Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained)
- Thread starter greybeard
- Start date
Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
It was, you just don't understand.
If you moved the cockpit, lengthened the fuselage, widened the wings, moved the two cowl .50MGs to the wings alingside the other two .50MGs, changed the radio location and upgraded the engine to an R-1830...wait, I just created an F4F.
Nevermind...
GregP
Major
Hi Schweik,
All U.S. WWII airplanes had to meet the specs ± a few percent. IIRC, the P-40 has to meet specs ±5%. That means a P-40E could be right on the 360 mph spec or could be as much as 18 mph faster or slower. You claim they were all slower. I say bunk. Some were, some weren't. Same went for the P-40F. In point of fact, I'd say most P-40E models were 350 - 360 mpg airplanes and most P-40Fs were 360 - 370 mph airplanes. A few were a small bit faster and a few were a small bit slower.
As for the P-40s I know of today, almost all I know of (5 of them personally) are faster than spec, no doubt due to having less weight (no armor or armament), having replica fake guns that are not quite as draggy as real installations, and are generally in better shape than wartime airplanes that sat outside in a dirt field all the time.
In 2017, at the Reno Races, there was a stock (take with a grain of salt) P-51D, "Little Horse," that flew the course at 267.192 mph in Bronze class. There was a P-40E, "Texas Warhawk," that flew the course at 267.527 mph in Bronze class and beat the P-51D. It surely didn't look slow, and was also not much modified, if at all. These guys were running 3,000 rpm and whatever MAP they wanted to run with stock engines, but they were not there to lose. They weren't at 25,000 feet, but instead were down low at Reno (5,050 feet MSL plus whatever density altitude was added due to temperature).
Sorry, but someone saying the "real" P-40s were slower than spec doesn't cut it. One test does not a production run of airplanes specify. According to real former AVG pilots, they used to fly them at 70" - 75" when in combat, and they weren't "slow" and bettered ALL specs at high power levels.
When I look at WWIIaircraftperformance, I see a test of a P-40E, SN 40-633, and it had a top speed of 342 mph at 11,400 feet. Best climb rate was 2,400 fpm. Note the MAP ws 43.9" MAP. When I scroll down to the P-40F test, SN 41-13635, I see a top speed of 365.5 mph with belly tank sway braces installed and 374 mph without the sway braces. At 12,800 feet, the closest I can see to the P-40E, it went 350 mph, or about 87 mph faster about 1,400 feet higher. Best climb rate was 2,210 fpm. Note, the MAP was at 48" MAP. Now, myself, I'd wonder why they didn't run the Allison at 48" MAP if they wanted an apples-to-apples comparison, but these were individual test and NOT a comparison.
The P-40E was tested 5 Apr 43 and the P-40F was tested 11 Jul 42, so the P-40E had a LOT more hours on it than the P-40F did. I'm surmising you are inferring the P-40E was a 345 mph airplane based on one test. But, the test was on a 2+ year old airplane while the P-40F test was on a much newer and I have read many reports where a P-40E did 360 mph.
All in all, seems like they weren't exactly stretching the P-40E in the test on the website. But, that particular airplane WAS20 mph slower at the power they used.
All U.S. WWII airplanes had to meet the specs ± a few percent. IIRC, the P-40 has to meet specs ±5%. That means a P-40E could be right on the 360 mph spec or could be as much as 18 mph faster or slower. You claim they were all slower. I say bunk. Some were, some weren't. Same went for the P-40F. In point of fact, I'd say most P-40E models were 350 - 360 mpg airplanes and most P-40Fs were 360 - 370 mph airplanes. A few were a small bit faster and a few were a small bit slower.
As for the P-40s I know of today, almost all I know of (5 of them personally) are faster than spec, no doubt due to having less weight (no armor or armament), having replica fake guns that are not quite as draggy as real installations, and are generally in better shape than wartime airplanes that sat outside in a dirt field all the time.
In 2017, at the Reno Races, there was a stock (take with a grain of salt) P-51D, "Little Horse," that flew the course at 267.192 mph in Bronze class. There was a P-40E, "Texas Warhawk," that flew the course at 267.527 mph in Bronze class and beat the P-51D. It surely didn't look slow, and was also not much modified, if at all. These guys were running 3,000 rpm and whatever MAP they wanted to run with stock engines, but they were not there to lose. They weren't at 25,000 feet, but instead were down low at Reno (5,050 feet MSL plus whatever density altitude was added due to temperature).
Sorry, but someone saying the "real" P-40s were slower than spec doesn't cut it. One test does not a production run of airplanes specify. According to real former AVG pilots, they used to fly them at 70" - 75" when in combat, and they weren't "slow" and bettered ALL specs at high power levels.
When I look at WWIIaircraftperformance, I see a test of a P-40E, SN 40-633, and it had a top speed of 342 mph at 11,400 feet. Best climb rate was 2,400 fpm. Note the MAP ws 43.9" MAP. When I scroll down to the P-40F test, SN 41-13635, I see a top speed of 365.5 mph with belly tank sway braces installed and 374 mph without the sway braces. At 12,800 feet, the closest I can see to the P-40E, it went 350 mph, or about 87 mph faster about 1,400 feet higher. Best climb rate was 2,210 fpm. Note, the MAP was at 48" MAP. Now, myself, I'd wonder why they didn't run the Allison at 48" MAP if they wanted an apples-to-apples comparison, but these were individual test and NOT a comparison.
The P-40E was tested 5 Apr 43 and the P-40F was tested 11 Jul 42, so the P-40E had a LOT more hours on it than the P-40F did. I'm surmising you are inferring the P-40E was a 345 mph airplane based on one test. But, the test was on a 2+ year old airplane while the P-40F test was on a much newer and I have read many reports where a P-40E did 360 mph.
All in all, seems like they weren't exactly stretching the P-40E in the test on the website. But, that particular airplane WAS20 mph slower at the power they used.
Last edited:
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
See? It wasn't hard. Thanks GrauGeist.
The speed - and especially altitude performance - depends on weight and drag. The British tests were done with field conditions. For example the P-40F they clocked at 370 mph had bomb shackles on it. Bomb shackles, and other things like rearview mirror, direction finding antenna, radio mast, open gun ports etc. slow a plane down to a surprising degree. Weight has slightly less effect on speed but it does affect altitude performance... which in turn affects speed.
When the companies do the tests to validate their contract, they did everything allowed to improve the performance. This often means reduced fuel, reduced or no ammunition, and typically no external accoutrements. They also sanded and waxed the planes and even sometimes puttied over little gaps and holes. By contrast, the tests I posted links to, which are not invented or made up, they are actual WW2 evaluations, were done at full combat weight, with the usual gear used in the field, and at the boost settings recommended in the manual. One of those speed tests I posted on the P-40E was done in Australia and the other in Britain. Yet they came up with fairly identical results.
Exactly. This is the issue. I don't think the P-40 was slow or sluggish, especially once they increased the boost settings past 45". The issue is basically a matter of altitude. As has been noted before in this thread I believe, in one of the other tests done in Australia it was noted that the P-40E was faster than the Spitfire Mk V they were testing at low to mid altitude. At say, 8,000 ft the P-40 was quite fast, at 2,000 feet using WEP or overboost, it was extremely fast for the time period. But precious few WW2 fighters were exceeding 350 mph at 2,000 feet.
The speed, in other words, is largely a function of altitude. Specifically power at altitude. The reason the P-40F was 30-40 mph faster than the P-40E was because it's engine was still generating pretty good power at higher altitude where the air is thinner. The second speed gives it a bump up above 15,000 ft.
Part of the reason the P-51 was so fast was that it was very well streamlined, and it had a bit of thrust from it's exhaust system etc., but the other (main) reason is that it had plenty of power at 30,000' where the air is a lot thinner.
Right, and down low, I can imagine the P-40 could be competitive with the P-51, as you say depending on Manifold pressure they were willing to push the engine to. The Mustang is less draggy etc. but the Allison has plenty of power down low especially if it's in good shape and they are willing to push it a bit.
Yes but you can't do 70" boost when you are up at 20,000 ft. More like 2,000 ft. I have spoken to some real AVG and other P-40 pilots in person by the way, and read plenty of their biographies and autobiographies, as I'm sure you have.
I am not a critic of the P-40. To the contrary I've been accused on this forum more than once of being a fanboy. But I try to stay within the parameters of reality. As far as I can tell the 'brochure specs' for just about all WW2 aircraft are a bit distorted. It seems like whatever was published by the War department in 1942 and then written down in some 'Fighters of the World' type book in the early 1960s by Bill Gunston or somebody just seems to be repeated over and over. This goes for positive and negative tropes. For ages everyone said that P-40s were 'slow and unmaneuverable' but we know both of those things were false. It was slower than a Bf 109 and less manueverable than an A6M, but it was actually a reasonably fast and very maneuverable fighter by the standards of it's time. But P-40Es weren't making 360 mph in the field with a full fuel load. Maybe after they'd flown for an hour.
The P-40, from what I understand, was like a lot of WW2 fighters, especially American ones, in that it was right at the tipping point in terms of weight when they put in everything it needed for combat. I don't know about modern air shows and air races, (you can perhaps tell me) but I doubt they are putting 160 gallons of fuel, not to mention guns, self sealing fuel tanks, or all the armor. (I know they do keep some armor in some of those planes because I've seen the back of the seat armor on a P-40N at an airshow with my own eyes). But generally speaking, a fighter used in war conditions is going to be heavier and more draggy, and therefore not going to be as fast as one used in an airshow.
The difference in performance between the P-40F/L and the Allison powered P-40s, especially the E and the K, is basically that of altitude. The Allison can probably produce more horsepower, the K was rated for 1550 hp whereas the highest rating I've seen for the Merlin 28 / V-1650-1 is 1450 hp. I am pretty sure a P-40K could outrun a P-40F at Reno Air Races altitudes, (and probably a Bf 109 too, depending on the subtype). But the Merlin was still delivering around ~1100 hp at 20,000 ft, and that is where the speed came into play. And at that altitude, the P-40E was basically a sitting duck for the swift Bf 109F or MC 202 with their hydromatic superchargers, while the P-40F/L was still at least competitive.
At ~8500 lbs, a P-40 was close to overloaded. At ~ 8000 lbs, it was a lot more spry. The same aircraft that takes off to attack an enemy base might be a lot more snappy once it gets to the target. That is why you see such disparities quoted for nearly the same aircraft. A P-40F or P-40N with six guns and full fuel load has an initial climb rate of ~ 2,000 fpm, but with two guns out and a bit less fuel and armor, it bumps up to around 3,200 fpm. The difference is the weight.
GregP
Major
Hi Schweik, you are correct they don't put everything into a modern warbird ... MOSTLY.
There are several types of flying warbirds. One is just a flyer, and likely has had everything except what is needed to fly removed, and likely has the gun ports faired over and all excess weight removed. There are quite a few of these flying about. They generally outperform stock specs considerably due to lightness and better aerodynamics due to no armament and maybe fewer antennas.
A second type is a flying warbird that is pretty stock on the outside but is also still a LOT lighter than stock. An example might be the P-51A that the Planes of Fame flies. It is VERY light and had no armor, no guns or simulate gun weight, and is likely flying at just over 5,000 pounds! It is very sprightly, to say the least, for a P-51A. These birds may even have a glass cockpit installed! I've seen a Hawker Hunter with a full-glass cockpit in Boise, Idaho, U.S.A. . It was polished to a fine shine and had a "big" engine in it. I would not be at all surprised if it were capable of Mach 1+. Of course, nobody was pushing it to go that fast over Idaho since there is no supersonic corridor there AFAIK.
A third type warbird is the restoration to factory wartime stock condition. It has the armor, likely the guns (disabled, of course), and much of the stuff that is stock, but useless in peacetime. I have seen several of these type warbirds. The owners want them to represent a stock WWII bird. These perform slightly lower than wartime stock birds due to lack of late-war fuels being available to them. They run on 100LL fuel.
I'm not too sure I believe a P-40F with belly tank shackles installed went 370 mph. and I'm not too sure a stock P-40E was only a 345 mph airplane. I KNOW that John Paul's is faster than that, and his is pretty stock. Actually, I think the P-40E is Sue Paul's airplane! At least, she thinks it is
, especially since it says SUE on the side.
I know what you mean about everyone repeating the specs from some test in some book. Of course, that is likely because nobody who currently owns a warbird wants to let someone flog their warbird doing performance tests unless someone is paying for a rebuild after the testing. And I don't know of anyone willing to fund a million+ dollar rebuild just to get a stock performance test on a bird that is more or less stock with an engine and propeller of unknown health. So, they are left with old performance test results. Oh well, it is the best we can do at this time and likely not to change, huh? As time goes on we are less and less likely to see any real performance testing. Presently, we are likely to see real performance test of a WWII warbird at a probability level of 0.00000148 or so ... and it is dropping all the time.
Cheers! In the end, I don't really know exactly how fast an average P-40E was. Of course, I can say the same for a P-40F. All I can say for sure is that the Merlin P-40s were better looking because the carb airscoop was not there and the fuselage was stretched to be longer than the P-40E fuselage was.
There are several types of flying warbirds. One is just a flyer, and likely has had everything except what is needed to fly removed, and likely has the gun ports faired over and all excess weight removed. There are quite a few of these flying about. They generally outperform stock specs considerably due to lightness and better aerodynamics due to no armament and maybe fewer antennas.
A second type is a flying warbird that is pretty stock on the outside but is also still a LOT lighter than stock. An example might be the P-51A that the Planes of Fame flies. It is VERY light and had no armor, no guns or simulate gun weight, and is likely flying at just over 5,000 pounds! It is very sprightly, to say the least, for a P-51A. These birds may even have a glass cockpit installed! I've seen a Hawker Hunter with a full-glass cockpit in Boise, Idaho, U.S.A. . It was polished to a fine shine and had a "big" engine in it. I would not be at all surprised if it were capable of Mach 1+. Of course, nobody was pushing it to go that fast over Idaho since there is no supersonic corridor there AFAIK.
A third type warbird is the restoration to factory wartime stock condition. It has the armor, likely the guns (disabled, of course), and much of the stuff that is stock, but useless in peacetime. I have seen several of these type warbirds. The owners want them to represent a stock WWII bird. These perform slightly lower than wartime stock birds due to lack of late-war fuels being available to them. They run on 100LL fuel.
I'm not too sure I believe a P-40F with belly tank shackles installed went 370 mph. and I'm not too sure a stock P-40E was only a 345 mph airplane. I KNOW that John Paul's is faster than that, and his is pretty stock. Actually, I think the P-40E is Sue Paul's airplane! At least, she thinks it is
, especially since it says SUE on the side.I know what you mean about everyone repeating the specs from some test in some book. Of course, that is likely because nobody who currently owns a warbird wants to let someone flog their warbird doing performance tests unless someone is paying for a rebuild after the testing. And I don't know of anyone willing to fund a million+ dollar rebuild just to get a stock performance test on a bird that is more or less stock with an engine and propeller of unknown health. So, they are left with old performance test results. Oh well, it is the best we can do at this time and likely not to change, huh? As time goes on we are less and less likely to see any real performance testing. Presently, we are likely to see real performance test of a WWII warbird at a probability level of 0.00000148 or so ... and it is dropping all the time.
Cheers! In the end, I don't really know exactly how fast an average P-40E was. Of course, I can say the same for a P-40F. All I can say for sure is that the Merlin P-40s were better looking because the carb airscoop was not there and the fuselage was stretched to be longer than the P-40E fuselage was.
Last edited:
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
Always glad to help!
Glider
Captain
More like the
'I've been smoking something P39, where all my fantasies are real.
Where all the thousands of pilots who flew it, all the engineers who worked on it, all the designers who designed it, were all so foolish and inept, that they couldn't see how these simple changes would have changed the world. Where the Fw190, P51A, Spit 12, Me109, Typhoon and all Japanese aircraft would bow down at the altar of the P39.
The same P39 where all the pilots (with the exception of the Russians, granted) couldn't wait to get rid of it, just as fast as they can.
P-39 Expert
Non-Expert
Attached. Page 27.
P-39 Expert
Non-Expert
Shortround6
Major General
Who all designed the P-39E/P-76 and P-63 to hold the engine/s that is claimed to fit into the P-39 with ease.
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
"Where did you get the coconuts?"
Glider
Captain
They were the ballast
buffnut453
Captain
I surrender....
Thumpalumpacus
Major
It's funny how our after-action reports and debriefings on a fire differed one from the other, even though my crew-chief was backing me up on a handline, or the other crash truck was set up only 100' away. They didn't see what I saw, and vice-versa. Perspective is a bitch.
Claims should clearly be compared to losses in order to tot them up straight as possible, because human perception is flawed for a number of reasons -- especially in a fast-flowing event.
varsity07840
Airman 1st Class
- 176
- Jun 25, 2013
Since when was the P-40N in any of its sub types noted as an interceptor?
GregP
Major
The interceptor version of it had 4 machine guns. The other gun ports were fared over. It was a bit lighter, faster, and rolled & climbed better than the 6-gun variety.
Clayton Magnet
Staff Sergeant
- 868
- Feb 16, 2013
I think you would be flying an Allison P-40 well beyond the Pearl Harbor timeline.
When did the P-40F enter service? Pardon my ignorance, but I think there would be a significant gap between Dec 1941 and the introduction of P-40F's into combat.
MIflyer
1st Lieutenant
XP-40F flew on 25 Nov 1941. they built 1311 P-40F in 1942 and 700 P-40L with Merlin engines in 1943.
The P-40N-1-CU was the stripped model, with only 4 guns, no battery, and less fuel, and had top speed of 378 MPH. In contrast the P-40N-15 had a top speed of only 343 MPH at 15,000 ft. .
The P-40N-1-CU was the stripped model, with only 4 guns, no battery, and less fuel, and had top speed of 378 MPH. In contrast the P-40N-15 had a top speed of only 343 MPH at 15,000 ft. .
Clayton Magnet
Staff Sergeant
- 868
- Feb 16, 2013
I see, so you theoretically could have a P-40F right after Pearl Harbor. Disregard my previous post then
