I've noted that start conditions alone are often too slow when not specified by document. How the controls are worked is never given and it does make a difference which is why there are champion race drivers, pilots, skiers even, who do far better than average people. A trained car driver will get better MPG out of the same car than most regular drivers for another example.

In those zoom climbs, the starting speeds and especially the execution of the pull up are critical. In the dives, just what did they do? Nice to say the model is off but thinking of change it needs to be just how far off and to get that wrong by too much would leave an exploitable hole. In long shallow dives I get the P-47's up around 900 kph IAS at low alt before losing parts. That is around 550-560 mph. Someone else might fly it faster with steadier control and not lose pieces at all.

Just how steady and perfectly coordinated the plane is controlled makes a big difference in acceleration as well as top end, what the player tests is as much the player as the model. Why so many players forget that or never figure it out I dunno. Same thing happened with P-47 roll rates, most 'test' tracks sent to Oleg showed improper roll technique and IIRC at one point a track showing a proper roll was released, but also with a patch that changed the rate... how much was changed vs how much was called for? It has been a problem with flight sims since the BBS days, there is no number called *about*.

RegRag1977
10-26-2010, 05:33 AM
This "gamer's testing issue" could be resolved by asking an IL2 ace pilot to do the testing and then post a video of it. Same would be great when it comes to weapon efficiency BTW.

This could be really great: i know from my own experience that watching someone being able to do something i can't, with the same gear etc, is the best way to start questionning myself and try to think on how to improve my technique. To learn you first have to get rid of the worst part of your ego, and start working http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif .

Still the problem that remains is that the different aircraft in the game really require different handling to get max performance out of them. Few people master all the different ac and techniques, so we would need al lot of different "ace" people to test the different "departements" of a same aircraft http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif .

There's nothing better than actually see with one's own eyes, a master performing the correct moves perfectly to make you want to learn to master them too.

BillSwagger
10-26-2010, 03:21 PM
In those zoom climbs, the starting speeds and especially the execution of the pull up are critical. In the dives, just what did they do? Nice to say the model is off but thinking of change it needs to be just how far off and to get that wrong by too much would leave an exploitable hole. In long shallow dives I get the P-47's up around 900 kph IAS at low alt before losing parts. That is around 550-560 mph. Someone else might fly it faster with steadier control and not lose pieces at all.

When i play, i pay attention to altitude and speed. There is a certain expectation for speed with the dive from altitude depending on the angle. Some planes are better at this than others, and as a rule, the heavier and higher powered planes should be better at this. There is speed, and there is acceleration, and most of the differences between aircraft to aircraft can be circumvented with a shallow dive. You see this when pulling away from an opponent, so he uses a decent to gain speed to catch up. Some planes need only dive 1000ft to accelerate, while others need much more altitude.

Why should a lighter plane with less horsepower be better at this than the heavier one with more power?
Its not really a question of top speed. If one plane is faster but it takes 3 minutes to reach top speed, while the other is marginally slower but it only takes 1 minute to reach top speed, you'd quickly rate the slower plane as faster.
This is because planes that gain performance from lower drag profiles also need to maintain trim and slip positions, while high thrust designs have enough power to push forward until the drag is a limiting factor. I can only guess how fast you'd need to be going for drag to be a limiting factor against that much horse power and weight, but its probably somewhere over 400mph.

At some point i think aircraft designers realized that higher thrust was not the way to higher top speed if it sacrificed the ability to create a low drag profile. Then again, it was war and aircraft not only had to achieve a speed specification, but also meet other requirements such as load, and altitude, turn, climb, etc, depending on the roll of the plane.
We see many prop designs that achieved 400mph, where increasing engine output only marginally increased top speeds. We see the P-47 go from 2000hp to 2500hp, and yet only make a gain in top speed from 420 to 440 mph. However, climb and acceleration had more significant gains in performance.




Bill

M_Gunz
10-26-2010, 05:48 PM
Total HP to Weight is not what is important. What is important is Excess Power to Weight. Excess Power varies with speed and loading and altitude from plane to plane. For instance the heavy plane with the massive engine and high wing loading at what for it is low speed level flight will be spending a large part of its power on induced drag. A lighter, lower top end plane with less wing loading might not be and will accelerate faster at the same speed in level flight. In the beginning of a dive during those seconds just going from level to nose down at angle the one that you don't expect to will often pull a lead. Even when establishing the dive if you nose down fast enough to make negative G's, you get induced drag from that.

I've flown a lot of test dives and taken tracks of test dives from others and gone over all with UDSP years ago, even before FB. The trend was not outside what it should be. There have been many discussions and rakings-over on the subject.

It's a simple breakdown BTW; you have gravity as the strongest factor pulling down, thrust as a much smaller factor, and drag that eventually equals the other two. Going straight down in free fall, gravity will add 9.81 m/s to the speed of the object every second that it is in free fall. That's 35 kph added per second, in free fall which you won't see in diving flight though before you get moving fast you might see half for a short time. And the other guy isn't standing still. So if you expect for any one plane to pull away from another in a straight dive by anything really big then you're dreaming.

There is a simple way to dive quickly and leave the other guy like he's standing still though. You roll 180 quicker than he can even begin his roll and you pull back into a multi-G transition that whips your plane down hard and there you have it! Gravity can only get you one G while your wings can get you six.

In a long dive contest between two planes with different top dive speeds like a 109G and P-47, the P-47 will cover the distance faster in IL2. Funny enough when I read Gunther Rall's interview in Finland and he addressed dive chases it was the top speeds that he spoke of. He was overtaken and shot in a 109G by P-47's after a long dive.

If you have Curtiss data or a link to it then please let's go over it and see if any of the AE types will enter into discussion, those that haven't tired of it already. The last six or ten times it was shown that expectations are -more- in error than the models which do have some unavoidable error.

BillSwagger
10-26-2010, 07:56 PM
I see your point and it isn't something that i haven't recognized before. Thats always the issue of the debate, drag vs power + weight. I guess i've just been over too many combat reports and tests that tell me differently than how some planes behave in game, particularly in dive.
I could yank out charts and examples to further the argument but i think the actual point i was making earlier was in trying to fix the issue with climb. If it gained more speed in a dive, its subsequent zoom climb would be more proportionate to its weight.

rfxcasey
10-27-2010, 05:15 AM
The P-47 is just plane bad aced. When engaging in ground pounding it's a little bit of a toss up if I have the option of P-38 vs. P-47. I like the fact that the 47 can carry slightly more bombs but conversely less wockets. Not to mention it is tough as nails much like the IL-2 though probably not as tough.

The 38 on the other hand has more wockets, two engines and when your done dropping all your external ordinance you can climb up and hunt down Focke Wulfs or zeros. Not to say this isn't possible in the 47 but I don't fly it enough and the 38 seems to excel in both departments. Though it does seem more susceptible to ground fire and the dag gone elevator control always seems to be the first thing to go probably cause of the huge boom tail.

Still the 38 with its dual engines is perfectly capable of making it home if one engine is completely missing and that may just be the final advantage that puts it over the edge.

M_Gunz
10-27-2010, 05:26 AM
Bill, if the report says -how- it was all done then we need that info. If it doesn't then how do we repeat what they did to check results in a sim?

Zoom is not about weight. It's about speed. The inertia of the heavy plane is greater but so is the energy required to lift that extra weight to any height, they cancel each other. But speed is a squared factor in zoom, it counts greatly. The thing is that you have to have the speed not at the end of the dive but as you're going up, what is lost during transition doesn't help. A poor transition can blow the whole thing, piloting makes the difference. In test terms it's simpler to cut all the data before the plane is heading up in the zoom and working with that.

Before you run tests, define your expectations and do a reality check. If you're looking to get beyond guns range in a few seconds purely by acceleration from a side by side start, your check should fail.

Please, the Curtiss dive test? Didn't you say you have that? Didn't you say that IL2 doesn't match that?

BillSwagger
10-27-2010, 01:31 PM
Bill, if the report says -how- it was all done then we need that info. If it doesn't then how do we repeat what they did to check results in a sim?
which report?, the one posted gives speed, angle of dive, time marks at different heights, as well as elevator deflection and CdO calculations. It doesn't address the issue, and thats a shallow dive into a zoom, but its still more concrete than "the P-47 is fast in a dive, and has good initial acceleration," as what repeated on every report on the P-47.
The actual study was done to calculate the drag characteristics of the Spitfire. That just happened to be included in the data.
The Spitfire chart i have is interesting too. It reports a higher mach number, but it's dive was recorded from 40,000ft. The actual top TAS calculated is the same as the P-47 but at different heights. It took 47 seconds for the Spit to reach its record speed while the P-47D took 22 seconds before dive flaps were deployed.
Its still apples to oranges, seeing as the P-47 data is gathered from a test for dive flaps so the dive was steeper.
However, you combine the Spitfire data with earlier comparisons reporting the P-47 easily out dove a Spitfire, and a picture of acceleration and speed begins to develop for shallower dives.


Originally posted by M_Gunz:
Zoom is not about weight. It's about speed. The inertia of the heavy plane is greater but so is the energy required to lift that extra weight to any height, they cancel each other.

Its not just speed, its velocity, which incorporates mass.
I've been over this topic with you before and i made the point that a heavier ball on a pendulum will swing higher on the upstroke. If the string attaching the ball simulates lift and drag, the heavier ball carries more inertia through the swing from the start. It does this because its heavier and more speed is gained on the down stroke. You can actually use velocity equations to figure out what the speed of two different objects would need to be to have the same velocity if there is a large disparity in weight. I know you know this.
I try not to carry the expectation of pulling away from a guns solution, rather, i carry the expectation that a certain velocity should be attained and maintained depending on the angle, altitude, and start speed. In other words, i carry no expectations other than what seems logical.
BTW, for one reason or another, the Curtis test is no longer available online, however if you are up to searching for it, try looking under Herbert Fisher, the test pilot for Curtis.

Xiolablu3
10-27-2010, 04:04 PM
The P47 is awesome, you just have to be sure to keep your speed up at all times and never be caught low and slow.

Shes basically the American FW190 or Tempest.

I dont like the P38 for fighter to fighter work, because she loses her manouverability the faster you go, whereas the P47 keeps it well.

M_Gunz
10-27-2010, 07:15 PM
Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by M_Gunz:
Zoom is not about weight. It's about speed. The inertia of the heavy plane is greater but so is the energy required to lift that extra weight to any height, they cancel each other.

Its not just speed, its velocity, which incorporates mass. </div></BLOCKQUOTE>

Velocity is speed and direction, nothing to do with mass.


I've been over this topic with you before and i made the point that a heavier ball on a pendulum will swing higher on the upstroke. If the string attaching the ball simulates lift and drag, the heavier ball carries more inertia through the swing from the start. It does this because its heavier and more speed is gained on the down stroke. You can actually use velocity equations to figure out what the speed of two different objects would need to be to have the same velocity if there is a large disparity in weight. I know you know this.

Leaving the 'balloons vs elephants' comparisons aside, you drop a 12 lb bowling ball and a 16 lb bowling ball off a roof and they both get to the ground at the same time. Turn them into pendulums, swing them from the same height and they swing the same. Swing them both with the same speed from dead bottom and they both swing to the same height.

It's only at high speed where drag is a large factor that the heavier ball has an advantage. If the balls are made of the same density then the 12 lb ball will be smaller and Bill, the advantage of the heavier won't be as much as you might like.
We've had people put up examples of identical planes but one has half the power. You find WWII prop fighters that disparate. The P-47 is not only heavier than a 109G but it is bigger too and has less power to weight.

BOTH fighters get the same acceleration from gravity. Each one has thrust enough to take it to its top level speed. At top level speed each one is using about 1% of its power fighting induced drag and the rest fighting parasitic drag. Which is faster? How about a 109G-10 or G-14 vs a P-47M for contemporaries? Or a P-47N?

In the dive BOTH get the same acceleration from gravity and the difference in acceleration from there is thrust to weight until nearing top level speed. This has been shown here time and time again using force equations, where each plane gets advantage at different speeds in the dive and yet give it a few months and again we have the same contradictory claims pop up.

The P-47 won't get the jump from the start with both planes starting from the same conditions all the time. There are conditions where it will but it's not rare that it won't especially the way that IL2 is played.


I try not to carry the expectation of pulling away from a guns solution, rather, i carry the expectation that a certain velocity should be attained and maintained depending on the angle, altitude, and start speed. In other words, i carry no expectations other than what seems logical.

Certain velocity, certain conditions, certain results but none of that specified and the data is now not at the link nor did you 'Save-As' when you had it but hey by golly IL2 is WRONG. Like I've never seen -that- before!


BTW, for one reason or another, the Curtis test is no longer available online, however if you are up to searching for it, try looking under Herbert Fisher, the test pilot for Curtis.

Herbert O. Fischer, Curtiss Wright Test Pilot (http://www.p47pilots.com/P47-Pilots.cfm?c=incP47BiographyHome.cfm&vm=BIO&pilotid=157&p=Herbert O. Fisher)


Utilizing a P-47 he made 100 high mach number precision dives from 38,000 feet at speeds from 500 to 590 miles per hour evaluating a series of experimental transonic and supersonic type propellers.

A Curtiss Test Pilot flying a Republic P-47 with special experimental props. Those were done post-WWII BTW. Yeah, let's compare that to IL2 and say what should be.

It's funny how many times I am seeing those test dives 'quoted' without any mention of the special props. Typical forum debate tactics.

BTW, that was a P-47D-30-RE --- recon variant as in no guns?

OTOH the man himself seems to have been one hell of a test pilot!

More detail on Fischer's P-47 dive tests. (http://www.motortopia.com/Thunder3/plane-blogs)
Note the source: Big THanks to C.C. Jordan and Aviation History for this article


After the war, the development of propellers did not cease. Even with the introduction of turbojet powered aircraft, propeller design evolved. The desire to develop a propeller that maintained its efficiency at transonic speeds led the Curtiss Propeller Division to design and test several different concepts. Herb Fisher was the logical choice to fly the test aircraft. Curtiss was able to obtain a P-47D-30-RE from the Air Corps. Fitted with one of several different “supersonic” propellers, Fisher undertook a long and risky flight test program that incorporated high Mach dives from high altitudes. Typically, Fisher would climb above 35,000 ft. He would then push over into a steep dive, allowing his airspeed to build beyond 560 mph (true airspeed). He would then execute a pullout at 18,000 ft. Several of these dives resulted in speeds of Mach .83. However, that was as fast as the P-47 could go.


Despite having a propeller that was designed to be more efficient at these speeds, the fact remained that the drag rise across the prop was so great that it functioned like a giant disk shaped air brake. Fisher had proved beyond any doubt that all previous claims of exceeding the speed of sound while diving a prop driven aircraft were untrue. There is little doubt that the pilots who reported speeds in excess of Mach 1 were honestly and accurately reporting what they has seen on their air speed indicator. However, due to the extreme rate of descent, the pressure differential in the static pressure airspeed indicator lags far behind the actual altitude of the aircraft. Air speed indicators of the era were not designed to cope with descents that could exceed 40,000 feet per minute. This difference between outside pressure and that within the system would indicate wildly ambitious speeds. These pilots had simply been fooled. When we stop and consider that the ultra-sleek P-80A Shooting Star jet fighter was never able to exceed Mach .94, how can anyone believe that a prop driven fighter could even come close?


Fisher would test several different transonic propellers of varying geometry and design. These included scimitar shaped blades and straight, non-tapered blades. What each design had in common was that the blades were razor thin. They were prone to flexing at high aerodynamic and torque loads. Moreover, they suffered severe leading edge erosion at high speeds. This required that the pilot apply power very gently to avoid damaging the fragile blades. That Fisher was able to complete all of this remarkably dangerous testing speaks volumes of not only his engineering talents, but of his extraordinary flying skills as well.

VIII Fighter Command Tactical Trials on P-47 note:


7. Dive. The airplane accelerates quickly, particularly when rolled into a dive, and generally speaking is very stable through entire speed range. As the speeds increase all controls get very stiff and at speeds over 600 m.p.h. true it is virtually impossible to move the elevator in effecting recovery without the use of trim tab.

Take the 600 m.p.h. as limited by their understanding at the time and not absolute fact.

berg417448
10-27-2010, 07:25 PM
P-47D-30-RE does not stand for Recon. The letters RE denote the factory where the plane was built. P-47s manufactured in Evansville used the letters RA instead of RE.

USAF recon planes used an "F" designator at that time. Recon P-38s were know as F-4 or F-5. Recon P-51s were designated as F-6.

BillSwagger
10-27-2010, 08:37 PM
It might be easier to say that i disagree with you here. Its a drag to weight figure that determines dive acceleration, tack on thrust from the engine and the P-47 wins in both departments. Assuming its not from a dead drop or a ridiculously low cruising speed, the heavier plane will usually fall faster.


the fact remained that the drag rise across the prop was so great that it functioned like a giant disk shaped air brake.
Wow, this should jump out at you skeptics.
A lighter plane will have less weight to push against the drag caused by the prop disc and theoretically less output means it would be pushing against the disc sooner in the dive. Different prop designs allow for varying degrees of performance in dives while sacrificing other areas such as climb, level acceleration, or top speed.
There are several different variables of which are fallible, however situations that lead to a 109 out diving a P-47 were not the norm.
Anyway, consider these concepts discussed in a steep dive and think how that is applied to a shallow dive into a zoom climb.


Leaving the 'balloons vs elephants' comparisons aside, you drop a 12 lb bowling ball and a 16 lb bowling ball off a roof and they both get to the ground at the same time. Turn them into pendulums, swing them from the same height and they swing the same. Swing them both with the same speed from dead bottom and they both swing to the same height.

Have you done this? It would be neat if i had the means to try it.
A drop from roof top height would not be easy to measure because the difference would be too subtle.
But drop from 100ft or 200ft and it would be a different case. The extra velocity gained on the downswing would translate to a subsequent upswing, each ball held back by the drag of a 100ft of rope.
That's my prediction anyways.

M_Gunz
10-28-2010, 03:26 AM
The Tower of Pisa is 190 feet tall.

from Joe Milana, Department of Physics, University of Maryland

The Tale of Galileo and the Tower of Pisa
The story goes that in order to demonstrate to Aristotlean scholars that two balls of different weights fall at the same rate, Galileo dropped a cannon ball and wooden ball from the top of the Tower of Pisa.

This story is apocryphal. While some of his earlier predecessors actually performed this experiment, Galileo did not. However, when Galileo was an old man, one of his students did perform the demonstration to an audience of Aristotlean scholars and found in fact a slight difference in the time the two balls struck the ground. This came as no surprise to Galileo who had already explained the effects of viscosity (wind friction) years before. However the Aristotlean scholars, completely ignorant of the (then new) scientific method, walked away from this demonstration convinced that their old master had been thereby proven correct. Talk about "accommodation"!
by: Joe Milana : milana@quark.umd.edu

Iron cannonball vs wooden ball 1/2 the weight... slight difference after 190 foot drop, you can hear one strike first.
Free fall from 200 feet, the end velocity should be just over 77 mph.

Add 100' of rope to make a pendulum, it would have to be a thick rope to make much difference. Care to deny that total drag on a P-47 airframe is more than that on the much smaller 109G airframe? Or which has the larger diameter prop? You like to pound on about weight difference but nothing about what that is scaled against.

But of course since you are very careful to not put any numbers to your claim that makes is possible for you to cling to small differences even though the claim started as the P-47 should reach terminal velocity in half the dive distance. Small or slight differences should not matter at that rate, should they?

In the dive, the prop doesn't become a drag source until _after_ reaching top level speed. If you start the dive from near top level speed then yeah sure more weight benefits but until you reach top speed the extra weight just makes the thrust you do have less effective. All planes can produce excess thrust when flying below top level speed, that's how they can go faster until they reach that speed.

Back to Gunther Rall who flew all of those planes as a LW Opfor training pilot. He said that it was the structure of the P-47 and P-51 planes that let them be dived faster. Much faster. And that let the P-47 and P-51 catch up in the dives.

I have no doubt that the P-47 should have a high top dive speed and in IL2 -- it does. Just how accurate is the model? Not terribly at over .72 Mach since as we know compression is not really modeled at all. BUT ---
Please, find accurate historic data with enough detail to repeat the method in IL2 and THEN the world can know! Of course IL2 does not include special experimental transonic/supersonic prop designs so Fischer's dive tests can't be duplicated with IL2.

BillSwagger
10-28-2010, 02:04 PM
Like i say, i just disagree with you.
Its not my goal to unravel Il2 flight modeling down to finite idioms. You'd have to assume that historical test data reflects numbers and data similar to Il2 instrumentation. You know they don't, so proving with hard facts does nothing more than invite criticism. Making blanketed statements about how the P-47 should fall faster is simply my educated opinion. I'd say it has less to do with actual figures than it does in relation to how other aircraft perform. We can nickle and dime the sim, and reveal how off other flight models are. You might discover other aircraft actually dive too fast which would make it seem like the P-47 is too slow. Not saying that's the case, but it offers another point of what i was getting at.
I haven't seen anything to justify dive quickness of other planes, nor have i asked for them, but what i've seen does not validate them either.


Care to deny that total drag on a P-47 airframe is more than that on the much smaller 109G airframe? Or which has the larger diameter prop? You like to pound on about weight difference but nothing about what that is scaled against.
Its because this came up before and i thought you were part of that discussion. It's weight to drag. The P-47 would need to have more than twice the drag as a 109 for its weight to cancel its benefits in a dive. I think its something like 20% more drag, but don't whip me for guessing because it was brought up before and it turned out to be a trivial figure like that. Nowhere near twice the drag.
Factor in thrust.....I'm not even sure of the 109s output above 10,000ft, 20,000ft?, but i know the P-47 retains sea level output up to 30,000+ft. Do i have to site everything to have an opinion? More to the point, i think there is a reasonable expectation for aircraft performance in a sim, and if the figures aren't exact but it flies proportionately or whats deemed historical, then what do figures mean anyway?
I've done research and i don't think it benefits me to post it on the net every time someone disagrees with my opinion. Its because there are people who actually get paid for that kind of work, so someone might reap the rewards of my efforts. In other words, Gunz, i dont think there is much you can say to me that would change my opinion.

Bill

M_Gunz
10-28-2010, 03:15 PM
Making blanketed statements about how the P-47 should fall faster is simply my educated opinion. I'd say it has less to do with actual figures than it does in relation to how other aircraft perform.

What actual figures? You haven't provided any of those. You've only alluded to post-war tests made with experimental props.

And your opinion ... you can keep it all you want. I just pointed out a few things about it. Bring it up again later when a few more people may have forgotten yet another rethrashing of the same old dead horse or maybe enough new people show up and maybe you can fool someone else.

P-47 did not always dive fastest from the start. Any sim that has it so is wrong.

BillSwagger
10-28-2010, 04:12 PM
http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif Yes it did.

I think you missed my point.
To clarify, i mean it should be faster than its currently modeled, not faster than plane A or B or C, or what ever other plane you want to compare it to. It has less to do with actual numbers than to do with what's historically expected.
Most people know its more than speed and climb data that makes a model, but unfortunately other areas of the flight model, like dive, are not always available.
I doubt some planes in game are scaled properly, and for that reason we see supersonic planes. Its because many are too fast, and so it trickles up, imo. The faster planes have to be modeled to fit historical expectations.
Ie, Its been historically shown Plane A out dives Plane B, and that Plane C out dives both planes A and B. However Plane C is matched and corrected to historical figures which are not available for planes A and B. Now Plane C out dives plane B but doesn't out dive Plane A.
To some degree it also works against the faster planes because people see the speed and don't immediately put two and two together. Planes like Plane C that should be proportionately faster than Plane A or B, will have its speed cut because no plane should be flying around at Mach 1 or what ever speed is deemed too fast to be realistic.
You see the flaw of arguing historical figures in the situation of Plane C?


Bill

M_Gunz
10-28-2010, 06:58 PM
We see planes at too high Mach because there is not good compression modeling in IL2. That has F-All to do with speeds below .6 Mach where the P-47 will not lead in the dive to some others. But go ahead and invent your own reasons. The last classic was that IL2 did not model gravity which lead to some really rich laffs.

Straight from:

S.& 0.1718. STABILITY AND CONTROL SUB-COMMITTEE. S.& C.1718.
AERONAUTICAL RESEARCH COMMITTEE.

The P-47 Versus FW-190 at Low Altitude.

Communicated by D.S.R., M.A.P.

24th April, 1944

..........

(c) Diving:

(1) 10,000 feet to 3,000 feet, starting at 250 m.p.h., diving at angle of 65 (degrees) with constant throttle setting. The FW-190 pulled away rapidly at the beginning but the P-47 passed it at 3,000 feet (Gee, pullout was at 3,000 feet too!) with a much greater speed and had a decidedly better angle of pull out.

---------------------------------------------------------------------

So in a HISTORIC TEST comparing a P-47D4 to a captured FW-190, THE FW PULLED AWAY RAPIDLY AT THE BEGINNING +and+ the P-47 DID NOT CATCH UP UNTIL 7,000 FEET ALT, OVER 8,000 FEET DISTANCE LATER!

Here we have A HISTORIC TEST saying that the P-47 did not lead in a dive, as in "does not always".

Now YOU write to me that I ignore HISTORIC DATA and yet you do not post any such and here I am giving you HISTORIC DATA saying "You Is Wrong!". http://forums.ubi.com/images/smilies/16x16_smiley-tongue.gif

Squirm on the floor and kick your feet all you want, that's what happened in April 1944.

---------------------------------------------------------------------

AFDU Tactical Trials Report # 66: 2nd January 1943

A P-47C compared in dive with a Mustang X:

34. Dive -- Several full throttle dives were carried out at these heights (20,000 to 27,000 feet) and I each the Mustang accelerated away from the P-47 and remained in front.

---------------------------------------------------------------------

Well not in Thunderbolt-Fanboy Heaven it didn't! No! Only on Planet Earth! http://forums.ubi.com/images/smilies/88.gif

BillSwagger
10-28-2010, 08:53 PM
http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

Actually i've seen a couple Mustang vs P-47 tests. Might've been the same one written about in separate texts.
The Mustang pulled 300 yards in front and remained there through the dive, other than that they appear to have dived at the same speed.

Im also aware of a couple of the Fw-190 tests. It also explained the P-47C had difficulty escaping a bounce from an incoming 190. This information is not new to me.
That dive information is still revealing if you know what your looking at. I like how it explains it surpassed the 190 in 7000ft with more speed and was able to pull out at a better angle, which tells me that it was not lower than the 190 on pull out.
I still dont think this tests says much and it doesn't repute anything that i've said before. I'm not arguing it accelerated faster than plane A, or Plane B, i'm arguing it should fall faster than it currently does or ... the current dive modeling of other planes is too fast.
The test is good for what? A D-4 and a captured Fw190. Neither a P-47D-4, P-47C, or P-51X are modeled in game, and i have to assume that the Fw190 being captured was not up to par with contemporary 190s. It makes sense to think that a 300-500 increase in horsepower would close that gap more, then again, all planes saw an improvement.
I would add that most P-47 pilots complained that the 190 would escape through a climb, and that a dive was never an out for the 190. That all changed with ADI and paddle blades, allowing better acceleration and climb where the 190 had a harder time escaping the P-47 in climbs.

Bill

Buzzsaw-
10-28-2010, 09:52 PM
109's and 190's diving away from P-47's:

http://www.wwiiaircraftperformance.org/p-47/er/4-chatterley-29jan44.jpg
http://www.wwiiaircraftperformance.org/p-47/er/4-garrison-10feb44.jpg
http://www.wwiiaircraftperformance.org/p-47/er/4-garrison-14jan44.jpg
http://www.wwiiaircraftperformance.org/p-47/er/4-gentile-14jan44.jpg
http://www.wwiiaircraftperformance.org/p-47/er/4-gentile-5jan44.jpg
http://www.wwiiaircraftperformance.org/p-47/er/4-****anos-29jan44.jpg
http://www.wwiiaircraftperformance.org/p-47/er/4-sobanski-31jan44.jpg

Should I go on?

Hmmm... let's see...

2600 hp, pointed straight down, better drag coefficient... who is going to accelerate faster?

M_Gunz
10-28-2010, 09:59 PM
In the AFDU P-47 vs FW dive test it showed that from a starting speed of 250 mph the FW benefited more from mass vs drag tahn the P-47. If you look at the wing loading of the two alone it should be no big surprise, the FW had more to gain by unloading. But then again that is part of why the P-47 had the better pullout, the other part being more lift available due to its greater speed. Greater in this case being around 20-30 mph faster.

Slice it how you want, the P-47 is not faster in all dives throughout the dive. Get some new expectations if you think so.

What the P-47 did have was an excellent roll rate and good transition capability. Fast roll allowed it to be split-essed quickly for extremely quick dive start and acceleration as opposed to nosing down and the good transition allowed for keeping more of the dive speed in subsequent zoom. You just have to be able to pull the maneuvers off. FW has great roll but not so great transition as the P-47. The P-47 transition and roll were also used by one Ace as in defense and reversal vs Germans on his tail, he would pull up into a rolling tight spiral climb (speed bleeding) and the ones that followed would end up in front while the smart ones just kept going. What I'd have to check, was it R.S. Johnson who told that or not? The Ace was last name Johnson. Again, that was an Ace maneuver that not just any pilot could pull off successfully yet so many gamers think that if they can't it's the game and not them that is at fault. Oh well, call a Whaaaaaambulance!

M_Gunz
10-28-2010, 10:31 PM
Originally posted by Buzzsaw-:
109's and 190's diving away from P-47's:

< a bunch of combat reports, see above >

Should I go on?

Hmmm... let's see...

2600 hp, pointed straight down, better drag coefficient... who is going to accelerate faster?

Yeah you go on and on about something DIFFERENT than what was just discussed. NOBODY said that the P-47 was never going to catch up. Your knee jerk reflexes are faster than your ability to check just what was stated, can go back to DEFCON 1 and take your tape measure with you. Perhaps you need new reading glasses though, you might check that out.

For BOTH; start speeds, end speeds, how long a dive, initial separation and angles at start of engagement, ... Hmmmm, let's see... do ANY of those accounts give even 1/4 of the data? NOOOOOOPE!

Better drag coefficient with a MUCH BIGGER DRAG AREA... who is trying to BS faster?
2600 hp, how much of that as Excess Power trying to accelerate as in divided by over 14,000 lbs weight?
Pointed straight down... I see one account stating a 50 degree dive and NONE stating straight down. Hmmmmmmm.....

Funny how I supply that NOT ALWAYS ALL THROUGH THE DIVE will the P-47 accelerate better. Funny how I show that eventually the P-47 tends to catch up and wrote about Gunther Rall's view on the subject. Funny how I don't see anything in those accounts you linked to that contradicts ANY of that.

Buzzsaw-
10-28-2010, 11:43 PM
By the way, the USAAF pilot by the name of Johnson who you referred to has something to say about the dive of the P-47. Here is an excerpt from an interview before he died:

>>>

From 'WideWing', a longtime flight enthusiast who used to be a fixture on the ACES HIGH boards.



A few months before Robert Johnson died (December 27th, 1998), I conducted nearly five hours of telephone interviews with Bob over the course of three weeks. I managed to record all but the first hour. During our conversations, we discussed the tactics he employed while battling the Luftwaffe. The following are some excerpts of our discussions:

CCJ: I have read an article about you and the tactics you used, that described you as one of the first fighter pilots to truly fight in the vertical plane.

RSJ: I don't know about that, there were others who fought that way.

CCJ: But not in the Thunderbolt....

RSJ: No, I guess not, at least when we first went operational.

CCJ: Can you describe how you used vertical maneuvering to your advantage, especially in the heavy-weight Jug?

RSJ: I think that you need to understand that everyone thought that the P-47 was a deathtrap. RAF pilots told us that we wouldn't have a chance against single-engine fighters. Those of us who had been flying the P-47 for a while knew otherwise, but there was nothing we could say that would convince the British, or the guys in the 4th.

CCJ: Guys in the 4th? You mean the 4th Fighter Group?

RSJ: Yeah. They were not at all happy trading in their Spitfires for the Thunderbolt.

CCJ: Didn't the 56th surrender their P-47s to the 4th after you arrived?

RSJ: Yes, we were told that we would be getting new planes.

CCJ: I'll bet that struck a nerve in the 56th.

RSJ: It sure did. We already had hundreds of hours in P-47Bs and Cs. No other group of pilots in the ETO had anywhere near our experience in the Thunderbolt. So naturally, we were not happy to hand them over to another Group. In retrospect, it was obviously a good idea. We realized as soon as we got into combat that there was no substitute for actual combat missions under your belt. Anyway, we trained the 4th on the Thunderbolt and then waited for what seemed like forever, to get our new planes.

CCJ: To get back to tactics, how did your tactics evolve?

RSJ: My tactics were rooted in what I had learned flying the P-47 in the States. We could always find some Navy Corsairs over Long Island Sound. We would bounce them, or they would try to bounce us. Usually, we had the advantage in height so the Corsairs were a lot busier than us.

CCJ: I take it that you seldom let an opportunity to jump them go waste?

RSJ: No, we usually went straight for them.

CCJ: Didn't they see you rolling in?

RSJ: Sometimes. We tried to use the sun to hide in. If they didn't spot us, we would lay it on them good. Their first hint that we were there was when we tore through them at high speed and zoomed back up above them.

CCJ: How did they react?

RSJ: They would usually scatter every which way. We would come back down on them again, but they would be alert now and break into us.

CCJ: I guess that is the point where it would break down into a big brawl?

RSJ: It did at first. The Corsair was just a fast as the Thunderbolt was around 20,000 feet., and it was very maneuverable. As we mixed it up and lost altitude, the Corsair became a real handful to outfly with our P-47Bs. I discovered that the Corsair pilots did not like fighting up hill. What I mean is, they would not or maybe could not follow you if you pulled the nose up into a steep climb. I realized that the Corsair couldn't climb any better than the P-47, and would tend to spin out of a vertical stall. I also found that that any P-47, even the P-47B, could out-dive the Corsair. So that gave me two important advantages that I would use every chance I got.

CCJ: So these mock dogfights helped you learn how to exploit the inherent strengths of the Thunderbolt.

RSJ: Yes, very much so.

CCJ: What about facing the Fw 190 and Messerschmitts?

RSJ: The Focke Wulf reminded me of the Corsair. It was much smaller of course, but they both had similar maneuverability. It wasn't quite as fast, but turned well. It was unusual to find Focke Wulfs above us. Generally, we held the advantage in height.
The Me 109 was another story. They could often be seen up above 35,000 feet.

CCJ: What was the biggest mistake a German pilot could make?

RSJ: Trying to escape in a dive or split-S.

CCJ: Why?

RSJ: Because they were not going to out-run the Thunderbolt in a dive.

CCJ: You could catch them without a problem.

RSJ: I could catch them in nothing flat.

CCJ: Really?

RSJ: Absolutely. One thing about the 190, if the pilot continued his dive below 7 or 8 thousand feet, he could not pull out before he hit the ground. I guess they had compressibility problems or the elevators got too stiff. Whatever the problem was, I watched several of them pancake in before they could level off.

CCJ: What about the Thunderbolt?

RSJ: It did not have that problem down that low. Up high, above 25,000 feet, yes, I could get into compressibility and the elevators locked up like they were in concrete. But once you got down to thicker air, you regained control.

CCJ: So, what would you do if suddenly discovered a German fighter on your tail?

RSJ: you mean in close?

CCJ: Yes.

RSJ: That depended a lot on how fast the German was going. If he was moving much faster, I'd simply side-step him by rolling.
The German would whiz right on by and I would firewall the throttle and take off after him. If he was a smart German, he would climb straight ahead. If he was a dumb German, he would try to turn. If he turns, his higher speed will make for a wide turn, and I will cut across and be all over him. If he dives, I can follow and eventually catch up. Now, if the German's speed was close to mine, then I had another emergency maneuver that always worked for me.

CCJ: And, that was?

RSJ: I would pull the nose straight up into a vertical rolling spiral, usually to the left. You would stall out, but so would the guy behind you. That killed his advantage.

CCJ: So, what you are describing sounds like a rolling hammerhead stall, right?

RSJ: That's a pretty good description.

CCJ: So what happens next?

RSJ: Well, the enemy would stall first because the Jug's mass allowed to retain its,
er...

CCJ: Energy?

RSJ: Yes, energy. The P-47's mass allowed it to retain its energy better and it stalled a few seconds after the enemy plane. The German would snap over and head down. Except, now I was right behind him and there was no getting away.

CCJ: Wouldn't he still be directly behind you?

RSJ: No. Pulling up so suddenly always caught them by surprise. The second or two that it took for them to react took care of that.

CCJ: Why did you roll?

RSJ: Because that killed my speed faster than the enemy if he didn't, which gained me the advantage of being to his rear as he zoomed up. If he rolled too, that also worked to my advantage because it killed his speed faster than mine.

CCJ: So, you would get the advantage no matter what, if the German also pulled up into a vertical climb. What if he didn't follow?

RSJ: Then he would just fly by. If he still wanted to fight, he could extend out and turn around, but I would be waiting for him.
If he turned either left or right, I would be on him in a few seconds.

CCJ: The smart Germans just kept on going when you pulled up.

RSJ: I never ran across one smart enough to keep going. They all tried to follow.

CCJ: How many got away after falling for your trap?

RSJ: I really can't say for sure. Some got away because he had friends to cover his tail. Besides, that maneuver was not so much to get him, but to prevent him from getting me. In that respect, it always worked.

CCJ: Much has been written about the incredible roll rate of the Fw 190. Was it as good as they say?

RSJ: The 190 rolled very fast. But, so did the Thunderbolt.

CCJ: But not as quickly as the Focke Wulf.

RSJ: I would say just as fast. I never had a 190 out-roll my Jug. Never.

CCJ: What about a situation where you end up in rolling scissors with a Focke Wulf? Do you follow him by reversing the turn too?

RSJ: No. Whenever you get into a series of reverses, the airplane tends to mush-out a bit when you reverse your turn. The Jug tended to mush a bit more than the 190. The way to avoid this was roll into the reverse.

CCJ: I'm not sure I follow you.

RSJ: Picture this in your mind. The 190 rolls into a hard left. You follow, firing as he crosses your guns. Suddenly, he reverses his turn, hard right. Rather than reverse, you continue rolling left until you are in a right bank, just like the 190. Now, pull hard. No mushing. If he reverses again, you roll left and fire as he crosses your guns again. If he doesn't reverse, I pull the nose high and roll out behind him.

CCJ: A high yo-yo?

RSJ: Of a sorts, yes. Continuing the roll simply eliminated the mushing caused by reversing a turn and I could would get a clear shot every time the enemy reversed.

CCJ: What do you define as the most important things a fighter must know to be successful, relating to air combat maneuvering?

RSJ: It's pretty simple, really. Know the absolute limits of your plane's capabilities.
Know its strengths and weaknesses. Know the strengths and weaknesses of you enemy's fighters. Never fight the way your enemy fights best. Always fight the way you fight best. Never be predictable.

CCJ: I remember reading where you thought that your P-47 was the fastest fighter in the ETO.

RSJ: I still believe that it was.

CCJ: Really?

RSJ: Sure. My second Jug, a D-5 was the best P-47 that I ever flew, and I flew them all, including the P-47M which the 56th got near the end of the war.

CCJ: What made this one Thunderbolt so fast?

RSJ: Several things. My crew sanded every joint smooth, and waxed it to a high gloss. Factory technical reps showed my crew chief, Pappy Gould, how to adjust the wastegates to keep the boost pressure higher than normal. My D-5, which I named Lucky, had water injection. I never used the water injection in combat. I didn't need it. From time to time I'd switch it on, push the throttle up to 72" of manifold pressure and the head rest would smack me from behind. I would let her run for a few minutes just for the fun of it.

CCJ: 72 inches!? Did you ever take note of your airspeed during one of those runs?

RSJ: Of course.

CCJ: And....... how fast did it go?

RSJ: I've seen just over 300 at altitude.

CCJ: 300 indicated?

RSJ: Yes.

CCJ: What was your altitude?

RSJ: I guess it was right around 32,000 feet.

CCJ: Geez, thats well over 450 mph!

RSJ: Oh, I figure closer to 470.

CCJ: Maybe you did have the fastest fighter in the ETO after all.

RSJ: Like I said, Lucky was the fastest.

CCJ: What ever happened to Lucky?

RSJ: She was lost in a mid-air collision over the North Sea. I don't recall the pilot's name who was flying her on that ramrod. I was very upset. Lucky got at least 24 enemy aircraft and was the best Jug I ever flew. She was trouble free and I never had a single abort while flying her.

CCJ: Bob, one final item before I let you go tonight.

RSJ: Sure.

CCJ: Is it true that you flew two 25 hour tour extensions after your 25th victory, and that you never were involved in a single combat during that time?

RSJ: Basically, yes. I took a 25 hour extension with the idea that as soon as I got 2 more enemy aircraft, I would stop there and go home. After the 25 hours were up and I hadn't had a chance to even fire at an enemy airplane, so I convinced the brass to give me another 25 hour extension under the same understanding. Finally, on the last mission of that tour, I got two more and they sent me home.

CCJ: Why do you think that German fighters became so hard to come by at that time. When was that, in April and May of 1944?

RSJ: I can't say for sure, but we now know that the long range of the P-38 and P-51 caused the Luftwaffe to pull back many of their fighter squadrons deep into Germany. This makes sense when you think that we could put up over 600 P-47s for a ramrod. If they pull back beyond the range of the Jugs, we won't see much of them. Another thing was simple bad luck. When the Germans did come up to fight, they attacked the bombers well away from our assigned area. So, it really was a combination of factors.

CCJ: So, what was the date of your last two victories?

RSJ: May 8th, 1944.

CCJ: Well, Bob, I'll let you go now. Thanks for your time. This will make for a terrific article.

RSJ: It was my pleasure.

CCJ: Are you up for another discussion in a week or two?

RSJ: If you don't mind my long stories, sure. You can call almost anytime.

CCJ: Believe me, it's an honor for me. By the way, Art Heiden, your remember me talking about Art, Art wants to talk to you about Jack. Do you mind if I pass your number to him?

RSJ: Please do.

CCJ: Well, thanks again and have a good evening.

RSJ: You to.


I will post more of our discussions after I get it all transposed from the tapes.

My regards,

Widewing

BillSwagger
10-29-2010, 12:03 AM
Greater in this case being around 20-30 mph faster.
Thats the first figure i've seen touted. Any proof there mate or are you estimating off of a test based on underpowered variants?
The other parts of your statement make sense. The 190 as well as other planes probably benefit more in initial acceleration in a steep dive. Do you recall if that test actually mentions how far ahead it gets? In other words, is it able to escape a guns solution from height and speed?
Many of the encounter reports seem to suggest not, though not based on a straight forward steep dive.
Other reports, including some not posted, also show that the dives may go the entirety of 10,000ft to 20,000ft but it always leaves the P-47 bearing down on its opponent if not short after pull out, usually at some point in the dive. This probably has much to do with start speeds as well as the initial separation and positioning of the aircraft.
Its not something that needs to be beat on to much. I get that as much.

"I slid over immediately back of the number one 190 and closed in to about 250 yards and started firing, closing to about 150 yards. We were in a very shallow dive from 4000ft."

This is more what i was getting at.

"I saw another Me-109 dive head-on in a 50-degree angle and I followed him as he went past us. I gave him a short burst in a 70-degree dive,"
Thats pretty telling, no?
The 109 dives in steep and the P-47 is able to transition and follow and catch it in a dive. That would take some pretty good acceleration.



Bill

M_Gunz
10-29-2010, 10:10 AM
Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Greater in this case being around 20-30 mph faster.
Thats the first figure i've seen touted. Any proof there mate or are you estimating off of a test based on underpowered variants? </div></BLOCKQUOTE>

I've seen one AFDU conclusions quote in the same paragraph using both "much faster" and the estimated speeds which were 20-30 mph apart. It's the only time I've seen numbers put to the adjective.
Consider viewing two planes in the air, or another plane from the one you're in. You don't have ground cues to tell the speed. You have relative motion and if the two are close even 20 mph looks fast. Or as Oleg says, have a bicycle pass you within a few feet when you are standing still and it is going perhaps 30 kph, it seems very fast. Or consider when you are going down the highway at 70 mph and passed by someone else doing about 90 the term usually applied involves doors blowing off. It's the relative motion and closeness that makes the impression, not the absolute speeds and percentages of those.
Something else to remember is that those reports were written before the jet age let alone the space age, TV, computer games and video. Those guys grew up in times just a bit slower than you or I. They didn't go down highways at 70 mph very often let alone the speeds I remember between pre-pollution muscle cars (110-120 going up I-95) or the 240Z I've seen 135 in. While they did fly planes, the planes aren't right next to the ground but still hey yeah they knew high speed then!


The other parts of your statement make sense. The 190 as well as other planes probably benefit more in initial acceleration in a steep dive. Do you recall if that test actually mentions how far ahead it gets? In other words, is it able to escape a guns solution from height and speed?

From a side by side same speed start? NOT A CHANCE! In those combat reports some of the shooting began at 800-900 yards and I doubt that the FW got more than half that much lead if that.


Many of the encounter reports seem to suggest not, though not based on a straight forward steep dive.
Other reports, including some not posted, also show that the dives may go the entirety of 10,000ft to 20,000ft but it always leaves the P-47 bearing down on its opponent if not short after pull out, usually at some point in the dive. This probably has much to do with start speeds as well as the initial separation and positioning of the aircraft.
Its not something that needs to be beat on to much. I get that as much.

"I slid over immediately back of the number one 190 and closed in to about 250 yards and started firing, closing to about 150 yards. We were in a very shallow dive from 4000ft."

This is more what i was getting at.

"I saw another Me-109 dive head-on in a 50-degree angle and I followed him as he went past us. I gave him a short burst in a 70-degree dive,"
Thats pretty telling, no?
The 109 dives in steep and the P-47 is able to transition and follow and catch it in a dive. That would take some pretty good acceleration.

In that last one I would guess that the P-47 pilot rolled and pulled. He got his acceleration from his wings as acceleration is not just change in speed but any change in direction. That's why turning makes G's. Between his changing direction to follow and his taking the shot, how much time elapsed even if it seemed like "no time at all"?

Did the 109 stay in a 50 degree dive? Then how do you intercept in a steeper dive unless he dove well in front of you? You could do it then and maybe get the shot pretty quickly, especially if you rolled into the dive before he got down to your height. You would then sort of be following as he went past. For sure you'd never be able to do it by nosing down into an outside loop!

Pretty telling?
It tells some but it doesn't tell a whole lot more. That's my problem with combat reports, you can't reliably duplicate the feat when you can match the words in dozens of different setups involving speeds, distances and placements 5% or more apart from each other. When you're guessing at more than is given it becomes all too easy to rig the results.
All that tells me is the 'data' is not usable.

BillSwagger
10-29-2010, 02:45 PM
Did the 109 stay in a 50 degree dive? Then how do you intercept in a steeper dive unless he dove well in front of you? You could do it then and maybe get the shot pretty quickly, especially if you rolled into the dive before he got down to your height. You would then sort of be following as he went past.

If anything the 109 may have steepened his dive. Does it matter? The 109 doesn't pull out til he is fired upon according to the report. The point i was making is the ability for the P-47 to transition and catch a plane that dove at him head on from a relatively steep angle. The report has a lot it doesn't say, agreed. For example: he may have anticipated the trajectory of the 109 prior to him flying past, so it seems more probable he began his transition before hand and timing it so he fell behind him in his dive. You can't really nit pick for clarity. Its part of the reason i only mull over combat reports once or twice and then move to the next one.


What do you think about Johnson's depictions?

Bill

M_Gunz
10-29-2010, 03:29 PM
Can't nit pick? But you want to know if someone could get beyond firing range? At level combat speed you can go that far in a full second but let's not nit pick! Paint the picture however you want.

Xiolablu3
10-29-2010, 04:11 PM
I think that the p47 was a good plane for the escort missions done over Europe as they could get very high before meeting the enemy and be sure to have lots of energy under their belt.

I think the P47 would have been an awful plane in a defensive situation like Malta or the Battle of Britian, where teh enemy appears with more height and energy, and you need to climb to attack.

Reade Tilley (A US ace who flew right through the war in all types) was convinced that had the defenders on Malta been equipped with P47's instead of Spitfires, they would have been masacred. This was a crucial defensive battle where defensive tight turns and climb rate were the most important factor for the defender. The defenders had no early warning system, and had only minutes (often none) warning before being attacked. They climbed hard away from the island, into the sun, and then came back witht he sun behind them. If the enemy fighters caught them on this climb, they suffered badly. Therefore climb rate was crucial.

On the other hand when it has time to built up its speed and height, the P47 was a formidable plane.

M_Gunz
10-29-2010, 05:43 PM
It made a really good fighter-bomber too!

Bremspropeller
10-30-2010, 01:43 PM
RSJ: Absolutely. One thing about the 190, if the pilot continued his dive below 7 or 8 thousand feet, he could not pull out before he hit the ground. I guess they had compressibility problems or the elevators got too stiff. Whatever the problem was, I watched several of them pancake in before they could level off.

The problem with pilot-stories is...they're often just plain wrong.

M_Gunz
10-30-2010, 02:45 PM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">RSJ: Absolutely. One thing about the 190, if the pilot continued his dive below 7 or 8 thousand feet, he could not pull out before he hit the ground. I guess they had compressibility problems or the elevators got too stiff. Whatever the problem was, I watched several of them pancake in before they could level off.

The problem with pilot-stories is...they're often just plain wrong. </div></BLOCKQUOTE>

Brems, what he saw... doesn't say who was that the controls or if the plane had previously taken damage.
What they don't say is many times more important than what they did say.

M_Gunz
10-30-2010, 02:49 PM
AFDU - P-47C (http://www.wwiiaircraftperformance.org/p-47/p-47c-afdu.html)


Dive

16. The P-47C dives very fast. Its initial acceleration is good an it quickly reaches its limiting figures (520 m.p.h., I.A.S. at 10,000 feet, 450 m.p.h. at 20,000 feet). At these speeds the recovery needs several thousand feet and can only be effected by careful use of the trimming tab. There is no tendency to recover fiercely from the dive, but a large amount of left trim is required on the rudder to hold the aircraft straight.

Bremspropeller
10-30-2010, 03:41 PM
At these speeds the recovery needs several thousand feet and can only be effected by careful use of the trimming tab.

The 190 doesn't have a tab.
It's trimmable tail behaves differently and allows full (yet careful) control - if known to the pilot and done correctly.

Boosher
10-30-2010, 04:18 PM
Originally posted by M_Gunz:
Either they do to the dev team or they are possibly the result of sloppy work or outcome of FM shortcuts and limited time getting tweaks done.

I try to say that a D-22 is -supposed- to be a D-22 at some stage but not a later time just as our 190A-4 is from some period Russian Front. Our Spit VB is mislabeled, supposed to be Aug 42 not 1941 but there again someone will point out the speed and climb together are neither.

It's no good to say prop and boost were later changed with reference to these models unless the model is from after the change. I don't expect more than a certain closeness that I do not define anyway and I have been thrilled to get as good as IL2 has been even with the known warts.

The P-47's we have in game are representative of Lend-Lease models that were sent to the Soviet Union, the types of which being were the -10, -22, and -27. All approximately 250 aircraft sent were sent in mid-43 to early 44. The Russians reported that the aircraft were underpowered, underarmed, and too heavy for fighter-to-fighter combat. The few examples that did see combat were assigned to bomber units for anti-shipping duties in the Gulf of Leningrad.

BillSwagger
10-30-2010, 05:15 PM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">RSJ: Absolutely. One thing about the 190, if the pilot continued his dive below 7 or 8 thousand feet, he could not pull out before he hit the ground. I guess they had compressibility problems or the elevators got too stiff. Whatever the problem was, I watched several of them pancake in before they could level off.

The problem with pilot-stories is...they're often just plain wrong. </div></BLOCKQUOTE>

why is that so unconceivable?

It was a fact of flying. Dive pull outs required several thousands of feet in the cases of high speed and steep angle. Planes that pancake in did not initiate a pull out procedure soon enough. This was not an exclusive problem for the 190. The P-51 pilots manual even illustrates this, demonstrating that a safe pullout might require as much as 8000ft diving a P-51 at a steep angle from above 20,000ft.

The ability of the trim tab is also overstated. The description from some pilots diving in planes suggests that most aircraft actually want to nose up in a dive, and so positive elevator force is required to maintain the same angle of dive. As speed increases more stick forward force is required. Pilots would trim off these forces so they could comfortably maintain a decent. If the pilot anticipates a dive, he can trim prior to the dive and nose over. Control forces grow increasingly heavy with airspeed, this included trim tabs on some aircraft. As speed increased the nose would want to tuck, and the onset was rather sudden, so a pilot pushing the stick forward to maintain a dive would now have to pull on the stick to keep the dive from steepening. Not a good situation to be in, since elevator surfaces grow heavier and the plane no longer wants to nose up on its own, instead it wants to steepen on its own. So a pull out now works against the tendency of the aircraft making control forces much higher. If the pilot doesn't have the altitude, --- pancake.


1) 10,000 feet to 3,000 feet, starting at 250 m.p.h., diving at angle of 65 (degrees) with constant throttle setting. The FW-190 pulled away rapidly at the beginning but the P-47 passed it at 3,000 feet with a much greater speed and had a decidedly better angle of pull out.

What this tells me is that the P-47 was able to dive faster and pull out at a better angle, meaning that either the P-47 could pull lead if needed, or cut inside the Fw190s pull out.
Other tests/reports reveal that the speed of this match up was often what decided better angle. At higher airspeeds the P-47 could turn inside the 190, which makes sense considering that a dive is likely to be in this area of the envelope. At a slower speed, turns favored the 190.
Reading up on the development of the P-47, it went through rigorous dive tests and in some cases costing the lives of the test pilots. However, the benefits gained by such tests was able to shape and mold an aircraft that could not only withstand the structural challenges of a high speed dive, but also maintain stability and control.

Bremspropeller
10-30-2010, 05:52 PM
It was a fact of flying. Dive pull outs required several thousands of feet in the cases of high speed and steep angle. Planes that pancake in did not initiate a pull out procedure soon enough. This was not an exclusive problem for the 190.

Exactly, and as such, the example given by RSJ is moot.


Not a good situation to be in, since elevator surfaces grow heavier and the plane no longer wants to nose up on its own, instead it wants to steepen on its own.

Fortunately, the 190 has a trimmable stabilzer, giving the pilot a good amount of pitch-control if used carefully.
A Flettner-Tab might be rendered useless, if it's placed within the stalled boundary-layer following a shock-wave on the stabilizer (M > Mcrit)


What this tells me is that the P-47 was able to dive faster and pull out at a better angle, meaning that either the P-47 could pull lead if needed, or cut inside the Fw190s pull out.

...if the 190-driver decides not to use any trim within his pullout.
In contrary to just adjusting control-forces (as with a trim-tab), the 190's all-flying tail creates an increased amount of pitch-authority.
Then again - this is only of use when known to the pilot and used accordingly.

Speaking of control:

The 190's trimmable stabilizer is better-suited for high-speed diving than the P-47's trim-tabs.

BillSwagger
10-30-2010, 07:26 PM
Originally posted by Bremspropeller:
The 190's trimmable stabilizer is better-suited for high-speed diving than the P-47's trim-tabs.

RSJs description mentions "pancake" which implies the aircraft sank on pull out. This has been documented in other reports that make note of the 190. It doesn't sound like it was a matter of trimming or pilot strength. Getting the nose up is part of the equation, while acquiring lift before it hits the ground is the other. It may have been more complex than simply pulling the plane up to recover.

I still think the use of trim is over stated. Like pulling on the stick AND wheeling out trim to recover would be easily achieved. Thats why it takes the altitude it does. There's also the fact that trim tabs stiffen the same way other control forces do. They can even lock or freeze depending on speed. You factor in 'sink' and it only adds to the dilemma. Its not possible for most aircraft to recover from a steep dive in less than 5000ft. They can trim so that they have to push forward on the stick to hold the dive. In that case, recovery is made by relaxing forward pressure and the nose comes up. Thats a different procedure than attempting to wheel out trim with one hand, and yank back on the stick with the other.
Know your limits. If you don't, you lawn dart, "pancake" or break your plane. A trained pilot isn't likely to have that problem. A pilot who panics and finds himself in a dive with little room to recover might have trouble.


Bill

M_Gunz
10-30-2010, 09:11 PM
Originally posted by Boosher:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by M_Gunz:
Either they do to the dev team or they are possibly the result of sloppy work or outcome of FM shortcuts and limited time getting tweaks done.

I try to say that a D-22 is -supposed- to be a D-22 at some stage but not a later time just as our 190A-4 is from some period Russian Front. Our Spit VB is mislabeled, supposed to be Aug 42 not 1941 but there again someone will point out the speed and climb together are neither.

It's no good to say prop and boost were later changed with reference to these models unless the model is from after the change. I don't expect more than a certain closeness that I do not define anyway and I have been thrilled to get as good as IL2 has been even with the known warts.

The P-47's we have in game are representative of Lend-Lease models that were sent to the Soviet Union, the types of which being were the -10, -22, and -27. All approximately 250 aircraft sent were sent in mid-43 to early 44. The Russians reported that the aircraft were underpowered, underarmed, and too heavy for fighter-to-fighter combat. The few examples that did see combat were assigned to bomber units for anti-shipping duties in the Gulf of Leningrad. </div></BLOCKQUOTE>

IMHO the Russians did not know how to use those planes properly as to tactical style. They are not suited to the way that the Russians fought but would have been good assets as free hunters vs the higher flying Germans that deviled the Yaks and La's.

M_Gunz
10-30-2010, 09:16 PM
Originally posted by Bremspropeller:
The 190's trimmable stabilizer is better-suited for high-speed diving than the P-47's trim-tabs.

I know that the 109 had trimmable stabilizer, seen the pics, but the FW 190?

M_Gunz
10-30-2010, 09:19 PM
Originally posted by BillSwagger:

RSJs description mentions "pancake" which implies the aircraft sank on pull out.

Maybe to you. That's a general term for crashing, perhaps because lawn darts weren't invented yet.

BillSwagger
10-30-2010, 09:29 PM
http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

c'mon Gunz, how else would "pancake" from an interview taken in 1998 be used to describe a crash?

Or are pilots from WW2 stuck with the vocabulary of the 1940s
"He 'flapjack'ed in..." http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Bill

AndyJWest
10-30-2010, 10:21 PM
Come on guys, isn't there something more important to argue about? For what it's worth, in relation to aircraft, I've only ever seen the term 'pancake' used in the context of a 'pancake landing', and a quick check on online dictionaries seems to concur, but that doesn't necessarily mean that it is always used that way - metaphors mean different things to different people.

BTW, BillSwagger, nice 'J' on the website we can't mention. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

M_Gunz
10-30-2010, 11:04 PM
Originally posted by BillSwagger:
http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

c'mon Gunz, how else would "pancake" from an interview taken in 1998 be used to describe a crash?

Or are pilots from WW2 stuck with the vocabulary of the 1940s
"He 'flapjack'ed in..." http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Bill

I've watched period videos showing WWII fighters hitting the ground nose first so hard they spread out in a round, flat, explosion. Boom! Pancake is as good a term as any, want to bet I can't find it used in a WWII combat report?

BillSwagger
10-31-2010, 01:12 AM
Originally posted by M_Gunz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BillSwagger:
http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

c'mon Gunz, how else would "pancake" from an interview taken in 1998 be used to describe a crash?

Or are pilots from WW2 stuck with the vocabulary of the 1940s
"He 'flapjack'ed in..." http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Bill

I've watched period videos showing WWII fighters hitting the ground nose first so hard they spread out in a round, flat, explosion. Boom! Pancake is as good a term as any, want to bet I can't find it used in a WWII combat report? </div></BLOCKQUOTE>

yeah, because they called them flapjacks back then. http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

You aren't likely to find a report where the pilot takes credit for a plane that dives into the ground with out first shooting it. If you find one please share. I think the over all context of the description from RSJ was that the dives were fast and steep enough to cause problems for his opponents who weren't prepared to pull out sooner in the dive. In some regards, dive limits are set because the planes control surfaces become too heavy to properly control the plane. I don't see why there would be exceptions for the 190. To my knowledge the 190 sank much more on pull out by comparison, which probably contributed to matters.
I don't know, maybe entering the thicker air from a dive put much more force on the controls than what pilots anticipated.
All the factors are there that would require more altitude to pull out before the plane meets the ground. Knowing that, i find it hard to discount what pilot's have to say about it.
The Fw190 pilot who lives obviously isn't the one who had the problems, so naturally his opinion, if he lived, is that the plane recovers fine in a dive. He may have never been in that situation or avoided putting his plane in the red zone, so to say.

Bremspropeller
10-31-2010, 05:45 AM
It may have been more complex than simply pulling the plane up to recover.

No.
It's more an indication of a pilot not knowing his plane's systems entirely, or panicing.


I still think the use of trim is over stated. Like pulling on the stick AND wheeling out trim to recover would be easily achieved.

That's why the 190 had electricly operated trim, comtrolled by an electric switch.


Its not possible for most aircraft to recover from a steep dive in less than 5000ft.

That's too generic.
It depends on speed, pitch-authority, max G, etc.


Know your limits. If you don't, you lawn dart, "pancake" or break your plane.

Exactly.


To my knowledge the 190 sank much more on pull out by comparison, which probably contributed to matters.

Compared to which plane?
"Sinking" is a function of wing-loading and can to a large degree be minimized by technique.
Nobody will max-perform any airplane by just throwing around the stick in the cockpit and expecting different airplanes behave similaryly.

I haven't read anything about "sinking" in any Rechlin-trial reports, so mabe the problem wasn't that much of a show-stopper as some people might think it was.
Perception is subjective.


I know that the 109 had trimmable stabilizer, seen the pics, but the FW 190?



Yes.
http://www.airventure.de/FW190/Flug_Werk_FW190_Leitwerk.jpg
http://www.airventure.de/FW190/Flug_Werk_FW190_Vorstellung_2.jpg
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

BillSwagger
10-31-2010, 03:35 PM
I still don't see how electrically powered trimming of the tail frame makes any difference.
Electrical motors have limitations and become less responsive at high speeds or even jam.
Is the trim function on the stick so the pilot can operate trim and pull on the stick with both hands?


No.
It's more an indication of a pilot not knowing his plane's systems entirely, or panicing.

RSJ saw what he saw, obviously enough times to make note of it. You'd have to use more than speculation to argue against it. Who knows, these could've been well trained pilots, and their equipment failed. It happens.


I haven't read anything about "sinking" in any Rechlin-trial reports, so mabe the problem wasn't that much of a show-stopper as some people might think it was.

You'd have to assume Rechlin tested and observed that part of the envelope. If they never put the plane into a dangerous dive , how would they observe its ability on pull out? With that logic i could say the P-47 never entered compressibility because it doesn't show up on a Rechlin report.

There are other comparisons with the Spitfire, F4U, and P-47, as well as countless pilot reports. There is a lot to go off of for making the conclusion that the 190 sank on pull out. Comparisons with the Spit reveal it as a loss of speed, so pull out had to be made less aggressively.

Diving in a steep dive usually compromises a lot of the maneuver options for many aircraft, for a combination of factors.
Control forces can become heavy, G limits on the airframe as well as the pilot, and aerodynamic defects such as compressibility, nose tuck, buffeting, sinking, high speed stall, spinning, autorotation etc. All of which challenge a pilot on pull out.

Bill

Bremspropeller
10-31-2010, 03:57 PM
Is the trim function on the stick so the pilot can operate trim and pull on the stick with both hands?

The pilot doesn't need both of his hands, as positive trim will automaticly result in a nose-up movement.
The trick is not to over-g the airframe while doing it.

There's no hinge-limitation mentioned.
The flying-stabilizer supports it's own movement, as the pressure-distribution amounts hardly any hinge-moment required to move the stab.


RSJ saw what he saw, obviously enough times to make note of it. You'd have to use more than speculation to argue against it. Who knows, these could've been well trained pilots, and their equipment failed. It happens.

1) How many did he see?
Did he have direct radio-contact to the pilot and had him indicate any of the problems?
Were the pilots just dead/ massively wounded/ knocked-out/ paralysed?

2) I'm not speculating, RSJ is.
See above.


You'd have to assume Rechlin tested and observed that part of the envelope. If they never put the plane into a dangerous dive , how would they observe its ability on pull out?

Rechlin, as the proving-ground of the german aviation has put any airplane through all it's paces.
Had any critical problem surfaced through these tests, the airplane would have either gone into re-design or there had been a limitation on the airframe.


With that logic i could say the P-47 never entered compressibility because it doesn't show up on a Rechlin report.

That's a flawed logic, as foreign types will not be tested into those flight-regimes for the lack of replacement in case of a crash.


There are other comparisons with the Spitfire, F4U, and P-47, as well as countless pilot reports. There is a lot to go off of for making the conclusion that the 190 sank on pull out. Comparisons with the Spit reveal it as a loss of speed, so pull out had to be made less aggressively.


So far, there's only Brown's report on any "sinking" during pull-up.
I haven't read anything else suggesting there was a major problem as you're trying to label it.
I have never read a german account on any speed-losses during pull-out.
I've only read of a couple of popped rivets, indicating an over-g pull-out that can hardly be associated with "excessive sinking".

BillSwagger
10-31-2010, 04:18 PM
Every plane has a limit even the 190.
Its ridiculous to think only the 190 was capable of a high speed dive with out dangerous consequences.

I would not enter a debate on speculation. What a pilot sees is not speculation. He does speculate the causes, but is uncertain of the issue, he just comments that he saw several planes pancake into the ground on pull out. The pilot condition is not known, and should really remain out of the discussion since there is know way of knowing. It would be a baseless argument.

I also wouldn't ignore what Rechlin says.

That's a flawed logic

If the aircraft in question is never put into a scenario that showed a problem then it would not reveal itself on a test.
Its the same logic your using.
Obviously, we don't rely on one source.
Try to look beyond German propaganda.


Bill

Bremspropeller
10-31-2010, 04:34 PM
Every plane has a limit even the 190.
Its ridiculous to think only the 190 was capable of a high speed dive with out dangerous consequences.

I'm not suggesting this.
I'm suggesting it's unlikely a 190 can't recover from a dive a P-47 could, based on the controls of both planes.


If the aircraft in question is never put into a scenario that showed a problem then it would not reveal itself on a test.
Its the same logic your using.

1) That's why test-programmes usually last longer than one day
2) It's not, as Rechlin was responsible for the type-certification and thus for the proving of the entire flight-envelope, including max diving-speed.
Testing a P-47 in Rechlin is not going anywhere near the really dangerous parts as there's the chance of losing the aircaft and thus losing the chance of showing the aircraft around (Zirkus Rosarius).


Try to look beyond German propaganda.


Which propaganda?

M_Gunz
10-31-2010, 10:09 PM
I would not enter a debate on speculation.

RSJ saw some 190's dive into the ground. What are you trying to make about the use of the word pancake as proof of Kit Carson's allegations of 'sink' is completely speculation. And you are discussing it.

Please, the merry go round has to stop, your ticket has run out!

BillSwagger
10-31-2010, 11:22 PM
I disagree with your interpretation then.

I also draw from experience and intelligence reports on the matter.

Its not my interpretation that the 190 pancakes in every dive it makes. The fact is that many aircraft would crash on pull out under the wrong conditions, and perhaps Johnsons observations verify a portion of those occurances. The arguement for trim pull out is convincing. The reality is that every pilot would use trim in a matter that's beneficial to stick forces regardless of the plane they fly.
What makes the 190 so special? Why are Johnson's words described as inaccurate or flawed?
There are pros and cons to every aircraft. Its easier to except that really rather than obscure the proof presented.
In fact, rather than attempting to discredit whats presented, try to present something new that might add to the discussion.
Otherwise its a rather petty discussion to mull over what RSJ meant by the use of the word "pancake".



Bill

M_Gunz
11-01-2010, 12:10 AM
Originally posted by BillSwagger:
What makes the 190 so special?

Good question.


Why are Johnson's words described as inaccurate or flawed?

Who said that? For that matter, who brought as Johnson's words and what importance did he attach to them in the first place?

Like I wrote, merry go round.

BillSwagger
11-01-2010, 12:46 AM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Every plane has a limit even the 190.
Its ridiculous to think only the 190 was capable of a high speed dive with out dangerous consequences.

I'm not suggesting this.
I'm suggesting it's unlikely a 190 can't recover from a dive a P-47 could, based on the controls of both planes.


If the aircraft in question is never put into a scenario that showed a problem then it would not reveal itself on a test.
Its the same logic your using.

1) That's why test-programmes usually last longer than one day
2) It's not, as Rechlin was responsible for the type-certification and thus for the proving of the entire flight-envelope, including max diving-speed.
Testing a P-47 in Rechlin is not going anywhere near the really dangerous parts as there's the chance of losing the aircaft and thus losing the chance of showing the aircraft around (Zirkus Rosarius).


Try to look beyond German propaganda.


Which propaganda? </div></BLOCKQUOTE>

To be honest, Brems.. all due respect for your knowledge of the plane, i'm really worn out by this discussion as it is.

I just hope you see my point that a report need to test and observe the conditions that might cause problems for an aircraft.
That is to say that if the aircraft was not put in a position that might make a pull out challenging or dangerous, then you really can't say it wasn't a problem as the way Johnson described it.
Its easy to object to what a pilot like RSJ says, but consider for a moment that the dives that pit a P-47 after a 190 obviously occur at very high speed and as such might present more challenging conditions than what's described by a Rechlin report. By your own admission you say Rechlin would not push the P-47 because of scarcity of supply or parts. I have no way of knowing if thats true, but like i say, if it isn't on the report doesn't mean it could not happen outside the boundaries of the test.
I could probably go back and forth with you more on this issue, but i think it really boils down to speed and angle of dive.
There are tests that pit a P-47D-4 and Fw190, revealing level turn favored the P-47 above 300IAS, while it favored the 190 below that speed. A dive pull out is probably likely to correlate a similar way, although angle of bank would also make a difference.





Bill

PhantomKira
11-01-2010, 01:46 AM
Hey guys, keep in mind just who exactly was using these airplanes in the first place. These weren't aerodynamics engineers; they were kids, with a minimal level of training. Also, keep in mind that the airplanes were throw away, and so too, to an extent, were the kids. Only a very few got specialized training, particularly from the tech rep types from the company who made the airplane. Most knew the basics of flight, the basics of dogfighting, and that was it. There were people in R.S. Tuck's (British, 1940) squadron who hadn't a clue what they were up against when the Italians showed up. They had confined there studies to German aircraft. Most people are the same way: learn what they're required to learn, and no more.

Just because the airplane could, didn't mean the kid could. And some airplanes, like Johnson's, were given special treatment and special care, making them, of course, faster, due to modifications (72" MP?!) and a better handler of the controls.

By the way, there were concepts that were unknown to even the engineers then, like the phenomenon known today as "ground effect". Nobody knew why it was that a shot up B-17 would get back after it fell to within feet of the North Sea... and then quit falling.

M_Gunz
11-01-2010, 01:57 AM
Bill; P-38's, P-47's, P-51's, all have crashed from terminal dives. Is NACA to blame?

The dive speed limits, once compression was known as a problem, are printed in the POH same for the FW or any other fighter. That doesn't mean that the limits were not exceeded in combat!

Why do you attach to RSJ's observations of 190's that crashed in high speed dives your own meanings and expect objections to those meanings to be objections to RSJ's observations? Can't you see the difference?

You already agree that it can take 1,000's of feet to recover from a high speed dive. Some pilots waited too long, is that a failing in the design process? Oh yes, of course, the designers should have done a better job and made planes that could always pull out of the dive! How utterly STUPID of me to miss that! And at the same time the plane should be able to dive however fast necessary to escape being destroyed, unlike the earlier planes that never hit compression because they were too slow! And to make things worse, nobody has yet made a super-plane that can do everything and won't crash no matter how you fly. All because of incompetent aircraft designers of course!

OTOH the whole line about 190's crashing could just be a really poor gambit to argue about dives and P-47's.

Bremspropeller
11-01-2010, 05:07 AM
So, which propaganda - I'm still keen on seeing an answer to that...


There are tests that pit a P-47D-4 and Fw190, revealing level turn favored the P-47 above 300IAS, while it favored the 190 below that speed

..which is due to the P-47's better excess-power at speed, not due to some malfunctioning elevator http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

M_Gunz
11-01-2010, 11:49 AM
What's the difference between speculation and innuendo when used as debate gambits?

It's funny watching someone turn 180 to get to 360 while trying to cover their butt.

BillSwagger
11-01-2010, 11:48 PM
Why do you attach to RSJ's observations of 190's that crashed in high speed dives your own meanings and expect objections to those meanings to be objections to RSJ's observations? Can't you see the difference?

Explain what you're getting at, and i might be able to answer your question.
I read the interview with Johnson, and afterward it was posted that he was wrong about planes pancaking into the ground.
A pilot sees a plane crash into the ground, after diving after them. How is that adding meaning to it?
You can't say he is wrong. A plane crashes or it doesn't.
The argument is why, but none of that could be gathered by Johnson's words.

The dive limit for the 190 is nearly 80mph(indicated) lower than the P-47 at 10,000ft. Thats a considerable gap, and if the 190 pushed it beyond this capacity its likely it only made things more difficult for dive recovery where the P-47 was still with in its own dive limit. Why is that so hard to fathom? A Rechlin report that doesn't even test the 190 beyond its dive limits? It seems obvious that the 190 had problems with dive recovery if it exceeded its dive limits, or if proper pull out procedure was not initiated in time. Its because controls grow increasingly heavy and become less responsive. There is no exception to the 190 here, only that the speeds at which these problems occur was much lower than that of a P-47.



Bill

M_Gunz
11-02-2010, 08:47 AM
Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Why do you attach to RSJ's observations of 190's that crashed in high speed dives your own meanings and expect objections to those meanings to be objections to RSJ's observations? Can't you see the difference?

Explain what you're getting at, and i might be able to answer your question.
I read the interview with Johnson, and afterward it was posted that he was wrong about planes pancaking into the ground.
A pilot sees a plane crash into the ground, after diving after them. How is that adding meaning to it?
You can't say he is wrong. A plane crashes or it doesn't.
The argument is why, but none of that could be gathered by Johnson's words. </div></BLOCKQUOTE>

Do you mean this?

Bremspropeller
Picture of Bremspropeller

Posted Sat October 30 2010 15:43 Hide Post

quote:
RSJ: Absolutely. One thing about the 190, if the pilot continued his dive below 7 or 8 thousand feet, he could not pull out before he hit the ground. I guess they had compressibility problems or the elevators got too stiff. Whatever the problem was, I watched several of them pancake in before they could level off.



The problem with pilot-stories is...they're often just plain wrong.

Perhaps he disagreed with RSJ's speculation of why those planes crashed rather than that those planes crashed.

What I disagreed with was your contention that:

RSJs description mentions "pancake" which implies the aircraft sank on pull out. This has been documented in other reports that make note of the 190.

Bremspropeller
11-02-2010, 10:03 AM
Its because controls grow increasingly heavy and become less responsive.

Do I need to draw you a picture to make you understand that nobody could care less about control-heavyness, when having a moving stab?

It's all a matter if the pilot knows it (if not: too bad...)


Perhaps he disagreed with RSJ's speculation of why those planes crashed rather than that those planes crashed.


x-actly


RSJs description mentions "pancake" which implies the aircraft sank on pull out. This has been documented in other reports that make note of the 190.


BS

M_Gunz
11-02-2010, 11:46 AM
BS = Bitty Speculation? http://forums.ubi.com/images/smilies/halo.gif

Bremspropeller
11-02-2010, 11:56 AM
Almost http://forums.ubi.com/images/smilies/59.gif

horseback
11-02-2010, 12:19 PM
After all this back-and-forth about dive recoveries, I was reminded about the early P-47's fabric elevators tending to balloon out at high speeds, which led to their replacement with metal skinned elevators. Ditto the Merlin Mustang and I also recall that the Spitfire had problems with ballooning ailerons (although, oddly enough, I think that the Spit always had fabric elevators throughout its operational career).

I have not seen anything that indicates that the German fighter designers gave any thought to metal elevators. Was German dope/fabric that much better, or did the basic design (shape, or possibly the way they were hinged) render the issue moot?

cheers

horseback

Xiolablu3
11-02-2010, 03:06 PM
Originally posted by horseback:
After all this back-and-forth about dive recoveries, I was reminded about the early P-47's fabric elevators tending to balloon out at high speeds, which led to their replacement with metal skinned elevators. Ditto the Merlin Mustang and I also recall that the Spitfire had problems with ballooning ailerons (although, oddly enough, I think that the Spit always had fabric elevators throughout its operational career).



cheers

horseback

Hi Horseback, the Spitfire was upgraded to metal elevators during its mk2 era. (very late 1940 early 1941 the changeover was done)

Not sure about ailerons?

There is a good part in Johnnie Johnsons 'Wing leader' about the time in early 1941 when some of the Spits in the same Squadron had metal elevators and others had fabric.

The Metal elevatored Spits could perform manouvres that the fabric ones could not keep up with.

EDIT : Or am I mixing elevators with Ailerons? I'm not sure, will have to dig out the book.

I know that Baders/Johnsons Squadron flew especially to the factory to have metal elevcators or ailerons fitted, cant recall which now.

Can anyone correct me on which it was pls?

berg417448
11-02-2010, 03:33 PM
It was ailerons.

BillSwagger
11-02-2010, 04:09 PM
Do I need to draw you a picture to make you understand that nobody could care less about control-heavyness, when having a moving stab?

It's all a matter if the pilot knows it (if not: too bad...)

I get what your saying, your saying the pilot can dive as fast as he wants, exceeding dive limits, as long as he knows about his super trusty trimmable stabilizer. He doesn't even have to use the stick, he could just use trim, right? Thats why heavy controls don't matter. That's because the trimming creates enough deflection all by its self, right?
It doesn't matter how fast either, the 190 trim is just as responsive at mach .8 as it as at cruising speeds.
I get what your saying, it just seems incomplete.

A more concrete answer is the 190 has dive limits. If the pilot exceeds those limits, too bad.

Beyond those limits who knows. Trim could fail, the pressure exerted on the tail frame could bend parts rendering them useless. Whatever the case, it seems apparent the 190 had problems with recovery from excessive dives.


Bill

Bremspropeller
11-02-2010, 05:08 PM
Whatever the case, it seems apparent the 190 had problems with recovery from excessive dives.

Nothing does suggest that - well, except Mr. Johnson.

BillSwagger
11-02-2010, 05:29 PM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Whatever the case, it seems apparent the 190 had problems with recovery from excessive dives.

Nothing does suggest that - well, except Mr. Johnson. </div></BLOCKQUOTE>

Actually, nothing suggests otherwise. In fact, its perpetuated on other reports, and the fact that the Fw190 had lower dive limits than a P-47.
I'm going in circles here. I've already made my point.

Bill

TS_Sancho
11-02-2010, 05:39 PM
Bill, remember that a similar design point to the FW190's variable incidence tailplane was incorporated into the Bell X-1 to solve the same problem under discussion.


After the aircraft ran into compressibility problems in 1947, it was modified to feature a variable-incidence tailplane. An all-moving tail was developed by the British for the Miles M.52, and first saw actual transonic flight on the Bell X-1 that allowed it to pass through the sound barrier safely.


Bell X-1 Design and development (http://en.wikipedia.org/wiki/Bell_X-1)

As Brems said earlier...


In contrary to just adjusting control-forces (as with a trim-tab), the 190's all-flying tail creates an increased amount of pitch-authority.
Then again - this is only of use when known to the pilot and used accordingly.


In a post sound barrier world we now know that the particular design of the FW190's variable incidence trim system would allow pitch authority farther into the transonic envelope than the trim tabs on the elevators in the P-47.

Whether or not the average Luftwaffe pilot would have known of this and understood its implications for maintaining pitch authority past the red line would be a different matter entirely.

My two cents...

BillSwagger
11-02-2010, 06:04 PM
I think its a bit of a stretch to compare the Bell to the 190. Although i'm sure the technology has implications for transonic flight, most WW2 aircraft aren't capable of transonic flight at 10,000ft, nor does that imply that the 190 was capable of remaining in control in transonic flight.
An increased pitch authority would only be beneficial if the controls were responsive in the first place. Otherwise the incidence is the only thing changing the pitch of the aircraft, and that might not create enough deflection to recovery from an excessive dive. The structure of the aircraft might not support a change in the incidence at higher speeds so changes in trim are not as responsive.
There are dive limits for a reason, and this has something to do with control response or structural strength, usually both.
I also don't imagine these aircraft nosed straight into the ground. They probably weren't able to level off in time.
There are a combination of factors which effect every aircraft, the 190 was no exception.


Bill

M_Gunz
11-02-2010, 10:19 PM
Even with stabilizer trim you still have limits to how fast you can pull out from extreme speed dives. Just the stress that the airframe and pilot can take impose limits. And as stated before, we can't tell from his comment what the states of the planes or pilots that 'pancaked' were, damaged or wounded or anything else. To speculate on why and come up with a single cause is a bit thick.

I don't see anything in what RSJ wrote that says he was next to the 190 and co-speed at any point to make a comparison between FW-190 and P-47 pullout capabilities either. There is again less specifics than there is information to assume to be able to make a qualified statement about pullout capabilities of either plane let alone compare the two from that report.

All this because of a poorly based yet rigidly held belief in overblown dive and zoom capabilities for the P-47!

M_Gunz
11-02-2010, 10:24 PM
Originally posted by BillSwagger:
I think its a bit of a stretch to compare the Bell to the 190. Although i'm sure the technology has implications for transonic flight, most WW2 aircraft aren't capable of transonic flight at 10,000ft, nor does that imply that the 190 was capable of remaining in control in transonic flight.

Did you actually read what Sancho posted? And the linked information?


In a post sound barrier world we now know that the particular design of the FW190's variable incidence trim system would allow pitch authority farther into the transonic envelope than the trim tabs on the elevators in the P-47.

This is true even though the FW could not reach X-1 speeds.

BillSwagger
11-02-2010, 11:09 PM
I get that and i've seen stats upside down, frontwards and backwards and still put the P-47 ahead of a 190 in a dive, and at a decidedly better angle of pull out.
You can disagree, it doesn't change my opinion or the outcome of what RSJ observed.


In a post sound barrier world we now know that the particular design of the FW190's variable incidence trim system would allow pitch authority farther into the transonic envelope than the trim tabs on the elevators in the P-47
Where is this quoted from??

The article mentions Bell's use of a variable incidence trim, but i fail to see how that relates to the 190s superiority in the transonic realm. In the transonic realm the Fw190 probably bounced all over the sky.
Fundamentally I actually agree with the premise, because the shock wave would have to cover the entirety of the stabilizer which is less likely to occur as it does when disrupting the airflow over the elevator tabs. There's more surface area.

So what about outside of transonic flight, say at lower altitudes where compressibility isn't an issue?
How does that make for a superior dive pull out in a situation where one aircraft, by design, is made to dive above 500 IAS, and the other meets its dive limit at closer to 430 IAS at 10,000ft?

I think people get lost in the semantics of arguing that the 190 could not recover from a dive, and that's not what im saying. At slower speeds, its becomes obvious the 190 was more responsive in turns and in pull out. A
The bottom line is the 190 had lower dive limits than the P-47 and its evident that exceeding those limits caused problems on pull out.




Bill

Xiolablu3
11-03-2010, 05:05 AM
Originally posted by berg417448:
It was ailerons.


Thanks Berg http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

More on the metal elevators :-

If the Spitfire was fitted with a rear long range tank behind the cockpit (some mark IX's, XVI and later particularly 2nd TAF) then they HAD to have metal elevators fitted.

SO the answer is that SOME Spitfires had metal elevators, but the majority had fabric.

Seafires had Metal elevators also.

M_Gunz
11-03-2010, 07:36 AM
How does that make for a superior dive pull out in a situation where one aircraft, by design, is made to dive above 500 IAS, and the other meets its dive limit at closer to 430 IAS at 10,000ft?

Are you joking? What FW-190 hit dive limit close to 690 kph IAS at 3 km alt? Did you get that from the same forum as the Herbert Fischer P-47 dives? Yeah, I've seen the posts, anything goes when fanboys "discuss" their obsessions.


The bottom line is the 190 had lower dive limits than the P-47 and its evident that exceeding those limits caused problems on pull out.

Every fast plane in the war had someone not pull out from a dive for the same reason, including P-47's! What's the big deal? You failed to make one point so now you take it out on the FW-190???

Bremspropeller
11-03-2010, 10:18 AM
The article mentions Bell's use of a variable incidence trim, but i fail to see how that relates to the 190s superiority in the transonic realm. In the transonic realm the Fw190 probably bounced all over the sky.


No, in the transonic realm, which is the speed-band in which both, subsonic and supersonic airstreams do locally exist in the vicinity of the airframe, the 190 would tuck-under just like any other airplane that wasn't designed to go supersonic.
However, the 190's all-flying tail does give it a lot of pitch-authority beyond Mcrit - possibly enough to negate the P-47's "speed advantage" - with the difference that the 190-pilot still had some control over his aircraft, while the P-47-pilot could do all but pray for thicker air to reder his aircraft controllable in time to recover.


How does that make for a superior dive pull out in a situation where one aircraft, by design, is made to dive above 500 IAS, and the other meets its dive limit at closer to 430 IAS at 10,000ft?


Dive-limits are directly linked to compressability.
No compressability, no limits - unless there's flutter, but there wasn't any on the 190.


The bottom line is the 190 had lower dive limits than the P-47 and its evident that exceeding those limits caused problems on pull out.

With trim neutral, yes.
With trim on "tail-heavy", no.
Better be on guard, though:
With the pitch-authority rapidly coming back when going below Mcrit, you're in danger of tearing the plane apart.

A couple of Phantoms have supposedly crashed due to exctly this phenomenon...

M_Gunz
11-03-2010, 12:15 PM
The all-flying tail is not quite the same as an adjustable stab with elevator surfaces. Elevator surfaces do get buzz and shake when the shockwaves form on them, same as ailerons but IIRC aileron buzz occurs at lower Mach. Go fast enough and all the controls shake, pilot limits might make the difference before physical limits of the airframe, like -just- before or all the down until it's another physical limit, plane vs ground.

I wonder how many 190's crashed in dives without P-47's catching up 1000's of feet higher that any did crash whole to be seen? After all, he must have got away and guns range is 100's of meters, I've seen 800m and parts knocked off in one report in this thread! So nowhere in the dive did the P-47's get within firing range of the 190 before they had to pull out, starting wayyyyyyyy behind the 190 (out of gunnery range), to avoid crashing themselves and watch the 190 augur in from above in passing. Not exactly catching up in nothing flat every time. So you shouldn't expect to, check with RSJ.

Bremspropeller
11-03-2010, 12:28 PM
The controls per se won't shake that much.
The elevator is just stalled (if the shock-wave is strong-enough to make the boundary-layer disattach completely from the surface) and won't move or just barely move.

Shaking of the aileron occurs during stalls or closely below CLstall, due to little eddies/ vortices disattaching from the ailerons.

Then there's flutter, but that's a completely different affair.

M_Gunz
11-03-2010, 05:03 PM
At some speed above .72 Mach in some corporate JETS when the shockwaves form right on the control surfaces as it will before it moves forward of them, there's enough shake to feel through hydraulics. Those are not supersonic-capable planes, they start to tuck even before then. They are also quite a lot bigger than WWII fighters and have swept wings, what shakes those controls would rattle a WWII fighter and IIRC the record-attempt dive tales also involved a lot of control rattle, and that's the ones that lived!

BillSwagger
11-03-2010, 07:30 PM
Originally posted by M_Gunz:
Are you joking? What FW-190 hit dive limit close to 690 kph IAS at 3 km alt? Did you get that from the same forum as the Herbert Fischer P-47 dives? Yeah, I've seen the posts, anything goes when fanboys "discuss" their obsessions.

Probably does depend as much on the source there there Gunz, as it does the model in question.
here's mine: http://www.wwiiaircraftperform...g/fw190/ptr-1107.pdf (http://www.wwiiaircraftperformance.org/fw190/ptr-1107.pdf)

Stability and Controllability in Dives:
In general, stability and controllability of the FW-190 in dives were satisfactory. However, at diving speeds above 350knots, indicated, vibrations were felt and control forces became noticeable. In no case did control forces become objectionable. Diving restrictions indicated by a captured document, and as posted on the airspeed indicator in the airplane, were as follows:

466 mph (ind) below 10,000ft
426 mph (ind), 10,000ft to 16500ft
360mph (ind) 16,500 feet to 25000 ft




However, the 190's all-flying tail does give it a lot of pitch-authority beyond Mcrit - possibly enough to negate the P-47's "speed advantage" - with the difference that the 190-pilot still had some control over his aircraft, while the P-47-pilot could do all but pray for thicker air to render his aircraft controllable in time to recover.

The 190 had no speed advantage in a dive other than the initial acceleration in very steep dives. You might hint at a control advantage at higher speeds, and at higher altitudes. The idea the P-47 pilot prayed for thicker air is not relevant beyond a test dive or those dives that are initiated from above 30,000ft. Revel over combat reports and there is not one that mentions the inability to follow a 190 because of loss of control.

Much like the Spitfire, if you dove the 190 from high enough altitudes then those attributes might show themselves.
What was the likelihood of seeing a 190 above 30,000ft in combat? Maybe a Dora. Not to say compressibility wasn't an issue for the P-47, it had dive flaps installed after all, but it doesn't appear it had problems chasing down 190s.

I haven't been able to nail down a mach limit for the Fw190, but some sources say it was close to the Bf109 at 0.78.
The limiting mach for the P-47 was .76 and complete loss of elevator response was experienced closer to 0.80 mach.
This is in part due to the P-47s longer tail frame, where initial mach effects are noticed on the wings effecting aileron control, and at higher speeds the shock wave engulfs the tail frame.

It'd be a big stretch to say the 190 was as stable in a dive as a P-47. The P-51 could not be dove with the same aggressiveness either. What's that say about mach limits?? Mach effects will effect different aircraft in different ways, from onset to the extremes.


Dive-limits are directly linked to compressibility.
No compressability, no limits - unless there's flutter, but there wasn't any on the 190.
I disagree. See the beginning of the post.
If you do the math with mach numbers and the speed of sound, dive limits would be much higher.
Some aircraft experience heaviness of control long before compressibility is reached, especially when pulling Gs, and dive limits are set for safer recovery. If you can't pull out of a dive before you reach compressibility, is it still a safe speed?




With trim neutral, yes.
With trim on "tail-heavy", no.
Better be on guard, though:
With the pitch-authority rapidly coming back when going below Mcrit, you're in danger of tearing the plane apart.

The "tail heavy" trim makes sense, but my logic says as speed increases the pilot would have to push more and more on the stick to hold a dive. Assuming stick forces were not a factor, it would even get to a point where pushing full deflection on the stick would cause the nose to come up from the trim. So, obviously there is a balance there that the pilot uses.
From that view point, it negates the use of fully trimmed "tail-heavy" flying, the pilot would never be able to keep the nose down. Factor in control heaviness and the pilot would tire from having to push forward for the entirety of the dive especially as speed increases. It just seems like the use of trim is overstated, and for performance reasons uses of trim was much more subtle.
In contrast, everything i've read about compressibility dives in a P-47 says they were advised to leave trim in neutral, and that a tail heavy trim would be dangerous because of blacking out the pilot to such extremes that they might not wake up.
From the descriptions it actually sounds like when elevator control is lost, the pilot uses neg trim to begin pulling the nose up, but its not as effective so he wheels out more trim to get the same effect. As the aircraft noses up, it slows, the shock-wave subsides and the trim catches more air, pulling the plane harder blacking out the pilot.

Bremspropeller
11-03-2010, 08:40 PM
In no case did control forces become objectionable.

Bingo.


You might hint at a control advantage at higher speeds, and at higher altitudes.

No, I'm hinting at a control-advantage beyond Mcrit.


Not to say compressibility wasn't an issue for the P-47,

It was - Mach Tuck was actually a big problem on the P-47 and a couple were lost that way.


it had dive flaps installed after all

Are you sure you're not confusing the 47 and 38 here?


I haven't been able to nail down a mach limit for the Fw190, but some sources say it was close to the Bf109 at 0.78.
The limiting mach for the P-47 was .76

Those figures are about what I had in my head.
So we agree, the 190 had a higher Mach-limit than the P-47?


It'd be a big stretch to say the 190 was as stable in a dive as a P-47.

Why?
Most pilot-reports remark the 190 as one of the most stable planes they've ever flown.


If you do the math with mach numbers and the speed of sound, dive limits would be much higher.

That's because the speeds are put there in order to give a margin for
1) differences between the standardized atmosphere taken as model and the actual atmosphere:
Desity changes all the time at altitude and so does the speed of sound - would be a nasty surprise for the pilot if IAS wasn't corected for that http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif
2) safety


Some aircraft experience heaviness of control long before compressibility is reached,

See report-excerpt above.
Heaviness of controls is never too much to recover, pulling both-handed.
What really spoils the party is compressibility, when elevator-forces become excessive very quickly, mixed with a tendency to go nose-dowm.


The "tail heavy" trim makes sense, but my logic says as speed increases the pilot would have to push more and more on the stick to hold a dive.

Your logic is true, but that's not what I said:

Recovery from compressibility would be difficult in the 190 when trim is in "neutral".
If the pilot trims into "tail heavy", however, the nose will come up.
What he has to be careful about, though, is re-applying trim into "neutral" as soon as he recognizes an increase in pitch-authority once the Mach-number goes down, as he would quicly over-g his aircraft, leaving trim in "tail-heavy".

Tail-heavy trim over here would be a lot more dangerous than, say, in a P-47 because as opposed to the Jug where trim merely changes "control-force", trim actually changes pitch-authority in the 190.

That's the big difference.

M_Gunz
11-03-2010, 09:58 PM
Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by M_Gunz:
Are you joking? What FW-190 hit dive limit close to 690 kph IAS at 3 km alt? Did you get that from the same forum as the Herbert Fischer P-47 dives? Yeah, I've seen the posts, anything goes when fanboys "discuss" their obsessions.

Probably does depend as much on the source there there Gunz, as it does the model in question.
here's mine: http://www.wwiiaircraftperform...g/fw190/ptr-1107.pdf (http://www.wwiiaircraftperformance.org/fw190/ptr-1107.pdf)

Stability and Controllability in Dives:
In general, stability and controllability of the FW-190 in dives were satisfactory. However, at diving speeds above 350knots, indicated, vibrations were felt and control forces became noticeable. In no case did control forces become objectionable. Diving restrictions indicated by a captured document, and as posted on the airspeed indicator in the airplane, were as follows:

466 mph (ind) below 10,000ft
426 mph (ind), 10,000ft to 16500ft
360mph (ind) 16,500 feet to 25000 ft
</div></BLOCKQUOTE>

Without knowing the CAS which includes position error of each plane, comparisons of the IAS limits are not 1:1. And some altimeters had to work a bit better than another one at keeping up with high speed dives. That IAS gauge is just something to give the pilot a number to use by the time the plane passes .6 Mach. It's only how the air 'feels' to the pitot, not a direct input for TAS calculation.

It's been posted here about two USN fighters flying side by side together and one IAS read 20 mph faster than the other, just between two different planes cruising along. And as for IAS, how many times have the reported IAS in high speed dives have worked out to Mach 1.something? IAS multiplies with compression and so do differences between planes. You can't know without correcting the airspeed for the planes who went just how fast between 20,000 and 0 feet, and more importantly by how much.



P-47 is what, 520 IAS under 20,000 ft? Is there a way to get the CAS or TAS at 6000m from a P-47 manual?

But then the FW data is for an FW 190-A/4 in 1944 when 190-D's were flying much faster than the A/4!

M_Gunz
11-03-2010, 10:12 PM
Originally posted by BillSwagger:
Revel over combat reports and there is not one that mentions the inability to follow a 190 because of loss of control.

Yah cause you have to survive the mission to turn in a report! LOL!

If the 190 dives away with a large lead, the P-47 would have to a whole lot faster to close range with it. Are there any combat reports from that selected set on the wwiiaircraft site where a P-47 did anything without make a kill as part of it?

Hmmmmmmmmm?

BillSwagger
11-03-2010, 10:25 PM
No, I'm hinting at a control-advantage beyond Mcrit.
i read you the first time.
Altitude is an important part of that presmise, and that's just not the case when looking at combat reports.
A P-47 would have trouble in dives initiated from above 30,000ft.
A 190 might not reach critical mach unless it also started a dive from that height.
You see why its not an issue in combat where the 190 typically flew?
I guess what i'm saying is that diving straight down was not typical for more than couple thousand feet because it would be difficult for most aircraft to level off below their dive limits.
There is more about compressibility later in the post.


quote:
Not to say compressibility wasn't an issue for the P-47,
It was - Mach Tuck was actually a big problem on the P-47 and a couple were lost that way.

There were several more P-47s lost just in the test phase alone. Much of the plane was designed and teethed to fly at transonic speeds. Its an exaggeration to say mach tuck was a huge problem for the P-47, it was a problem for most propeller driven aircraft in transonic flight. The difference is the P-47 was more structurally sound for such dives.



Why?
Most pilot-reports remark the 190 as one of the most stable planes they've ever flown.
No, no,..4 out of 5 dentists agree the P-47 was a more stable plane in a dive.
I would look for context in your source here. It assumes the surveyed pilots not only had the luxury of flying the various war birds in question, but also had the luxury of pushing them into their dive limits. Rechlin admittedly didn't push aircraft.
I'm no genius, but i'd also bet if you asked Germans which planes were better, and asked Americans, Russians, or Japanese which planes were better, they'd all point to their tried and true.



Are you sure you're not confusing the 47 and 38 here?

Dive flaps went into to the P-47D-30 production block and were retrofitted into the universal wing introduced on ealier production blocks. The Germans were introducing jets into the war, and the only way to catch them was to get a running start from a dive from altitude, where compressibility was an issue.



So we agree, the 190 had a higher Mach-limit than the P-47?
Not so fast.
It would be nice to know the actual figures and behavior of the aircraft as it approached and exceeded it's mach limit.
Maybe we can figure it out using your explanation below:



Dive-limits are directly linked to compressibility.
No compressability, no limits - unless there's flutter, but there wasn't any on the 190.


The dive limit posted for the 190 is 426mph from 10,000ft to 16,000ft.

The speed of sound at 16,000ft is what? 718 mph (TAS)in a standard atmosphere.

Take 426mph indicated and convert it to TAS, ends up being approx 526mph (assumes 2 percent correction error)

526 into 718mph and that gives a mach limit of 0.73

No, i disagree Brems, the Fw190 didn't have a higher mach limit than the P-47. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

I'd actually sooner agree that dive speeds are determined by compressibility.
Dive limits take into consideration other factors like load, Gs, control heaviness as well as dive angle.
I've said it before and i'll say it again, a plane might reach its dive limit before it reaches compressibility.


This segways into this......


Tail-heavy trim over here would be a lot more dangerous than, say, in a P-47 because as opposed to the Jug where trim merely changes "control-force", trim actually changes pitch-authority in the 190.
That's the big difference.

understood.
Do you think pitch authority made a difference in safety of pull out given the G limits of the aircraft?
How does that present an advantage in pulling out of a high speed dive?
Its starting to look like high speed kills any maneuver advantage the 190 might have. Wait a sec, that's what the reports say. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif



What really spoils the party is compressibility, when elevator-forces become excessive very quickly, mixed with a tendency to go nose-dowm.

You hit heavier air at higher speed you may no longer be in compressibility but you'd still have to contend with the heavier air pressure against the hinge points.
That was the case with the A6M, and happened with other aircraft at higher speeds.

Some aircraft actually maintain elevator authority well into compressibility, but instead are presented with issues of tuck which require trimming to correct.
There is an unverified source that compares the mach effects of the 190 similar to the P-51. The onset of tuck occurring at about 0.75 mach, however controllable up to 0.80 in the case of the Mustang. Maybe the onset of tuck is 0.73 for the 190, and the limit is 0.78??? You know, cause the Mustang is better. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif
The tuck ends up being the bigger issue, imo, and aircraft like the Mustang were teethed to deal with it late in the war.
The pilot had to trim down stick force to hold a dive, tuck is experienced pulling the aircraft steeper, so trim had to be let out a bit, but in the drop tuck disappears and nose pulls up again. It was an issue in steeper more aggressive dives and found to be quite dangerous if the pilot was not able to steady his dive.
The tuck is also the reason elevator controls grow heavier because the pilot has to fight the tendency of the aircraft. Trimming works, but then tuck disappears and the nose wants to pop back up.



Bill

BillSwagger
11-03-2010, 11:28 PM
Originally posted by M_Gunz:


Without knowing the CAS which includes position error of each plane, comparisons of the IAS limits are not 1:1. And some altimeters had to work a bit better than another one at keeping up with high speed dives. That IAS gauge is just something to give the pilot a number to use by the time the plane passes .6 Mach. It's only how the air 'feels' to the pitot, not a direct input for TAS calculation.


It was a source, be glad i posted it.
You can provide a more accurate document about 190 dive limits, by all means post it.




it's been posted here about two USN fighters flying side by side together and one IAS read 20 mph faster than the other, just between two different planes cruising along. And as for IAS, how many times have the reported IAS in high speed dives have worked out to Mach 1.something?

This presmise suggests that the P-47 could show 400IAS, and 190 show 400IAS, and yet still close on the 190 at a rate of 20mph.

hmmmmmmmmmmmmm....indeed.




Originally posted by M_Gunz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BillSwagger:
Revel over combat reports and there is not one that mentions the inability to follow a 190 because of loss of control.

Yah cause you have to survive the mission to turn in a report! LOL!
</div></BLOCKQUOTE>

Yep, and most did survive. My guess is that wwiiaircraft includes only combat reports where actual combat took place.
Selection and organization appears to be by Pilot Name, and Squadron number
ie the 4th, the 56th, the 352nd, the 353rd, the 355th, and the 361st all major squadrons that flew P-47s.

There are also reports that mention when aircraft dove away, and there are many more where the pilot mentions going after them and catching them. It depended on the scenario of course.
By Johnson's own words, he says compressibility was only a problem in dives above 25,000ft.
It would be nice to see reports that mention dives initiated with the intent of escaping as those were likely to push the aircraft beyond its limits. In fact, that's typically why a pilot might exceed the dive limits and in the case of the 190 pilots Johnson describes, they probably found themselves in problematic circumstances. A case could be made that P-47 pilots probably found themselves in similar predicaments, its just well known that under such circumstances the P-47 usually out ran its adversaries, barring a bounce at lower altitude, or in the occurrence they were caught in a climb.
Luftwaffe score records indicate this as well. There are very little score statistics for the P-47 above 20,000ft, even above 10,000ft. The bulk of scores on fighters were under 5,000ft and most of them were P-38s.
Other than those, the majority of scores were bombers at all heights.

Bill

M_Gunz
11-04-2010, 05:24 AM
Originally posted by BillSwagger:

By Johnson's own words, he says compressibility was only a problem in dives above 25,000ft.



Well, MCrit is supposed to be .74 Mach? So there is Johnson saying that if a P-47 starts a dive below 25,000 ft that it can't reach .74 Mach.

That puts a speed limit on P-47 dives. Oh thank You RSJ!

BillSwagger
11-04-2010, 07:57 AM
I keep seeing the critical mach for the 47 quoted as 0.76, said to be where aileron snatch occurred. Elevators stiffened up closer to 0.80
Johnson's words were compressibility was not a problem below 25,000ft, not that he didn't encounter it.
At higher altitudes reaching mach limits didn't require the same amount of dive for two reasons: the thinner air and faster start speeds (TAS).
The P-47s top speeds are achieved near 30,000ft, and it maintains a top speed above above 420mph up to 40,000ft. Cruising speeds would correlate, no?
So not only is the plane going faster from the start, its also in thinner air.
That elaborates more on what Johnson said.
I'm sure if the pilot intended to reach mach limits under 25,000ft he could, but it would probably be difficult to exceed mach limits the lower the plane gets. That's why the mach dives were tested above 20,000ft.

To illustrate a point, according to the dive test information for the Spitfire and P-47 they both reached the same calculated TAS but at different heights.
This gave a recorded mach number of .86 to the P-47, and a mach number of 0.89 to the Spitfire.
Both achieving 608 mph. The difference was 5000ft of altitude, but everyone brags the Spit reached a higher mach number. It also took the spit twice as long to reach those speeds, and nearly twice the altitude. (10 seconds of which were the P-47 ramping up speed in level flight.) Amazing. http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

jameson2010
11-04-2010, 09:10 AM
@ 1.48
http://www.youtube.com/watch?v=5vO9NKJNjiw

Bremspropeller
11-04-2010, 10:50 AM
@ 1.48


He's talking about the 109.


Its an exaggeration to say mach tuck was a huge problem for the P-47, it was a problem for most propeller driven aircraft in transonic flight.

It's not.
The Jug was well known for that bahaviour - propably because it was easier to get to those speeds with the -47 in the first place.


The difference is the P-47 was more structurally sound for such dives.


There isn't much to chose between the 190 and the 47.


No, no,..4 out of 5 dentists agree the P-47 was a more stable plane in a dive.


By what standards? Inability to move the elevator?
You betcha!


The speed of sound at 16,000ft is what? 718 mph (TAS)in a standard atmosphere.


Exactly - in a STANDARD-atmosphere.
As I already wrote, standard-conditions prevail only 1% of all the time.
That's why there are conservative margins put into the numbers.
Have you ever wondered why speeds apply to a 6000ft speed-band?
Exactly, because there are margins in there to cope for that.


Do you think pitch authority made a difference in safety of pull out given the G limits of the aircraft?


There are onl two extrmes:
a) no pitch-authority at all, getting 1g or less
b) too much pitch-authority resulting in an over-g

The issue is not that pitch-authority is too much from the start, it's that pitch-autority rapidly increases as the Mach gets lower (centre of pressure quickly shifts + shockwaves disappear from the elevator).


You hit heavier air at higher speed you may no longer be in compressibility but you'd still have to contend with the heavier air pressure against the hinge points.
That was the case with the A6M, and happened with other aircraft at higher speeds.


Not with the 190, as written in the excerpt of the pilot-report you posted.


The onset of tuck occurring at about 0.75 mach, however controllable up to 0.80 in the case of the Mustang. Maybe the onset of tuck is 0.73 for the 190, and the limit is 0.78??? You know, cause the Mustang is better.

Critical Mach (Mcrit) is defined as the speed at which the first supersonic-flow can be seen.
Consequently, there's no tuck below Mcrit.
Mcrit being 0.78 for the 190, there can be no 0.73 "tuck-onset".

jameson2010
11-04-2010, 11:41 AM
He's talking about the 109

LOL! I think you should watch it again, he's definitely talking about the 190. Clue: "air cooled". Nobody's mentioned the 190's vicious snap stall either. You lot should really get out more! S!

Bremspropeller
11-04-2010, 11:47 AM
No, he's talking about the 109, I've heard the interview in German and he's talking of the 109's trailing-edge cooler-flaps opening -asymmetrically at times - without the pilot having any ability to control them.

TS_Sancho
11-04-2010, 11:48 AM
Originally posted by Bremspropeller:

b) too much pitch-authority resulting in an over-g

The issue is not that pitch-authority is too much from the start, it's that pitch-autority rapidly increases as the Mach gets lower (centre of pressure quickly shifts + shockwaves disappear from the elevator).



I cant help but wonder if some of the "pancaking" aircraft descriptions could be attributed to the phenomena above?

Pilot is diving for his life past VNE loses pitch control, knows enough to trim his way out of trouble, hits the thicker air and wham! pitch authority returns so quickly the G forces incapacitate the pilot and the aircraft crashes mid pullout.

From an observers point of view with no way to know what was happening in the cockpit of the diving aircraft, would this be described as the aircraft "pancaking" into the ground?

BillSwagger
11-04-2010, 11:50 AM
He's talking about the 109. http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif
I had to listen to it a few times myself.



Exactly - in a STANDARD-atmosphere.
As I already wrote, standard-conditions prevail only 1% of all the time.
That's why there are conservative margins put into the numbers.
Have you ever wondered why speeds apply to a 6000ft speed-band?
Exactly, because there are margins in there to cope for that.

However, you'd like to word it Brems. There is more to dive limits than mach limits.


There isn't much to chose between the 190 and the 47.
More wishful thinking from the wunderwaffe.
Yes they are both airplanes with one engine and two wings but its a stretch to call them the same plane.
The 190 had more in common with the P-40 than the P-47, even Russian accounts make that comparison.



The issue is not that pitch-authority is too much from the start, it's that pitch-autority rapidly increases as the Mach gets lower (centre of pressure quickly shifts + shockwaves disappear from the elevator).
I guess what i'm getting at is that the P-47 pilots had the same problem with their trim tabs, so they were advised to keep them in neutral for steep dives where compressibility was encountered. How is the 190s mechanism superior for dive pull out if it presented the same problem?


Critical Mach (Mcrit) is defined as the speed at which the first supersonic-flow can be seen.

To clarify, its the mach number at which the supersonic air-flow first occurs over the wing. You might see supersonic airflow on other parts of the aircraft before the wing, but this is not related to critical mach, by definition.

I've also seen mach number, or mach limits defined as the point at which the aircraft loses the ability to maintain controlled flight.
With this understanding....

Mcrit being 0.78 for the 190, there can be no 0.73 "tuck-onset".
Its possible to experience the onset of tuck as the aircraft enters compressibility. Its actually related to the drag curve of the aircraft, isn't it?

Bill

Bremspropeller
11-04-2010, 11:51 AM
Sancho, in that case, the aircraft was too close to the ground for recovery anyway...

Bremspropeller
11-04-2010, 12:02 PM
I had to listen to it a few times myself.

I didn't, because I'm not listening to an incompetetnt narrator who can't even pronounce "Messerschmitt" correctly, but to the originally interviewed. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif


However, you'd like to word it Brems. There is more to dive limits than mach limits.


Yes, flutter and speed-limitations for turbulent air. None of it applying here.


The 190 had more in common with the P-40 than the P-47, even Russian accounts make that comparison.


The 190 is a couple of tons lighter, hence the same stability for less material used.
It's called "lightweight-construction".


I guess what i'm getting at is that the P-47 pilots had the same problem with their trim tabs, so they were advised to keep them in neutral for steep dives where compressibility was encountered.

It doesn't matter where the trim-tab is, when it's in stalled airflow http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif


How is the 190s mechanism superior for dive pull out if it presented the same problem?

Because it can't stall in the first place http://forums.ubi.com/images/smilies/compsmash.gif


To clarify, its the mach number at which the supersonic air-flow first occurs over the wing. You might see supersonic airflow on other parts of the aircraft before the wing, but this is not related to critical mach, by definition.


That's what I was talking about, but you're correct on that anyway.


Its possible to experience the onset of tuck as the aircraft enters compressibility. Its actually related to the drag curve of the aircraft, isn't it?


"Compressibility" is a different term for "Mcrit or greater" (actually the M of tuck-onset).

What you are talking about is the "compression" of air:
Air is a compressible gas and air will compress at much lower Mach-numbers than "compressibility".
Generally, that compression may be not considered at M lower than 0.4 - anwhere above, it has to be taken into consideration to get correct readings and performance-predictions (CAS=>EAS).

BillSwagger
11-04-2010, 12:25 PM
Because it can't stall in the first place

But the same problem is encountered on pull out.
The P-47 has a trim tab that stalls more at higher speeds.
The 190 has a trimmed incidence of the tail plane, that is said to stall less.
In both cockpits, the pilot would wheel out trim to help recover from a dive and in both situations where mach effects were present, the trimmed surfaces would catch more air as the mach effects tapered off. Both aircraft would experience an undesirable gain in pitch. So how is the 190s mechanism more beneficial in a pull out?


The 190 is a couple of tons lighter, hence the same stability for less material used.
It's called "lightweight-construction".

Same stability?
What you mean is the stability that's expected of any aircraft that flies with in its limits, correct?

horseback
11-04-2010, 12:32 PM
From this interview with Gunther Rall (http://www.historynet.com/aviation-history-interview-with-world-war-ii-luftwaffe-ace-gunther-rall.htm/2):

Now the big thing in the Home Defense as far as problems was the P-51. The P-51 was a damned good airplane and it had tremendous endurance, which for us was a new dimension. The P-47, which as you know shot me down, we knew right away. It had tremendous diving speed and could run up to 1,400 kilometers per hour, where the Bf-109 was limited to 1,000 kph. I learned this quickly when they chased me, and I could do nothing else. The structural layout design of the P-47 was much stronger, yet I consider the P-51 the best battle horse you had of all the fighter escorts.

It has long been my impression that of all the Allied fighters that saw long service during the war (unlike, say the Tempest), the P-47 was recognized as being the best in a dive; it accelerated quickly, reached very high speeds and still allowed the pilot to maintain control and as long as he started in time, recovered from a dive easily.

It was considered to be superior in this regime to all Axis fighters before the Me-262, particularly if the pilots were of equal combat experience levels; Jug pilots often commented on the tendency for 109 and 190 pilots to reflexively resort to the dive as an escape mechanism and paying the price.

I also remeber at least a couple comments/descriptions that led me to believe that the 190 in a terminal dive would often 'mush', or change attitude without significantly changing the direction it was going for some time, and would in these cases crash into the ground in a relatively nose up attitude, hence the expression 'pancake'.

Bob Johnson's memoir is the first of several American Aces' autobiographies and biographies that I've read, and his comment about that behavior is classic: "They never learn."

The trend continues.

cheers

horseback

Bremspropeller
11-04-2010, 12:34 PM
In both cockpits, the pilot would wheel out trim to help recover from a dive and in both situations where mach effects were present, the trimmed surfaces would catch more air as the mach effects tapered off. Both aircraft would experience an undesirable gain in pitch. So how is the 190s mechanism more beneficial in a pull out?

Because the 190 can recover before having to wait for more dense air, while the P-47 rides down the dive until the Mach-number decreases sufficiently for the trim-tab/ elevator to "bite" into the air.


Same stability?

Yes, the heavier you are, the more structural weight you'll need to get the same structural strength out of the airframe.
The same principle works the other way round: the lighter you are, the less structural weight is needed to support the same loads as with the heavier aircraft.


What you mean is the stability that's expected of any aircraft that flies with in its limits, correct?


AFAIK, there hasn't been any crash due to structural-weakness on the 190 in any kind of maneuvering (including exceeding the safe dive-speeds by a couple of hundred kph).

That's stable enough for me - anything beyond that is just dead weight carried around.

Bremspropeller
11-04-2010, 12:39 PM
I also remeber at least a couple comments/descriptions that led me to believe that the 190 in a terminal dive would often 'mush', or change attitude without significantly changing the direction it was going for some time, and would in these cases crash into the ground in a relatively nose up attitude, hence the expression 'pancake'.

Figuratively, this would rather imply a high-speed-stall than a locked-up elevator.

It might be an example of bad trim-management (too much pitch-autority, quickly overshooting the alpha-band, right into stall - as opposed to more slowly going through the alpha-band (somewhere near CLmax) and over-g'ing the airframe).

As I said before, fiddling with the stab can get you into trouble.

horseback
11-04-2010, 01:24 PM
Actually, what I pictured was what happened to many Allied pilots who made the transition form the P-40 and P-40B/C type models to the P-40D/E models: the earlier models would enter a dive and build up speed quite quickly, but could recover from a dive smoothly. While the D/E and later models had very similar handling charactoristics, they took a good bit longer and several thousand feet more (the figure of over 3,000 ft rings a bell, but I don't have it available to me at this moment) to recover from a dive than their precessors.

Observors usually reported that the Warhawks would change attitude just like a Tomahawk would, but would continue towards the ground at nearly the same speed and vector for some time before the aircraft's direction would change. Guys who pulled out just a bit earlier would describe the aircraft as being stable (as long as you kept it trimmed) throughout the dive, it just seemed to take longer for the wings to 'bite'.

This inevitably led to a number of experienced young pilots losing their lives.

Regardless of the technical terms, it still amounts to attempting to recover too late and/or too sharply. Having a term or technical description for something is not a cure, or even always the beginning to one.

No where do I see accounts of P-47s consistantly flying into the ground while being pursued by FWs in a dive; the evidence indicates that the Jug was usually the more feared pursuer in the downhill regime, and that its pilots were more likely to be able to recover safely.

It seems likely to me that less experienced LW pilots might extend their dives past safe limits because they had a P-47 or three in hot pursuit; it may also be that those who did recover in time got shot to pieces shortly thereafter fairly often, because the P-47s could pull out more sharply without mushing.

cheers

horseback

Bremspropeller
11-04-2010, 01:58 PM
Having a term or technical description for something is not a cure, or even always the beginning to one.

Understanding a phenomena is the first step to curing it.
The cure is there and quite simple: down't play around with the trim if you're not entirely familiar with the plane's special characteristics.


No where do I see accounts of P-47s consistantly flying into the ground while being pursued by FWs in a dive;

That's because dead pilots have a hard time writing reports.


and that its pilots were more likely to be able to recover safely.

Unless they couldn't because they were pushing too far.


It seems likely to me that less experienced LW pilots might extend their dives past safe limits

..which (Mach) were higher than on the P-47..


it may also be that those who did recover in time got shot to pieces shortly thereafter fairly often, because the P-47s could pull out more sharply without mushing.

Nothing out of any flight-test suggests that - except one has the stab set incorrectly:

The point here is that no german pilot suggested that the 190 would sink excessively during pull-out - even at very high speeds.
Such behaviour has never been remarked in flight-testing, nor in operational flying.

It's highly unrealistic to asume that everybody who ever encountered such a "problem" was killed and thus the "problem" went by unnoticed - not with a fleet of 20,000 a/c built and flown extensively over a course of more than six years.

The bottom-line is that young pilots were likely to play around with trim during pull-outs and their instructors told them to be carefull doing so, because the stab easily overpowers the elevator.

It's quite easy for an undertrained, young pilot to think that with the use of trim, one could out-turn the follower during pull-out.
The result is what you describe over here: a tendency to "mush"/ "sink" or even stall altogether with a good chance for the follower to shoot the poor guy down, or even watch him go in.

That, however, is not a problem with the plane, but a mis-management of trim.

BillSwagger
11-04-2010, 02:53 PM
quote:
Same stability?
Yes, the heavier you are, the more structural weight you'll need to get the same structural strength out of the airframe.
The same principle works the other way round: the lighter you are, the less structural weight is needed to support the same loads as with the heavier aircraft.

right, and that explains why the A6M can outdive the P-47.

You miss my point brems, every aircraft is stable if kept with in design limits. That includes load limits which factors in weight as well as dive limits, etc.
Your trying to argue the 190 could dive like a P-47, and that's just not the case. Thats why they flew into the ground.


It seems likely to me that less experienced LW pilots might extend their dives past safe limits because they had a P-47 or three in hot pursuit; it may also be that those who did recover in time got shot to pieces shortly thereafter fairly often, because the P-47s could pull out more sharply without mushing.

i made this point earlier, horseback, that's how we got to 'trimming the tail plane'.
He made the same rebut before, citing pilot skill, which lead to speaking more about the aircraft limits.
I'd sooner make the argument the aircraft exceeded its dive limits, probably something a more experienced pilot would be able to handle. I just hate always pointing to pilot skill because at some point the aircraft can only take so much before pilot skill becomes a moot point.



Because the 190 can recover before having to wait for more dense air, while the P-47 rides down the dive until the Mach-number decreases sufficiently for the trim-tab/ elevator to "bite" into the air.

And so here we are, aircraft trim.
The P-47 is traveling at a much higher velocity when the elevator's become unresponsive, barring above 30,000ft where 190s were known to fly (sarcasm).
This goes back to structure. The P-47 is larger with a longer tail frame. The 190 is smaller and experiences dive effects in a different way. You can't assume they'd meet the same challenges at the same speeds, that's just not accurate.


Because the 190 can recover before having to wait for more dense air...
Yeah, your assuming the P-47 can't just pull up in dives where the 190 needs more air. See the difference?
By design the P-47 is better suited for the dive. Its what Seversky strived for since the introduction of the P-43.

It still doesn't answer my question, since trimming tail heavy seems to induce a heavier than desired pitch on pull out in either plane.

Bremspropeller
11-04-2010, 03:25 PM
right, and that explains why the A6M can outdive the P-47.


The A6M is limited by control-forces (and possibly by flutter), not by structural integrity.
Bad example.


That includes load limits which factors in weight as well as dive limits

Load-limits are identical for pretty much all WW2-era fighters.

The 190's dive-limit is above the P-47's, as we've found out together.


Your trying to argue the 190 could dive like a P-47, and that's just not the case.

No, I'm not.
The P-47 will eventually overtake the 190.
But that's not what we're talking about, is it?


The P-47 is traveling at a much higher velocity when the elevator's become unresponsive,

Speed is irrelevant, Mach is the name of the game - 190 having a .02 edge here.

Again: speed-limitations are rule-of-thump figures for the pilot to safe-guess.
They aren't absolute figures, but I've told you that three times now.


The P-47 is larger with a longer tail frame.

And that does make exactly what kind of a difference?
The longer tail is there to keep the plane stable at slower speeds ("high power/ low speed" mixture).


The 190 is smaller

So the CoP-shift is shorter, meaning one doesn't need a large arm to begin with.


You can't assume they'd meet the same challenges at the same speeds, that's just not accurate.

Right, because effects are entirely Mach-reliant - again, the 190 having a .02 edge.
The problem with your logic is that you're always assuming the 190 had a lower dive-limit because of "structural limitations" - it didn't.

The safe dive-speed is reliant on a couple of factors:

1) Flutter - not the case.
2) Turbulence - not the case.
3) Mach limit - the case.


Yeah, your assuming the P-47 can't just pull up in dives where the 190 needs more air

No, what I'm saying (not assuming, because that's a fact) is that the 190 retains pitch-autority into a higher Mach than the P-47, thus being able to recover at higher Mach-numbers.
If the pilot does take advantage of that capability is another story.


By design the P-47 is better suited for the dive.

It gets faster, but that's not the entire issue.
The Spitfire had the highest Mcrit of all prop-fighters, unfortunately it very seldomly reached those speeds because of drag.

The P-47 is the opposite case: a plane that would quickly accelerate - up to a speed from which it's unable to recover if dived too steeply and recovered too late (any of the two is a show-stopper, a combination makes it look funny, on top).

BillSwagger
11-04-2010, 04:10 PM
Right, because effects are entirely Mach-reliant - again, the 190 having a .02 edge.

http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif
You ever verify that mach limit?
Why argue on speculation, oh well hear'goes.
The elevators don't freeze until mach .80m, that gives the edge to the P-47.
Since altitude seems to determine mach, whats to say either plane reached those mach numbers in a dive anyhow,
Afterall its TAS that determines closing rate in a dive, and the P-47 clearly had more of it.
At lower heights both planes experience a lower mach, and as they dive, mach numbers plumet.

I'm not sure why i'm still debating this with you. It seems obvious to me, but i guess you think differently.

Bill

Daiichidoku
11-04-2010, 04:10 PM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">right, and that explains why the A6M can outdive the P-47.


The A6M is limited by control-forces (and possibly by flutter), not by structural integrity.
Bad example.
</div></BLOCKQUOTE>

A6M5a introduced thicker skinning (in the wings at least), improving dive limits

BillSwagger
11-04-2010, 04:53 PM
The Spitfire had the highest Mcrit of all prop-fighters, unfortunately it very seldomly reached those speeds because of drag.
But most people ignore it was at the same speed as the P-47 at a different height.
Mach number is not the end all to speed.


The P-47 is the opposite case: a plane that would quickly accelerate - up to a speed from which it's unable to recover if dived too steeply and recovered too late (any of the two is a show-stopper, a combination makes it look funny, on top).

Yet, we seldom see situations where pilots ended up in those situations because typical combats with 190s were not initiated from 30,000ft. Most were from 20,000ft and often initiated in a spiraling dive, not one that nosed straight down after them. Pilot's had techniques, they did not fly to their weaknesses.
You see a dive test for dive flaps and think that was the norm for a combat dive. Not the same. I do agree that the P-47 could not just nose over at 60 degrees from 30,000ft with out a hitch, but that isn't typical for most planes either. In fact most planes reach dive limits rather quickly at steeper angles. A P-51 attempting what a P-47 does causes the wing to fold over.

I recently read an account from an Me-262 pilot who said he feared the black spots in the sky the most, he knew they were thunderbolts and had the speed to not only catch the Me-262, but pushed him to fly it to where it was nearly breaking apart.
It also mentioned dive flaps, and how easy it made recovery from a high mach dive.
There were a couple techniques to using them:
One way was to dive, and try to keep as much speed as possible with out losing control. If he lost control he would just ride it out until he wanted to pull out and the plane would recover in a couple seconds at 4 - 5 Gs.
Another pilot mentions extending the flaps before the dive so that mach limits were actually maintained rather than exceeded. This seemed to be the method for dive bombing, allowing for better accuracy. There is no doubt that pilots mastered use of the dive flaps to better combat fighters at altitude.

Bremspropeller
11-04-2010, 05:17 PM
You ever verify that mach limit?

Why don't you verify your .8 tuck first?
The 109 has a Mcrit of 0.78 and the 190 is reasonably close.


Afterall its TAS that determines closing rate in a dive, and the P-47 clearly had more of it.

..outside of transonic speeds, yes.
Withing transonic speeds, the P-47's superiority vanishes.


But most people ignore it was at the same speed as the P-47 at a different height.


No, it's higher speed @ given altitude.


Mach number is not the end all to speed.


That almost sounds philosophical http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif
Same Mach at same conditions means same speed.
Same Mach at diferent conditions means different speed.
However, M 0.89 is an awful lot more than M 0.76.

The Spit is a winner here - provided it actually reaches the associated airspeed.


A P-51 attempting what a P-47 does causes the wing to fold over.

Well, actually only because of bad design on the ammo-by doors - at first.
The Mcrits are reasonably close for both fighters.


I recently read an account from an Me-262 pilot who said he feared the black spots in the sky the most, he knew they were thunderbolts and had the speed to not only catch the Me-262, but pushed him to fly it to where it was nearly breaking apart.

BS - the Me 262 had a Mcrit of 0.86 - that's 0.1 better than the P-47.
A 262 giving a P-47 a run for it's money's not gonna be caught unless the Jug has a head-start.

BillSwagger
11-04-2010, 05:48 PM
You can throw around mach numbers from the 1940s all you'd like, if thats the standard of proof then i'm sitting on P-47 stats up to o.95m with repeated measurements at o.9om. It easily ran down the Me-262 from a dive, even a German pilot makes note of it. Oleg also modeled this.

This is getting dumb, it would be great to see a dive test of the 190. In fact, it would be better than guessing what the mach limit is. Most planes only achieved their mach limits from higher altitudes. I would say that a 190 couldn't even achieve a mach number of 0.78 with out a similar experimental dive. Your guesses just aren't relevant to the combats between the 190 and the P-47 when diving under 20,000ft.

M_Gunz
11-04-2010, 05:52 PM
Originally posted by Bremspropeller:
No, he's talking about the 109, I've heard the interview in German and he's talking of the 109's trailing-edge cooler-flaps opening -asymmetrically at times - without the pilot having any ability to control them.

English text of complete Gunther Rall interviews in Finland at virtualpilots.fi (http://www.virtualpilots.fi/hist/WW2History-GuntherRallEnglish.html)

BillSwagger
11-04-2010, 05:56 PM
lol remember this?
http://i145.photobucket.com/albums/r201/spre77/P-47crapsoneveryplane.jpg

it pains me to show you again.

M_Gunz
11-04-2010, 05:58 PM
Originally posted by TS_Sancho:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bremspropeller:

b) too much pitch-authority resulting in an over-g

The issue is not that pitch-authority is too much from the start, it's that pitch-autority rapidly increases as the Mach gets lower (centre of pressure quickly shifts + shockwaves disappear from the elevator).



I cant help but wonder if some of the "pancaking" aircraft descriptions could be attributed to the phenomena above?

Pilot is diving for his life past VNE loses pitch control, knows enough to trim his way out of trouble, hits the thicker air and wham! pitch authority returns so quickly the G forces incapacitate the pilot and the aircraft crashes mid pullout.

From an observers point of view with no way to know what was happening in the cockpit of the diving aircraft, would this be described as the aircraft "pancaking" into the ground? </div></BLOCKQUOTE>

Find guncam videos where a plane is shown hitting the ground at high speed. It looks like some kind of special effect.

Bremspropeller
11-04-2010, 06:04 PM
You can throw around mach numbers from the 1940s all you'd like, if thats the standard of proof then i'm sitting on P-47 stats up to o.95m with repeated measurements at o.9om.

You can read the Mach-numbers up.
Nothing stops you from doing it.
I won't play the library-dude for you, though.


It easily ran down the Me-262 from a dive, even a German pilot makes note of it.

But not when the 262 also dives http://forums.ubi.com/images/smilies/compsmash.gif


This is getting dumb, it would be great to see a dive test of the 190

There are plenty allied dive-tests.
The funny part is how they contradict each other about "control-stiffnes" or "vibrations".


Your guesses just aren't relevant to the combats between the 190 and the P-47 when diving under 20,000ft.

Obviously they are - how else come that 190s "couldn't pull out from a dive"? http://forums.ubi.com/images/smilies/88.gif

----

MG, care to take the specific quote?
I just don't want to read through the entire interview.

M_Gunz
11-04-2010, 06:31 PM
Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Because it can't stall in the first place

But the same problem is encountered on pull out.
The P-47 has a trim tab that stalls more at higher speeds.
The 190 has a trimmed incidence of the tail plane, that is said to stall less.
In both cockpits, the pilot would wheel out trim to help recover from a dive and in both situations where mach effects were present, the trimmed surfaces would catch more air as the mach effects tapered off. Both aircraft would experience an undesirable gain in pitch. So how is the 190s mechanism more beneficial in a pull out?
</div></BLOCKQUOTE>

The 190 adjusts the entire tailplane from the front with a jack screw. The front of the stabilizer stays in clear air and so the effect of the trim works even when the elevators are shadowed. Trim by tabs works from the back of the elevator and does get shadowed.

Moving tailplane is just more efficient, less elevator deflection from the stabilizer needed to push on for the same nose pitch force. With tabs the elevators move farther but you have drag-powered assist from the trim tab which has to effect once shadowed.

M_Gunz
11-04-2010, 07:07 PM
Originally posted by Bremspropeller:
MG, care to take the specific quote?
I just don't want to read through the entire interview.

I was just providing a link so everyone could bookmark the full taco.

BillSwagger
11-04-2010, 07:20 PM
won't play the library-dude for you, though.

Your better suited for the "shotty guesswork-dude" although if you want another roll, i think you also might find the "discrediting documented claims-dude" also a good fit. http://forums.ubi.com/images/smilies/59.gif

"Unverified source-dude" is already covered, and so is "make up sh*t as i go-man"

That should about do it then.

thanks

Bill

Bremspropeller
11-04-2010, 07:32 PM
I was just providing a link so everyone could bookmark the full taco.

Alright, I misunderstood you there.


Your better suited for the "shotty guesswork-dude" although if you want another roll, i think you also might find the "discrediting documented claims-dude" also a good fit.


Funny double-standard there:
Believing "RSJ's Amazinng Stories" of pancaking planes on one hand, yet failing to understand basic aerodynamics about trim-set-ups on the other (despite repetitios mention) and claiming it to be guesswork. http://forums.ubi.com/images/smilies/metal.gif

You know what the problem with your highly-valued "sources" is?
They all contradict each other.
I've seen about five sources of Mcrits for the P-51 and all five of them claim different Mcrits - ranging from M 0.75 to M 0.82.
Same for other fighters.

Of course eating fancy pilot-stories is a bit easier in the first place that trying to kickstart one's brain, isn't it?

BillSwagger
11-04-2010, 08:15 PM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I was just providing a link so everyone could bookmark the full taco.

Alright, I misunderstood you there.


Your better suited for the "shotty guesswork-dude" although if you want another roll, i think you also might find the "discrediting documented claims-dude" also a good fit.


Funny double-standard there:
Believing "RSJ's Amazinng Stories" of pancaking planes on one hand, yet failing to understand basic aerodynamics about trim-set-ups on the other (despite repetitios mention) and claiming it to be guesswork. http://forums.ubi.com/images/smilies/metal.gif

You know what the problem with your highly-valued "sources" is?
They all contradict each other.
I've seen about five sources of Mcrits for the P-51 and all five of them claim different Mcrits - ranging from M 0.75 to M 0.82.
Same for other fighters.

Of course eating fancy pilot-stories is a bit easier in the first place that trying to kickstart one's brain, isn't it? </div></BLOCKQUOTE>
I actually was "funny double-standard-guy" for a couple bits.
You could probably search post's under my name and find all the sources if you wanted. Its sometimes a waste to repost them over and over especially when someone like yourself finds it rather easy to side step what a verified source is saying.
Sure the numbers don't always match. Planes aren't all tested on the same day, at the same heights or under the same conditions. That hardly constitutes a contradiction. Wording is different when written by different people, but somehow that should not be that confusing when searching for some validation of the opinion. I can tell when i'm debating with someone who's smart enough to figure that out, but then doesn't apply it to their own arguments.
When i'm presented with a counter source, or something that challenges my view i can usually look into that source with more detail rather than passing it off as BS. The argument sometimes spirals into petty spats over whether the plane flew in hot or cold weather, or what ever petty argument pops up in lue of what was originally debated.
"pancake"....he had it all wrong, he should of just said "crashed", then he would've sold you, right Brems?

Actually a lot of the questions that i ask are genuine, and i'm not always out to prove a point.
Thats usually when i hammer on aerodynamics over and over, because rather than just answering the question the person would rather debate the issue.

So when its mentioned the 190 pilot has to use trim carefully to not over G the airframe, and its also recognized the P-47 has the same exact issue, i have to ask what the difference is?

Okay, so the trim is more responsive on the 190, but at the same speeds as the P-47?
see harmless question.


Bill

Bremspropeller
11-05-2010, 10:33 AM
It's not so much the atmospheric conditions that have an impact on the Mach-number-pool we see here, as Mach is a function of temperature (and thus density).

What CAN change very much is the finish of the airplane and I actually think that this is where the story's at:
At our supersonic wind-tunnel (M 2.0 @ SL+50m pressure-altitude) we use a piece of tape to create a shockwave.
A tape (a couple of microns thick) is enouch to provoke a s****wave - dents or bulges on the finish could have similar effect, pushing the airstream locally into the supersonic realm, thus provoking a lower Mcrit than with a cleaner airframe used in another test.

Another issue might be wrongly calibrated intrumentation.

It's propably a mixture of the two.


Now back to the trim-question:

The point is how the different types of trim do work:

The P-47's trim, being of flettner-type primarily "flies" the elevator to a point at which it's force on the elevator equals-out the pressure-difference created by the stab/ elevator combination.
It's thus an elevator for the elevator.
The pilot working against this "elevator's elevator" feels a varying control-force.
Thus the sensation of "trimming away the control-pressure for the specific speed".

Flettner-tabs may also be used as the primary mean of control, as with the MD-80/ DC-9's elevator or the BAe-146's elevator, which are controlled by the flettner-tabs ONLY - there's no connetion between the elevator itself and the control-column of the pilot.


The variable-incidence stabilizer is a different animal:
Instead of trimming away the resistance of the pressure-difference on the elevator, it actually reduces the pressure by shifting control from the elevator to the stabilizer itself, thus requireing the elevator to be moved to a lesser degree and thus relieving control-pressure.

Now, th pilot at the first glance feels the same (less control-pressure to work against), but the difference here is that with the flettner-tab, the the stick-deflection is the same as if pulling manually, so a portion of of elevator-travel is used, whereupon on the stab-trim, the stabilizer takes over some load of the elvator, thus the stick/ elevator being less deflected as when pulling the amount of pitch manually.

End of the story is the following:
While the flettner-tab can only relief the pressure up to the max elevator-deflection, the variable incidence-stab can first be trimmed to max deflection (-3 to +5 degres on the 190) and then, the elevator can be used ON TOP of this.
That's where the increased pitch-authority-potential comes from.

The point as to why the stab is more powerful around Mcrit or beyond it is because the flattner-tab may be (and will be from a certain Mach-number) in the stalled airflow behind the shock-wave on the elevator, rendering it USELESS => no trimming possible.
The stab in contrary will deflect air in any case, no matter if there's a shockwave ir not (the shockwave will only be present at the leading-edge from M 1.0 onwards).
Thus, it is effective without any Mach-restriction.
The only limiting factor here is the shift of the aircraft's center of pressure which will eventually overpower the stab/ elevator's downforce and the aircraft will tuck, no matter what the pilot does.

The point now is that the 190 MIGHT (that's what I said from the start) keep it's pitch-trim authority longer than the P-47, which is even more propable when looking at the Mach-numbers of .78 for the 190 and .73 for the P-47 (the 190 number looks pretty solid, the P-47's is the one in doubt).

So, in all, trim-responsiveness only comes down to Mach, not speed, as both trim-systems are strong enough (there isn't much to it) to support the forces required up to terminal speed.

BillSwagger
11-05-2010, 03:59 PM
thanks for the explanation, i will rephrase to make sure i understand.

The trimmed incidence of the stab relieves pressure so the elevators remain flat allowing the pilot to fight the air from 0 degrees elevator deflection.

The flettner tabs add elevator to the elevator which means the pilot has to fight the air from a less/greater than 0 elevator deflection. In the case of really heavy stick forces, desired deflection angle could also add to the weight of the stick if fighting against the added deflection of the trim tab. He would also feel lighter stick forces while moving with the deflection of the tabs.

I can see why the trimmed incidence of the stab is the better design.

Assuming the 190 had equal or better stick forces to the P-47 at high mach speeds, your theory about the 190s superior maneuverability would hold true.
However if the 190 was confronted with higher stick forces than the P-47, then your theory would not be true.

The limiting speed is 500IAS up to 25,000ft where its lowered to 400IAS for the P-47. (P-47C manual)
The P-47N training manual probably gives more accurate numbers (IAS):
5k ft 564
10k ft 522
15k ft 482
20k ft 400
25k ft 360
30k ft 318
Determined after extensive dive tests, the pilot could reach these speeds with out the expectation of ever reaching compressibility. (Probably for training purposes) It adds, the cockpit chart varies slightly and should be followed more rigidly.
It goes on, mentioning that the threshold of compressibility is felt when the plane seems nose heavy and there is a tightness in elevator control. Decreasing the throttle could steepen the dive, a natural reaction of the pilot.
It also appears they had a better understanding of compressibility recovery procedures, but it doesn't mention dive flaps because the N had wing tanks instead.
http://www.ww2aircraft.net/for...lt-manuals-5081.html (http://www.ww2aircraft.net/forum/other-mechanical-systems-tech/p-47-thunderbolt-manuals-5081.html)

Even with a 20mph margin of error, the 190 limiting speeds are way lower than the indicated speed posted. The question is, are the stick forces of the 190 comparative to the P-47 despite excessive speed?


Bill

Gaston444
11-07-2010, 03:51 AM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">You can throw around mach numbers from the 1940s all you'd like, if thats the standard of proof then i'm sitting on P-47 stats up to o.95m with repeated measurements at o.9om.

You can read the Mach-numbers up.
Nothing stops you from doing it.
I won't play the library-dude for you, though.


It easily ran down the Me-262 from a dive, even a German pilot makes note of it.

But not when the 262 also dives http://forums.ubi.com/images/smilies/compsmash.gif


This is getting dumb, it would be great to see a dive test of the 190

There are plenty allied dive-tests.
The funny part is how they contradict each other about "control-stiffnes" or "vibrations".


Your guesses just aren't relevant to the combats between the 190 and the P-47 when diving under 20,000ft.

Obviously they are - how else come that 190s "couldn't pull out from a dive"? http://forums.ubi.com/images/smilies/88.gif

----

MG, care to take the specific quote?
I just don't want to read through the entire interview. </div></BLOCKQUOTE>

Bremspropeller, instead of going to the library, would you please read THIS:

http://img105.imageshack.us/img105/3950/pag20pl.jpg

...And please explain to me, and everyone else here, what they mean by "P-47D has a far superior angle of dive pull-out to the FW-190A"...?!?

And also explain to me WHAT this Russian evaluation summary meant when it says:

http://www.ww2f.com/eastern-eu...iences-fw-190-a.html (http://www.ww2f.com/eastern-europe/21828-russian-combat-experiences-fw-190-a.html)

Quote: "However, the FW-190 is never able to come out of a dive below 300 or 250 meters (930 ft or 795 ft). Coming out of a dive, made from 1,500 meters (4,650 ft) and at an angle of 40 to 45 degrees, the FW-190 falls an extra 200 meters (620 ft)."

Now doesn't that jive nicely with Johnson's description of "pancaking" FW-190As?

Now where exactly is your evidence of great FW-190A high speed handling, and especially high speed dive pull-outs, may I ask?

Jeeze.

Gaston

P.S. Yes it DID have a very great high altitude dive speed limit, around 550-600 MPH in fact (about even with the P-51 or close to the P-47D, which explains why it was a tempting tactic), but by 8000 feet, in US pilot words, it had better start pulling out and slowing down or it would "pancake" itself, meaning low-altitude dives were a very dangerous idea (as E. Brown noted in so many words)...

This trouble when pulling on the stick manifested itself as early as 250-300 MPH, as you can read in the P-47 comparison, where the P-47D waxes it all over the place past 250 MPH...

Not quite a great boom and zoomer in other words...

G.

Bremspropeller
11-07-2010, 06:06 AM
Assuming the 190 had equal or better stick forces to the P-47 at high mach speeds, your theory about the 190s superior maneuverability would hold true.
However if the 190 was confronted with higher stick forces than the P-47, then your theory would not be true.


Let's put it that way: the Flettner-tab is quicker, while the Flosse provides better ultimate authority.

The point is, stick-forces are subjective, as the forces one might regard adequate, another pilot might regard excessive.

The Navy-report on the 190 says "control-forces become noticeable but not objectionable", while others will say generally "heavy".



Decreasing the throttle could steepen the dive, a natural reaction of the pilot.

I have read about the B and C Jugs that pilots were required to close the throtle instantly at buffet-onset.
The point makes more sense, because: shutting the throttle leads to a complete loss of thrust, increasing drag and thus would provide better chances (airframe drag + no more acceleration while going down into thicker altitude + drag of the prop) of defeating buffet/ tuck-onset.

Maybe the 47N was signifigantly different to the B/C and really did require opening the throttle - I don't think so, though.


Even with a 20mph margin of error, the 190 limiting speeds are way lower than the indicated speed posted. The question is, are the stick forces of the 190 comparative to the P-47 despite excessive speed?


The issue is, the dive-speed limit isn't put in place to safe the plane from coming apart, but in order to give the average pilot a safe band of operation:
A 500-hour pilot might want to push the boundary; the last thing you want to experience as a 10-h pilot is severe buffetting or vibration which may occur when going vastly beyond the recommended limits.
Some 190s did do so, while others didn't or weren't just pushed far enough.

In regard to what Gaston postesd:
The 190 is said to have a worse turn, despite "blacking-out the pilot" above 250mph.

This sounds fishy for me.

For the blacking-out of the pilot (that requires two pilots with the same blackout-threshhold in the fist place, otherwise this statement is moot anyway) one plane has to turn tighter than the other (keep in mind that the 190 has the better high-g sitting position, maybe worth a half g).

So what happened?
Did the 190-pilot have a bad day and blacked out too early?
Did the 190 have a better instantaneous turn and initially turned inside the P-47 (= the pilot blacking out), with the 47 having a better sustained turn? (my bet's on this, especially the part of the 47 "overtaking" suggests that)

BillSwagger
11-07-2010, 07:17 AM
Maybe the 47N was signifigantly different to the B/C and really did require opening the throttle - I don't think so, though.
Nahh, backing off throttle was discovered to be part of the problem with increased tuck.
I think pilots first encountering the problem of compressibility didn't really know how to handle it and so it probably only contributed to the dangers it presented. If you read the manuals for the B/C it mentions this but they elaborate on it more in later manuals. Basically, pilots are advised to start dives with a slightly trim up position so it requires stick force to hold the plane in a dive. The second part talks about throttle and pitch, recommending a middle throttle setting so that increases in throttle could be made through out the dive.

I was looking over the dive charts again, and does anyone know how much dives effect altimeter readings? Does it ever cause a faster reading in the decent of an aircraft?

Bremspropeller
11-07-2010, 07:53 AM
There are a couple things that cause false readings on the altimeter.

One is hysteresis, making the altimeter lag behind - the faster the descend, the greater the lag.

The other effect is the compressibility of air, leading to a greater static pressure (much depending on where the static-probe on your aircraft is), thus a lower indicated altitude.
Usually, this is not a problem, though, as static ports are usually placed at areas with smooth airflow and without any local flow-acceleration - therefore, this effect is mostly insignifigant.

Of course, altitude is measured in ISA-conditions, so a deviation in temperature also gets you false readings.

BillSwagger
11-07-2010, 08:09 AM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Even with a 20mph margin of error, the 190 limiting speeds are way lower than the indicated speed posted. The question is, are the stick forces of the 190 comparative to the P-47 despite excessive speed?


The issue is, the dive-speed limit isn't put in place to safe the plane from coming apart, but in order to give the average pilot a safe band of operation:
A 500-hour pilot might want to push the boundary; the last thing you want to experience as a 10-h pilot is severe buffetting or vibration which may occur when going vastly beyond the recommended limits.
Some 190s did do so, while others didn't or weren't just pushed far enough.
</div></BLOCKQUOTE>

I find it hard to debate aircraft limits because most pilots i've talked to, including vets, have always said posted limits are the limits of the airframe or that flight conditions become hazardous. What the pilot experiences beyond the safe zone is as subjective as stick forces, no?
I also find it hard to debate pilot skills, though what you're saying makes perfect sense. Pilot experience will help in dealing with emergencies and a pilot who goes beyond the safe zone of his aircraft puts himself in an emergency situation.

Despite these elaborate and intuitive explanations, it doesn't answer the original question.
Are the stick forces of the 190 comparative to the P-47 despite excessive speed?
So far, i have nothing to validate that it did and more to validate that it didn't.
I was hoping you had something on the Fw that could change that Brems. I sure can't find anything.



So what happened?
Mush?? Not saying thats what it was, but considering the term "mush" actually comes from the feeling the pilots felt in the pit, the feeling of being "mushed down in your seat" so to say. Its also possible pilot position accented or decayed this effect on the body.
Mush might actually push an irregular amount of Gs from the high 6 position, in which case a pilot in a layed back position would feel more vertical Gs on the body, where the upright pilot feels mushed forward and down in his seat.
That's just another intuitive explanation, though, i could be completely wrong. Besides i don't think the 190 pilots were that more layed back in their seats, they just had their legs more out in front of them.

Bremspropeller
11-07-2010, 08:33 AM
I find it hard to debate aircraft limits because most pilots i've talked to, including vets, have always said posted limits are the limits of the airframe or that flight conditions become hazardous. What the pilot experiences beyond the safe zone is as subjective as stick forces, no?
I also find it hard to debate pilot skills, though what you're saying makes perfect sense. Pilot experience will help in dealing with emergencies and a pilot who goes beyond the safe zone of his aircraft puts himself in an emergency situation.

Totally agree.
I've read a couple of accounts where the diving-limits have been exceeded (one pilot even claiming 1000kph indicated) without the airplane coming apart, though.
The same pilot claimed there weren't any diving-limits - he was flying a 190F.
At the bottom-line, it comes down to pilot-ability and willingness to cope with what he asked for.

I haven't heard of either plane, 190 or P-47, breaking apart during dive-testing or diving in general (unless being shot at, of course)


So far, i have nothing to validate that it did and more to validate that it didn't.


The reports we see don't give enough data as to which trim-settings were flown and how the aircraft were handled.
The lack of RLM-imposed limitations indicates that the "nose heaviness" comes from false handling of the controls.


Besides i don't think the 190 pilots were that more layed back in their seats, they just had their legs more out in front of them.

And that's the trick:
Minimize dh between heart and lower extremties, so lower force is needed to keep the blood inside the head. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif


Mush??

The only thing I can find to that is the 190 having a tendency to high-speed-stall, when pulled too aggressively; skid-angle and -rate determining whether the aircraft just "mushes" or "flips over".

That suggestests both:
- bad technique by the test-pilot (too aggressive at pitch-onset)
- satisfactory (and beyond) pitch-authority at speed

BillSwagger
11-07-2010, 09:04 AM
Originally posted by Bremspropeller:
I've read a couple of accounts where the diving-limits have been exceeded (one pilot even claiming 1000kph indicated) without the airplane coming apart, though.

We also know of instrument error, especially in the case of dives. I can point to reports that routinely show indicated speeds of 600mph. It doesn't mean much for arguing structural integrity.



I haven't heard of either plane, 190 or P-47, breaking apart during dive-testing or diving in general (unless being shot at, of course)
I have, but that was in the test phases of the XP-47 and P-47B. I also know cases of 109s bending tail frames; i'm certain this could happen with the 190 under the right circumstances.
Even so, if a plane crashed from such an accident would the pilot be likely to tell about it?
In reading some manuals it tells more about the stresses exerted on the tail frame and wings during certain maneuvers. It also stresses the importance of trim and dive limits. Manuals can actually be quite revealing when explaining aircraft limits. They actually take a lot of guesswork out of combat reports. To some degree they are probably the most concrete document on aircraft limitations a person can find.



The reports we see don't give enough data as to which trim-settings were flown and how the aircraft were handled.
The lack of RLM-imposed limitations indicates that the "nose heaviness" comes from false handling of the controls.


They still have more validity than "nothing", ( http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif )when answering the question of stick forces in excessive speed.

Bremspropeller
11-07-2010, 10:14 AM
Even so, if a plane crashed from such an accident would the pilot be likely to tell about it?

No, but in case of structural failure, design-changes would have taken place just as with the 109's tail and the 109's wing.

BillSwagger
11-07-2010, 10:57 AM
Of course, altitude is measured in ISA-conditions, so a deviation in temperature also gets you false readings.
Would that create an increase or decrease in the reading? and how far off can that be?

Bremspropeller
11-07-2010, 12:03 PM
That depends if it's colder or warmer than ISA http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Buzzsaw-
11-07-2010, 04:07 PM
Salute

Lots of disinformation being provided here.

First of all, P-47 crashes in dives were in the P-47B model, a pre-war version. These had more to do with tail structure than compressibility, although it was a factor. Many changes were made to the P-47C and C-1RE to deal with these issues.

The P-47C was the next production version of the Thunderbolt. It began to leave the production lines in September of 1942. It was externally similar to the P-47B, but had a strengthened and revised fin with a metal-covered rudder to eliminate a tail flutter problem which had resulted in several crashes of P-47Bs during high-speed dives. The revised rudder resulting in an increase in overall length of about an inch. A revised oxygen system was fitted, with four oxygen cylinders (one of them in the leading edge of the port wing) in place of the single cylinder of the P-47B. A new radio (SCR-274-N command set and SCR-515-A) was fitted, and the forward-slanted radio antenna mast of the P-47B was replaced by a shorter upright mast.

The first P-47C (41-6066) was completed on September 14, 1942. Even though the P-47C incorporated strengthened tail surfaces, the P-47C still had problems in recovering from high-speed dives. Beyond 500 mph, recovery from power dives was extremely hazardous, with the elevators being unable to respond because of compressibility forces.

The P-47C-1-RE production block differed by having an extra 8-inch section added to the fuselage forward of the firewall giving improved flight characteristics through movement of the center of gravity. The first P-47C (41-6066) was used as a prototype for the fuselage modifications. There were some detail changes to the main undercarriage and brakes. There were also some changes in the tail wheel, and steering was eliminated. There were som changes in the supercharger air ducting. Bob weights were installed in the elevator control system in order to help to overcome the compressibility problems that had made high speed dives in the earlier P-47C extremely dangerous.

2nd, the Critical Mach number for the P-47 was .79 (achieving 562 mph TAS), not .76 See this chart from a 1949 test of a P-47D-30:

http://img168.imageshack.us/img168/428/divechart.jpg

P-47's with dive brakes were cleared to exceed these speeds in dives, 550 mph IAS was allowed below 15,000 ft.

M_Gunz
11-07-2010, 05:57 PM
Originally posted by Buzzsaw-:
http://img168.imageshack.us/img168/428/divechart.jpg

1949... Herbet Fischer diving with experimental TS/SS Curtiss props by any chance? Oh wait, those dives recorded up to Mach .83!

But it does beg the question of what was different between the 1949 and war-time... unless it is that .76 was for pilot's manual 'safe' and .79 was for 'all-out test', in which case comparing the latter to other planes recommended safe is absurd. Compare P-51 POH top dive speed to the Wright Field P-51 at .86 Mach that landed with a bent airframe.

I also have dives from a P-51 that had no prop, was towed to alt for dive tests and did quite well. Think they matter except for Mach effect studies?

BillSwagger
11-07-2010, 06:35 PM
Originally posted by M_Gunz:
But it does beg the question of what was different between the 1949 and war-time... unless it is that .76 was for pilot's manual 'safe' and .79 was for 'all-out test', in which case comparing the latter to other planes recommended safe is absurd.


It could be the use of better instrumentation and experience with compressibility calculations.
You might also be comparing figures done on tests that range from 1941-1942 developmental dive tests, to post war experimental prop tests.
Is there information on Fischer's dive that shows where the elevators lock up?
I'm no longer able to find this article for some reason.

I was working with some formulas because the dive chart i have also gives angle, which would allow a TAS calculation if the altimeter reading wasn't too prone to error.

Ruling that out, i was able to find some average speeds over certain parts of the dive. The caption said the pilot dove until he reported the elevators had become unresponsive, and then deployed the dive flaps to make a recovery.
I used the part of the dive that was steepest and had the most consistent angle (+/- 1 degree).
By taking the height readings at different intervals i was able to average speed in feet per second, each interval taken every two seconds.
Using a triangle formula, i then used the average angle and decent speed to find the hypotenuse which would be the average TAS.
I averaged the speed of the dive up to the point where the pilot pulled the dive flaps, and that came out to 585mph (8 second average). If i drop the interval that included the dive flaps, then it averaged out to 580mph. (8 second average)
I also took the average beginning from the two intervals before the dive flaps were deployed to the two intervals after the dive flaps were deployed, presumably the fastest part of the dive. That averaged 630mph. (6 second average)
The whole of the dive averaged 597mph. (12 second average)
I did some mach speed calculations using standard conditions and median altitudes and they all came out to about 0.82 give or take 0.005, with the exception of the faster part of the dive reading closer to mach 0.88.
Its presumable these tests weren't done in standard conditions, so these mach figures would come down.
Before i continued i thought i would ask about the altimeter reading errors, seeing as thats the most debatable part of these methods.







Bill

M_Gunz
11-08-2010, 12:04 AM
That chart tells in plain English that the plane was an EF-47 with 19606 blade (gee. blade as in.. prop?) Flight #6 10-27-49.

We're looking at a test dive with an EF-47 with special prop, not a wartime P-47. Maybe this was one of Fischer's dives!

But to a fanboy, any chart with better numbers... well the rest can't be seen because of the special-fixation blinkers.

BillSwagger
11-08-2010, 01:06 AM
Im not sure what your getting at. Yes, I'm a fan of the plane, but i'm an even bigger fan for accuracy.
I know there are charts with different numbers, some of them better, and usually later instrumentation is more accurate.
I actually don't have the Fischer article to refer to but i do remember the test blades not being adequate for anything other than a dive. In fact, Fischer had to be careful when throttling up for take off as well as in climbs not to bend or warp the blades. It sounds like they were pretty thin, the idea being a course chord could be used to alleviate the drag of the prop disc.

If that's the case do you think it still managed the same acceleration in a dive as with a conventional wartime blade?
Despite the experimental prop it doesn't elaborate on the differences in dives achieved with a conventional blade and the experimental one. There is no control dive made where we can make this comparison. There is no way of knowing if it even made a difference, based on this chart alone.
There are critics of the drag profile for the P-47 because its problems when met with compressibility. The shockwave from compressibility alone multiplies the drag ten fold and probably kept the plane from ever exceeding a certain mach value.
Why the prop disc makes a difference i'm not sure, only that its less obstructive in the dive up to where compressibility is met, however less acceleration for less drag might actually leave the speed of the plane in more or less the same circumstances when it meets compressibility. It would be nice to know for sure.
Having more data is a pluss, but being able to translate it, is another.

M_Gunz
11-08-2010, 04:35 AM
Originally posted by BillSwagger:
If that's the case do you think it still managed the same acceleration in a dive as with a conventional wartime blade?

If they ran the dives by going level to top speed before diving (roll 180 and pull back) then hey the start speed with the fancy prop may have been higher than with a regular prop. The only acceleration they would care about is at high speed. If it wasn't any better then they screwed up the design since by then the regular prop was a drag source.

The greatest amount of acceleration in those dives is due to gravity, not thrust, unless you count the acceleration of changing from level flight to vertical in which case the pull-down is high-G's and the vertical data should show a big surge at start.


Despite the experimental prop it doesn't elaborate on the differences in dives achieved with a conventional blade and the experimental one. There is no control dive made where we can make this comparison. There is no way of knowing if it even made a difference, based on this chart alone.

Sure it did. It achieved a higher Mach dive than the wartime P-47. Not a huge difference but big in WWII terms. And it was beaten by jet engine aircraft, even the ones with experimental props up front, the future was clear as far as piston-engine prop fighters.


There are critics of the drag profile for the P-47 because its problems when met with compressibility. The shockwave from compressibility alone multiplies the drag ten fold and probably kept the plane from ever exceeding a certain mach value.
Why the prop disc makes a difference i'm not sure, only that its less obstructive in the dive up to where compressibility is met, however less acceleration for less drag might actually leave the speed of the plane in more or less the same circumstances when it meets compressibility. It would be nice to know for sure.
Having more data is a pluss, but being able to translate it, is another.

Ten fold? It cubes the drag, if not more. And the prop disk at extreme speeds is taken to be the same drag as a solid disk. With the P-47 having such a LARGE prop (it's a large plane) and the experimental prop being an unknown diameter, who knows how much of the extra dive Mach came from the shape of the blades and maybe just a smaller diameter?

This 1949 dive data keeps turning up on WWII fighter sites. And I haven't seen any mention about the experimental props. What I did see was the data being used for 'revising' P-47 dive capability to a higher Mach. IOW, revisionism at work. What a load of manure. Those are not the same as wartime P-47's and the data does not apply. Let's not let this fly another page here at The Zoo.

If you combine the time it takes to roll over and go from level to vertical-down flight at high cruise, I bet that the P-47 gets farther down in the first 10 seconds than almost every other WWII fighter if not every other WWII fighter. But the roll time must be part of the total and high cruise must be no more than 10% less than top level speed. Compare P-47 level acceleration to a contemporary FW-190 at 360+ mph TAS while you're picturing that. The thing about tactics is to play to your strengths and acceleration at higher speed is a strength of the P-47 over the FW at least in those AFDU tests. Never say always, just say WHEN.

BillSwagger
11-08-2010, 06:34 PM
(roll 180 and pull back)

The manual forbids entering a dive from a split S. Not saying pilots never did it, but its likely most test dives are made by nosing the plane over. There are several ways to enter a dive.

As for conventional Mach dives, both the P-51 and P-47 were taken up as high as they could climb and dove by Chuck Yeager and another well known Ace. This was cerca 1947, and both planes reaching mach .80.
I don't doubt the experimental prop may have allowed for a faster mach dive, but then how much faster?
Several dives were taken, and only one yielded a mach 0.83 number. I guess what i'm saying is that the experimental prop may have only made a trivial difference in the top speed of the dive. With out a control dive its hard to say.


Bill

M_Gunz
11-09-2010, 12:22 AM
Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">(roll 180 and pull back)

The manual forbids entering a dive from a split S. Not saying pilots never did it, but its likely most test dives are made by nosing the plane over. There are several ways to enter a dive. </div></BLOCKQUOTE>

You're not supposed to jump the rudder to snap roll in the process either. http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif But when you're looking for confirmation of the war stories and combat reports you love so much, there it is. It doesn't have to be a split-s either. A barrel roll can set you up for any angle dive you want more quickly than forward stick alone. And a split-s from high cruise at over 20,000 ft isn't going put your nose in the dirt instantly nor is it going to get you to speed over your dive limits.

In all your reading, have you ever read of a completely-by-the-book WWII Ace? Or have I got it all wrong and you've been reading test pilot stories?

BillSwagger
11-09-2010, 01:04 AM
Sure pilots probably used a split S or a wing over, but how can you say nosing over is a slower way to enter a dive? I get that the lift from the wings would help in bringing the plane down, but then how is rolling 180 degrees quicker than pushing the stick forward.
It also appears to be the way the tests dives were entered.
Come to think of it, you don't here much of snap rolling in a P-47 either, although there are a handful of reports that mention "flicking" out of the turn.

I was looking at that FW vs D-4 report again.
Its also possible the P-47 had a better angle of pull out because it wasn't diving at the same angle. Maybe the 190 was also in a steeper dive? Just a thought.



Bill

Gaston444
11-09-2010, 03:41 AM
Originally posted by Bremspropeller:
[QUOTE]

In regard to what Gaston postesd:
The 190 is said to have a worse turn, despite "blacking-out the pilot" above 250mph.

This sounds fishy for me.

For the blacking-out of the pilot (that requires two pilots with the same blackout-threshhold in the fist place, otherwise this statement is moot anyway) one plane has to turn tighter than the other (keep in mind that the 190 has the better high-g sitting position, maybe worth a half g).

So what happened?
Did the 190-pilot have a bad day and blacked out too early?
Did the 190 have a better instantaneous turn and initially turned inside the P-47 (= the pilot blacking out), with the 47 having a better sustained turn? (my bet's on this, especially the part of the 47 "overtaking" suggests that)

I am very glad you point that out because I could never figure it out myself, for years on end: How can crappy high-speed handling STILL produce more black-out than the P-47D's SUPERIOR high speed handling?!?

The answer lies in the Russian evaluation and many other sources, including E. Brown: The FW-190A tail-stalls and the "black-out" comes from nose-up DECELERATION, but still with full 3 axis control... So if you pull back on the stick while "sinking", you get even more nose up and thus "pull" even more Gs, BUT THOSE Gs ARE DECELERATION Gs and produce only a loose curve as you go belly-forward...

This "shift" into the Gs separating from the actual trajectory change by becoming deceleration are what is meant by "a tendency to black-out the pilot": A tendency to pitch up abruptly and go into a "deceleration" mode.

Look at the Russian evaluation: A short 40° dive from 1500 m can produce, on nose-level on pull-out, over 220 m (660 feet!) of nose level "sinking" which according to E. Brown: "Care must be taken not to kill speed by "sinking" or the FW-190A will be very vulnerable on dive pull-out exit", meaning that you STILL get hammered by Gs despite your trajectory being looser: It is the worst way to suffer Gs because you lose speed at a high rate...

This is also why Kurt Tank could claim 7Gs at 400 MPH with just 14 pounds of stick pull force...: I'll bet it wasn't a true 7G trajectory, as those stick forces are clearly abnormally light, and with this capacity, if it was what it appeared to be, the FW-190A would then crush all the opposition at high speeds, which is clearly at odds with the spectacle of it being kicked all over the place when speeds get high, constantly having to shift sides by rolling to make up for its evidently pathetic high speed turning ability...

Gaston

Bremspropeller
11-09-2010, 10:06 AM
The FW-190A tail-stalls and the "black-out" comes from nose-up DECELERATION, but still with full 3 axis control...

No, it's a high-speed stall, the blackout being a completely diferent phenomenon.
Tail-stalls do not occur at high speed-scenarios, unless having a T-tail (pitch-up), which is a completely different animal.

High-speed- stall:
G-onset/ pitch-onset too high, airplane dynamically stalls (at lower angle of attack than when gradually onsetting backpressure/ g/ AoA)

Black-out:
G-onset/ pitch-onset correct, g taken beyond pilot's capabilities, but within static CL/alpha range.

@ Bill:

What's described around the "low level pullout limitation" is actually a high-speed stall, contributed by a relatively sharp-edged wing-profile, high wingloading and good elevator responsiveness:

If the pilot initiates a too sharp pull-up, the wing's AoA will skyrocket quick enough for whe air-flow not being able to cope with the rate of change of AoA and dis-attaching at a lower AoA than if gradually applied.
In short terms: AoAcrit is lower than AoAcrit when slowly, yet progressively pulling-thrugh.
This usually happens during the initial part of the pull-onset (within the first few degrees AoA of pullout).

The trick is to slowly pull through and not overshoot the G-onset onto a rate that would lead to high-speed stall.
On a rapid descend (eg. dive with low-level pullout), the ground may come into perceived vision (wind-shield fillng, = primary source of danger) quite quickly.
It's very easy to over-react at that moment and put too much of initial backpressure into the recovery-attempt, leading to a high-speed stall and the describd "nose high, travel ahead" crash-mode of "pancaking".

A conservative initial amount of backpressure and then a gradual but dertermined opening of the AoA-value will prevent that state of dynamicly stalling.

That takes some training and getting used to, in order to max-perform this technique, but it works pretty well.
You can do the same in game.

M_Gunz
11-09-2010, 11:03 AM
Originally posted by BillSwagger:
Sure pilots probably used a split S or a wing over, but how can you say nosing over is a slower way to enter a dive?

I hope you're kidding and yet I can already see that you aren't. And I'm not going to point out everything you can come up with.

First understand that acceleration is change in speed on any axis. When you turn, you are changing speed in two or more axes. You are slowing down on one while speeding up on another. Turning is accomplished through acceleration. (Although there are people who will play stupid horse and cart games about it, please do some thinking and just don't play them with me. You do something with the controls that changes the movement of the plane which results in the turn, turning is not merely the act of control movement.) Low turn acceleration means slower turns including the turn going from level to dive.

Nosing down gets your vertical movement heading downward at less than 1 G acceleration. Rolling a P-47 180 takes very little time and most planes not a hell of a lot more and after that you can change to a downward course at many G's. That is how it's faster.

BillSwagger
11-09-2010, 05:18 PM
Nosing down gets your vertical movement heading downward at less than 1 G acceleration. Rolling a P-47 180 takes very little time and most planes not a hell of a lot more and after that you can change to a downward course at many G's. That is how it's faster.

I think pilots might favor the wing over so they didn't encounter an uncomfortable amount of neg Gs, sometimes as much as -3 or -4. However, there would be little to gain in downward acceleration since that has more to do with the angle of decent., ie which way the nose is pointing, rather than which way the wings are facing.
That's just my opinion though, I haven't seen any tests that compare the two methods, or heard that one was better for faster dives by a pilot.
I read through more combat reports last night, and most of them mention nosing over, while a few mention following planes in a split S. It was certainly a capable plane in both capacities and probably had more to do with the situation that was presented.

M_Gunz
11-09-2010, 05:51 PM
You don't encounter negative G's in a wingover and part of the wingover requires a somewhat steep climb in the start. If you roll 180 then for a short time you get -1 G but after that it's all positive. If you nose down however, then you get negative G's but not more than about 1 if that.

That's just my opinion though, I haven't seen any tests that compare the two methods, or heard that one was better for faster dives by a pilot.

I don't read much that the letter A comes before the letter B in the alphabet. Suppose that's because everyone is supposed to know from school if not before? The real pilots went to flight school and just the ground portion teaches things that the average gamer might only grasp intuitively yet still have some warped explanation for. Sometimes a passage in a book or story will tell the difference but mostly they don't. If you want to do more reading then try pilot training books.

The only method of acceleration more than 1.little G that those planes could do in flight was through their lift at a cost in speed. The 1.little would be at full power straight down before speed got to level maximum, otherwise 1 G or less with the majority being much less. Exceptions of course being in Hollyweird movies, on TV, in books and comics and in imaginations.

Like I wrote before, rolling into a dive does explain the kinds of things you've brought up from reading. I will go another step. IF you could achieve the 'no time' catch-ups through the comparatively nosing-down process the rolling and diving would be just how fast? Adjust that to fit your perceptions, LOL!

BillSwagger
11-09-2010, 05:53 PM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The FW-190A tail-stalls and the "black-out" comes from nose-up DECELERATION, but still with full 3 axis control...

No, it's a high-speed stall, the blackout being a completely diferent phenomenon.
Tail-stalls do not occur at high speed-scenarios, unless having a T-tail (pitch-up), which is a completely different animal.

High-speed- stall:
</div></BLOCKQUOTE>

I think a tail stall would make the elevators unresponsive to even enter a turn in the first place, so probably not a tail stall.
A high speed stall makes more sense, and if both wings stall evenly such as when the angle of bank is 0 then there would be less tendency to spin. Essentially, you'd end up with a plane "mushing" at high speeds if it didn't enter a spin, right?
To echo what Gaston said, I think it would contribute to the black out.

http://i709.photobucket.com/albums/ww99/billswagger/untitled-1.jpg

The more perpendicular the plane gets to its trajectory then the more the acceleration and deceleration from the plane combine, probably averaging out somewhere near high six.

Bill

BillSwagger
11-09-2010, 06:52 PM
Originally posted by M_Gunz:
If you want to do more reading then try pilot training books.

http://forums.ubi.com/images/smilies/partyhat.gif
In training books it says entering a dive from a spit S is forbidden, remember?
I'm sure it still took place in combat, and i'm sure there are many ways to enter a dive depending on the combat scenario.

IF you could achieve the 'no time' catch-ups through the comparatively nosing-down process the rolling and diving would be just how fast?

Depends on the angle of decent, the only difference is the wing is lifting into the dive in one case, while the other is lifting away. The speed gain would still depend on the angle.

There are added benefits to a wing over:
- less neg Gs on the pilot
- ability to maintain visual contact with a target
- sets up an entry/exit maneuver

The only conceivable advantage would be less tail drag from winging over, but then induced drag from aileron roll would probably nullify any noticeable difference.

Acceleration would still be dependent on the angle of decent, seeing as in either winging over or nosing over, the plane will following the nose at what ever angle its pitched at.


I don't read much that the letter A comes before the letter B in the alphabet. http://forums.ubi.com/images/smilies/sleepzzz.gif
Since you put it that way. Letter A comes before letter B but neither has been shown to be the better letter.

Despite your crafty explanations, i don't agree with them. Its always rather peculiar when you elude to something i don't know rather than coming forward with something tangible. Ie, "The real pilots went to flight school" "just the ground portion teaches things that the average gamer might only grasp intuitively yet still have some warped explanation for."
Well, no kidding.. sounds a lot like you. http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif
"If you want to do more reading then try pilot training books." http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif
What the heck do you think i've been doing?
It contradicts what your telling me, Gunz.

Where did you get the idea that a wing over/spit S made for faster acceleration?
Surely this notion has some root in a source or maybe an article that explains it better.

"No, Bill, its because your not a WW2 pilot. If you were, you'd know."
http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

Bill

M_Gunz
11-09-2010, 09:22 PM
Crafty... yeah right.

The faster you get vertical, the faster your dive develops. Nosing down takes longer than using your lift, hands down. It's so fast that you're not supposed to do it yet even you admit "it was probably done". I'm not going to take the time to go search up P-47 war stories but if you never read any that told of doing that then you probably haven't either read or remembered much of what you did. I'm sure that arguing against it is enough of a mental block to keep you from seeing it in text by now anyway.

You're not trying to find out how or why the stories tell you what they do, you're just defending your own little hill. You like it so much then stay there.

JtD
11-09-2010, 10:46 PM
Just a quick note on your turning picture, Bill:

The maximum AoA you can reasonably expect from a WW2 fighter aircraft at high speeds might be about 15°. Your graph is showing about 30, way too much.

BillSwagger
11-09-2010, 10:52 PM
Hey your entitled to your own opinion.
Just seems like you'd need to validate it a bit more before you start upholding it as fact.

Bill

BillSwagger
11-09-2010, 10:58 PM
Originally posted by JtD:
Just a quick note on your turning picture, Bill:

The maximum AoA you can reasonably expect from a WW2 fighter aircraft at high speeds might be about 15°.

You don't know that.
Anyway, the graph was more to demonstrate the principal.

Bill

Gaston444
11-09-2010, 11:12 PM
Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The FW-190A tail-stalls and the "black-out" comes from nose-up DECELERATION, but still with full 3 axis control...

No, it's a high-speed stall, the blackout being a completely diferent phenomenon.
Tail-stalls do not occur at high speed-scenarios, unless having a T-tail (pitch-up), which is a completely different animal.

High-speed- stall:
</div></BLOCKQUOTE>

I think a tail stall would make the elevators unresponsive to even enter a turn in the first place, so probably not a tail stall.
A high speed stall makes more sense, and if both wings stall evenly such as when the angle of bank is 0 then there would be less tendency to spin. Essentially, you'd end up with a plane "mushing" at high speeds if it didn't enter a spin, right?
To echo what Gaston said, I think it would contribute to the black out.

http://i709.photobucket.com/albums/ww99/billswagger/untitled-1.jpg

The more perpendicular the plane gets to its trajectory then the more the acceleration and deceleration from the plane combine, probably averaging out somewhere near high six.

Bill </div></BLOCKQUOTE>

Your drawing illustrates what I meant very well Bill.

I think there could be a way that what you say is not correct however: Think of it this way: To effectuate the turn, the elevator surface normally creates drag by presenting its UPPER surface, depressing the tail and causing the turn.

When you get into "the tendency to black-out the pilot" pitch-up aspect, the angle of attack is suddenly so different that the elevator may be achieving the same effect in a completely different way: In fact the angle of attack may be nearly perpendicular to the trajectory, but your drawing certainly depicts this as close enough to perpendicular to in fact turn the whole airplane into a giant airbrake...

Yet Kurt Tank, when he claimed 7Gs at 400 MPH with 14 pounds of stick force, was certainly not thinking of it as a high-speed stall: The Gs were STILL responding to his stick input on the elevators (and the ailerons responded also).

What happens at such high angles of attack is that the entire plan view of the aircraft becomes just a giant airbrake: What happens if, in plan view, you pull on the elevators?:

Their plan view becomes smaller.

This reduces the tail's plan view drag, and thus depresses the tail even more, creating MORE deceleration from the main wings decelerating the aircraft at a more acute, more "perpendicular" angle.

Relax the pull on the stick: The elevators become bigger in plan view, they then lift the tail by consequently "braking" with more exposed BOTTOM surface (as opposed to using their UPPER surface drag to create turn Gs in a more normal, more horizontal airflow), and this reduces the angle of attack of the main wing and thus REDUCES the OVERALL deceleration by INCREASING the deceleration of the tailplanes selectively...

Pitch control through selective deceleration, to put it simply.

The same effect occurs on the ailerons, and in both cases it is due to zone-SELECTIVE plan view deceleration changes that, by altering the aircraft's "braking" profile in plan view from below, create the exact same attitude effects as they did in a normal horizontal airflow...

There is an outside chance that Kurt Tank may not even have been aware that his very light controls, producing powerful Gs, were in fact not a normal response at all, but a normal and progressive-SEEMING response, and that he was in fact carving a very loose curve despite the punishing Gs... (I think however it is likely he was aware of the pitch-up, but if the sky is very uniform in colour at the time of the test, all blue or all clouds for instance, it is possible to not be aware of what movements the aircraft is actually doing)

2 pounds of stick pull force per G at 400 MPH, with purely mechanical, unassisted controls, certainly indicate to me the elevators were not tightly sandwiched between two layers of 400 MPH airflow...

Just because his FW-190A was massively decelerating, making say a true 4G 400 MPH curve with 3Gs of nose-up deceleration, doesn't mean it would take large control forces to upset the balance of an aircraft decelerating at 3Gs: In fact, a violently decelerating aircraft's attitude may be very easy to upset by small plan view control surfaces changes, which would account as to WHY his control forces were so incredibly low per registered G at 400 MPH...

This even more so when you consider the FW-190A had probably among the worst dive pull-out performance of any WWII fighters, although it could zoom well from a dive initially, at least for the first zoom from high speed if, to take Eric Brown's own words, "you take care not to kill speed by sinking".

Gaston

JtD
11-09-2010, 11:14 PM
Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
Just a quick note on your turning picture, Bill:

The maximum AoA you can reasonably expect from a WW2 fighter aircraft at high speeds might be about 15°.

You don't know that.
Anyway, the graph was more to demonstrate the principal.

Bill </div></BLOCKQUOTE>

I know you were only trying to demonstrate the principle, but it might be leading to wrong conclusions for folks who take it at face value.

The stall angle of attack for most WW2 aircraft, in particular without leading edge slats, is only slightly above 15°. It is not within a humans ability to control this type of plane in post stall conditions at high speed.

Gaston444
11-09-2010, 11:33 PM
Originally posted by JtD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:
Just a quick note on your turning picture, Bill:

The maximum AoA you can reasonably expect from a WW2 fighter aircraft at high speeds might be about 15°.

You don't know that.
Anyway, the graph was more to demonstrate the principal.

Bill </div></BLOCKQUOTE>

I know you were only trying to demonstrate the principle, but it might be leading to wrong conclusions for folks who take it at face value.

The stall angle of attack for most WW2 aircraft, in particular without leading edge slats, is only slightly above 15°. It is not within a humans ability to control this type of plane in post stall conditions at high speed. </div></BLOCKQUOTE>

-Jeez JtD, I think Bill's initial response is more than obviously spot-on... It would help if you realized from time to time there are things you and aeronautical engineers don't know about severely outdated fighters...

Apparently the real FW-190A never heard of a 15° rule at high speed... If you listened for a second to anything posted here, including even Eric Brown's own words (for all his foibles and mistaken conclusions), you would realize it would be difficult for a person to detect a significant "sinking" that is only slanted at 15°...

That "sinking" feeling, you know...

Nor would the Russians call it "hanging", creating a "perfect target" from the point of view of an aircraft that follows it... "It is then convenient to fire", remember that? Hmm... I'm getting the unimpressed feeling now...

Gaston

JtD
11-10-2010, 12:25 AM
Thanks for disagreeing with me, Gaston, this proves beyond doubt that I am right. However, if I ever cross over into your universe where the rules of physics don't apply, I'll be carefully listening to you.

BillSwagger
11-10-2010, 02:46 AM
Originally posted by JtD:
The stall angle of attack for most WW2 aircraft, in particular without leading edge slats, is only slightly above 15°. It is not within a humans ability to control this type of plane in post stall conditions at high speed.

I don't know what the limit would be, but it certainly would be a challenge in prolonged flight.
I think in pull outs where mush is present, higher angles of attack (>20-30 degrees) are present if for only brief moments, something like tenths to hundredths of a second before the trajectory of the aircraft changes. Once the trajectory of the aircraft changes then the AoA lowers to match what ever the new trajectory is. The idea the plane could hold a higher AoA in prolonged flight would be a different argument.

M_Gunz
11-10-2010, 04:25 AM
LOL JtD, are you trying to tell BS or Gas from long accepted aeronautical facts? Might as well forget it!

Just seems like you'd need to validate it a bit more before you start upholding it as fact.

Neither one accepts even the simplest facts, nor the use of logic. They're just playing their own fantasies.

BillSwagger
11-10-2010, 06:23 AM
uhhill hill hill..... http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Careful, they might put you on time out again Gunz.

Not really my place to say this, but here'goes. If you don't agree, you don't agree. If you can't handle disagreements, find a forum where everyone agrees with you. How boring would that be?


Bill

JtD
11-10-2010, 07:21 AM
Originally posted by BillSwagger:

I don't know what the limit would be, but it certainly would be a challenge in prolonged flight.
I think in pull outs where mush is present, higher angles of attack (>20-30 degrees) are present if for only brief moments, something like tenths to hundredths of a second before the trajectory of the aircraft changes. Once the trajectory of the aircraft changes then the AoA lowers to match what ever the new trajectory is. The idea the plane could hold a higher AoA in prolonged flight would be a different argument.

Could you please repeat your definition of "mush"?
If you're talking about dynamic components, wouldn't "buffeting" be the more exact word?

BillSwagger
11-10-2010, 07:56 AM
Originally posted by JtD:
If you're talking about dynamic components, wouldn't "buffeting" be the more exact word?

I took 'buffeting' to be shaking or violent rocking of the aircraft. I'm sure buffeting is also a component of uncoordinated flight.

Mush has always been a confusing term to define. Its like sink, but it occurs with a change in trajectory. I heard someone earlier describe as when the aircraft changes AoA but the wings don't quite bite the air due to weight or excessive load.
The higher AoA causes deceleration which is usually why Mush is not a favorable trait to an aircraft.

JtD
11-10-2010, 09:23 AM
Wings will always give the lift that is to be expected from them under the current conditions. A situation where they don't "bite" doesn't really exist.

What I can imagine is that the linear correlation between AoA and lift, which a pilot might be used to but which does not exist at high AoA's, can give the feeling of mushing at high AoA's as you describe it. It also creates a lot of drag, but it is not past the maximum AoA possible for the aircraft.

Bremspropeller
11-10-2010, 09:57 AM
The stall angle of attack for most WW2 aircraft, in particular without leading edge slats, is only slightly above 15°.

True, but even taht figure is too high when talking about high-speed-stalls.

The HSS will occur between about 5° and 10° - you're not going along the CL/ alpha curve anymore, which is recorded by slowly changing AoA.
If the change in AoA is too abrupt and quick, the air will disattach from the profile-nose and the wing just stalls - there's no stall-progression (boundray-layer disattachment travelling from aft to front) anymore as when setting up AoA more slowly.

Thus, the "deceleration-g"-theory is baloney.
In a HSS, there's no centrifugal acceleration as there's virtually no usable lift and the deceleration-g is
1) low in the first place because deceleration is relatively modest, somewhat like when normally pulling max G
2) the angle is so small that the deceleration-component isn't anything worth mentioning

BillSwagger
11-10-2010, 10:14 AM
So whats happening with a plane that falls another 220m or so after leveling off from a dive made from 1500m at 40 degrees?
The reference refers to it as nose level "sinking".

Bill

M_Gunz
11-10-2010, 10:18 AM
Salute Brems;

That part of the circulation out in front of the wing doesn't change instantly then? Or as fast as the stick can jerk the plane?
(LOL, shock and amazement that the acronym AOA isn't some kind of magic syntax to play with in sentences!)

I do wonder though if the IL2 FM engine goes so far and expect it does not.

Bremspropeller
11-10-2010, 10:56 AM
That part of the circulation out in front of the wing doesn't change instantly then?

No - air is not a perfect fluid.
Maybe at smaller Re-numbers.

M_Gunz
11-10-2010, 11:16 AM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">That part of the circulation out in front of the wing doesn't change instantly then?

No - air is not a perfect fluid.
Maybe at smaller Re-numbers. </div></BLOCKQUOTE>

I thought it got worse as you scaled down, and that's the smaller numbers. Pretty sure that efficiency of a big wing like a jumbo jet beats that of a small plane which beats that of an average model which beats insect wings but maybe I have that wrong?

Bremspropeller
11-10-2010, 11:21 AM
Pretty sure that efficiency of a big wing like a jumbo jet beats that of a small plane which beats that of an average model which beats insect wings but maybe I have that wrong?

That's not due to the scales involved.

Sea-birds have much more efficient wings (L/D) than a 747, but those wings are optimized for a certain (low) range of Re-numbers.
Fly that wing at higher speeds and scale it up and it's bound to suck.

Xiolablu3
11-11-2010, 05:21 AM
Excatly.

Creating an aircraft is always a compromise.

Do you want it to handle better at faster speeds (Blackbird,FW190), or low speeds? (A10/Frogfoot, Zero, even Red Bull airace prop planes)

You always have to make compromises in design to achieve the best balance for the design goal.

BillSwagger
11-11-2010, 10:59 AM
Missing models

1) D10 using 64-65 inches boost and paddle blade prop.

2) D10 using 70 inches boost with 100/130 octane and paddle blade (this would be the best performing P-47, with low weight/high horsepower, better handling properties of the Razor back without underwing pods) Robert Johnson, the 2nd highest scoring P-47 pilot flew a P-47D-5 named 'Lucky' similar to a D10, which was upgraded with water injection. His crew chief modded it to allow 70 inches boost, and according to Johnson, this was the best P-47 he flew in Europe. It was destroyed by another pilot who borrowed it for a mission Johnson missed. According to Johnson and other pilots, 70 inches of boost was not a problem with 100/130 octane. This level of boost was commonly used for the P-47's based on the continent, even though 100/130 octane fuel was the only variety available to the 9th AAF Groups there.

Picture of Johnson's D5:

3) D22 with 64-65 inches of boost and Paddle blade prop

4) D22 with 70 inches of boost using 150 octane and Paddle blade (Razorback P-47's were still the most numerous version of the aircraft right up to September of 1944, after the introduction of 100/150 octane and clearance for 70 inchs of boost in the 8th AAF)

Now that i think about it, it would be great to see more models of this plane in game.

Bremspropeller
11-12-2010, 04:31 AM
Do you want it to handle better at faster speeds (Blackbird,FW190), or low speeds? (A10/Frogfoot, Zero, even Red Bull airace prop planes)

Generally right, but I wouldn't put the SR-71 in the "maneuvering"-category and I wouldn't put the A-10 and Su-25 (especially the latter) as "slow" up against the Fw 190 as "fast".

The SR-71 is designed to go fast and nothing else.
The A-10 is designed to haul a lot of iron and to make a several-ton gun fly.
The Su-25 is a modern descendant of the IL-2 and can even go supersonic in a dive, IIRC.

The Red-Bull Racers are a class of their own:
They're intended to go fast, yet still around the corner.
It's funny how those racers have evolved from competition "unlimited" aerobatic-planes in the beginning to dedicated racers with completely different technology (concerning ing-profiles, etc).

Example: The new Rcer by Corvus (that also make very interesting and fast ultralights/ LSA)..
http://www.youtube.com/watch?v=J_pKMqJ-XfU

Xiolablu3
11-12-2010, 05:34 AM
Originally posted by Bremspropeller:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Do you want it to handle better at faster speeds (Blackbird,FW190), or low speeds? (A10/Frogfoot, Zero, even Red Bull airace prop planes)

Generally right, but I wouldn't put the SR-71 in the "maneuvering"-category and I wouldn't put the A-10 and Su-25 (especially the latter) as "slow" up against the Fw 190 as "fast".

The SR-71 is designed to go fast and nothing else.
The A-10 is designed to haul a lot of iron and to make a several-ton gun fly.
The Su-25 is a modern descendant of the IL-2 and can even go supersonic in a dive, IIRC.

The Red-Bull Racers are a class of their own:
They're intended to go fast, yet still around the corner.
It's funny how those racers have evolved from competition "unlimited" aerobatic-planes in the beginning to dedicated racers with completely different technology (concerning ing-profiles, etc).

Example: The new Rcer by Corvus (that also make very interesting and fast ultralights/ LSA)..
http://www.youtube.com/watch?v=J_pKMqJ-XfU </div></BLOCKQUOTE>

You are sort of correct, but Red Bull Air Race planes are not fast in a straight line. A Spitfire from 1943 could beat a Red Bull Air Race plane in a straight line.

http://www.youtube.com/watch?v=4A2ZVhqJJKI

See what the pilots think in the link above. They make the point very well, the SPitfire was a weapon of war and is faster in a straight line. The Red Bull Racer is incredibly manouverable, but not as fast in a straight line. Design is always a compromise.

Bremspropeller
11-12-2010, 05:41 AM
I want to see a Spitfire with the avaliable HP-output (350-ish) outperform a RB-Racer http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

M_Gunz
11-12-2010, 05:42 AM
Those Red Bull racers are making better than 250 mph -in short distance- at sea level. Not exactly slow and able to pull tight aerobatics in between. I doubt that any model Spitfire would be competitive on the Red Bull courses.

Xiolablu3
11-12-2010, 05:48 AM
Originally posted by M_Gunz:
Those Red Bull racers are making better than 250 mph -in short distance- at sea level. Not exactly slow and able to pull tight aerobatics in between. I doubt that any model Spitfire would be competitive on the Red Bull courses.

Absolutely.

Nowhere near agile enough.

Xiolablu3
11-12-2010, 05:50 AM
Originally posted by Bremspropeller:
I want to see a Spitfire with the avaliable HP-output (350-ish) outperform a RB-Racer http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

And thats all part of the compromise. Put a heavier engine in the Red Bull adn it wont be as Agile, put a lighter engine in the Spitfire and it will be more agile (Than another Spit, not a Red Bull Racer!(Spit 1 vs SPitfire IX))

Obviously we are talking extremes here and the tech has changed massively in favour of the Red Bull, but it still illustrates the point well, I think.

Bremspropeller
11-12-2010, 06:02 AM
It's a bit more complicated than just swapping engines, but you're getting the general idea.

It's pretty much an overall comparison in design, propulsion, aerodynamics, etc.

The RBR's airframe is so much more efficient than the Spitfire's, it's an entirely different animal - no surprise, there are 80 years of experience splitting the two apart.

What would be really interesting is how many HP a WW2-warbird designed with today's technology (composite airframes, new wing-profiles, new engine-technology) could do without.

BillSwagger
11-12-2010, 06:24 AM
I think Brems point is you design a plane for a certain task.
In WW2, they knew what they were up against, and design features improved or were created to always have the advantage.
There are also designs that were made to meet a demand for specific missions or campaigns.
"We need a plane that travel 'this' far, and 'this' fast, and at 'this' altitude, and we need it to have 'this' much firepower."
You might sacrifice low speed turn ability especially if you knew the design was able to maintain high speeds in combat.
Speed probably became an increased focus of a design because it gave the pilot the ability to engage or disengage at will.
The winning formula was found with designs that could maintain both high speed in combat, and high maneuverability.

RegRag1977
11-12-2010, 08:30 AM
Just out of curiosity: how would a Red Bull racer do above 6K in terms of speed and agility?
Maybe the Spit would be more competitive up there?

Bremspropeller
11-12-2010, 09:01 AM
Exactly Bill - you can only do so much of a compromise.
There is no "Jack of all trades" that excells everywhere.
For that reason, the Russians weren't designing high-altitude planes: they justs didn't need to, and that's the reason why they were so much (comparatively) behind the other major powers at the end of the war.


Just out of curiosity: how would a Red Bull racer do above 6K in terms of speed and agility?


No turbocharger, so the lights are gonna fade quickly above 15-18kft.
Agility in itself is not so much compromised, but there's much less engine-power to play around with.
Put in a turbocharger and you'll be able to take the speed/ agility to higher levels.
Why would you wanna do so, though? http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

RegRag1977
11-12-2010, 09:13 AM
Originally posted by Bremspropeller:

Why would you wanna do so, though? http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

Ha! I don't want to do that, i prefer it to stay low, so that i can see it fly, from close http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

M_Gunz
11-12-2010, 04:09 PM
Not to mention what even 2 MG's would do to a Red Bull Racer's performance. It would be like putting a trailer hitch on a Prius.

BillSwagger
11-13-2010, 08:29 AM
http://www.wwiiaircraftperform...3-beckham-2oct43.jpg (http://www.wwiiaircraftperformance.org/p-47/er/353-beckham-2oct43.jpg)
Began to close fairly soon and am sure the 109 pilot saw me for he went into a sharp left turn, diving slightly. If he was doing his maximum rate of turn, which he certainly should have been under the circumstances, it is safe to say that the 47 will outturn the 109 because i had very little difficulty in definitely turning inside of him.

http://www.wwiiaircraftperform...3-beckham-3feb44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/353-beckham-3feb44.jpg)
In this case the P-47 definitely out-climbed (29k to 32k feet) the 109, out-turned and out-dived it.

http://www.wwiiaircraftperform...-meroney-10feb44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/352-meroney-10feb44.jpg)
I did a split S onto his tail and as I closed to 300 yrds, he chopped his throttle and did a tight climbing turn. I was unable to get enough deflection so I pulled up and away.

http://www.wwiiaircraftperform...hnson-13april44a.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-johnson-13april44a.jpg)
As I got about 600 yards or 700 yards behind him, he pulled up from the deck in a right chandelle. I followed, chopping throttle and fired a deflection shot and hit him, seeing strikes near the engine and fuselage.

http://www.wwiiaircraftperform...53-duncan-5jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/353-duncan-5jan44.jpg)
The Me109 shot away, out of range and peeled off to the left. By this time i was behind the Me and coming in range. He must have had a sore neck because he did not look on his tail, or either thought that he could out run a P-47. We were diving at a very slight dive and I closed fairly fast.

http://www.wwiiaircraftperform...-meroney-30jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/352-meroney-30jan44.jpg)
I had no trouble staying with the 109 and could overtake him at will

http://www.wwiiaircraftperform...-beckham-21jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/353-beckham-21jan44.jpg)
I followed this 109 down in a series of maneuvers, with throttle full back, and turning so sharply that i was stalling most of the time. I think he was also stalling. The electrical sight went out after the first burst at the second 109. Each time he straightened out, I gave him a burst, using the mechanical gunsight.

Bremspropeller
11-13-2010, 08:39 AM
So?
A couple of insignifigant pilot-reports, some even stating that the other pilot "may or may not" have max-performed his plane http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

M_Gunz
11-13-2010, 10:19 AM
LOL! "I turned inside a noob who turned well ahead of me and shot him, proving that my plane is better!" LMAO!
It also proves that 'I' don't much understand geometry or algebra as well!

BillSwagger
11-13-2010, 02:57 PM
http://www.wwiiaircraftperform...4-goodson-7jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-goodson-7jan44.jpg)
He broke hard port, but although he pulled streamers from his wing tips, I was able to pull my sights through him. He suddenly did 2 1/2 flickrolls, and then split Sed vertically through some light cloud

http://www.wwiiaircraftperform...ntgomery-14jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-montgomery-14jan44.jpg)
E/A continued diving steeply until i was forced to pull up at about 500 feet to keep from going into the deck. The last I saw was a high column of smoke where the FW had crashed. IAS 500-550.
As White 3 pulled out of his dive the FW190 rolled three quarters of the way on his back at 300 feet with his nose 45 degrees down and IAS approximately 450mph.

http://www.wwiiaircraftperform...-padgett-26nov43.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-padgett-26nov43.jpg)
I led green section in a 360 degree turn to port and came out on the tail of number 1 E/A as he zoomed up in a steep climbing turn to port. I fired a short deflection burst at about 200 yards while in a steep climbing turn but observed no strikes

http://www.wwiiaircraftperform...richards-21jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-richards-21jan44.jpg)
He pulled up to the right to try to break into me. As he did that I laid off a little deflection above him and hit him all over the cockpit.

http://www.wwiiaircraftperform...sobanski-31jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-sobanski-31jan44.jpg)
I gave him a short burst in a 70 degree dive, observing no strikes. He started pulling up, turning left and I fired a 20 degree deflection shot. I observed strikes in the wings and near the cockpit. A large patch of white smoke came out after my last burst, and he flicked left, smoking badly, I flicked at the same time and lost sight of him.

http://www.wwiiaircraftperform...stanhope-16aug43.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-stanhope-16aug43.jpg)
He turned to the left, then to the right and i closed more and fired a 2-3 second burst from line astern.

http://www.wwiiaircraftperform...adrianse-22feb44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-adrianse-22feb44.jpg)
I climbed back up to 22,000 where i was bounced by a Me 109. After two turns I gained the advantage and he hit the deck. I could not follow as i was very low on fuel at this time, and headed out.

http://www.wwiiaircraftperform...-anderson-2dec44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-anderson-2dec44.jpg)
We made a 180 degree turn and let down through the overcast and broke out at about 18,000ft. Directly ahead of us were 40 plus Me 109s. I spotted four of them flying top cover and climbed up to about 26,000ft and made a head-on pass, firing but did not score any hits. I then spotted another e/a off to my left and he was turning as i fired. His plane flicked from the strikes and finally went into a spin. He had spun approximately ten turns when one of his wings came off.

http://www.wwiiaircraftperform...anderson-5sept44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-anderson-5sept44.jpg)
and had just pulled up to approxomately 2000ft when six Me 109s bounced us from above. One was on my tail and I pulled up hard and turned and managed to get on his tail. We fought in this manner up to approximatley 8000 feet. I was scoring many strikes on his fuselage when he split-S'd and went straight into the ground and exploded.
I followed him in his Split-S and fired continually, causing a small pieces of his tail to fall off.

http://www.wwiiaircraftperform...56-baker-4july44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-baker-4july44.jpg)
The #2 Jerry had pulled away and turned 180 degrees to me about 2000 yards distant. I outturned him, however, and at 4000' he went for the deck in a 70-degree dive.

http://www.wwiiaircraftperform...56-barnum-5nov43.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-barnum-5nov43.jpg)
The FW-190 turned left and started into a slight dive. We followed him and Major Gabreski opened fire at about 150-175 yards. The e/a had sighted him and broke into the attack in a climbing turn which the Major could not follow. I was further back and was able to follow the Fw-190 through his climbing turn.
http://www.wwiiaircraftperform...-gabreski-5nov43.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-gabreski-5nov43.jpg)
Gabreski-the plane continued to orbit. I broke off the attack to the left, as I ran out of ammunition


http://www.wwiiaircraftperform.../56-bast-23dec44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-bast-23dec44.jpg)
We started turning at about 20,000, continuing on down to the deck. This particular pilot was very experienced, I believe. He outturned me three times, while I sliced up and grabbed on again. Every time I fired he would turn violently and do a flick, causing my fire to go wild. Finally I got dead astern and hammered the wing roots and fuselage,

http://www.wwiiaircraftperform...6-batson-23dec44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-batson-23dec44.jpg)
As I started to close he made a sharp climbing turn to the right, where at this point, i fixed him in my K-14 sight and began firing, the range being approximately 800 yards. He continued his climbing turn and I kept firing but did not observe any strikes until he had almost completed his turn, and i had closed to approximately 400 yards. I then saw strikes all over his airplane and his engine caught fire.

http://www.wwiiaircraftperform...anderson-30jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-anderson-30jan44.jpg)
Upon seeing my A/C they started to climb immediately. I followed them up and fired at the one on the left from about 350 yards.

http://www.wwiiaircraftperform...8-turley-10feb44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/78-turley-10feb44.jpg)
when two Me109s with red noses bounced the flight. I broke right into them and they made a climbing turn to the left. I opened everything up and cut them off on their turn; but when i got astern i could not seem to close.

http://www.wwiiaircraftperform...6-klibbe-21feb44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-klibbe-21feb44.jpg)
at about 28,000ft. We went into a Luftberry with them and made about five turns with them. We had just begun to gain on the tail end one, when i saw one going across in front of me at about a 75 degree angle.

Bremspropeller
11-13-2010, 04:38 PM
A couple of insignifigant pireps more.

Erkki_M
11-13-2010, 05:43 PM
Would be interesting to see the reports from those battles where the enemy was a German ace. One of those 100+ kills guys the P-47s and P-51s managed to shoot down in 44 and 45.

Or even better, reports from German side, or the P-47 pilots that never shook off that 190.

M_Gunz
11-13-2010, 07:40 PM
Originally posted by BillSwagger:
http://www.wwiiaircraftperform...4-goodson-7jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-goodson-7jan44.jpg)
He broke hard port, but although he pulled streamers from his wing tips, I was able to pull my sights through him. He suddenly did 2 1/2 flickrolls, and then split Sed vertically through some light cloud

http://www.wwiiaircraftperform...ntgomery-14jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-montgomery-14jan44.jpg)
E/A continued diving steeply until i was forced to pull up at about 500 feet to keep from going into the deck. The last I saw was a high column of smoke where the FW had crashed. IAS 500-550.
As White 3 pulled out of his dive the FW190 rolled three quarters of the way on his back at 300 feet with his nose 45 degrees down and IAS approximately 450mph.

http://www.wwiiaircraftperform...-padgett-26nov43.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-padgett-26nov43.jpg)
I led green section in a 360 degree turn to port and came out on the tail of number 1 E/A as he zoomed up in a steep climbing turn to port. I fired a short deflection burst at about 200 yards while in a steep climbing turn but observed no strikes

http://www.wwiiaircraftperform...richards-21jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-richards-21jan44.jpg)
He pulled up to the right to try to break into me. As he did that I laid off a little deflection above him and hit him all over the cockpit.

http://www.wwiiaircraftperform...sobanski-31jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-sobanski-31jan44.jpg)
I gave him a short burst in a 70 degree dive, observing no strikes. He started pulling up, turning left and I fired a 20 degree deflection shot. I observed strikes in the wings and near the cockpit. A large patch of white smoke came out after my last burst, and he flicked left, smoking badly, I flicked at the same time and lost sight of him.

http://www.wwiiaircraftperform...stanhope-16aug43.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-stanhope-16aug43.jpg)
He turned to the left, then to the right and i closed more and fired a 2-3 second burst from line astern.

http://www.wwiiaircraftperform...adrianse-22feb44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-adrianse-22feb44.jpg)
I climbed back up to 22,000 where i was bounced by a Me 109. After two turns I gained the advantage and he hit the deck. I could not follow as i was very low on fuel at this time, and headed out.

http://www.wwiiaircraftperform...-anderson-2dec44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-anderson-2dec44.jpg)
We made a 180 degree turn and let down through the overcast and broke out at about 18,000ft. Directly ahead of us were 40 plus Me 109s. I spotted four of them flying top cover and climbed up to about 26,000ft and made a head-on pass, firing but did not score any hits. I then spotted another e/a off to my left and he was turning as i fired. His plane flicked from the strikes and finally went into a spin. He had spun approximately ten turns when one of his wings came off.

http://www.wwiiaircraftperform...anderson-5sept44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-anderson-5sept44.jpg)
and had just pulled up to approxomately 2000ft when six Me 109s bounced us from above. One was on my tail and I pulled up hard and turned and managed to get on his tail. We fought in this manner up to approximatley 8000 feet. I was scoring many strikes on his fuselage when he split-S'd and went straight into the ground and exploded.
I followed him in his Split-S and fired continually, causing a small pieces of his tail to fall off.

http://www.wwiiaircraftperform...56-baker-4july44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-baker-4july44.jpg)
The #2 Jerry had pulled away and turned 180 degrees to me about 2000 yards distant. I outturned him, however, and at 4000' he went for the deck in a 70-degree dive.

http://www.wwiiaircraftperform...56-barnum-5nov43.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-barnum-5nov43.jpg)
The FW-190 turned left and started into a slight dive. We followed him and Major Gabreski opened fire at about 150-175 yards. The e/a had sighted him and broke into the attack in a climbing turn which the Major could not follow. I was further back and was able to follow the Fw-190 through his climbing turn.
http://www.wwiiaircraftperform...-gabreski-5nov43.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-gabreski-5nov43.jpg)
Gabreski-the plane continued to orbit. I broke off the attack to the left, as I ran out of ammunition


http://www.wwiiaircraftperform.../56-bast-23dec44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-bast-23dec44.jpg)
We started turning at about 20,000, continuing on down to the deck. This particular pilot was very experienced, I believe. He outturned me three times, while I sliced up and grabbed on again. Every time I fired he would turn violently and do a flick, causing my fire to go wild. Finally I got dead astern and hammered the wing roots and fuselage,

http://www.wwiiaircraftperform...6-batson-23dec44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-batson-23dec44.jpg)
As I started to close he made a sharp climbing turn to the right, where at this point, i fixed him in my K-14 sight and began firing, the range being approximately 800 yards. He continued his climbing turn and I kept firing but did not observe any strikes until he had almost completed his turn, and i had closed to approximately 400 yards. I then saw strikes all over his airplane and his engine caught fire.

http://www.wwiiaircraftperform...anderson-30jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-anderson-30jan44.jpg)
Upon seeing my A/C they started to climb immediately. I followed them up and fired at the one on the left from about 350 yards.

http://www.wwiiaircraftperform...8-turley-10feb44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/78-turley-10feb44.jpg)
when two Me109s with red noses bounced the flight. I broke right into them and they made a climbing turn to the left. I opened everything up and cut them off on their turn; but when i got astern i could not seem to close.

http://www.wwiiaircraftperform...6-klibbe-21feb44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-klibbe-21feb44.jpg)
at about 28,000ft. We went into a Luftberry with them and made about five turns with them. We had just begun to gain on the tail end one, when i saw one going across in front of me at about a 75 degree angle.

Would you care for any or all of these to describe just what was done in terms of positions, distances, speeds, altitudes, maneuvers and times... enough to set up a training mission in IL2 that starts exactly how the reported encounter started? And for bonus points, how experienced the opposing pilot was? Think you can find one that states all the parameters within 10%? Because the reports that don't tell enough to duplicate within reason can be too many different starts that all fit the description but have real differences in how possible it is for Plane X to achieve the kill, so which do you choose? And if you think there's only one that fits the story then check anyway.
This is even after going through what's wrong with using most combat reports once in this thread already. So you should know not to link to accounts like the first where the 190 that crashed had earlier taken fire. It doesn't give more than it does, the whole report. You grasped at that?

C'mon, I'm not reading through the stack when the first one's a dud. Pick out the ones without a load of unknowns if you can find any.

M_Gunz
11-13-2010, 08:33 PM
Originally posted by BillSwagger:
http://www.wwiiaircraftperform...4-goodson-7jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-goodson-7jan44.jpg)
He broke hard port, but although he pulled streamers from his wing tips, I was able to pull my sights through him. He suddenly did 2 1/2 flickrolls, and then split Sed vertically through some light cloud


Actual text:

When I started getting strikes on him, he (he as in not He as quoted above) broke hard port, but although he pulled streamers from his wing tips, I was able to pull my sights through him. He suddenly did 2 1/2 flickrolls, and then split Sed vertically through some light cloud.

What range? How fast was the P-47 closing, or was it co-speed but since it had jumped in behind Blakeslee whom Goodson was following (co-speed +/- not much with Blakeslee) was the 190 the faster moving plane? It - doesn't - say.

Lag Pursuit: The farther I am behind a target the less degrees of turn I have to pull than he does to put shots and target together. A lag pursuit means being able to follow a target and get gun solutions on a lower energy path than that of the target. Meaning when I shoot from lag pursuit I pull less G's than my target, the inherent geometry lets me do so. That is why being able to pull your sights through a turning target from a ways back is not the same as ability to turn comparison but rather it is ability to make a certain shot and that's it. And I note that: Goodson doesn't claim to have turned harder, only that he turned enough to pull his sight through the target.

BillSwagger
11-14-2010, 12:16 AM
I went through about 50 reports and picked out the ones that were more explanatory than the typical, "dive, shoot, crash, claim..." encounter. I think there are many reports that report "dive, shoot, kill" because of the unfamiliarity with combat German pilots had facing the plane. They usually thought they could dive away but that wasn't the case.


Originally posted by Erkki_M:
Or even better, reports from German side, or the P-47 pilots that never shook off that 190.

It would be great to see those too, but i have a feeling they don't exist. The closest I've found is combat score records for the Luftwaffe.
They are separated by year and front, and iirc the squadron. You can review them and see all the P-47s that were shot down, as well as P-51s, P-38s, and many many more bombers. The great thing is it also shows the altitude.
There is a quote from Oblt Hans Hartigs discussing tactics favored by JG 26 pilots when flying against P-47s in 1944:
If attacked, we should draw the P-47s to a lower altitude (3,000 meters) by diving, then turn about suddenly. The P-47s will overshoot: if they try to turn, they will lose speed and are vulnerable. The P-47 should zoom-climb and dive again. If we get into a turning combat, a P-47 can often get us on the first turn. If the Fw 190 climbs slightly in the turn (below 5000meters, it will gain on the P-47.
Perhaps in reviewing some of these reports you might see parts of these tactics being used. The idea being to lure the 47 into maneuvers that bleed down speed and taking away the zoom advantage. Then once the planes were on even energy footing, the 190 should start a climbing turn to gain the advantage. The problem of course is that the 190 wasn't always able to lure a P-47 into bleeding down speed with out also bleeding down speed, and such as was combat in this case, usually another P-47 with more energy would be there to cover.

I take notice to the pilots who dove into a steep climbing turn, even chopping throttle, in attempt to avoid a guns solution. I also realize that the maneuvering in combat is also a game of chance, where if the P-47 decides he is well covered by wingmen, then he might also chop throttle and apparently, at times, had no problem following in the steep climbing turn.

Your all welcome to posture your arguments how you'd like, but there are other things that i took notice of. It seems the P-47 had a significantly easier time with the 109 than the 190. I only say this from the context of speed where the P-47 was moving quickly, which seems obvious by the reports posted.
We know that the P-47 was much more vulnerable at lower speeds, but as long as it kept its combat speeds up, it doesn't appear to have had trouble following the 109 through Spit S maneuvers, as well as turning climbs. This should be no surprise as 109 turn performance is said to have suffered at high speeds.
The 190 and P-47 were pretty much on even terms when it came to turn performance at high speed, but if the fight was faster, such as speeds that result in a spiraling dive, the P-47 could easily maneuver inside the 190. If the speed fell off, then the advantage shifts to the 190. I also realize that a big part of the turn advantage while in pursuit can vary greatly depending on the positioning, for example if in a lead pursuit or lag pursuit as well as the spacing between the aircraft when the turn is started. I sort of rule out spacing given the pilots discussion of distance when closing, say from 700 yards to 50 yards at 20-30 degrees deflection.
There are many hundreds of reports more to read, but so far it seems more typical to see P-47s bouncing 190s in pursuit of bombers, and engaging 109s in a fighter roll. This may have been because of the 109s superior altitude performance and the designations that the fighters were put into.

BillSwagger
11-14-2010, 12:52 AM
Originally posted by Bremspropeller:
A couple of insignifigant pireps more.

I thought this one might've grabbed your attention.
It might give your experienced pilot argument a little help.
http://www.wwiiaircraftperform.../56-bast-23dec44.jpg
We started turning at about 20,000, continuing on down to the deck. This particular pilot was very experienced, I believe. He outturned me three times, while I sliced up and grabbed on again. Every time I fired he would turn violently and do a flick, causing my fire to go wild. Finally I got dead astern and hammered the wing roots and fuselage,

I just hate hearing of pilot experience as a constant cop out to the bulk of the claims, because next week, when we're talking about P-51s again, someone is bound to say those claims are because all the good pilots were killed off and the Luftwaffe had untrained pilots. So basically, the P-47s killed mostly the bad pilots?, and the P-51s killed the rest of the bad pilots, and some of the new pilots, which means that the good pilots were actually killed by the British in BoB? http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif
At least I can say i'm not biased here.

Bill

M_Gunz
11-14-2010, 02:03 AM
LW started out with a large base of pilots trained on gliders when young, they had to understand energy more in the gliders they had made from the materials they had then. How many of those pilots did they lose by mid-41? And then how many were lost on the East Front by 1943? Marseilles was lost in Africa and others too. Yeah, the P-47's got em all, uh-huh.

It's no cop out to note that MOST of the pilots shot down were less experienced, that there were rookies thrown in at a steady rate and you are reading from choice combat reports, ie da whinna's dat red da bess. Capiche? Picked samples and you pick through those.

If the report has room for ambiguity of 1/2 effective guns range or more then how do you decide that you can duplicate the scene well enough to "check" with any sim made? No way, sorry, what a joke, I don't think so!

Bremspropeller
11-14-2010, 05:42 AM
So basically, the P-47s killed mostly the <STRIKE>bad</STRIKE> untrained pilots?

Yes.
There's more to it than being a "good" pilot, though.
If you look how many of the "good" pilots died, you'll recognize that a great deal of them just ran out of luck.

BillSwagger
11-14-2010, 10:53 AM
LW started out with a large base of pilots trained on gliders when young, they had to understand energy more in the gliders they had made from the materials they had then. How many of those pilots did they lose by mid-41? And then how many were lost on the East Front by 1943? Marseilles was lost in Africa and others too. Yeah, the P-47's got em all, uh-huh.
Another way to look at it is that the Luftwaffe was facing inferior aircraft (inferior in the sense of altitude and speed) at the start of the war. The Spitfire was able to combat them on more even terms. The introduction of planes like the P-47 and P-51 were able to put many of the Luftwaffe fighters on the bottom end of a bounce even at relatively higher altitudes.
Pilot experience doesn't give your plane more speed, or make it fly higher and climb faster. The hardware has its limitations and i think many pilots were maxed out despite their abilities.

I only need separate the ones that are more distinguished than the typical bounce scenario, ie ones that describe maneuvering and at least some sort of pilot awareness that they were being attacked.
Other than that, the site only includes reports where combat took place so you won't hear about scenarios where the other pilot escaped or prevailed.
TBH, there just aren't that many kill scores for the Luftwaffe against the P-47 in air battles above 5000ft. The P-47 has one of the best combat kill ratios in the ETO.


If the report has room for ambiguity of 1/2 effective guns range or more then how do you decide that you can duplicate the scene well enough to "check" with any sim made?
If that's your goal you'd have to look into other sources than just combat reports. You can look into the history behind gunnery training, and the types of weapons used and their guns sights, for starters.
I often find i can duplicate many of the tactics used here but to get 100 percent perfect duplication in a simulator would be impossible. You'd need more information than combat reports alone.

Bremspropeller
11-14-2010, 11:28 AM
The hardware has its limitations and i think many pilots were maxed out despite their abilities.

Quamtity > Quality

Bremspropeller
11-14-2010, 11:42 AM
Yeah, the P-47's got em all, uh-huh.

Exactly:
This completely outbraces the efforts of the RAF, flying Rhubarbs and medium-heavy bombers into France since '41 and frequently tossing up LW-fighters in the prcess.

Thinking the P-47 "got all the aces" is just pure whishful thinking.

M_Gunz
11-14-2010, 12:04 PM
Originally posted by BillSwagger:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">LW started out with a large base of pilots trained on gliders when young, they had to understand energy more in the gliders they had made from the materials they had then. How many of those pilots did they lose by mid-41? And then how many were lost on the East Front by 1943? Marseilles was lost in Africa and others too. Yeah, the P-47's got em all, uh-huh.
Another way to look at it is that the Luftwaffe was facing inferior aircraft (inferior in the sense of altitude and speed) at the start of the war. The Spitfire was able to combat them on more even terms. The introduction of planes like the P-47 and P-51 were able to put many of the Luftwaffe fighters on the bottom end of a bounce even at relatively higher altitudes.


Try checking the LW losses to other than P-47 and P-51 and maybe wake up a bit for this impression that P-47's wiped the LW out?

[QUOTE]Pilot experience doesn't give your plane more speed, or make it fly higher and climb faster. The hardware has its limitations and i think many pilots were maxed out despite their abilities.

LACK OF pilot experience makes the plane take longer to get to speed, not fly as fast, not climb as fast, turn less well, completely miss out on use of different maneuvers and choices and generally "fly like a noob". The rookies don't keep up with the veterans. It was that way IRL and it works out that way in flight sims for over 20 years now. It shows even more in IL2 where the cleaner you fly the better your results.

i think many pilots were maxed out despite their abilities

That's right. Even the aces. The ones who max out able to fly better are the ones that can get higher and/or faster on average in any combat and the difference shows. That's why there's an OLD saying: It's not the plane, it's the pilot that makes the difference.

Have you been playing flight sims much or for long at all?


I only need separate the ones that are more distinguished than the typical bounce scenario, ie ones that describe maneuvering and at least some sort of pilot awareness that they were being attacked.
Other than that, the site only includes reports where combat took place so you won't hear about scenarios where the other pilot escaped or prevailed.
TBH, there just aren't that many kill scores for the Luftwaffe against the P-47 in air battles above 5000ft. The P-47 has one of the best combat kill ratios in the ETO.
[QUOTE]
If the report has room for ambiguity of 1/2 effective guns range or more then how do you decide that you can duplicate the scene well enough to "check" with any sim made?
If that's your goal you'd have to look into other sources than just combat reports. You can look into the history behind gunnery training, and the types of weapons used and their guns sights, for starters.
I often find i can duplicate many of the tactics used here but to get 100 percent perfect duplication in a simulator would be impossible. You'd need more information than combat reports alone. </div></BLOCKQUOTE>

And what's your goal? You started out with the claim that IL2 doesn't model P-47 dive acceleration by HALF. Go back to the start of the thread and read your own posts if you don't agree NOW.

How do you check IL2 against combat reports that don't give enough specifics to allow them to be checked? How do you even get your impressions if you aren't reading from specifics? I mean, besides reading from 1949 test dives using experimental props and pulling context out of combat reports and supplying your own specifics? What's the criteria for success except being able to lay effective shots on the target in some time period -- hence the guns range criteria.

Just pointing out that you've made claims that can't be tested given the information you've provided. If that's what you base your judgment on then you should re-evaluate your ideas.

BillSwagger
11-14-2010, 02:35 PM
Is it far easier for you to twist the creditability of documented sources than it is to supply your own? geez.

I could just post the sources, and say nothing. The data speaks for itself.

I've already won the argument that the P-47 should fall faster, or that rather the other planes are too fast. That was the only point i was making about the sim.



Bill

BillSwagger
11-14-2010, 02:44 PM
Originally posted by Bremspropeller:
Thinking the P-47 "got all the aces" is just pure whishful thinking.
agreed.
I don't think it had much to do with ace pilots at all. It was a war of attrition.
Speaking of wishful thinking:
http://www.1jma.dk/articles/1j...clesww2luftwaffe.htm (http://www.1jma.dk/articles/1jmaarticlesww2luftwaffe.htm)

I'm actually a bit worried that Ubi might shut down for a while because people are starting to actually post facts on their site again.

Bill

Bremspropeller
11-14-2010, 02:56 PM
I've already won the argument that the P-47 should fall faster

Which argument?

M_Gunz
11-14-2010, 03:20 PM
Originally posted by BillSwagger:
Is it far easier for you to twist the creditability of documented sources than it is to supply your own? geez.

You haven't shown anything that can be checked close enough to matter and I have pointed that out, not twisted anything.

Geez Louise.

BillSwagger
11-14-2010, 03:25 PM
wrong Gunz.
http://www.youtube.com/watch?v...maW0&feature=related (http://www.youtube.com/watch?v=poDLjwSmaW0&feature=related)
Your nay-saying is hardly a substitute.
Seems to be the same two takers.
brems and gunz.
The two of you should be able to provide something, otherwise taking the back seat on the discussion is rather easy.

LACK OF pilot experience makes the plane take longer to get to speed, not fly as fast, not climb as fast, turn less well, completely miss out on use of different maneuvers and choices and generally "fly like a noob". The rookies don't keep up with the veterans.

Its an intuitive explanation on the face of it, but still a baseless argument.
How are you going to go about proving pilot experience?
Don't tell me pilot experience gives a plane a higher ceiling, faster diving speed, better stall conditions, or load limits.
The bottom line is you can't prove experience, or the fact that the P-47 pilots scoring the kills were any more/less experienced than the pilots they flew against.
I don't expect its something you'd be able to prove, not that i disagree, but it always appears to be the cop out in such discussions.
It would be great to see a margin of error for pilot experience. I happen to think it has less to do with actual performance, except maybe that 2 percent better overall performance, than actually knowing where to be or how to position the plane through consecutive maneuvers.



Bill

Bremspropeller
11-14-2010, 03:52 PM
The two of you should be able to provide something, otherwise taking the back seat on the discussion is rather easy.

You're the one claiming the game is wrong, so you're the guy to present hard data, instead of pointless pireps.


Don't tell me pilot experience gives a plane a higher ceiling, or faster diving speed.


http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

The plane is flown by the pilot, and unless he's doing it correctly, the plane will fail to meet it's max performance.


happen to think it has less to do with actual performance, except maybe that 2 percent better overall performance,

Do you have the faintest idea of what operating complex aircraft under operational conditions is like?
You know, switching charger-gears, correctly operating the engine, weapon-systems, oxygen, etc?
No?

Guessed so.

2% performance-diff is a joke.

BillSwagger
11-14-2010, 03:54 PM
2% performance-diff is a joke.

no no no....
this is a joke.

This is my take off song for when ever i fly the P-47 in game.
http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif
http://www.youtube.com/watch?v=PXO3gKfOUN8

M_Gunz
11-14-2010, 04:38 PM
I guess it takes some kind of gamer to think that flying is some kind of push-button affair, push the button and get the results.

It's not true and there are many accounts of rookies not being able to keep up on missions. You might be able to reach close to full speed without being a test pilot but how long it takes you to get there will be less the better you are.

2% compounds continuously, the end result in minutes is one pilot behind and below struggling along trying to keep up.

I wonder Bill if you really play or played IL2 or any other sim much except maybe with newbs and other mudhens? Maybe you've just never had time with the good players because I guarantee they can show you the difference that you blow off. That's of course unless you play the kind of denial game you play here. You'd have to call them cheats because of how much better they do than you. And NO I don't think you're that good simply because if you were then you'd have noticed how much better you do than the noobs and mudhens and wouldn't be playing the denial game. You don't know so I know you're not that good or if you even play or played at all.

You come off like Josf. All claims, all pointing at nothing much and all not accepting what you're shown. If what I have posted to you was even 1/4 as far off base as you suggest it would have been pounced on and corrected already. But I'm sure that you'll keep playing your game. You don't feel a need to compare F-86's and MiG-15's by any chance?

BillSwagger
11-14-2010, 06:30 PM
It's not true and there are many accounts of rookies not being able to keep up on missions. You might be able to reach close to full speed without being a test pilot but how long it takes you to get there will be less the better you are.

2% compounds continuously, the end result in minutes is one pilot behind and below struggling along trying to keep up.

My reasoning that its a cop out excuse for combat results is because both sides had various degrees of pilot experience as well as equipment trouble. Your assuming the winning side was always prepared or better experienced. what if it was a rookie taking out an Ace?
We can talk "maybes" and "what ifs" til the forum hits its kilobyte limit. It wouldn't change the facts presented.

You want to start picking at my competency at playing flight sims? or do you have nothing to back up your nay-saying opinion.


all pointing at nothing much and all not accepting what you're shown
what have you shown?

"nothing"

what have i shown.
"something"

"something" > "nothing"

"Bill wins again"

http://forums.ubi.com/images/smilies/11.gif

Gaston444
11-14-2010, 11:27 PM
Originally posted by M_Gunz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BillSwagger:
http://www.wwiiaircraftperform...4-goodson-7jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-goodson-7jan44.jpg)
He broke hard port, but although he pulled streamers from his wing tips, I was able to pull my sights through him. He suddenly did 2 1/2 flickrolls, and then split Sed vertically through some light cloud

http://www.wwiiaircraftperform...ntgomery-14jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-montgomery-14jan44.jpg)
E/A continued diving steeply until i was forced to pull up at about 500 feet to keep from going into the deck. The last I saw was a high column of smoke where the FW had crashed. IAS 500-550.
As White 3 pulled out of his dive the FW190 rolled three quarters of the way on his back at 300 feet with his nose 45 degrees down and IAS approximately 450mph.

http://www.wwiiaircraftperform...-padgett-26nov43.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-padgett-26nov43.jpg)
I led green section in a 360 degree turn to port and came out on the tail of number 1 E/A as he zoomed up in a steep climbing turn to port. I fired a short deflection burst at about 200 yards while in a steep climbing turn but observed no strikes

http://www.wwiiaircraftperform...richards-21jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-richards-21jan44.jpg)
He pulled up to the right to try to break into me. As he did that I laid off a little deflection above him and hit him all over the cockpit.

http://www.wwiiaircraftperform...sobanski-31jan44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-sobanski-31jan44.jpg)
I gave him a short burst in a 70 degree dive, observing no strikes. He started pulling up, turning left and I fired a 20 degree deflection shot. I observed strikes in the wings and near the cockpit. A large patch of white smoke came out after my last burst, and he flicked left, smoking badly, I flicked at the same time and lost sight of him.

http://www.wwiiaircraftperform...stanhope-16aug43.jpg (http://www.wwiiaircraftperformance.org/p-47/er/4-stanhope-16aug43.jpg)
He turned to the left, then to the right and i closed more and fired a 2-3 second burst from line astern.

http://www.wwiiaircraftperform...adrianse-22feb44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-adrianse-22feb44.jpg)
I climbed back up to 22,000 where i was bounced by a Me 109. After two turns I gained the advantage and he hit the deck. I could not follow as i was very low on fuel at this time, and headed out.

http://www.wwiiaircraftperform...-anderson-2dec44.jpg (http://www.wwiiaircraftperformance.org/p-47/er/56-anderson-2dec44.jpg)
We made a 180 degree turn and let down through the overcast and broke out at about 18,000ft. Directly ahead of us were 40 plus Me 109s. I spotted four of them flying top cover and climbed up to about 26,000ft and made a head-on pass, firing but did not score any