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Grey_Mouser67
02-18-2006, 11:57 AM
Many probably already know this...but I am in the process of reconfirming Sea Level speeds for many aircraft after the new patch and the P-51B Mustang will fly at 589Km/hr at sea level...give or take my usual error in crimea, 12 noon etc etc etc....

I retested the plane with radiators open and in auto after overheat and the plane will fly at 560km/hr on the deck.

I have found that most aircraft suffer a 20km/hr penalty for flying with radiators open...why on earth would the Mustang suffer a 30km/hr penalty???? Study after study indicates the placement and operation of the radaitor on the Mustang was "best in class". The only thing that has ever been argued is how much! No way it should suffer the same penalty as other aircraft and more???

Does anyone have any official documentation in terms of speed testing on the Mustang that indicates whether radiators were open or closed. Things I have read about the radiator indicated that it was at its most efficient with radiators in auto which led me to believe its top speeds could be reached with radiator in auto...but I don't have any hard evidence. The climb rate and radiator drag need to be corrected.

some statistics...

Army Air Forces Material Command
Wright Field, Dayton, Ohio
15 May 1944
P-51B-15-NA 43-24777
(Packard Merlin V-1650-7)
Performance Tests on P-38J, P-47D and P-51B Airplanes
Tested with 44-1 Fuel. (GRADE 104/150)

1. Flight tests were started on P-38J, P-47D, and P-51B airplanes at Wright Field on approximately 20 March 1944 in order to measure the performance and note any effect on flight characteristics when flown with 44-1 fuel. Tests on the P-51B have been completed but tests on the P-38J and P-47D have not been completed to date.
2. All tests were flown with the airplanes loaded to their maximum combat gross weight. The P-38J airplane tested was P-38J-15, AAF No. 43-28392, equipped with Allison V-1710-89 and 91 engines with Curtiss electric three blade propellers. Gross weight at take-off was 17,360 lbs. with the c.g. at 26.72%. The P-47D tested was AAF No. 42-26167 and was equipped with Pratt & Whitney R-2800-63 engine and an A-23 turbo regulator. Gross weight at take-off was 13,320 lbs. with the c.g. at 29.5%, gear up. The P-51B tested was the P-51B-15, AAF No. 43-24777 and was equipped with a Packard V-1650-7 engine with a 11 ft. 2 in., four blade constant speed propeller. Gross weight at take-off was approximately 9680 lbs. The weight included 265 gal. of fuel, full oil, and no ammunition (85 gal. in auxiliary tank instead of ballast for ammunition).

3. There was no noticeable change in handling characteristics of any of the airplanes tested when operating at the higher powers which were obtainable with the 44-1 fuel. Only a slight increase in vibration was noted at the higher powers. On one long range test made with the P-51B, there was no apparent trouble due to the 44-1 fuel.

4. All performance data obtained on the P-51B is included in the attached curves. It will be noted that all tests were run with the wing racks installed. Speeds would be approximately 12 mph faster with the wing racks removed as shown by the dash line curve on the Speed vs Altitude Curve. Approximately 16 MPH increases in speed below critical altitude and approximately 600 ft. per minute increase in rate of climb below critical altitude was obtained by using the 75€ Hg. Manifold pressure allowed by 44-1 fuel. No tests were made on this airplane with standard fuel.


Level speed performance

With Wing Racks Without Wing Racks
67" Hg., 3000 RPM 75" Hg., 3000 RPM 75" Hg., 3000 RPM
Max. speed at Sea Level 364 mph 380 mph 388 mph
Max. speed in MS gear 408 mph at 10400 ft. 411 mph at 7400 ft. 422 mph at 7400 ft.
Max. speed in FS gear 426 mph at 23900 ft. 431 mph at 20600 ft. 444 mph at 20600 ft.


Rate of Climb
With Wing Racks, 9,680 Lbs

67" Hg., 3000 RPM 75" Hg., 3000 RPM
Max. speed in MS gear 3,920 ft/min at 5,600 ft. 4,380 ft/min at 2,300 ft.
Max. speed in FS gear 3,170 ft/min at 19,200 ft. 3,700 ft/min at 15,700 ft.


The current plane runs at 67" according to the gauge...and based on the above data, if one wants to accept this as accurate, it looks like the plane is very well modelled at Sea Level speed...EXCEPT...the above test plane was tested with wing racks...our plane doesn't have them so it should be approximately 12 mph faster...or 602km/hr on the deck.

Its rated climb is 3,920 ft/min at 5600 ft....now I haven't seen Robban or Target climb test the B model, but if I were a betting man I'd bet the plane is sorely undermodelled in that aspect to.

The Mustang woe's continue...so if you think the current Mustang is underperforming, IT IS!

If you don't want the Mustang to be improved...well I can understand because as it is, it is sorely undermodelled and if this bird got 12 mph faster and took a 0, 5 or even 10 km/hr hit with radiator open and its climb rate was adjusted to the above numbers, the plane would become an excellent energy fighter...with accompanied low drag design, we might actually understand why the Mustang got its reputation.

Grey_Mouser67
02-18-2006, 12:09 PM
And...if you want to know more about the porpoising in the Mustang and how fast it can be dived before structural failure...look here:

http://www.spitfireperformance.com/mustang/p-51d-dive-27-feb-45.pdf

Mach .84 is really, really fast!

vanjast
02-18-2006, 12:20 PM
Were there any other allied planes in the 'mustangs class' = I'm the only one therefore I'm the best.

Just think if you were a test pilot. You're zipping around at low level. Do you watch your instruments which give you 50 kph notches and you spend time working out the exact possible gradings, or do you look where the hell you're going and occasionaly glance at the speedo.
Later when you write your report you write down a speed that you 'think' it was.
Then somebody forgot to tell you that your indicated speed is actually dpendent on air pressure, temperature, and had the speedo been calibrated properly, and did they use proper calibration methods...

I can see the kph's peeling off here. IL2 is a close approximation, and a dam good one at that.
WHY ARE YOU COMPLAININGGGGGGGG!!!!
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

heywooood
02-18-2006, 12:21 PM
its possible that when data is assigned to a specific plane type as 'flight model' code and tested in beta - it performs a certain way...then, when that code is inserted into the full simulation, some other 'global' programming for atmospherics etc. have an effect that is noticeable.
One thing that would help P51 drivers immeasurably is control over the fuel load - specifically the option to either carry no fuel in the main fuselage tank or the ability to select and drain that one first.

WRT the radiator - I remember Oleg himself saying that he beleived the North American data regarding the drag penalty being minimal was not accurate..and that the possibility of thrust actually being generated by the radiators design to offset the drag penalty unlikely.

Too bad - such was the case as observed by NACA test pilot reports and research but only in US documentation...that makes it 'propaganda' I guess.

TX-Zen
02-18-2006, 12:54 PM
Originally posted by Grey_Mouser67:
it is sorely undermodelled and if this bird got 12 mph faster and took a 0, 5 or even 10 km/hr hit with radiator open and its climb rate was adjusted to the above numbers, the plane would become an excellent energy fighter...with accompanied low drag design, we might actually understand why the Mustang got its reputation.


You raise a fair point about the mustang not having its possible true speed and it's probably worth looking into. I'm all for all aircraft in the sim getting as close to historically accurate performance as possible, but to say a plane is sorely undermodelled because of 10km/h is a bit of an over statement imho.

And for the plane becoming an excellent energy fighter with +10km/h....not going to happen.

This sim is flawed when it comes to energy fighters and the P51 is included along with all the rest them. You can add 50km/h sea level speed and it won't help in vertical manuevers simply due to the nature of the sim.

If you really feel this needs to be looked into then I encourage you to post tracks and charts as applicable...maybe 1C will take another look and maybe that would be good for the sim, but seriously, don't expect the mustang to become dramatically better than its current peformance if that 10km/h is added. We just don't have a physics engine that gives historical advantage to high thrust to weight ratio, high wingloaded/heavy aircraft.

It always has and continues to favor low wingloaded agility over everything else.

Grey_Mouser67
02-18-2006, 01:08 PM
I do lots of speed testing and many aircraft in the game are within 5 km/hr of true speeds...Oleg just adjusted a couple this last patch.

The issue I take with the Mustang is why would a Mustang receive a 30km/hr penalty when other aircraft recieve a 20km/hr penalty. Even if Oleg doesn't believe the drag is better...why worse? Now throw in a 12 mph bump for no wing racks and suddenly we're not talking about a few mph but rather 18 mph...in this game that is ALOT! Now if the B is climbing at the same rate as the D...don't know if it is or isn't at this point it is also a good 600+ fpm too low in climb....I didn't post about the D, but it is too slow also if wing racks are removed...if it were to gain 12 mph by removal of wing racks then it would be flying, if modelled correctly 619 km/hr on the deck, not its current 605....and throw in the climb rate penalty of 300 fpm and its radiator drag penalty of 10-30km/hr depending on data...

Common guys...this is a big error in this game...were not talking about 3 km/hr or 50 fpm in climb!

What I'm looking for, cause I can't find it is if the Mustang's speeds were reached with radiator in auto or closed...I doubt there is anything on how much it should slow it down, so in the absence of data...lets make it like the rest of the planes.

idonno
02-18-2006, 01:11 PM
Originally posted by heywooood:
...I remember Oleg himself saying that he beleived the North American data regarding the drag penalty being minimal was not accurate..and that the possibility of thrust actually being generated by the radiators design to offset the drag penalty unlikely.

If Oleg really said that then I may just have to stop rolling my eyes at the people who claim that he is biased.

Aaron_GT
02-18-2006, 01:38 PM
...I remember Oleg himself saying that he beleived the North American data regarding the drag penalty being minimal was not accurate..and that the possibility of thrust actually being generated by the radiators design to offset the drag penalty unlikely.

No, he said that the location of the radiator was good for minimal drag, but was not convinced that the thrust generated by the radiator arrangement was greater than the the drag. He's not alone as most assessments of the design suggest that the thrust is less than the drag, apart from one NAA study.

Grey_Mouser67
02-18-2006, 01:42 PM
The radiator effect is called the "Meredith" effect...from the pages of http://www.airandspacemagazine.com/ASM/Mag/Index/1996/AS/wmtm.html

Air and Space Magazine....looks like there is some discussion as to how much the radiator reduced the drag, but for people who read stuff like this, one can understand that the Mustang was superior in all things related to drag, to include the radiator....my question remains...how much less drag should there be from a Mustang...not should there be less drag...let alone more drag http://forums.ubi.com/images/smilies/51.gif

I never read where Oleg posted that, but something is amiss no doubt....energy fighting is helped greatly by energy retention through low drag, climb rate and accelaration...at least for me. The Mustang was clean, clean, clean...name me another aircraft, with the engine power the Mustang had at 67" of Mercury could fly at 378mph on the deck and 440 at altitude...radiator in auto! or not?



Inline and narrow-V liquid-cooled engines had an obvious advantage for airplanes: They allowed for a far more streamlined nose. But air still had to flow over some kind of heat exchanger in sufficient quantity to cool the engine, and the drag reduction won from a more streamlined cowling would be lost if cooling airflow were not properly controlled. The treatment of the cooling radiator was the crux of the design of liquid-cooled fighters. None of the early liquid-cooled fighters--the P-40, Spitfire, Bf 109, Hurricane--had dealt very elegantly with this problem. A lot was at stake; fully 10 percent of the total drag of an airplane could typically be blamed on engine cooling.

The problem was that in order to reduce drag, which increases with the square of speed, and also keep the air in contact with the radiator long enough to allow heat transfer, it was necessary to slow the air passing through the radiator. The lower the velocity of the air for a given mass flow, however, the larger the cross-section of the radiator and its associated ducting had to be. The ideal radiator was so large that it would barely fit in the airplane--certainly not in the small underwing ducts used on the Spitfire and Bf 109.

Every possible location for radiators was tried. Indeed, the prototype XP-40 of 1938 carried its radiator in almost the same place as the P-51 would, as did the Curtiss XP-46, a proposed--but discarded--P-40 replacement built in 1940. No position had yet displayed a convincing superiority to any other. But Lee Atwood believed that pay dirt would be found there somehow, and he was mulling over this and other fighter design problems early in 1940, as were other engineers at North American who knew that a fighter project might be in the offing.

Today this rather esoteric question of radiator placement is the fulcrum of a controversy over the genesis of the Mustang. In a 1993 article in the historical journal Air Power History, Lee Atwood asserted that the idea of placing the Mustang's radiator behind the pilot--a decision that in many ways defined the rest of the design--was his. He relates that he had seen papers from the Royal Aircraft Establishment at Farnborough reporting on experiments with radiator ducting. A scientist named Frederick W. Meredith had provided a theoretical basis for a drastic reduction in cooling drag. The principle was similar to that of the jet engine: Heat imparted to the incoming air would make it expand, requiring that the outlet be larger than the inlet. The result, assuming roughly constant total pressure in the duct, would be a modest thrust. A long duct, gradually expanding ahead of the radiator and gradually converging behind it, was essential--the ideal duct, in fact, would have been as long as the entire airplane. While it might be utopian to expect a net thrust, Atwood hoped that what he came to call "the Meredith effect" would offset some or even most of the cooling drag.

Atwood's article brought a rebuttal from aerodynamicist Ed Horkey, who had come to North American from the California Institute of Technology in 1938 to work under Schmued. The aft location, he said, was an obvious choice; there was no room for a suitable radiator anywhere else. Neither he nor Irv Ashkenas, another Caltech-trained aerodynamicist who worked on the Mustang, remembers Lee Atwood having had a role in that decision. Horkey dismisses the algebra that Atwood used to explain the Meredith Effect to the lay reader with the words, "We used calculus." The British Purchasing Commission, Horkey thinks, was impressed less by the Meredith effect than by Dutch Kindelberger's magnetic personality and Ed Schmued's German accent.

This disagreement, surfacing more than half a century after the fact, is emblematic of the personal politics of NAA at the time. The engineering department was divided, with Atwood and chief engineer Raymond Rice on one side and Schmued and the rest of the aerodynamics staff on the other. Edgar Schmued's son Rolf says his father actively disliked Raymond Rice, while Atwood, who seemed haughty and reserved alongside the charismatic Kindelberger, was merely "not his favorite person." Schmued's persistent animus toward Rice is evident in his 1985 memoir of the Mustang design days, prepared for historian Ray Wagner. In this account, Rice emerges as either remote from Mustang development or skeptical of Schmued's design decisions and choice of collaborators.

Grey_Mouser67
02-18-2006, 01:53 PM
Another gem! Tell me again that the Mustang should have a 30km/hr penalty when other aircraft have a 20km/hr penalty...I think we need to send Oleg a subscription...


In the case of the Mustang, the air duct pumping system at full speed at 25,000 feet was processing some 500 cubic feet of air per second, and discharge speed of the outlet was between 500 and 600 feet per second relative to the airplane. This air jet counteracted much of the radiator drag and had the effect of offsetting most of the total cooling drag. To offer some approximate numbers, the full power propeller thrust was about 1,000 pounds and the radiator drag (gross) was about 400 pounds, but the momentum recovery was some 350 pounds of compensating thrust--for a net cooling drag of only some 3% of the thrust of the propeller.

This air discharge had what can actually be called a regenerative effect. Maximum aircraft speed is the point where the line of power available, created in the engine and delivered by the propeller, crosses the line of power required to propel the plane through the air. Since the propelling force of the pressurized air from the radiator discharge increases as the square of the speed, we have the favorable situation where the faster you fly the more help you are getting from this regenerative air pumping system.

Since this high speed phenomenon could not be effectively measured by regular wind tunnel model test, it was viewed as ephemeral or even imaginary by many in the engineering practice. Actually, it is quite real and has a close relationship with jet propulsion.

Regarding the Mustang, I have always referred to the work of F. W. Meredith of the RAE, whose report (RAE No. 1683) of August 1935, greatly influenced me as chief engineer for North American Aviation to offer the British Purchasing Commission the ducted radiator design configuration in 1940. That report showed how the momentum loss in the cooling radiator could be largely restored when excess cooling air was being forced through the radiator at high speed. As noted before, this involved closing the air exit enough to get a substantial back pressure behind the radiator which largely restored the momentum loss--which was quite large as described above. This was possible, in Meredith's words, because the outlet was "adjusted to suit the speed,o and back pressure was available accordingly.

Here again, while Meredith's analysis was coherent and mathematically instructive, he failed to convey the practical aspects through an example or two, although he did offer a chart showing drag reduction for various discharge area ratios and conditions. The point I am making was that his work was generally in unfamiliar mathematical terms and was poorly understood. In fact, in two cases I know about, it was described in terms of mild ridicule. In any case, some if not most of the designs of wartime aircraft, including the Spitfire, failed to get the full advantage of this available air pump.

It should be pointed out here that the controversy and misunderstanding of the Meredith Effect on the performance of the Mustang developed largely because it was essentially impossible to get a reasonable measure of the effect from wind tunnel models at the time. The mass flow and momentum could not be accurately measured on a scale model, and no large tunnels were fast enough--200 to 400 miles per hour--to get meaningful results.

It has been reported that Messerschmitt made extensive efforts to determine the reason for the low drag of the Mustang, but his wind tunnel measurements did not disclose the restoration of momentum to the radiator cooling air, and most probably could not have done so with the wind tunnel equipment available at the time.

At this point I would like to interpolate what is , to me, a most fascinating element in Meredith's 1935 report. As you may have noted, I have made no reference to the thermal element in the momentum recovery of the radiator cooling air and at the temperatures involved, the air expansion was relatively small and could be neglected. Real jet propulsion, however, involves fuel burning, and the velocity of the gases and heated air is greatly augmented by this high temperature.

In his report, undoubtedly independent of Whittle's jet engine work, Meredith suggests piping the engine exhaust heat and gases to discharge behind the radiator to heat the discharged air just as burning fuel would do. This would have increased the volume and velocity of the discharged air at the same back pressure and increased the favorable thrust force.

Of course, the thrust of the short stack exhausts had been recognized by Sir Stanley ****** of Rolls-Royce in his book, NOT MUCH OF AN ENGINEER, and others, but Meredith's suggestion might have produced a much more powerful effect, but it involved complications and practical difficulties. As far as I can determine, it was never tried on any airplane.

This brings me to the Spitfire comparison, although that is probably a poor choice of words. That airplane was in a class by itself and at the top level of defense against the Luftwaffe in 1940, and was undoubtedly the most important defensive weapon in history. It was some 1,000 pounds lighter than the Mustang and was at the peak of interceptor efficiency and was essentially in classic conformity with the objectives of the RAF fighter command. It overmatched its opposition and was there when most needed.

In the cold illumination of hindsight, however, and probably for reasons I have outlined above, it missed the opportunity to restore much of the air flow momentum to the radiator cooling air and, with it, a possible speed increment of more than 20 miles per hour. The late Jeffrey Quill, Supermarine test pilot, describes the incorporation of the Meredith Effect in the Spitfire in his book, SPITFIRE, A TEST PILOT'S STORY, and that the radiators were enclosed in ducts under the wings. Here I would like to quote from an article "The Mustang Margin" I wrote for the AIR POWER HISTORY JOURNAL which involves some background and detail on the subject. It will, of course, be glad to try to answer any questions you may have at the end of my presentation.

"The most notable and probably the first application of the Meredith Effect was incorporated in the Supermarine Spitfire, one of the world's most successful airplanes. Over 20,000 were built in various models, but the Mark IX, with the Merlin -61 engine, was typical of the later wartime production, and a sketch of this model with detail of the radiator installation is shown. Two aspects of this design are significant. First, the radiator outlet has two positions--that is, fully open and partly closed--and cannot be progressively 'adjusted to suit the speed.' Second the inlet upper wall is a continuation of the lower surface of the wing and expands the duct cross section by rapidly curving upward.

"The first, the non-adjustable exit, of course, is a deviation from Meredith's dictum and precludes the progressive build-up of pressure behind the radiator with increasing speed. However, the second can only be judged in hindsight, from an airplane design point of view. The inlet seemed to be configured properly to recover the ram air pressure, and the first Mustang design had a similar entry opening. It was later apparent that the thin boundary layer of air flowing along the lower surface of the wing was progressively thickening ahead of the duct opening, and that the flow would break away at a point on the upward curve of the duct wall. While the resulting turbulent unsteady flow apparently did not create a serious vibration, it certainly reduced the efficiency of the radiator and prevented a more complete closure of the exit opening, which is necessary to develop the jet thrust. Very interestingly, the R.A.E. Subcommittee on Aerodynamics in 1936--in commenting on the Meredith and Capon reports--rather accurately predicted this problem: 'Experiments upon air-cooled engines in the 24-foot tunnel have shown that it is necessary to pay particular attention to the design of the entrance to cowlings and the cooling ducts in order to avoid loss of energy by the formation of eddies.' (Somewhat easier said than done at that time.)

"In the case of the Mustang, the duct volume was larger and flow instability more violent, creating an unacceptable vibration and rumble. Resourceful engineers at North American, working with wind tunnel models, overcame the problem by lowering the intake upper lip below the wing surface boundary layer, thus beginning a new upper duct surface. In this design, the flow expanded gradually as the duct velocity decreased, and the pressure at the radiator face was reasonably uniform. This permitted the appropriate closure of the exit with a temperature-controlled power actuator, and a minimum pressure drop across the radiator consistent with efficient radiator function and cooling demand.

"As a result, the cooling drag was estimated at only 3 percent of the total and used only something like 40 horsepower for cooling purposes. While the comparable power used for cooling by the Spitfire is not available to me, the measurements made by Rolls-Royce show a total power required for the same speed (400 mph) as 200 horsepower more for the Spitfire than for the Mustang.

"Records show the P-51D's speed was 437 mph and the Spitfire Mk IX speed was 405 mph. While the Spitfire had exposed tail wheel and other small differences from the Mustang, most of the speed difference was in the cooling drag. The Mark VIII with retracted tail wheel is rated at 414 mph at a somewhat higher altitude. Advanced models of both airplanes with higher performance were produced late in the war, but were not available in significant numbers before V-E Day, May 8, 1945.

"It seems that most other contemporary airplanes attempting to take advantage of the Meredith Effect failed for one reason or another to combine an efficient duct system with a properly designed and regulated exit-closing mechanism and did not develop the energy recovery inherent in the Meredith method. They generally used 10 percent or more of their power available at high speed to overcome cooling drag. A notable exception was the DeHavilland Mosquito multi-purpose plane with the same Rolls-Royce engines and which used a wing leading edge radiator mounting with a short and direct inlet duct. The controllable exit opening had a minimum area little more than half that of the Spitfire, and while it was a larger two-engine airplane, it had a speed of 425 mph.

SnapdLikeAMutha
02-18-2006, 02:27 PM
How much is 'your usual error' ?

Grey_Mouser67
02-18-2006, 02:56 PM
plus or minus a couple km/hr...I'm not an expert, but sea level testing is fairly easy....every once in awhile I state something like the plane goes 580km/hr and someone else comes back and say...ya, well I get 582km/hr!

I don't give a hoot about that...the error we're talking about with the Mustang is anywhere from 12-31 mph depending on how you interpret the information...and likely a corresponding rate of climb error as well....the D model ROC is off and documented. I've just never seen devicelink data on the B model yet.

I am attempting to contact an owner/organization of a P-51 Mustang in hopes that he will be able to shed some light on the true affect of the radiator...cripes, there are like 150+ of these warbirds flying around...someone aught to be able to fly in auto and switch to closed and see if there is a change in speed and if so, how much!

Rjel
02-18-2006, 04:01 PM
While I'm not any sort of an expert on aeronautical design, I find it troubling so many here can dismiss both North American Aviation and NACA's tests from the war years as biased or inaccurate. These planes weren't simply slopped together nor were they built in someone's back yard. Tens of thousands, maybe hundreds of thousands of hours of engineering and design work went into these aircraft, by some of the greatest minds in both the U.S. and Britain. Remember, these people weren't simply trying to capture the next defense contract; they were making airplanes to survive and hopefully win a world war. A war that was, by the way, still very much in doubt at the time the Mustang and nearly every other major U.S. fighter and bomber design was on the drawing board.

Aaron_GT
02-18-2006, 04:45 PM
To offer some approximate numbers, the full power propeller thrust was about 1,000 pounds and the radiator drag (gross) was about 400 pounds, but the momentum recovery was some 350 pounds of compensating thrust

Exactly! The effect was less than the drag from the radiator. This came up about 18 months ago with various people posting parts of NAA reports and concluding that the P51 had net thrust from the radiator arrangement, and Oleg responded that it did not compensate for the entire radiator drag.

Chuck_Older
02-18-2006, 04:53 PM
Well in that case Oleg and I disagree http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif, because Dutch Kindelberger says differently, and he was there, so I sorta take his word

But I also have to wonder if some of this is a language barrier? Could it be possible that the way rad door/flap drag is modelled in general, that the sim engine can't compensate for the P-51's condition, and when Oleg says it doesn't compensate for the drag, he means the FM can't *allow* it to do that?

Grey_Mouser67
02-18-2006, 04:53 PM
Originally posted by Aaron_GT:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">To offer some approximate numbers, the full power propeller thrust was about 1,000 pounds and the radiator drag (gross) was about 400 pounds, but the momentum recovery was some 350 pounds of compensating thrust

Exactly! The effect was less than the drag from the radiator. This came up about 18 months ago with various people posting parts of NAA reports and concluding that the P51 had net thrust from the radiator arrangement, and Oleg responded that it did not compensate for the entire radiator drag. </div></BLOCKQUOTE>

I am in no way concluding that the radiator lent thrust to the aircraft...only that in game the plane suffers from a 30km/hr speed hit with radiators open while other aircraft I've tested have a 20km/hr hit to their speed....The Mustang should be no worse, and based on all the above stuff I copied...probably quite a bit better! I don't know if 20km/hr is correct, but Oleg chose that value...so why the Mustang worse? Why the Mustang modelled in plane with racks when it doesn't have them? Why is the plane undermodelled in climb when most of its enemies are modelled closely if not over modelled?

Take a P-51 Mustang and adjust its sea level climb of rate and upper altitude climb of rate to correct values, model its speed correctly and give it a less of a drag penalty...say 10km/hr instead of 30, fix the COG issue and I guarentee this plane won't be the same...it won't feel the same, won't fly the same, you won't recognize it and it will be much more accurate than it is today.

I don't know what the correct value is because no other radiator was studied like the Mustang's...lots of smart people trying to figure out why the Mustang is so much faster than aircraft with the exact same engine...but it was...and it didn't bleed energy easily either...it does in game now...just like the old 1.0 Fw's used to.

Chuck_Older
02-18-2006, 04:57 PM
Aaron means that the way the radiator 'doghouse' worked, it could generate sufficient thrust to overcome the inherent drag penalty of the doghouse, not that the doghouse actually generated useful forward thrust in and of itself that could augment the plane's speed- it just negated a drag penalty

Grey_Mouser67
02-18-2006, 05:11 PM
Thanks for the clarification

I have seen a documentary on the Mustang radiator configuration and the program made the claim that it added thrust to the aircraft...this seems impossible to me, but I am not a physicist.

I do know that radiator design and placement do have a significant impact on the performance of any plane...the length alone and position of the radiator in the Mustang would probably have given it a slight edge, but the ability to slowly restrict airflow and damper the output end so that input speed vs. surface area of cooling fins vs. outlet speed would be maximized means all by itself, it was a superior design and would offer less drag...

The two questions remain...how much? And did speed testing in the Mustang occur with radiators in auto?

ps. my e-mail to contact the Mustang owner was undeliverable...bad address I guess. I'll have to try another route. http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif

Aaron_GT
02-18-2006, 05:36 PM
I am in no way concluding that the radiator lent thrust to the aircraft...

I know you aren't, it was just in the thread from about 18 months ago that Oleg responded to some seemed to be claiming that it did, and Oleg said that this wasn't the case, that it offset it. Or that is what he seemed to be saying. Oleg's English isn't perfect and there are enough misinterpretations on these boards even for native English speakers!


I have seen a documentary on the Mustang radiator configuration and the program made the claim that it added thrust to the aircraft...this seems impossible to me, but I am not a physicist.

I think this is where some of the arguments from 18 months ago came from and it would seem the documentary makers didn't understand the relative levels of thrust and drag in the Mustang's radiator set up.

As to why the open rads make such a big different - who knows - there have been all sorts of radiator related bugs on a whole range of aircraft. It might be that it isn't being tested thoroughly enough given the huge numbers of planes and versions. Unless there was something weird about the P51's radiator when open then it looks like a bug in the P51 to be fixed. Ditto the racks (again there are a number of planes with similar things to be fixed - more testing required, probably).

With regards to the climb rate there seems to be a spread in results from those that tested in 4.02 that seemed to overlap the correct figure. I've not seen any tests for 4.03.

The first 90% of testing takes 10% of the time. The last 10% takes the rest. It might be a case of priorties, given BoB and all. Still, it would be nice to have everything fixed and I hope it will be.

Blutarski2004
02-18-2006, 05:47 PM
Originally posted by Grey_Mouser67:
Thanks for the clarification

I have seen a documentary on the Mustang radiator configuration and the program made the claim that it added thrust to the aircraft...this seems impossible to me, but I am not a physicist.

I do know that radiator design and placement do have a significant impact on the performance of any plane...the length alone and position of the radiator in the Mustang would probably have given it a slight edge, but the ability to slowly restrict airflow and damper the output end so that input speed vs. surface area of cooling fins vs. outlet speed would be maximized means all by itself, it was a superior design and would offer less drag...

The two questions remain...how much? And did speed testing in the Mustang occur with radiators in auto?

ps. my e-mail to contact the Mustang owner was undeliverable...bad address I guess. I'll have to try another route. http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif


Technically speaking, the Meredith Effect radiator design of the P51 did add thrust. It is just that the + thrust factor was not = to the - drag influence of the radiator.

I think that the real problem here may be that there is a standard algorithm in the FM code which varies drag versus radiator position and the real world operation of the P51 Meredith Effect radiator does not "obey" the assumptions upon which that algorithm was written.

SithSpeeder
02-18-2006, 06:05 PM
You go, Grey_Mouser!

http://forums.ubi.com/images/smilies/agreepost.gif

* _54th_Speeder *

Badsight.
02-18-2006, 06:11 PM
the radiator design did add thrust , just the effect wasnt greater than the drag created

& on the RL mustang it was with the rad slightly open

if anything , the Mustang should take no worse hit in speed with the rad open than any other A/C

Unknown-Pilot
02-18-2006, 06:25 PM
FWIW - I just went through an OS rebuild lastnight/this morning, and a full reinstall of the game, from FB, up. Prior to this, I was running on an install that started when FB first got released and has been patched up with each and every single patch along the way, plus IL2-MAT Manager (after something happened that Jiri's FBSE stopped working), god knows how many skins, backups of files all over the place, DGen problems, etc, etc (to say nothing of the OS corruption which had been building for even longer - I couldn't even update my video drivers without it causing problems).

With a totally clean OS install, fully updates, latest sound and video drivers and a fresh build of PF(m) using the shortcut method (FB->AEP->PF->3.03->4.01->4.02->4.03), and a cleaned up skins dir. and no IL2-MAT Manager **** clogging up the install, I have what feels like a totally different game.

All the planes feel better now, and the P-51D20NA felt untouchable. It was fast, kept it's speed, zoomed well, accelerated quickly in a dive, rolled well, and even turned half-way decently with combat flaps. And the 6 50s were shredding things up pretty well.

I really didn't see what all the complaining was about (other than the "But teh Mustang won teh war!!11!!oneone" whiners).

I fly E-fighters more often than not. I prefer the 190 and P-47 over them all. Never cared much for the mustang because it was an overpopular, overrated, glory hound with absolutely no soul. But, I do know how to use it. And I can say, even if it's off by a little bit here or there, it is most definitely *not* borked.

Just be glad you have an accurate cockpit for it and it's not pulling an invisible drag chute, unlike Oleg's Hellcat.

(This may not be the same case for them all, I didn't look at them all, I was just checking out the frame rates for the new install and happened to grab the D20 to look at a skin at the same time)

NonWonderDog
02-18-2006, 06:31 PM
If you know the radiator temperature, the outside air temperature, the intake area, and the exhaust area, you can actually calculate this "Meredith" effect quite accurately with a bit of fluid dynamics. You have to make a few assumptions about heating rate and such, but it's not too bad. I wouldn't be surprised if Oleg has already done the calculation.

I can't imagine that the effect would be very large, though. It would offset some of the drag, but it wouldn't be a magical jet engine.

Grey_Mouser67
02-18-2006, 08:08 PM
Well he may have calculated it...I remember reading he was an aeronautical engineer by profession or something like that...but it didn't get programmed into the sim for sure.

I'm certain that the drag on the Mustang should be less than that of other aircraft, I just don't know how much....and I'd really like to find out if speed testing with the Mustang was done radiator open or closed...

If it happened while it was open and its speeds were attained in auto...and Oleg adjusted in the game...you'd see a complete metamorphisis of the aircraft in the game...it would be hands down the fastest prop plane around except for some of the late, late war and fantasy stuff.

No there are large discrepencies in the performance of the Mustang and real life...I didn't think so, but when I stumbled across the radiator drag inequity I began researching performance numbers and the Meredith effect and I am reaching the conclusion that the aircraft is substantially undermodelled in speed...I used to think not, no I have changed my mind.

12 mph for wing racks, 30 km/hr hit for radiator instead of 20 or less? Climb rates...sure would be nice to fly a Mustang that climbs at 3900 fpm! Heck, how about the 3600+ in the D...and lets start talking 72" and 81" boost figures! But first, will the real P-51 Mustang please stand up?

Chuck_Older
02-18-2006, 08:58 PM
Originally posted by NonWonderDog:
If you know the radiator temperature, the outside air temperature, the intake area, and the exhaust area, you can actually calculate this "Meredith" effect quite accurately with a bit of fluid dynamics. You have to make a few assumptions about heating rate and such, but it's not too bad. I wouldn't be surprised if Oleg has already done the calculation.

I can't imagine that the effect would be very large, though. It would offset some of the drag, but it wouldn't be a magical jet engine.

http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif You don't have to calculate it though. It already exists, they did this 60 years ago, it's been calculated for more than a half century. It's not some hypothesis or guess.

Chuck_Older
02-18-2006, 09:00 PM
Originally posted by Grey_Mouser67:
Well he may have calculated it...I remember reading he was an aeronautical engineer by profession or something like that...but it didn't get programmed into the sim for sure.



Oleg is a real life aeronautical engineer, that was his profession for a long time

I am still wondering if the sim engine doesn't allow it- when rad door is open X amount, an equation calculates speed loss, and there's always a loss, end of story. That's my guess. the sim's old

Slickun
02-18-2006, 10:47 PM
Does everybody know about www.spitfireperformance.com (http://www.spitfireperformance.com)
A TON of great stuff there about Spitfires, Lightnings,Thunderbolts, and Mustangs. Every person on these boards, whether you like western allied planes or not, should bookmark it.

It has a section on P-51 tests, a rather extensive one.

The latest performance test added to it, courtesy of LRRP's post, is one wherein the P-51D was run at what would be "combat" speeds and loadout....less than 100% fuel, wing racks present. Just like a LW fighter would find it over Westphalia. The famous Don Gentile was one of the pilots I believe.

442 mph...
WITH wing racks
WITH radiator set on "automatic".

Many of the tests available at that site are with the radiator set on "auto", which I think was standard.

Grey_Mouser67
02-18-2006, 11:12 PM
OMG...how did I miss this?

2. High speeds obtained with the oil cooler flap and coolant flap set for automatic opertation since there were no provisions on this airplane for selective operation and no time was available for a test installation of a selective control.


True
Airspeed
M.P.H. R.P.M. Man.
Press.
" Hg. BHP
From
Power
Chart Altitude
Ft. Coolant Flap
Position
Inches open
From Flush Oil Flap
Position
Inches open
From Flush
(a) Low blower Operation
363 3,000 60.5 1,450 5,000 6.0 W.O (5)
394 3,000 60.5 1,485 10,000 5.0 3.5
425 3,000 60.5 1,530 16,800 1.5 1.0
422 3,000 49.0 1,270 23,200 1.0 Flush
(b) High blower Operation
422 3,000 60.5 1,270 23,200 1.0 .5
441 3,000 60.5 1,275 29,800 1.0 Flush
421 3,000 48.0 985 35,000 .5 Flush
403 3,000 40.7 815 38,000 .5 Flush

Opening coolant flap wide open from flush position slowed the airplane from 349 M.P.H. I.A.S. to 325 M.P.H. at 18,000 Ft.; opening the oil cooler flap decreased the speed an additional 10 M.P.H. I.A.S.


It was right there in front of me....So...the P-51B Mustang can reach 363 mph at Sea Level, with radiators in automatic, with bomb racks...without bomb racks add 12 mph or 376 mph. At atlitude...441 mph can be reached with bomb racks in automatic.

There you have it! Now I know why the Mustang under performs in this game.

Houston, we have a problem http://forums.ubi.com/images/smilies/35.gif http://forums.ubi.com/images/smilies/clap.gif

gkll
02-18-2006, 11:37 PM
Well I have some real sympathy for the pony drivers... having a pony with a draggy rad is like having a spit that blows e in a turn.... it is mucking with the thing that helps make the stang.

One of the accepted testers should take a run at these numbers (drag open closed) and compare it to some other plane. Seems this should be moddable by Oleg+crew, can't imagine that the global rad wouldn't have plane specific curves or parameters.

Lot of good detail in this post, appreciate the work in posting. I'm a gearhead RL and always enjoy.

Unknown-Pilot
02-19-2006, 12:07 AM
Solely looking at what you posted, that looks like 5,000 feet, *not* Sea Level.

Aaron_GT
02-19-2006, 01:49 AM
Opening coolant flap wide open from flush position slowed the airplane from 349 M.P.H. I.A.S. to 325 M.P.H. at 18,000 Ft

That's a whopping 38 km/h loss in IAS from opening the radiators! That's actually MORE than the loss we get in the game at sea level (any real world info for the real world at sea level?) Perhaps this is due to the fully open radiator position having more drag than closed and a loss of compensating Meredith effect?

Grey_Mouser67
02-19-2006, 07:46 AM
Originally posted by Unknown-Pilot:
Solely looking at what you posted, that looks like 5,000 feet, *not* Sea Level.

Yes, you are correct...I missed that. There are several aircraft tested and another B model obtained 364mph at sea level so I just read the 363 as sea level speed.

What is particularly interesting to me, is how several different aircraft are tested and noted...and they have slightly different performance figures....two D models, further down the page...one hits 369 mph and the other 375 mph...again with wing racks on both!

The current P-51B flies at 350 mph at sea level, radiators in auto and no wing racks...if we give it a 12 mph bump for no wing racks, the plane if modelled to best presented data should fly at 378mph....again...28 mph or 45km/hr is a HUGE error in this game! How would you like your favorite plane to fly 45km/hr too slow?

Not anyone I'm sure. I also have to say that, considering most other aircraft are measured with radiator closed, it must have been a huge combat asset to reach its maximum speed, which was already considerably fast with radiators in auto....no wonder nobody could catch a Mustang unless it was bounced!

Here are some numbers from a P51D...

Maximum speed at sea level

War Emergency power (3000 RPM and 67") 375 MPH
Military power (3000 RPM and 61") 364 MPH
Normal Rated power (2700 RPM and 46") 323 MPH


The D model lost ll mph from military power to wep...just about every aircraft in the sim can fly around on military power indefinitely either with radiator open or closed...so if the Mustang is flying around at 378mph on full boost and at military power, with radiators open which means a cool engine, no overheat, it could maintain a speed of 367 mph or 587km/hr and the D model would fly at 375 w/ racks and there is some data that indicates that at sea level the rack penalty was 8 mph and at critical altitude it was 13 mph so 375 becomes 383 mph without racks, in auto, or 372 mph at military power...very fast to be flying around with radiators in auto with a cooled engine!

OldMan____
02-19-2006, 08:03 AM
People.. radiaor drag is a complete simpe aproximation here. There are not enough data on radiator drag for most plaens to model it correclty. For example Some tests point that Dora looses (in RL) almost 50 kph) from fully opened radiators!! Probably most planes should also loose more than 20 kph.


But also in RL most planes coudl keep radiators fully closed since on most heights underheat was more problematic than overheat.

JG5_UnKle
02-19-2006, 08:16 AM
FWIW the Fw-190 A-9 loses 30kph at sea level with rad open too. I have no idea if this is correct or not.

I have long suspected that the airspeed loss for radiators was insufficent and agree with Oldman - it is an approximation of a complex system, both the aircraft themselves (different systems) and the aerodynamics involved.

Quick and dirty I get 600Kph rad closed and 570kph rad open. I'm sure I can get more speed (from both) but this was a good stretch at 8x speed.

Didn't test any others.

Grey_Mouser67
02-19-2006, 08:22 AM
agreed...but I was not trying to recalculate the appropriate radiator drag...Oleg chose 20km/hr from most aircraft and oddly chose 30 km/hr when, due to the facts presented above, the real hit to speed should be 0km/hr.

The whole post began due to speed testing indicating a 30km/hr drop...that was not correct, and now we know just how much! I'm hoping to see Robban or Target pop in here with some climb data...I'll be travelling most of the week so I won't be able to comment here, but when I get back, I think I'll bundle up a nice package for Oleg and send it on requesting the following:

1. Speeds be adjusted for B,C,D and Mustang MKIII to allow aircraft to hit those speeds with radiator in auto...in fact, the plane aught to be like the Spit Mk IX's...no way to shut radiator.

2. Suggest that the climb rates of said aircraft be corrected as well. I'll probably need some help with climb test data.

3. Inclusion or conversion of the -20NA to a higher boost specimen...probably the 75in. version.

4. Model current aircraft that have no wing racks with a positive 8-13 mph gain on listed speeds.

5. On a side note, convert the current Spitfire MkV 43 version to a 16lb. version.

Slickun
02-19-2006, 08:30 AM
Well, the data is there and easily available. These weren't, for the most part, pie-in-the-sky tests. The planes were taken from squadrons, had wing racks, full fuel for the most part.

The test that REALLY intrigues me is the P-51D going 442, wing racks, that I alluded to above. Nearly ALL P-51 tests we find are with full fuel. It appears the plane added quite a bit of speed as the fuel burned off. The above test is with something less than 100% fuel.

Interesting. It means without wing racks we are talking about the plane doing 450+.

Kocur_
02-19-2006, 08:35 AM
http://forums.ubi.com/images/smilies/agreepost.gif!

Khem: I would add also a point regarding correction of B/C cocpits if someone modelled one.

Aaron_GT
02-19-2006, 08:36 AM
If similar aircraft achieved varying speeds in real life then the procedure should probably be to model the average, not the outlier high speed.

Grey_Mouser67
02-19-2006, 08:47 AM
Aaron...if it were up to me, I would model average, wartime numbers. But, I think Oleg has chosen in most cases to model the best figures and aircraft in perfect operation condition...I know this to be the case with some of the late 109's, Ki-84's and La's...although Oleg did state he did not model the late russian planes with better fuel performance.

I would think that he would chose the best credible data...but first we have to convince him that a change is indeed warrented.

Again, now I understand a lot better why the Mustang is an average, if not below average performer in this sim when in real life it was an above average performer.

Slickun
02-19-2006, 09:01 AM
My point, Aaron, is that the "442" test was done with less fuel than most other Mustang tests. It is one test that shows what the LW would be facing over Weisbaden, rather than minutes after takeoff from Debden.

I think the surprisingly high speed is due more to a lower weight than anything else.

JtD
02-19-2006, 09:31 AM
Meredith effect only works when the rad is closed. You open it, you lose it. Thus you not only add drag, you also lose thrust and thus lose more speed than plane with a crappy rads design do.

Test results were the P-51B would lose 24mph IAS at 18.000ft when opening the coolant flap and another 10 when opening the oil cooler. That's about 45 kph.

The ingame P-51B is equipped with a -3 Packard, not a -7. Think the -3 is worse, less powerful at sealevel. If you pick a test with a -3 at 67" on a claen P-51B you'll find a sea level top speed of 595 kph. Rads were less than half open (on auto).

In FB you can dive the P-51 supersonic.

12 mph speed loss from bomb racks refers to top speed at alt. At sea level 6-7 mph are more reasonable.

Make of it what you want.

Grey_Mouser67
02-19-2006, 10:27 AM
I just checked the viewer and the B model is a -3 and the C model is a -7 according to it.

Based on what I've read, the Meredith effect/Mustang radiator should be at its peak performance with it in "auto". The apreture size on the outfeed end varies with demand and speed etc...

If you check one of the articles on the Merideth effect out of the science magazine, it states in there that the Spitfire didn't capitalize on the effect fully because the radiator only had 3 settings...closed, 50% and fully open.

The -3 engine is less powerful and has slightly less performance no doubt, but the top speed in radiator auto and the bump for no wing racks should still hold true no matter which engine.

Posted on the site, a D model Mustang gained 8 mph at sea level and 13 mph at critical altitude with the wing racks removed. I suspect if Oleg were to take this into account, he'd have to pick one value because I don't think the engine takes into account the effects of altitude on drag.

The speed tests clearly state that the test results were obtained with the settings in auto. The bottom paragraph, I believe, is intended to demonstrate the ineffectiveness of messing with the radiator in manual. Likely, at WEP, up high in the air where the air is cool the Mustang didn't need much of the radiator open to remain cool...makes me wonder if the "overheat" model is off. Maybe the plane doesn't "overheat"...I know my car doesn't nor does my boat when I have the pedal to the metal.

Chadburn
02-19-2006, 10:42 AM
Just an FYI

"Oleg posted 04-11-03 09:54
RE: The Mustang, its radiator and speed.

1. Finally we plan to have it Auto. In real life the temperature of the coolant determided by thermostat, Like on many other aircraft (Bf109F-G-K, Yak-3, Yak-9 late, etc).

2. The drag is present anyway for the closed radiator in P-51D. But in this position the construction of radiator cowling with laminar flow around it really has small drag that allow to get greater speed of the plane itself in comparison with usual radiator cowl placed in that aerodynamically 100% _optimal_ area (like say on Yak-3 or on Yak-9U, that has it in the same place, but hasn't laminar airflow in the place beween radiator airintake and fuselage. Germans also tried to place there after great experimantal works, but it was too late...You may see it on experimental FWs and Bfs). But when it begins to open - drag will increases anyway. So you are worng in your opinion. I know where you took that info But this isn't professional aerodynamical magazine, be sure. There was just private opinion. The only thing there is correct that the design of radiator cowling was really best comapring to other planes.


SkyChimp wrote:
- Just in case its modelled this way, the P-51's
- radiator air outlet shutter should be automatic. In
- real life, the temperature of the coolant determined
- how much the flap opened. Otherwise, there was a
- switch in the cockpit with "auto", "open", "closed"
- and "off." "Auto" was the usual setting.
-
- And when the P-51's radiator opens (the flap opens
- up), the Mustang should not loose speed. In fact,
- the Mustang's radiator design created thrust.
-
- If the Mustang is loosing speed with an open
- radiator, it should not.
-
- Regards,
-
- SkyChimp"

Full thread here: http://forums.ubi.com/eve/forums/a/tpc/f/63110913/m.../r/15210063#15210063 (http://forums.ubi.com/eve/forums/a/tpc/f/63110913/m/15210063/r/15210063#15210063)

VW-IceFire
02-19-2006, 10:43 AM
Just to understand the issue as best as possible...at present, the best way to "game the game" is to keep the radiator closed and open to cool only?

Sort of like how I now never open the radiators on any R-2800 aircraft because the radiator has no effect. Gaming the game...

JtD
02-19-2006, 10:43 AM
Overheat and radiator / drag is off for all planes I have checked.

Grey_Mouser67
02-19-2006, 10:52 AM
The data I posted that had the B model Mustang travelling at 363 mph at 5000 ft with radiator in "auto" was with a -3 engine.

It reached 441 mph, but at 29,800 ft which is indicative of the slightly lower powered engine...but again, it was in "auto". Every other official test document that specified it talked in terms of radiators being closed.

What is interesting is that the Mustang chart shows the size of the opening at various altitudes...it is more open at low altitue, and less at high altitude....again air is much cooler up there but I am beginning to believe based on all this evidence that aircraft could run at high boost settings without overheat and without the radiator all the way open...at least those that had "sufficient" cooling. Doesn't mean you won't damage the plane by running it like that, but it leaves me wondering if overheat was a problem at all for some planes up at 25,000ft..

Now I have read much documentation that the early Lightings had tremendous issues with cooling to the point where they could not reach even military power at altitudes above 27,000 ft due to insufficient cooling.

Well, again...one thing for certain..the Mustang reached its commonly published numbers with radiator in auto and with wing racks....that alone is substantial.

Grey_Mouser67
02-19-2006, 10:56 AM
Originally posted by VW-IceFire:
Just to understand the issue as best as possible...at present, the best way to "game the game" is to keep the radiator closed and open to cool only?

Sort of like how I now never open the radiators on any R-2800 aircraft because the radiator has no effect. Gaming the game...

I would leave the plane in auto but when you need speed, close it...you will have exactly 5 minutes before engine failure...and I confirmed through a test that it is based on "time" not temperature...I lowered the power settings and dove a few aircraft to increase cooling with no net effect on the time it takes to fry the engine.

The thing to remember about the Mustang, is if your radiator is open, you are losing 30km/hr, your opponent is likely losing 20km/hr...and yes, don't bother running the radials with radiator open...was not addressed and you can run a Hellcat 10 minutes and not a second longer in overheat before engine failure.

Aaron_GT
02-19-2006, 11:16 AM
Aaron...if it were up to me, I would model average, wartime numbers. But, I think Oleg has chosen in most cases to model the best figures and aircraft in perfect operation condition...

Aaron...if it were up to me, I would model average, wartime numbers.

It would give the P51 a better average advantage. Ideally there would be a 'random quality' option.

In general the P51 hits pretty much the right numbers, though, for the engine and boost modelled (-3 in the P51B). There are some slightly different figures, but it's not that far off. There's a case for versions with different engines and boosts, though. (I say this as one of the people involved in campaigning for the Mustang III)

I think JtD is right on the money (from what I've read of Meredith effects in radiators) that a radiator FORCED open would probably have more of an effect (as seems to have been the case IRL from figures earlier in the thread) on speed than others as you are adding drag AND wrecking the Meredith effect. When in auto the the automatic system would aim to open enough to cool the engine, whilst preserving the best Mereidth:drag effect, but it might still end up being worse than closed as cooling the engine comes first, obviously.

Aaron_GT
02-19-2006, 11:19 AM
Posted on the site, a D model Mustang gained 8 mph at sea level and 13 mph at critical altitude with the wing racks removed. I suspect if Oleg were to take this into account, he'd have to pick one value because I don't think the engine takes into account the effects of altitude on drag.

There might be a rack bug (these have been legion) in which the drag is modelled even if there is no rack. I am sure this (and the reverse) have been seen before. That might be worth a bug report if it is for definite. That would be a pretty easy and uncontroversial fix I'd imagine - take a P51B with tanks, drop tanks, and check the speed against a P51B without tanks from the outset. Saying this, I am not sure how you account for fuel weights in the tank/not in the tank in the fuel settings in the game.

Grey_Mouser67
02-19-2006, 02:18 PM
Well, just popped in and did another speed test...crimea etc..etc... loaded up 2 bombs and dropped them immediately, closed radiator and proceeded to accelarate up to a top speed figure of 556 km/hr.

I then opened up the radiator and put in auto after overheat...results same since radiator was fully open at that time...530 km/hr!

A Mustang in that configuration should be flying approximately 581 km/hr...not 530....here is a list of aircraft that are faster than the Mustang at that altitude when the Mustang has its radiators open...

All P-47's
All P-38's
Spitfire Mk VIII's and Mk IX's
All Fw's
All La's
Every Bf109 from the G2 up..F4 down is not
Ki84
Raiden

I don't have data on all planes...those are ones I've tested...it is faster than a Hellcat still and sneaks out a Bf110 by 10km/hr.

For all those who thought the Mustang was well modelled in speed, think again. Bearcat99...yes, the mustang is not "right".

lrrp22
02-19-2006, 05:06 PM
The Mustangs currently modeled in PF all reach historical top speeds only if radiators are fully closed and wing racks removed.

Virtually all historical USAAF and RAF P-51B/D test speeds were achieved with radiators set to 'Auto'. During those tests the radiators typically opened to between 6.5 and 7.5 inches from the aperature's 5.25 inches 'fully closed' position. Many test aircraft had the radiator exit flap blocked so that the 'fully closed' position was 7.5 inches. Neither coolant nor oil temperatutres ever exceeded the target ranges during these tests, even at increased 150 grade boost levels.

The gist of it is that the Mustangs in PF should reach their top speeds with the radiators set to 'Auto' and slightly open. That isn't currently the case. Overheat should not be a factor- in fact, even during max power climbs at 75" Hg all temperatures stayed in the normal range. Also, the Mustangs in PF suffer 2 to 3 times the speed penalty for wing racks that they did historically.

LRRP

BM357_Sniper
02-19-2006, 05:17 PM
Originally posted by vanjast:
Were there any other allied planes in the 'mustangs class' = I'm the only one therefore I'm the best.

Just think if you were a test pilot. You're zipping around at low level. Do you watch your instruments which give you 50 kph notches and you spend time working out the exact possible gradings, or do you look where the hell you're going and occasionaly glance at the speedo.
Later when you write your report you write down a speed that you 'think' it was.
Then somebody forgot to tell you that your indicated speed is actually dpendent on air pressure, temperature, and had the speedo been calibrated properly, and did they use proper calibration methods...

I can see the kph's peeling off here. IL2 is a close approximation, and a dam good one at that.
WHY ARE YOU COMPLAININGGGGGGGG!!!!
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif If you think thats what test pilots do, I'm glad you aren't one. lol "Well, uhhhh, I'm guessing here, I think I may have, not really sure, but, it felt like I was going 487 mph, give or take 100 mph. You know us test pilots don't really pay attention to those unreliable gauges." http://forums.ubi.com/images/smilies/compsmash.gif

Grey_Mouser67
02-19-2006, 07:03 PM
I'm amazed that the trolls aren't out in force...a couple surfaced, but most folks ignored them and they went away. In light of the inaccuracies exposed by the data in this thread, if Oleg were to change the Mustang, there would be substantial performance increases with the existing planes....that usually brings out the trolls.

Well, I'll be away on business till Thursday and this will be my last post till then. If anyone has any more data or sources to add, please do. If anyone has climb data or other stuff of note, pm me or post it.

I'd like to see the radiator effect, climb rates and overall speed corrected...and maybe throw in a 75" Mustang to boot...I'm going to wrap it up and send it Oleg's way next week some time.

Remember....Don't feed the trolls.

fordfan25
02-19-2006, 07:23 PM
Originally posted by Grey_Mouser67:
Well, just popped in and did another speed test...crimea etc..etc... loaded up 2 bombs and dropped them immediately, closed radiator and proceeded to accelarate up to a top speed figure of 556 km/hr.

I then opened up the radiator and put in auto after overheat...results same since radiator was fully open at that time...530 km/hr!

A Mustang in that configuration should be flying approximately 581 km/hr...not 530....here is a list of aircraft that are faster than the Mustang at that altitude when the Mustang has its radiators open...

All P-47's
All P-38's
Spitfire Mk VIII's and Mk IX's
All Fw's
All La's
Every Bf109 from the G2 up..F4 down is not
Ki84
Raiden

I don't have data on all planes...those are ones I've tested...it is faster than a Hellcat still and sneaks out a Bf110 by 10km/hr.

For all those who thought the Mustang was well modelled in speed, think again. Bearcat99...yes, the mustang is not "right". thats what i had been thinking for a long time in regardes to the plane being tested with RAD closed. didnt make sense to me.

lrrp22
02-19-2006, 09:14 PM
Originally posted by Grey_Mouser67:

I'd like to see the radiator effect, climb rates and overall speed corrected...and maybe throw in a 75" Mustang to boot...I'm going to wrap it up and send it Oleg's way next week some time.


Been there, done that. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif I've sent the original data, plus tracks. The wing rack issue can't be resolved in the current FM due to a single generic type of bomb rack being used for all aircraft.

Oleg is also aware that historical Mustang top speeds were achieved with partially open radiator flaps and that overheat was not an issue in that configuration. however, it might be worth pursuing further...

LRRP

Edit: Also, 75" Hg doesn't appear to have been used operationally. Squadron service boost levels were either 67" Hg on 100/130 grade fuel, or 72" (8th AAF) to 80-81" Hg (RAF and USAAF on Iwo Jima) on 100/150 and 115/145 grade fuel respectively.

JtD
02-19-2006, 10:28 PM
In fighter bomber configurations with rads open Fw's are not faster than 530 kph on the deck.

Abbuzze
02-20-2006, 12:19 AM
Originally posted by lrrp22:
The Mustangs currently modeled in PF all reach historical top speeds only if radiators are fully closed and wing racks removed.

Virtually all historical USAAF and RAF P-51B/D test speeds were achieved with radiators set to 'Auto'. During those tests the radiators typically opened to between 6.5 and 7.5 inches from the aperature's 5.25 inches 'fully closed' position. Many test aircraft had the radiator exit flap blocked so that the 'fully closed' position was 7.5 inches. Neither coolant nor oil temperatutres ever exceeded the target ranges during these tests, even at increased 150 grade boost levels.


LRRP

Thats a common problem for many planes, 109´s also reached max. speed not with closed radiators. Highspeed setting was 6.5 cm opend.
I haven´t the figure for the FW in my mind, but it was also not closed.
I fear it´s a limitation of the engine simulation, let´s hope that this will be changed in BOB.

lrrp22
02-20-2006, 12:33 AM
Originally posted by Abbuzze:

Thats a common problem for many planes, 109´s also reached max. speed not with closed radiators. Highspeed setting was 6.5 cm opend.
I haven´t the figure for the FW in my mind, but it was also not closed.
I fear it´s a limitation of the engine simulation, let´s hope that this will be changed in BOB.

I think there is a difference though between a 'high speed' radiator setting and radiator flaps set to automatically maintain a certain oil and coolant temperature. Also, the Mustang's coolant flaps, like the Spitifre's, were never completely closed. Even in the 'fully closed' position, the Mustang's coolant flap had a 5.25 inch exit aperature. 6.5 centimeters is only 2.5 inches- from what I know about the 109's radiator flaps, that sounds like the 'flush' position, not 'automatic'.

LRRP

alla7
02-20-2006, 12:56 AM
Originally posted by JtD:

Test results were the P-51B would lose 24mph IAS at 18.000ft when opening the coolant flap and another 10 when opening the oil cooler. That's about 45 kph.

Get your math right.

mynameisroland
02-20-2006, 08:17 AM
Originally posted by alla7:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:

Test results were the P-51B would lose 24mph IAS at 18.000ft when opening the coolant flap and another 10 when opening the oil cooler. That's about 45 kph.

Get your math right. </div></BLOCKQUOTE>

Get your english right smart a ss

JtD
02-20-2006, 08:49 AM
Originally posted by alla7:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JtD:

Test results were the P-51B would lose 24mph IAS at 18.000ft when opening the coolant flap and another 10 when opening the oil cooler. That's about 45 kph.

Get your math right. </div></BLOCKQUOTE>

Meant to say that's about 45 mph TAS. This of course means about 75 kph TAS.

AFJ_Locust
02-20-2006, 09:02 AM
Originally posted by vanjast:
Were there any other allied planes in the 'mustangs class' = I'm the only one therefore I'm the best.

Just think if you were a test pilot. You're zipping around at low level. Do you watch your instruments which give you 50 kph notches and you spend time working out the exact possible gradings, or do you look where the hell you're going and occasionaly glance at the speedo.
Later when you write your report you write down a speed that you 'think' it was.
Then somebody forgot to tell you that your indicated speed is actually dpendent on air pressure, temperature, and had the speedo been calibrated properly, and did they use proper calibration methods...

I can see the kph's peeling off here. IL2 is a close approximation, and a dam good one at that.
WHY ARE YOU COMPLAININGGGGGGGG!!!!
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif


BULLCHIT !!!!!!!!

When Im driving my car I am aware of everything that is going on with my vehical.

I gaurnte you thoes pilots wanted every single bit of power they could get, THERE LIFE WAS ON THE LINE REMBER !!!!!!!!!!!!!!!!!!!!!!!!

DONT BE A SMACKTARD

the guy has a point most ac suffer 20kmh loss with rad open, mustang is 30...? its stupid that an AC with one of the best Rad setups should be penalized an extra 10kmh ?

Tisk Tisk

JtD
02-20-2006, 09:08 AM
Originally posted by lrrp22:
I think there is a difference though between a 'high speed' radiator setting and radiator flaps set to automatically maintain a certain oil and coolant temperature. Also, the Mustang's coolant flaps, like the Spitifre's, were never completely closed. Even in the 'fully closed' position, the Mustang's coolant flap had a 5.25 inch exit aperature. 6.5 centimeters is only 2.5 inches- from what I know about the 109's radiator flaps, that sounds like the 'flush' position, not 'automatic'.LRRP

Overheating is no big issue when flying fast. Rads at Schnellflug setting would provide enough cooling on most altitudes with a minimum of drag.

Closed on a 109 is closed, to prevent the engine from cooling down too much, say at a extended descent at idle or while landing.

Abuzze is also correct that this also applied to the FW. The setting would be almost half open.

Both German planes would achieve their top speeds at radiator settings that would allow them to fly these settings with little danger of overheating.

Essentially the P-51B has the same problems as it's contemporary opponents, except for beeing 5 kph too slow in clean configuration. Most of these problems are known for ages and were not fixed, probably because of engine limitations (which - esp. the bomb racks problem - is quite disappointing).

If that's worth a long mail to 1C - you decide.

JtD
02-20-2006, 09:09 AM
Originally posted by AFJ_Locust:
the guy has a point most ac suffer 20kmh loss with rad open, mustang is 30...? its stupid that an AC with one of the best Rad setups should be penalized an extra 10kmh ?

No, should be 75 - as tested.

TX-Zen
02-20-2006, 09:40 AM
I don't say it's fair if the mustang is really losing 30km/h speed over the radiator, but imho I doubt it's because of specific anti mustang bias from 1C. And I doubt it will be corrected based purely on accounts of how the mustang's radiator worked in real life unfortunately, even if hard, proven and unreproachable data were included.

Remember that the game doesn't have a physics engine that accounts for ALL of the variables that occur in real life...1C has stated that its a reasonable compromise, as realistic as it can be but that there are area's that either cannot be simulated with the PC power we have available or that aren't worth the time to code. I'm willing to bet that radiator drag is one of things that isn't simulated to the fullest extent possible, and you end up with the mustang which has a much larger radiator inlet than most planes...but no deeper calculations to simulate the subtler aspects of its design which makes the net result more draggy than it should be.

Other planes are affected in various ways by the limitation of the sim...air temperature changes in altitude not having an effect on radiator efficiency (not sure if this was ever corrected, can't remember), P38 having torque and gunshake, Ta152 and it's unrealistic and unhistoric stall characteristics, heavy fighters having issues with dive and zoom performance relative to lighter fighters...I'm sure there are many more points that could be raised. All points with the game engine, not the planes themselves.

If there is a way to address the mustang's speed by tweaking the FM appropriately (and assuming it's justified, I haven't done the research but I trust that the information in this thread is accurate and in good faith) then I think it should be done, but if the expectation is on recalculating something in the global physics engine to better simulate the mustang's design... http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif

For what it's worth I would like to see the mustang get it's speed corrected if it truly is an issue, but as I said I don't see any changes to the physics engine in this instance.


And I'm also glad to see the lack of trolling. I've been following this topic and it's refreshing to see a good solid discussion on what could have easily been too controversial a subject. We need more debate like this.

Slickun
02-20-2006, 01:14 PM
Well, simply put, a Mustang without speed is a:

Spitfire not able to pull a lot of G's
An FW with bad guns and slow roll rate
A P-47 with a poor dive
P-38 with poor acceleration
109 with bad climb
Zero with bad low speed turning

or

A B-17 with a glass jaw

Get the message? It neuters the best thing about the plane. And make no mistake, the Mustang was fast, from the ground to 30,000 feet, the thing was fast, and better yet, controllable at those very high speeds.

Badsight.
02-20-2006, 10:01 PM
Originally posted by JtD:
Meredith effect only works when the rad is closed. You open it, you lose it. Thus you not only add drag, you also lose thrust and thus lose more speed than plane with a crappy rads design do. are people understanding this ?

id like to add that the best rad position for max effect was slightly opened (just)

or so it was agreed in ORR when this was debated in patch v2.01

JtD
02-20-2006, 10:30 PM
I know I do. http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

If you open the rad more air will enter which will be slowed down in the middle it, more drag.

If the rad was about closed, you'd have the meredith effect. Now it's wide open, you don't, the air does not get accelerated thus less thrust.

If you build a cooler that does not exploit the meredith effect, you naturally will not lose the thrust as there never was any. The planes speed will be less effected by the radiator setting.

"Closed" rad on a P-51 means slightly open, thus maximum effect.

Kurfurst__
02-21-2006, 02:01 AM
Originally posted by lrrp22:
Many test aircraft had the radiator exit flap blocked so that the 'fully closed' position was 7.5 inches. Neither coolant nor oil temperatutres ever exceeded the target ranges during these tests, even at increased 150 grade boost levels.

Mustang IV TK 589 was tested at 81" and 150 grade fuel. The test report noted the radiator flaps had to be opened to 8,5" iirc becauseo of overheating.

" In order to obtain adequate cooling, level speeds were done with the radiator duct flap set to a gap of 8 inches, as coolant temperatures were excessively high with the normal setting of 7" gap. "
LRRP seen that test.



Also, the Mustangs in PF suffer 2 to 3 times the speed penalty for wing racks that they did historically.

LRRP

Historically the Mustang did suffer some 8-12 mph speed loss when the wingracks were attached. If lrrp's statment hold any connection with the FM o the game - which I doubt - addign the wingracks would mean 24-36mph speed loss..

But, generally the radiator drag figure when opening and closin seems to be off accross the planese, at least I can confirm that for the 109s - their ROC vary very little to radiator position as well...

robban75
02-21-2006, 02:06 AM
Originally posted by Slickun:
An FW with bad guns and slow roll rate
A P-47 with a poor dive

Well, the 190 used to have bad guns. But this has been fixed. The roll rate used to be fast, now it's too slow. http://forums.ubi.com/images/smilies/53.gif

The P-47 ingame actually has poor dive performance. http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif


Get the message? It neuters the best thing about the plane. And make no mistake, the Mustang was fast, from the ground to 30,000 feet, the thing was fast, and better yet, controllable at those very high speeds.

We can only wait and see if Oleg decides to fix the rack speed bug. But don't get your hopes up on the radiator. The Mustang is not alone on this. The (real)D-9 for example, reached its maximum speeds with the rads open at 28%. But like all other planes ingame, it needs to fly with them fully closed. Frying the engine in less than 9 minutes at full speed.

Blutarski2004
02-21-2006, 05:51 AM
Originally posted by Kurfurst__:
But, generally the radiator drag figure when opening and closin seems to be off accross the planese, at least I can confirm that for the 109s - their ROC vary very little to radiator position as well...


..... Possibly so, but keep in mind that drag influences maximum speed a considerably more than maximum climb rate. Broadly speaking, a 10 percent increase in drag will reduce maximum speed by 3 percent, but only reduce initial climb rate at sea level by 1 percent.

Slickun
02-21-2006, 07:52 AM
I agree roban. There was a bit of irony included in my post. Poorly, as usual. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

I don't want a P-51 that turns unrealistically. Or rolls better than it should. Truly.

I can live with one that is just fast, like in real life. If you will throw in that great dive acceleration and top end, I will be a happy camper.

TX-Zen
02-21-2006, 08:12 AM
Originally posted by robban75:
The (real)D-9 for example, reached its maximum speeds with the rads open at 28%. But like all other planes ingame, it needs to fly with them fully closed. Frying the engine in less than 9 minutes at full speed.

I completely forgot about that Robban, thanks for the reminder. I recall that we all used to make a deal of out that because for all practical purposes the D9 (and Ta152) could never use their maximum speeds due to overheat.

I realized something when reading your post...I don't try to use my maximum speed to outrun anyone at altitude simply because there is no point. Down on the deck is another issue, but thats a last ditch defense anyway. Up high it seems everything is faster than the D9 mostly because of overheat and supercharger speed bug.

Hate to say it but I don't think the mustang is getting any kind of unfair treatment at all...sadly it's speed issue seems to be par for the course for what we have in game.

I do truly wish that we could get an overhaul so that planes could get better top speed at correct altitudes. Historically one of the supposed best matchups was the mustang and the dora, I don't feel we have a good approximation of that right now.

BoB might bring some changes, but deep down I feel that it won't. It will have better graphics certainly, but after all there is a particular mindset that drives the physics engine in this sim and thats the same mindset designing BoB.

[/doom and gloom rant off]

lrrp22
02-21-2006, 10:06 AM
Originally posted by Kurfurst__:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by lrrp22:
Many test aircraft had the radiator exit flap blocked so that the 'fully closed' position was 7.5 inches. Neither coolant nor oil temperatutres ever exceeded the target ranges during these tests, even at increased 150 grade boost levels.

Mustang IV TK 589 was tested at 81" and 150 grade fuel. The test report noted the radiator flaps had to be opened to 8,5" iirc becauseo of overheating.

" In order to obtain adequate cooling, level speeds were done with the radiator duct flap set to a gap of 8 inches, as coolant temperatures were excessively high with the normal setting of 7" gap. "
LRRP seen that test.
</div></BLOCKQUOTE>

Yep, and that is the only USAAF or RAF test that showed any problem with overheating. TK589 is also the worst performing of any RAF or USAAF tested P-51B/C/D. Not entirely suprising considering that TK589 was one of the first P-51D's to arrive in the UK (March '44) and was well-worn by the time that test was conducted (July/August '44). Of course TK589's test results are virtually the *only* Mustang tests that you are ever interested in quoting.

Here is a picture of the condition in which TK589 was tested:

http://img.photobucket.com/albums/v11/brentce/TK589swing.jpg


Not exactly factory fresh is it?


<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Also, the Mustangs in PF suffer 2 to 3 times the speed penalty for wing racks that they did historically.

LRRP

Historically the Mustang did suffer some 8-12 mph speed loss when the wingracks were attached. If lrrp's statment hold any connection with the FM o the game - which I doubt - addign the wingracks would mean 24-36mph speed loss..

But, generally the radiator drag figure when opening and closin seems to be off accross the planese, at least I can confirm that for the 109s - their ROC vary very little to radiator position as well... </div></BLOCKQUOTE>

Again- Yep- speed loss due to wing racks in-game ranges from a minimum of 24 mph at SL up to 40 mph at some altitudes.

LRRP

JtD
02-21-2006, 10:11 AM
Ever is ever - and if you say "no P-51 ever exceeded" it doesn't matter what condition the actual suspect is in.

Well, nevermind. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

lrrp22
02-21-2006, 10:27 AM
Originally posted by JtD:
Ever is ever - and if you say "no P-51 ever exceeded" it doesn't matter what condition the actual suspect is in.

Well, nevermind. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif


I stand corrected: all but one (well-used) tested example had no cooling problems during speed or climb tests.

LRRP

horseback
02-21-2006, 10:31 AM
I see that the usual suspects are playing the usual semantic games...

cheers

horseback

Slickun
02-21-2006, 02:32 PM
I would also love to have that P-51D in the game. Operating at 81" hg/25 pounds.

I'll take an open rad from time to time to have it.

Oh yes I would!

Viper2005_
02-21-2006, 03:00 PM
I think that this radiator thing is an almost universal problem; most aircraft in the game have unrealistic overheating problems; the faster aircraft generally suffer the most, and the few that don't suffer to any great degree (Spitfire at low speed, P-47 at high altitude) are therefore handed an unrealistic advantage which skews the game somewhat.

Of course the other side of this coin is that I can get into a Spitfire or a Bf-109 and ground run it all day without overheating...

The overheating model is the biggest problem with this game IMO. Whilst we need something to prevent people using WEP all the time, this isn't the way to do it; I hope that we can at least get this fixed for BoB if not before.

geetarman
02-21-2006, 05:54 PM
[QUOTE]Originally posted by Unknown-Pilot:
I really didn't see what all the complaining was about (other than the "But teh Mustang won teh war!!11!!oneone" whiners).

Never cared much for the mustang because it was an overpopular, overrated, glory hound with absolutely no soul.


And I guess we should somehow pack up the tent over the well-documented problems with the P-51 because of your obvious unbiased interest in seeing all planes perform accurately, coupled with your extensive testing of the Mustang. http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif