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XyZspineZyX
07-24-2003, 12:08 AM
I kind of borrowed it from russian forums. All regards to collected material are going to mr RB.


"From Flgiht Magazine.

In june 1943 I was selected to be the test pilot for the turbocharged Hellcat, but there was on fly in the ointment; I had never flown with a turbocharger. To give me a required turbosupercharger training, Bob Hall arranged for me to spend a week flying P-47 Thunderbolt at nearby Republic Avalon. I made six, most interesting flights, on of which was of the type I'm glad didn't happen often
My mentor at Republic was chief production test pilot Carl Bellinger. He was most amiable and spent much time en educating me about the rather complicated turbo-supercharging system and the flight characteristics of the high-wing-loading fighter (the P-47's wing loading was 48 pounds per square foot; the Hellcat's was 36 pounds per square foot). He warned me which aerobatic maneuvers I should not attempt in the P-47: spins, low-altitude spilt-S maneuvers ( a half roll followed by a half-loop) and slow rolls at airspeeds of below 150mph. The Hellcat allowed them because of its much lower wing loading
Carl didn't have to convince me about low-altitude spil-S's: during the winter of 1943; I saw the five holes in the ice of Long Island's Great South Bay that were result of Army Air Corps P-47B pilots following their leader in a spli-S maneuver below 15000 feet. His very detailed explanation were most informative to a young and "invulnerable" (euphemism for egocentric) test pilot who was still in the highly overconfident and dangerous 500-hour flight time range.
Four particularly interesting notation in the Pilot's Handbook applied to all pilots, but not, I was sure, to me:
1.Never make turns at less then 150mph in the landing pattern.
2.Don't stall; don't ever stall; never, ever stall; these are the three rules for a forced landing
3.Spin recoveries. Remember this. When your airplane goes out of control or is out of control below 4000 feet, jump!
4.Under no circumstances do a split-S at less then 15000 feet with the power on. The speed builds up at a dizzying rate. If started at speeds of more than 250mph, you can loose as much as 15000 feet before you can complete a recovery.
These admonishments were probably written into Handbook because of the 56th Fighter Group's high accident rate. It was the first Army Air Corps group to fly the Thunderbolts, and it lost 13 pilots and 41 aircraft during training at Mitchel Field, New York, before leaving for Europe!
The P-47 has often been written of as being "tremendous" in size. True, it was considerably bigger then Bell P-39 and Curtiss P-40, but to me, it wasn't much bigger that the Hellcat because it had the same wingspan and was only 3 feet longer. It was soon to find out that its much greater weight- and consequent 130-percent higher wing loading - would soon make me a respectful P-47B pilot.
The first obvious difference I noted during take off was the deep, muffled faraway exhaust noise sounded more like that of a Cadillac than of a fighter. Compared with that, the Hellcat's take-off exhaust racket - with the exhaust stacks very near cockpit sounded like an unturned hot-rod's
The P-47B's additional gross weight exceeded the Hellcat's by 3000 pounds and seemed to give it an all too disinterested acceleration rate when it tried to reach its 125mph take off speed. I immediately thought that Republic's 5000 foot runway was much too short, especially with main assembly plant right at the end of it. A few seconds later I was pleased that I had remembered to unlock the ground landing gear downlock. Had I not done this, I would have had to look back into the cockpit during takeoff to unlock it just when I wanted to be sure I would clear that onrushing factory roof. I found that P-47's lingering takeoff impressive.
I never did used to the long wait for the P-47 to leave the ground. One my first of several takeoff's, I instinctively looked back at the engine instruments several times, hoping that the throttle could be pushed much farther forward. I failed to ask why they don't use partial flap deflection to shorten its ground run.
The P-47's best climb speed was 45 mph higher than the Hellcat's 125mph, and that added to the long wait required to get away from the earth's crust, which seemed to scrape its fuselage bottom. At 10 000 feet I felt at home, so I moved the controls more then I moved my eyeballs.
Remembering the POH rebuke as I set up to do a stall, I very slowly reduced the P-47B's airspeed with the flaps and landing gear retracted . At 120mph it started to buffet, and at 110 it stalled. Surprisingly, it had very little wing drop, so I recovered and rechecked it several times with similar results. I then tried an accelerated stall at 125mph and found that even when I pulled the stick fairly hard it's stall was also preceded by pronounced buffeting, and very little wing drop. It seemed too good to be true. With the wheel and flaps down, it again stalled very gently, and the stall was preceded by an even stronger buffet warning and with absolutely no wing drop.
I was amazed because it's stall characteristics were better then the Hellcat's, but stall speed was 21mph higher. I was even more impressed when I returned from the flight and inspected the wing's leading edge expecting to find stall "fixes" such as a cambered leading edge or leading-edge spoilers that would give it required a more raid and larger throttle motion during the recovery to minimize altitude loss. It's heavier wing loading was quite noticeable during recovery.
Having acquired a more positive attitude towards its landing capabilities, I went to max cruise power of 32 inches manifold pressure and 2300 rpm to check its stability about all three axes at 250mph. I found stability in all three cases to be just what the doctor would ordered for a fighter: low but not too low for hands-off flight in moderately rough air. I also found that the rolling and pitching stick forces were in the proper ration to a fighter. The rudder forces however, seemed much to high to allow easy control coordination when turning. Later in its production cycle, a balance tab was added to the rudder to reduce forces and ensure comfortable aileron/rudder coordination in turns. As my satisfaction with this "Cadillac" increased, I tried a few mind wingovers and did slow rolls at well above 150mph! Its ailerons were much more powerful then Hellcat's and it was beginning to feel like a fighter. Rapid roll and/or roll reversals followed by tight turns were easy to do and were excellent evasive maneuvers in combat.
With increasing confidence, I decided to make a quantitative check of its longitudinal maneuvering forces to 5G at 300mph with my hand stick-force indicator. In other words, I would see whether I had to pull harder at higher speed to get as much G-force. The results showed 4 pounds per G-in the middle of the military requirement of 3 to 8 pound per G. The P-47 felt reasonably comfortable for holding G in ar-to air combat-turning and bombing-pullout maneuvers. I evaluated it a year before G-suits were issued to prevent pilots from blacking out when holding higher turning G for too long.."


RB, if you are reading this forum, thanks alot, it was a good read.

V!



Regards,
VFC*Crazyivan
http://www.rmutt.netfirms.com/ivan-reaper.gif

"No matter how good the violin may be, much depends on the violinist. I always felt respect for an enemy pilot whose plane I failed to down." Ivan Kozhedub

XyZspineZyX
07-24-2003, 12:08 AM
I kind of borrowed it from russian forums. All regards to collected material are going to mr RB.


"From Flgiht Magazine.

In june 1943 I was selected to be the test pilot for the turbocharged Hellcat, but there was on fly in the ointment; I had never flown with a turbocharger. To give me a required turbosupercharger training, Bob Hall arranged for me to spend a week flying P-47 Thunderbolt at nearby Republic Avalon. I made six, most interesting flights, on of which was of the type I'm glad didn't happen often
My mentor at Republic was chief production test pilot Carl Bellinger. He was most amiable and spent much time en educating me about the rather complicated turbo-supercharging system and the flight characteristics of the high-wing-loading fighter (the P-47's wing loading was 48 pounds per square foot; the Hellcat's was 36 pounds per square foot). He warned me which aerobatic maneuvers I should not attempt in the P-47: spins, low-altitude spilt-S maneuvers ( a half roll followed by a half-loop) and slow rolls at airspeeds of below 150mph. The Hellcat allowed them because of its much lower wing loading
Carl didn't have to convince me about low-altitude spil-S's: during the winter of 1943; I saw the five holes in the ice of Long Island's Great South Bay that were result of Army Air Corps P-47B pilots following their leader in a spli-S maneuver below 15000 feet. His very detailed explanation were most informative to a young and "invulnerable" (euphemism for egocentric) test pilot who was still in the highly overconfident and dangerous 500-hour flight time range.
Four particularly interesting notation in the Pilot's Handbook applied to all pilots, but not, I was sure, to me:
1.Never make turns at less then 150mph in the landing pattern.
2.Don't stall; don't ever stall; never, ever stall; these are the three rules for a forced landing
3.Spin recoveries. Remember this. When your airplane goes out of control or is out of control below 4000 feet, jump!
4.Under no circumstances do a split-S at less then 15000 feet with the power on. The speed builds up at a dizzying rate. If started at speeds of more than 250mph, you can loose as much as 15000 feet before you can complete a recovery.
These admonishments were probably written into Handbook because of the 56th Fighter Group's high accident rate. It was the first Army Air Corps group to fly the Thunderbolts, and it lost 13 pilots and 41 aircraft during training at Mitchel Field, New York, before leaving for Europe!
The P-47 has often been written of as being "tremendous" in size. True, it was considerably bigger then Bell P-39 and Curtiss P-40, but to me, it wasn't much bigger that the Hellcat because it had the same wingspan and was only 3 feet longer. It was soon to find out that its much greater weight- and consequent 130-percent higher wing loading - would soon make me a respectful P-47B pilot.
The first obvious difference I noted during take off was the deep, muffled faraway exhaust noise sounded more like that of a Cadillac than of a fighter. Compared with that, the Hellcat's take-off exhaust racket - with the exhaust stacks very near cockpit sounded like an unturned hot-rod's
The P-47B's additional gross weight exceeded the Hellcat's by 3000 pounds and seemed to give it an all too disinterested acceleration rate when it tried to reach its 125mph take off speed. I immediately thought that Republic's 5000 foot runway was much too short, especially with main assembly plant right at the end of it. A few seconds later I was pleased that I had remembered to unlock the ground landing gear downlock. Had I not done this, I would have had to look back into the cockpit during takeoff to unlock it just when I wanted to be sure I would clear that onrushing factory roof. I found that P-47's lingering takeoff impressive.
I never did used to the long wait for the P-47 to leave the ground. One my first of several takeoff's, I instinctively looked back at the engine instruments several times, hoping that the throttle could be pushed much farther forward. I failed to ask why they don't use partial flap deflection to shorten its ground run.
The P-47's best climb speed was 45 mph higher than the Hellcat's 125mph, and that added to the long wait required to get away from the earth's crust, which seemed to scrape its fuselage bottom. At 10 000 feet I felt at home, so I moved the controls more then I moved my eyeballs.
Remembering the POH rebuke as I set up to do a stall, I very slowly reduced the P-47B's airspeed with the flaps and landing gear retracted . At 120mph it started to buffet, and at 110 it stalled. Surprisingly, it had very little wing drop, so I recovered and rechecked it several times with similar results. I then tried an accelerated stall at 125mph and found that even when I pulled the stick fairly hard it's stall was also preceded by pronounced buffeting, and very little wing drop. It seemed too good to be true. With the wheel and flaps down, it again stalled very gently, and the stall was preceded by an even stronger buffet warning and with absolutely no wing drop.
I was amazed because it's stall characteristics were better then the Hellcat's, but stall speed was 21mph higher. I was even more impressed when I returned from the flight and inspected the wing's leading edge expecting to find stall "fixes" such as a cambered leading edge or leading-edge spoilers that would give it required a more raid and larger throttle motion during the recovery to minimize altitude loss. It's heavier wing loading was quite noticeable during recovery.
Having acquired a more positive attitude towards its landing capabilities, I went to max cruise power of 32 inches manifold pressure and 2300 rpm to check its stability about all three axes at 250mph. I found stability in all three cases to be just what the doctor would ordered for a fighter: low but not too low for hands-off flight in moderately rough air. I also found that the rolling and pitching stick forces were in the proper ration to a fighter. The rudder forces however, seemed much to high to allow easy control coordination when turning. Later in its production cycle, a balance tab was added to the rudder to reduce forces and ensure comfortable aileron/rudder coordination in turns. As my satisfaction with this "Cadillac" increased, I tried a few mind wingovers and did slow rolls at well above 150mph! Its ailerons were much more powerful then Hellcat's and it was beginning to feel like a fighter. Rapid roll and/or roll reversals followed by tight turns were easy to do and were excellent evasive maneuvers in combat.
With increasing confidence, I decided to make a quantitative check of its longitudinal maneuvering forces to 5G at 300mph with my hand stick-force indicator. In other words, I would see whether I had to pull harder at higher speed to get as much G-force. The results showed 4 pounds per G-in the middle of the military requirement of 3 to 8 pound per G. The P-47 felt reasonably comfortable for holding G in ar-to air combat-turning and bombing-pullout maneuvers. I evaluated it a year before G-suits were issued to prevent pilots from blacking out when holding higher turning G for too long.."


RB, if you are reading this forum, thanks alot, it was a good read.

V!



Regards,
VFC*Crazyivan
http://www.rmutt.netfirms.com/ivan-reaper.gif

"No matter how good the violin may be, much depends on the violinist. I always felt respect for an enemy pilot whose plane I failed to down." Ivan Kozhedub

XyZspineZyX
07-24-2003, 12:44 AM
Good read, thanks!

XyZspineZyX
07-24-2003, 12:59 AM
Thx for the info. /i/smilies/16x16_smiley-happy.gif

XyZspineZyX
07-24-2003, 01:43 AM
"Rapid roll and/or roll reversals followed by tight turns were easy to do and were excellent evasive maneuvers in combat."

Not in FB their not. /i/smilies/16x16_robot-sad.gif


<center>http://www.2001exhibit.org/science/img/sm_hal_9000_art.gif <marquee>The 9000 series is the most reliable computer ever made. No 9000 series has ever made a mistake or distorted information. We are all, by any practical definition of the word, fool-proof and incapable of error...Edited 00/00/00 00:00AM </marquee></center>

XyZspineZyX
07-24-2003, 04:58 AM
Then you haven't seen how the best of the P-47D pilots fight in FB.

It rolls too slow, have issues with high speed control lock-ups, the aiming reticles suck, too. But it does have that "charm" of low-speed reversals consisting of continuous flat scissors, unique to the US planes and even seen in even other sim games.

If anyone sees the "acealpha" server in Hyperlobby, which usually thrives in Far East pacific time zones, try and find a pilot named "bombrun", and see how he 'does' his P-47.

Quite impressive.


-----------
Due to pressure from the moderators, the sig returns to..

"It's the machine, not the man." - Materialist, and proud of it!

XyZspineZyX
07-24-2003, 05:21 AM
Bear in mind that this report is about P-47B, a P-47 variant weighting over 2000lb less than the plane in FB. Not significant at all. Also this report mentions only the pros but no cons of P-47B. In fact P-47B was never considered combat ready and had a very high accident rate. I don't think that happened because it was a plane easy to handle. And don't forget that P-47D was more powerful and suffered badly from torque related problems. There is a detalied report on handling characteristics of P-47D on NACA's report server.

XyZspineZyX
07-24-2003, 05:29 AM
Huckebein_FW wrote:
- There is a detalied report on handling characteristics
- of P-47D on NACA's report server.

Got Link?

and

NACA report number?



TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-24-2003, 05:31 AM
Yep, try it.

http://naca.larc.nasa.gov/reports/1952/naca-tn-2675/naca-tn-2675.pdf

XyZspineZyX
07-24-2003, 05:32 AM
The thread is complete. Huck is here telling us how bad American planes are again. You go Huck. Never give up the fight.

Da Buzz
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
<center>
http://www.elknet.pl/acestory/foto1/anderson3.jpg

XyZspineZyX
07-24-2003, 05:33 AM
BuzzU wrote:
- The thread is complete. Huck is here telling us how
- bad American planes are again. You go Huck. Never
- give up the fight.


No, I have no intentions to do so. This subject was already discussed.
Now P-39 is the topic for me.

XyZspineZyX
07-24-2003, 05:38 AM
Huckebein_FW wrote:
- Yep, try it.

BUD! THANK YOU!!

So... that is a gov sight? Have they started converting the microfish NACA doc to soft copies? If so, any idea on how far they are in the process? I noticed that the sub dir said 1952.. any insight or info would be great thanks a mill!!!!!



TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-24-2003, 05:45 AM
Huckebein_FW wrote:
- Yep, try it.

WOW this is great! I have been waiting for years for them to do this... how long has this sight been there? I had an NACA doc once that consisted of just the titles of all the other NACA docs... kind of like a index of the NACA reports! You wouldnt happen to know off hand the number of that one? God, this is a great resorce... I just wonder how complet it is? It looks like all the years are there.. and the dir are pretty full... WOW, thanks again!! This is the best link I have been given in years!!



TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-24-2003, 05:48 AM
Salute Huck

If I was to trot out that test which showed the 190's elevator being very heavy at speeds everytime someone said something nice about your Focke Wulfs you might get annoyed.

We've all seen that D30 report many times. And the fact that the data results on only 30 lbs stick force means it doesn't relate to the real rollrate of the P-47.

So just relax and go back to saying how nice the 190 is, instead of feeling the nesesity to smear any British or U.S. aircraft which happens to come up for discussion.


Cheers RAF74 Buzzsaw

XyZspineZyX
07-24-2003, 05:51 AM
Links to some naca/nasa report servers:

http://naca.larc.nasa.gov/

http://www.dfrc.nasa.gov/DTRS/


There are some other naca/nasa report servers also, just follow the links.
NACA reports are an incredible resource for technical data. Simply priceless.

XyZspineZyX
07-24-2003, 05:57 AM
Huckebein_FW wrote:
- NACA reports are an incredible resource for
- technical data. Simply priceless.

Agreed 100% My old school has them all, but they are all on micro-fish! Complete, but a real pain in the A to look things up! This is great, thanks a mill!!



TAGERT
-------------------------------------------------------------------------------------------------------
If WAR was not the ANSWER.. Than what the H was your QUESTION?

XyZspineZyX
07-24-2003, 06:02 AM
My pleasure tagert.

XyZspineZyX
07-24-2003, 06:05 AM
Can someone summarize it for me? ITs a 62 page doc....

XyZspineZyX
07-24-2003, 06:16 AM
RAF74Buzzsaw_XO wrote:
- Salute Huck
-
- If I was to trot out that test which showed the
- 190's elevator being very heavy at speeds everytime
- someone said something nice about your Focke Wulfs
- you might get annoyed.


I don't really understand what are you trying to say. Do you propose some sort of a trade? Buzzsaw, I don't care how bad Fw-190 flies as long as it is accurate. Same for P-47.



- We've all seen that D30 report many times. And the
- fact that the data results on only 30 lbs stick
- force means it doesn't relate to the real rollrate
- of the P-47.

Don't forget that full aileron deflection could not be applied because stick movement interfered with leg movement necessary to counter the yaw (the report mentions left roll), so those fifty whatever stick force were theoretical more than practical.
By the way I never saw anybody complaining about the P-47 overmodelled turn rate. You can do easily sustained turns in 22 sec instead of more than 26 sec. Fix the roll and cut the turn rate.





Message Edited on 07/24/0312:23AM by Huckebein_FW

XyZspineZyX
07-24-2003, 06:18 AM
TAW_Jenikov wrote:
- Can someone summarize it for me? ITs a 62 page
- doc....

It has conclusions on page 10.

XyZspineZyX
07-24-2003, 07:31 AM
Salute Huckebein

No, I don't propose a trade. Neither do I propose excluding anything, I prefer to post complete tests, and always offer the readers the opportunity to see the original for themselves.

I propose you include ALL the relevant information regarding a particular aircraft's performance, instead of only the negative. As you seem to have accused the original poster of doing.

Let's look at this test that you have provided a link to. It's often used in aid of attempts to smear the P-47 and suggest it only had a rollrate of 60 degrees per second.

First of all, it is not a test of the Aircraft's aileron response. As the title says, "Measurements of flying qualities of an F-47D-30 airplane to determine lateral and directional stability and control characteristics", it is a test of the directional stability of the aircraft. When the P-47 was converted to a bubble top model, the directional stability suffered as a result of the loss of the fuselage running back from the cockpit to the tail on the original "Razorback" design. The fact that the aileron response is included, is only as a comment on the fact that the aircraft directional stability during Aileron rolls was being assessed. In fact most of the charts included relate to directional stability and discuss the amount of sideslip produced at particular speeds and during particular maneuvers. As for example this one:

http://naca.larc.nasa.gov/reports/1952/naca-tn-2675/0034.gif


Also included, are a few charts dealing with actual aileron response. But they are not tests of the aircraft's maximum rollrate, they are tests of its rollrate when the arbitrary figure of 30 lbs stickforce is used as a force standard.

If one looks at the chart, you can see specifically, that it indicates 30 lbs stickforce was used to attain the particular rolling velocity:


http://naca.larc.nasa.gov/reports/1952/naca-tn-2675/0057.gif


There is no suggestion that 30 lbs is the maximum stickforce which can be applied, in fact there are other charts which clearly show that more than 30lbs can be applied. For example:

http://naca.larc.nasa.gov/reports/1952/naca-tn-2675/0053.gif


You can see clearly that 40 lbs stickforce is applied in this chart for tests at 300 mph. But again, this is not indicated as the maximum stickforce which can be applied, but simply the amount of force required to gain a particular aimed for result in the test. Less force was required to attain the desired result at lower speeds.

Using the provided chart at stick forces of 30lbs and then claiming it is indicative of the aircraft's maximum aileron response is simply misleading.

To get back to the original point:

The first poster kindly provided us with some material we had not seen before. At which point you found it nessesary to inteject with some obviously misinterpreted material in an effort to denigrate the original post.

Maybe next time you will think twice.

Cheers RAF74 Buzzsaw





Message Edited on 07/24/0306:34AM by RAF74Buzzsaw_XO

XyZspineZyX
07-24-2003, 11:38 AM
Just after a quick test, in FB, it is quite possible to perform a Spilt-S at 250 mph IAS at 110% with water injection from at low as 3,000 ft/1000m The entire operation only takes ~2,500 ft/750m to complete and the aircraft only reaches about 350mph in the dive.

The entire manuver only takes aproximately 10 seconds.

Huck where are you getting this 26 second turn time figure? Is this one of your "calculated" figures? The P-47 has the same wingloading as the P-51, 109 and 190, and its powerloading is also in the same range, if on the low side when fully loaded, and very close to the 190 when both are dogfight loaded. So where, pray tell is this extra 25% time coming from?

Harry Voyager

http://groups.msn.com/_Secure/0YQDLAswcqmIpvWP9dLzZVayPXOmo6IJ16aURujNfs4dDETH84 Q6eIkCbWQemjqF6O8ZfvzlsvUUauJyy9GYnKM6!o3fu!kBnWVh BgMt3q2T3BUQ8yjBBqECLxFaqXVV5U2kWiSIlq1s6VoaVvRqBy Q/Avatar%202%20500x500%20[final).jpg?dc=4675409848259594077

XyZspineZyX
07-24-2003, 12:47 PM
Very interesting text, thanks.

Btw, I hope that some warbirds pilots making aerobatics in meetings at low speed and low alitude will read these advices:


1.Never make turns at less then 150mph in the landing pattern.
2.Don't stall; don't ever stall; never, ever stall; these are the three rules for a forced landing
3.Spin recoveries. Remember this. When your airplane goes out of control or is out of control below 4000 feet, jump!
4.Under no circumstances do a split-S at less then 15000 feet with the power on. The speed builds up at a dizzying rate. If started at speeds of more than 250mph, you can loose as much as 15000 feet before you can complete a recovery.


Cheers,

XyZspineZyX
07-24-2003, 01:51 PM
HarryVoyager wrote:
- Just after a quick test, in FB, it is quite possible
- to perform a Spilt-S at 250 mph IAS at 110% with
- water injection from at low as 3,000 ft/1000m The
- entire operation only takes ~2,500 ft/750m to
- complete and the aircraft only reaches about 350mph
- in the dive.

I noticed how strange this is too. It's so completely at odds with the behaviour of any a/c in FB that either it means the real a/c manouver is allowing a huge safety margin, or that there is something very wrong with the FB flight model (and that of pretty much every other WWII sim I have ever played, for that matter).

To be fair to FB, requiring 15,000' to perform a Split-S sounds very odd. I can't remember hearing anything similar elsewhere, so I'm inclined to treat this with caution.

However, one possibility is that the dive acceleration was much greater in real life than we have in FB and that the a/c reached such high speeds that control authority was degraded in the pull out. This is something where the FB FM definitely has problems. In the out-of-the-box game, all a/c seem to accelerate at approximately the same rate in a dive. The inability of FB's P-47 to out-dive a Bf110 is very noticeable and suggests somrthing is not quite right. Of course, it would have to be very wrong indeed to require a 15,000' entry to a Split-S.

- Huck where are you getting this 26 second turn time
- figure? Is this one of your "calculated" figures?

I think Huck uses some very simplified assumptions to perform his calculations. Hence the inevitable errors. Take them with a large pinch of salt.

Regards,

RocketDog.

XyZspineZyX
07-24-2003, 02:36 PM
Seems to me the report boils down to "this thing doesn't fly slow very well, particularly at low altitudes. Nothing very surprising about that.

XyZspineZyX
07-24-2003, 02:56 PM
Just a correction to Crazy Ivan's original post. This was not written by a British test pilot, but by a Grumman test pilot named Corky Meyer. He's American. The full article can be found in a special P-47 feature edition from Flight Journal magazine. On news stands now!

XyZspineZyX
07-24-2003, 03:33 PM
Thanks to Buzzsaw for clarifying the data of the NACA report.

Later in the same article, Meyer talks about a later flight in a bubble top P-47 and remarks about the problems had with directional stability. According to Meyer the real problems occured in the landing approach with gear and flaps down. It seems at a certain point in the rudder input in that configuration, the airflow could sometimes cause a full deflection of the rudder in that direction and hard opposite rudder was then needed to correct. As we all know the addition of a dorsal fillet solved the problem.

Meyer's impressions of the later P-47 were even more favorable than the earlier B model (telling, since he worked for Republic's "rival" Long Island aircraft company, Grumman). I know it's hard for some people to deal with a positive assessment of an American plane. But there you have it.

XyZspineZyX
07-24-2003, 04:16 PM
RAF74Buzzsaw_XO wrote:
-
- Let's look at this test that you have provided a
- link to. It's often used in aid of attempts to
- smear the P-47 and suggest it only had a rollrate of
- 60 degrees per second.

So you discovered NACA's clear intention to "smear" the reputation of P-47. That's something to remember.



- First of all, it is not a test of the Aircraft's
- aileron response. As the title says, "Measurements
- of flying qualities of an F-47D-30 airplane to
- determine lateral and directional stability and
- control characteristics", it is a test of the
- directional stability of the aircraft. When the P-47
- was converted to a bubble top model, the directional
- stability suffered as a result of the loss of the
- fuselage running back from the cockpit to the tail
- on the original "Razorback" design. The fact that
- the aileron response is included, is only as a
- comment on the fact that the aircraft directional
- stability during Aileron rolls was being assessed.
- In fact most of the charts included relate to
- directional stability and discuss the amount of
- sideslip produced at particular speeds and during
- particular maneuvers. As for example this one:
- src="http://naca.larc.nasa.gov/reports/1952/naca-t
- n-2675/0057.gif">


No, it's not a test on roll but on stability. And the low speed stability problems discovered in this test are not present in the sim (except the torque roll, which should be present on all high powered aircraft). On the other hand the test clearly states that full aileron deflection could not be achieved if pilot tries to counter the yaw at the same time with rudder. So what's the maximum stick force? who knows. Also roll rate is NOT in linear dependence with stick force. Applying 100lb force won't change the roll rate at 50lb. Amusing is that the test pilot employed by NACA in the investigation of the reason for the inability of P-47 pilots to pull out from high speed dives was an Olympic champion weight lifter, Perry Ritchie. Maybe you want him modelled in the sim for a full (and definitive) aileron deflection?/i/smilies/16x16_smiley-very-happy.gif /i/smilies/16x16_smiley-very-happy.gif


- Using the provided chart at stick forces of 30lbs
- and then claiming it is indicative of the aircraft's
- maximum aileron response is simply misleading.

I never had such intention, can you point out where I said such a thing? Otherways you're just a liar.



- To get back to the original point:
-
- The first poster kindly provided us with some
- material we had not seen before. At which point you
- found it nessesary to inteject with some obviously
- misinterpreted material in an effort to denigrate
- the original post.

Obviously misinterpreted material??? I see, then please provide me with the "correct interpretation" of the conclusions of this report.
Let's take for example:

"The general characteristics of aileron were good but effectiveness of the aileron control was below the Air Force requirements. The maximum pb/2V obtainable was 0.074 as compared with the Air Force requirement of 0.09."

In a "correct interpretation" I should read that in fact aileron effectiveness met the Air Force requirements, isn't it?
Or probably not. It was just another proof for the NACA attempt to smear P-47.

Get a life Buzzsaw.

XyZspineZyX
07-24-2003, 04:45 PM
HarryVoyager wrote:
- Just after a quick test, in FB, it is quite possible
- to perform a Spilt-S at 250 mph IAS at 110% with
- water injection from at low as 3,000 ft/1000m The
- entire operation only takes ~2,500 ft/750m to
- complete and the aircraft only reaches about 350mph
- in the dive.
-
- The entire manuver only takes aproximately 10
- seconds.
-
- Huck where are you getting this 26 second turn time
- figure? Is this one of your "calculated" figures?
- The P-47 has the same wingloading as the P-51, 109
- and 190, and its powerloading is also in the same
- range, if on the low side when fully loaded, and
- very close to the 190 when both are dogfight loaded.
- So where, pray tell is this extra 25% time coming
- from?


Terribly incorrect. 190 has the same powerloading with P-47? I won't compare it 109 or A9/D9 cause you'll start crying, so big is the difference. Let's compare a P-47D-25 with an A8: 2.6kg/hp vs 2.1kg/hp, 23% bigger power loading for P-47D. Don't forget that in the formula for turning you have actually excess thrust divided by weight, and A8 produces much bigger excess thrust.


And this is supposed to be an irony?: "Is this one of your "calculated" figures?"
My calculated figures are obtained with NACA's own formulas, like those used in F2A turning test. Criticise them if you want.

One more thing, calculated figures are not less accurate than test figures. Test data measurement produces its own set of errors. In fact those calculations are made with some test based values, like stall speed or max speed, power rating and so on which are less prone to measurement errors. Others like climb rates and climb time, turn time or acceleration were first calculated (estimated) then flight test were made in order to confirm/infirm them.



Message Edited on 07/24/0310:49AM by Huckebein_FW

XyZspineZyX
07-24-2003, 04:45 PM
RAF74Buzzsaw_XO wrote:
- Salute Huck
-
- If I was to trot out that test which showed the
- 190's elevator being very heavy at speeds everytime
- someone said something nice about your Focke Wulfs
- you might get annoyed.
-
- We've all seen that D30 report many times. And the
- fact that the data results on only 30 lbs stick
- force means it doesn't relate to the real rollrate
- of the P-47.


There is another NACA Confidential Bulletin in circulation:

"Comparison of Aileron Control Characteristics as determined in Flight Tests of P-36, P-40, 'Spitfire' and 'Hurricane' Pursuit Airplanes."
Public Record Office Ref: DSIR 23/12117

Among other interesting stuff on the roll rate of the above planes, it says:
"...A force of 30 pounds is somewhat less then the greatest stick force expected by pilot. <u>Replicated flight measurements have shown, however, that this force is reasonable upper limit for maneuvering at high speed</u>..."


AKA_Bogun

---------------
The difference between fiction and reality? Fiction has to make sense.

- Tom Clancy

---------------
Ilsa: "That was the day the Germans marched into Paris."
Rick: "Not an easy day to forget. The Germans wore grey, you wore blue."
Ilsa: "Yes. I have put that dress away. When the Germans march out, I'll wear that dress again."

- Casablanca, 1942

XyZspineZyX
07-24-2003, 05:12 PM
Huckebein_FW wrote:

- "The general characteristics of aileron were good
- but effectiveness of the aileron control was below
- the Air Force requirements. The maximum pb/2V
- obtainable was 0.074 as compared with the Air Force
- requirement of 0.09."
-
- In a "correct interpretation" I should read that in
- fact aileron effectiveness met the Air Force
- requirements, isn't it?
- Or probably not. It was just another proof for the
- NACA attempt to smear P-47.


Then there MUST be something fishy about this report. Correct me if I'm wrong but didn't the P-47 have a better rate of roll than it's two front line brethren- the P-51 and the P-38 (at least until they boosted the ailerons)?

If so, then the Mustang's and Lightning's roll rates didn't meet the AF requirements either. And since Meyer states that the aileron response was better in the P-47 than in the Hellcat are we to assume that the Navy's requirements were below that of the AF for what was acceptable in that area of performance?

Doesn't make sense to me.

XyZspineZyX
07-24-2003, 05:27 PM
Huckebein_FW wrote:

- And this is supposed to be an irony?: "Is this one
- of your "calculated" figures?"
- My calculated figures are obtained with NACA's own
- formulas, like those used in F2A turning test.
- Criticise them if you want.
-
- One more thing, calculated figures are not less
- accurate than test figures. Test data measurement
- produces its own set of errors.

Hmmm...

I'm not convinced.

How accurate are these calculations? Are they +/- 5%, 10%, 20% 30%? What simplifications are made? How well do they compare to experiment?

Regards,

RocketDog.

XyZspineZyX
07-24-2003, 06:10 PM
LilHorse wrote:
- Just a correction to Crazy Ivan's original post.
- This was not written by a British test pilot, but by
- a Grumman test pilot named Corky Meyer. He's
- American. The full article can be found in a
- special P-47 feature edition from Flight Journal
- magazine. On news stands now!
-
-

LOL, you are right... i got confused with a title of it... RB meant it was written in english...not the english pilot...dang /i/smilies/16x16_smiley-very-happy.gif

Regards,
VFC*Crazyivan
http://www.rmutt.netfirms.com/ivan-reaper.gif

"No matter how good the violin may be, much depends on the violinist. I always felt respect for an enemy pilot whose plane I failed to down." Ivan Kozhedub

XyZspineZyX
07-24-2003, 08:27 PM
RocketDog wrote:
- Hmmm...
-
- I'm not convinced.
-
- How accurate are these calculations? Are they +/-
- 5%, 10%, 20% 30%? What simplifications are made? How
- well do they compare to experiment?


They match perfectly the results obtained in russian turning tests for russian planes. Test values for planes like I-153, Lagg3, La5/7, Mig3, Yak9, Yak9U, Hurri, P-40, Fw-190A and D, all of them match the calculations. There are very few that do not match the results: Yak1 and 3 are with a second better, Bf-109F and G with a second less (but the difference is not big).

Of course in calculations I use some simplifications:
* prop efficiency is derived from a generic formula giving values similar to those in a prop eff polar found in a NACA test - it's a very good aprox for all the props mounted on high speed planes of that period (varies with mach number)
* value for Oswald factor is calculated with a formula that has only a generic aproximation on fuselage interference (invariable)
* thrust takes into account the difference between rated power vs dynamic power and exhaust thrust in a generic manner (varies with alt and speed)

All of these do not have a significant effect on results (best estimation is at sea level). In fact in ww2 estimations even more drastic simplifications were used, like 0.8 prop eff, 0.8 Osw fact and no word on dynamic power or exhaust thrust. When I have these values from tests for certain planes (though they were also obtained with some degree of error) I use them in calculations.

Beside turn rates I obtain for climb rates a +/-5% difference from test results. But don't forget that real life tests are influenced by atmospheric conditions, like air density and turbulence (I use standard atmospheric conditions), which affect the results, beside the inherent errors in measurement. Even so the calculated and tested values are very very close.

There are two categories of tests that are always off. British tests made at Boscombe from '43 till the end of the war and USN tests on Corsair and Bearcat.
British tests do not list the power rating of the engines used in tests and if I use the values for operational planes I do get much less impressive values. Conclusion is that the test values are incorrect or the power rating of the engines is much bigger than those mounted in operational aircraft.
In USN tests they do not give the weight in test, weight having a big effect on climb rate, just like power rating. Most of them match the values at half internal fuel load. Though some sources list very good performance numbers on Corsair. Beside climb rates there is a problem with Corsair max speeds. And of course the obviously erroneous climb rate values for Bearcat (especially the prototype).

XyZspineZyX
07-24-2003, 11:20 PM
Huckebein_FW wrote:

- Applying 100lb force won't change
- the roll rate at 50lb.

I'm not sure what you are trying to say.

50lbs of force is sufficient to fully deflect the ailerons up to a certain speed. Once that certain speed is reached, 50lbs is no longer sufficient to fully deflect the aileron. So a higher force is needed to fully deflect the ailerons.

So, yes, if 20 lbs of force is sufficient to fully deflect the ailerons at some speed, applying 50lbs of force is wasted effort. The ailerons can't deflect anymore.

But if 50lbs of force is no longer sufficient to fully deflect the ailerons at a higher speed, then yes, more force will be needed to fully deflect them.




It's easy to figure out what the D-30 roll rate would be with a 50lb stick force if we already have the chart with the 30lb stick force. We simply need to know what the peak roll rate of the D-30 was.

My sources suggest the P-47D-25 had the same peak roll with a 50lb stick rate as the earlier D models had (about 85 degrees per second), just at a higher speed. That fits perfectly with the NACA D-30 chart. (The D-25, 27, etc and D-30 should roll at very closely the same rate). All we have to do is extend the roll line to the peak roll rate and there we have it:

http://pages.prodigy.net/4parks/_images/roll.JPG


50lbs was generally the test standard for US WWII aircraft (except of course in this test which is a slow speed analysis where high stick forces are not necessary).

Of course, higher stick forces could be applied at higher speeds achieving even higher roll rates. The limitation here is pilot ability, range of motion limitations, and structural limitations placed on the plane. Most high performance fighters had full throw aileron restrictions that usually ranged from 350mph IAS on up.





Regards,

SkyChimp

http://pages.prodigy.net/4parks/_uimages/SkyChimp.jpg

XyZspineZyX
07-24-2003, 11:45 PM
Huckebein_FW wrote:

- In USN tests they do not give the weight in test,
- weight having a big effect on climb rate, just like
- power rating. Most of them match the values at half
- internal fuel load. Though some sources list very
- good performance numbers on Corsair. Beside climb
- rates there is a problem with Corsair max speeds.
- And of course the obviously erroneous climb rate
- values for Bearcat (especially the prototype).


I'm not sure what you mean "most of them match the values at half internal fuel load." Which reports do you have that suggests this? The reports I have give a weight, just a weight. I've yet to see one that is not at or extremely close to the normal loaded weight.

And what is wrong with the XF8F's climb rate? You can't make you figures work out so it must be wrong? And what do you think the figures ought to be?

For instance, the F8F-1 Bearcat at 9,215lbs. What do you think the time to climb from sea level to 5,000 feet, 10,000 feet, 15,000 feet, 20,000 feet and 25,000 feet ought to be? Please post them, then we'll check your estimations with the actual numbers from the manual, which I have.


You have a propensity to declare something wrong if the US plane's performance exceeds your "expectations." You are very quick to declare US tests faulty because your math doesn't work out. Yet you were not present at the tests, you never flew the planes, and your life never depended on them performing the way they were supposed to. You seem to be the only person on these boards that continually declares tests performed by persons far more qualified than you erroneous.





Regards,

SkyChimp

http://pages.prodigy.net/4parks/_uimages/SkyChimp.jpg

The_Blue_Devil
07-25-2003, 12:15 AM
Wow...Chimp Layed it down....I have to see Huck's response to this.

<center>----------------------------------------------------------------------------</center>
<center>[b]"Pilots who liked to dogifght could do it their own way. I avoided it. I always attacked at full speed and I evaded a bounce in the same manner. When you were hit from above and behind, and your attacker held his fire until he was really close, you knew you were in with someone who had a great deal of experience.-Erich Hartmann"[b]</center>


<center> <img src=http://www.angelfire.lycos.com/art2/devilart/MySig.gif> </center>

XyZspineZyX
07-25-2003, 02:35 AM
LilHorse wrote:
-
- Huckebein_FW wrote:
-
-- "The general characteristics of aileron were good
-- but effectiveness of the aileron control was below
-- the Air Force requirements. The maximum pb/2V
-- obtainable was 0.074 as compared with the Air Force
-- requirement of 0.09."
--
-- In a "correct interpretation" I should read that in
-- fact aileron effectiveness met the Air Force
-- requirements, isn't it?
-- Or probably not. It was just another proof for the
-- NACA attempt to smear P-47.
-
-
- Then there MUST be something fishy about this
- report. Correct me if I'm wrong but didn't the P-47
- have a better rate of roll than it's two front line
- brethren- the P-51 and the P-38 (at least until they
- boosted the ailerons)?
-
- If so, then the Mustang's and Lightning's roll rates
- didn't meet the AF requirements either. And since
- Meyer states that the aileron response was better in
- the P-47 than in the Hellcat are we to assume that
- the Navy's requirements were below that of the AF
- for what was acceptable in that area of performance?
-
- Doesn't make sense to me.
-
-

The P-47 had the best roll rate of any USAAF front line fighter when it was introduced. The only two USAAF aircraft to surpass it during WWII were the P-51, and P-63. I do not have the precise roll rates handy at the moment, but I am sure many people here would be happy to provide them, for varrying stick forces.

As for your "Great Conspiracy" Huck, when we wish to better understand the performance of an aircraft in the middle of its performance range, we test it at the middle of its performance range, and record its performance at the middle of its performance range. We then use those figures to describe how the aircraft performs at the middle of its performance range.

We do not, say, test the speed of the aircraft at cruising power, and then declare that that speed at cruising power is its top speed. Rather, we say that that speed at cruising power, is its cruising speed, because sometimes we do need to know what its cuising speed, at cruising power is.

We do not always need to know the maximum speed, or the maximum climb rate, or the maximum roll rate for an aircraft. Some times we need to know what happens at a lesser speed, or a lesser climb, or a lesser roll, and we clearly mark that it is a less speed, or a lesser climb, or even a lesser roll that we have tested.

In this test, we desired to find the results at a lesser roll rate, so we used a lesser roll rate, and marked it as such.

Harry Voyager

http://groups.msn.com/_Secure/0YQDLAswcqmIpvWP9dLzZVayPXOmo6IJ16aURujNfs4dDETH84 Q6eIkCbWQemjqF6O8ZfvzlsvUUauJyy9GYnKM6!o3fu!kBnWVh BgMt3q2T3BUQ8yjBBqECLxFaqXVV5U2kWiSIlq1s6VoaVvRqBy Q/Avatar%202%20500x500%20[final).jpg?dc=4675409848259594077

XyZspineZyX
07-25-2003, 04:16 AM
Salute Bogun

In regards to your comment that the maximum stick force which can be applied in combat maneuvering is 30 lbs:

That may apply to the aircraft in the test, ie. the Spitfire, Hurricane, P-40 etc.

But the P-47 had a different stick arrangement, stick length, and a much larger cockpit, which allowed the pilot to actually apply body weight leverage to the stick, something which could not be done to any degree in a smaller cockpit such as the 109 or Spitfire.

Some reports from pilots said they felt they could apply up to 1/3 of their body weight. For guys like "Gabby" Gabreski, that meant 70 lbs.


Cheers Buzzsaw

XyZspineZyX
07-25-2003, 04:47 PM
SkyChimp wrote:
-
- You have a propensity to declare something wrong if
- the US plane's performance exceeds your
- "expectations." You are very quick to declare US
- tests faulty because your math doesn't work out.
- Yet you were not present at the tests, you never
- flew the planes, and your life never depended on
- them performing the way they were supposed to. You
- seem to be the only person on these boards that
- continually declares tests performed by persons far
- more qualified than you erroneous.


Ok, first let's check some max speed values:

The method is very simple, we'll check if thrust is a little bit bigger than the parasitic drag (we'll ignore induced drag because is quite small compared with parasitic drag, somewhere at 2-4% from parasitic drag, and it is harder to compute - and anyway if trust cannot cover the parasitic drag of course it won't cover parasitic + induced drag) produced at a certain speed with a known power rating:

Data for P-51D-25

thrust = prop_eff*(0.95*rated_power)*550/max_speed + 0.09*rated_power = 0.8*(0.95*1720)*550/542.66+0.09*1720= 1479 lb

drag(parasitic) = Cd0*wing_area*dynamic_pressure= 0.017*233*(0.5*0.002377*542.66^2)= 1394 lb

with an rough estimation on induced drag of 0.3*parasitic drag we'll have a total drag of 1436 lb which is well countered by the 1479 lb thrust


Same calculations for F4U-1D Corsair:

thrust = 0.8*(0.95*2250)*550/525+0.09*2250= 1994 lb

drag(parasitic) = 0.02*314*(0.5*0.002377*525^2) = 2057 lb
so we'll have a total drag of 2057 * 1.03 = 2118 lb

So we're off, the thrust cannot counter the drag. We'll need 2450hp for it, but that's 200hp more, quite a difference.

I obtained 3000fpm @ 2250hp and 3400fpm @ 2450hp, both for a gross weight of 12175 lb. I'm interested in what Corsair manual says about climb rates.

XyZspineZyX
07-25-2003, 06:12 PM
If folks are gonna toss off numbers about the P-47...

A few years ago, the Society of Experimental Test Pilots ran a flight test comparison of the F6F-5, FG-1D (Goodyear F4U), P-47D-40 and P-51D. Chief test pilot was John Ellis of Kal-Aero. Other pilots also participated.

The three radial jobs had versions of the R-2800 that produced appx. 2,000 hp, so differences in performance can be reasonably attributed to the airframe (and prop). The P-51 had a V-1650-9 Merlin rated at appx. 1,500 hp.

The P-47 had a Curtiss Electric constant-speed four-blade prop. The FG-1 and F6F both had Hamilton Standard three-bladed constant speed props (so only the airframe made the difference between these two). The P-51 had a Hamilton Standard Hydromatic four-bladed constant speed prop.

Because of the age of the aircraft, structural loads were kept to 6g max. Engines were fueled with 100LL, which limited MP by four inches on the radials. Power was limited to maximum continuous settings (except for
take-off & climb to 10,000 ft., when military power was used), superchargers were limited to low range. Altitude did not exceed 10,000 ft (so bomber escort altitudes were not reached).

Some of the findings:

CLIMB brake release to 10,000 ft.
Hellcat quickest at 4min 15 seconds, followed by the FG-1 at 4min 44 sec. However, the F6F required 100 lbs of continuous right rudder making it very tiring to operate. The P-47 trailed the FG-1 by a few seconds. The
P-51 came in last.

LEVEL ACCELERATION at 10,000 ft. using METO to max attainable speed:
P-51 accelerated from 110 KIAS to 242 KIAS in 133 seconds.
P-47 accelerated from 105 KIAS to 223 KIAS in 130 seconds.
F6F accelerated from 100 KIAS to 220 KIAS in 115 seconds.
FG-1 accelerated from 100 KIAS to 230 KIAS in 162 seconds.

STALL normal (straight and level decelerating at 1 kt/sec.) and accelerated (constant 3g turn decelerating at 1 kt/sec.)
Aerodynamic warning:
Best--P-47, with buffet 5 kt above stall.
Worst--P-51, no buffet or other warning.
FG-1 and F6F buffeted 2 kts above stall.
Decreasing aileron effectiveness and increasing longitudinal stick forces
were noticeable in all except the FG-1.
Height loss, accelerated stall:
Best--P-47, 100 ft.
Worst--P-51, 500 ft.
FG-1 and F6F both 150 ft.

Behavior during accelrated stall:
Most predictable and controllable: P-47 and F6F. Both could be flown at will into the pre-stall buffet, which at no time was heavy enough to present problems with tracking, and held at maximum usable lift coefficient with ease. Sideslip became noticeable as wing heaviness correctible with rudder. There was little tendency to depart controlled
flight. The FG-1 suffered severe airframe buffet shortly before the stall, but at the stall there was a strong g-break and rapid right wing drop--no matter which direction the turn. Careful left rudder could prevent wing drop,
but then at the stall the aircraft became very unpredictable, bucking and porpoising, with a tendency to a sudden departure. The P-51 gave no warning whatsoever of an accelerated stall. At the stall, the aircraft departed with complete loss of control, achieving 270-degree of roll before recovery. Departure was accompanied by violent
aileron snatch strong enough to rip the control stick from the hand. In short, the P-51 suffered from a Part I deficiency.

SUSTAINED TURN PERFORMANCE at METO at 10,000 ft.
The F6F out-turned the other three by a conclusive margin (1g). The other three were all about the same.
Corner speeds of all were very close to the maximum level flight speed, implying very rapid energy loss when turning at the structural limit. The F6F was in light airframe buffet at 6g at Vmax; the P-47 experiencedlight buffet at 4.8g. The FG-1 and P-51 were buffet-free up to 6g.

MANEUVERING STABILITY stick forces/g at Vmax
FG-1--5 lbs/g (too light)
P-47--7.5 lbs/g (ideal)
F6F--12.5 lbs/g (barely acceptable)
P-51--over 20 lbs/g (excessive)

STATIC LATERAL DIRECTION STABILITY steady heading sideslips
All aircraft except the P-47 exhibited moderate or greater adverse aileronyaw. Worst was the F6F, followed by the FG-1 and the P-51.

ROLL PERFORMANCE
1g 360-degree right (left slower--F6F worst, P-51 best)
FG-1--81 deg./sec.
F6F--78 deg./sec.
P-51--75 deg./sec.
P-47--74 deg./sec.
3g 180 degree right (left slower--P-51 and F6F best, FG-1 worst)
P-47--66 deg./sec.
FG-1--58 deg./sec.
P-51--55 deg./sec.
F6F--48 deg./sec.

DIVING ACCELERATION 30 deg. dive from 10,000 ft., 5,000 ft. begin pull-up, level off at 4,000 ft.
Aircraft P-47 FG-1 F6F P51

Start Speed 110 kts 100 kts 100 kts 120 kts
Max Speed 350 kts 348 kts 315 kts 350 kts
Time 23 secs 32 secs 28 secs 25 secs
All aircraft except the P-47 needed retrimming during the dive.

AGILITY
g capture of 3g target, held for 5 seconds.
G capture and hold was easiest in the P-47, predictable and accurate. F6F overshot the target by 0.2g. P-51 and FG-1 both overshot by 0.5g

Heading Change Time (180 deg at METO, 220 KIAS at 10,000 ft.)
FG-1--8.5 sec P-47--9.7 sec F6F--9.9 sec P-51--10.0 sec

AIR-TO-AIR TRACKING 210 KIAS at 10,000 ft. (straight & level into a 3g turn to the left building to 4g followed by a hard reversal into a 4g right turn.)
FG-1 best, followed by P-47, F6F and, trailing badly, the P-51. Lateral corrections in the P-51 were difficult thanks to the very high stick forces. During one run-thru, an effort at a longitudinal tracking correction that put 4.5g on the plane led to a sudden departure and spin.Poor forward visibility in all aircraft (P-47 worst, FG-1 best) made air-to-air tracking difficult. Depressed sight-line aiming difficult to impossible.

AIR-TO-GROUND TRACKING (90-degree roll into a 30-degree dive from 200 KIAS at 5,000 ft. into a 3.5g right rolling pullout to a 90-degree heading change initiated at 2,500 ft.)
The P-47 was far and away the best, accelerating 125 kts in the dive, no retrimming required, with crisp control response. Accurate target tracking very easy. FG-1 next best. 100 kt. acceleration. Agressive lateral corrections required. P-51 similar to FG-1 in acceleration and
control response, but with heavier stick forces. F6F also accelerated 100 kts., but stick forces increased 20 lbs and rudder forces became so high they interfered with accurate target tracking.

THROTTLE & PROPELLER RESPONSE
MP response instantaneous. Hamilton Standard propeller response quick and positive. Curtiss electric prop (on P-47) sluggish in response, delaying RPM change by 3 seconds in a change from 2,000 rpm (cruise) and 2,550 rpm (METO).
Radial engines required pilot to manage cowl and cooler flap settings. Merlin engine had automatic control of oil and coolant radiator flaps.

The P-47 is a good plane. The FM in FB does not it justice.

-Tom




img
src="http://a1.cpimg.com/image/EB/49/18120171-ed17-02000180-.jpg

XyZspineZyX
07-25-2003, 07:03 PM
I'm an engineer by trade, and in mechanical engineering we have a saying that applies to calculated answers:

In theory, theory and practice are the same.

In practice, they aren't.

I'll take the test data first, thanks.



************************************************** *********

I'll take my car with 382 fully forged cubic inches of fire-breathing, MPFI, nitrous sniffing, all aluminum, tire-roasting Chevrolet power, thank you very much.


"If you can turn, you aren't going fast enough."