Hypothetical battle: P40 Q2 VS P51K

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Staff Sergeant
Sep 19, 2005
Phoenix, AZ
Which would win different aspects of a compairson and a dog fight. I know the P40 had one of the best turning radiuses for the Allied aircraft inventory, but how would it fair against a P51K? The P40 Q2 was proposed to be equiped with a heavy armament of 4 20mms, would this have won the day against a P51K, or would the latter fighter come out on top. To even the odds a bit, the combat is pitting a captured P51K against a P40 Q2 at a medium to low level altitude.

One Allison V-1710-85 engine rated at 1200 hp at sea level and 1125 hp at 15,500 feet. Maximum speed 330 mph at 5000 feet, 357 mph at 10,000 feet, 376 mph at 15,000 feet. Climb to 5000 feet in 2.0 minutes. Climb to 20,000 feet in 8.5 minutes. Maximum range (clean) was 525 miles at 20,000 feet at 250 mph. With one 145.7 Imp gal drop tank, range was 1075 miles at 196 mph. Service ceiling was 35,000 feet. Weights were 5645 pounds empty, 7600 pounds normal loaded, 8300 pounds maximum loaded. Dimensions: Wingspan 34 feet 0 inches, length 30 feet 2 inches, height 12 feet 5 inches, wing area 213 square feet.



One 1695 hp Packard Merlin V-1650-7 twelve-cylinder Vee liquid-cooled engine. Maximum speed: 395 mph at 5000 feet, 416 mph at 10,000 feet, 424 mph at 20,000 feet, 437 mph at 25,000 feet. Range was 950 miles at 395 mph at 25,000 feet (clean), 2300 miles with maximum fuel (including drop tanks) of 489 US gallons under most economical cruise conditions. Initial climb rate was 3475 feet per minute. An altitude of 5000 feet could be reached in 1.7 minutes, 10,000 feet in 3.3 minutes, 20,000 feet in 7.3 minutes. Service ceiling was 41,900 feet. Weights were 7125 pounds empty, 10,100 pounds normal loaded, 12,100 pounds maximum. Wingspan was 37 feet 0 1/4 inches, length was 32 feet 3 inches, height was 8 feet 8 inches, and wing area was 233 square feet.


"The P-40Q was an experimental project which attempted to produce a really modern fighter out of the existing P-40. The modifications were in fact so drastic that there was very little in common with earlier P-40 versions.

Two P-40Ks (serial numbers 42-9987 and 42-45722) and one P-40N (serial number 43-24571) were extensively modified with revised cooling systems, two-stage superchargers, and structural changes which markedly altered their appearance. The project was assigned the designation XP-40Q.

The first XP-40Q was P-40K-10-CU ser no 42-9987 fitted with a new cooling system, a longer nose, and a four-bladed propeller. The radiators were moved into an under-fuselage position, with intakes between the undercarriage legs.

The most prominent XP-40Q feature, used on 42-45722 and 43-24571, was the cutting down of the rear fuselage and the addition of a bubble canopy as on the "XP-40N". Later the wingtips were clipped. The result was an aircraft which bore almost no resemblance whatsoever to its parent P-40 line. The V-1710-121 engine was fitted with water injection, resulting in a power of 1425 hp. Speed increased to 422 mph at 20,500 feet, making it the fastest of all the P-40s. An altitude of 20,000 feet could be reached in 4.8 minutes, and service ceiling was 39,000 feet. Four 0.5-inch machine guns were carried by the prototypes. Wingspan was 35 feet 3 inches (after clipping), and length was 35 feet 4 inches (2 feet longer than the P-40N).

The proposed production models of the P-40Q were to have carried either six 0.50-inch machine guns or four 20-mm cannon, but the XP-40Q was still inferior to contemporary production Mustangs and Thunderbolts, and development was therefore abandoned. Consequently, the production life of the P-40 ended with the N version.

The second XP-40Q was briefly used for postwar air racing. Registered NX300B, the second XP-40Q was an unauthorized starter in the 1947 Thompson Trophy race. It was in fourth place when it caught fire and had to drop out of the race."
But who would have won at varying altitudes, and who would have won in a pure (/looping) dogfight? I cite the source that says that the P40 had one of the best turning radi of the Allied aircraft arsenal. My vote goes to the P40 Q2; I like the P51 but it would not have lasted against 4 20mms, nor against a better turning fighter (could be wrong though).
Twitch said:
The P-40, any model was poor in turns. The P-47 had the best roll rate of American fighters too. Any Mustang would mop up the skies in a mock dogfight with any P-40 as I see it.....

America's Hundred Thousand puts the P-40 well ahead of the P-51 in turn performance. The P-51 has better acceleration, dive and climb though.

The P-47 never had the best roll rate of any American fighter, at least not according to the NACA 868 and Francis and Dean. At low speeds and medium speeds the best rolling of the USAAF fighters was the P-40, but above 350 mph the P-51 became better.
Although with an experienced pilot the P-38 would have a superior roll rate. Of course it all depends on the speed your travelling as well.
I'm going with Bob Johnson's observation coupled with his score of 27 kills when he say the Jug could out roll anything. Sometimes all the stats and specs just get too much focus when pilots actually do things with airplanes that result in victory through performance. Dry specs aren't the end-all.
AHT bases much of its data from the Pauxtent River Joint Fighter Conference of 1944. More than 30 service pilots from the Navy, Marines and AAF wnet and rated and assesed the performance of US fighter types.

I'll take standardised testing by a wide sample of combat AND test pilots, over the recollections of just a single man, no matter how good a pilot he was/is.
Jabberwocky said:
AHT bases much of its data from the Pauxtent River Joint Fighter Conference of 1944. More than 30 service pilots from the Navy, Marines and AAF wnet and rated and assesed the performance of US fighter types.

I'll take standardised testing by a wide sample of combat AND test pilots, over the recollections of just a single man, no matter how good a pilot he was/is.

Agree, and although you'll always have that odd pilot(s) to defy the odds, its under thoses circunstances where real and accurate performance data is attained...
One comment though, we're talking about real combat, not simulated combat between the two planes. I've heard before that the mustang could not absorb as much damage as its contemporaries in the Allied airforce, if so, then wouldn't it be the case that the P40 could out last the Mustang and bring the 20mms to bear following some dive and turn tactics. I could be wrong, but between the P40 and P47, those two planes had the highest diving speed, and the P40 held the speed after the dive for a while.
Are you sure about that Climb speed for the P-51D, my Pilots hand book gives 9min to 20,000ft @ METO power.

The P-38L has the fastest roll rate above 325mph, though it is just a bit slower than the P-51 below that.

I thought this thread was about the P-40Q and the P-51K (a "D" built in a different plant). The P-40 had the best roll rate of any American fighter if you believe the flight tests.

Captain Eric Brown of the RAF also said the P-40 rolled better than any otehr American fighter. I'd be a bit skeptical about claims from aces who flew only one type of fighter. Specifically, many P-47 aces flew several models of P-47 and each one got better ... but they were still P-47s. Eric Brown flew more types than anyone else in the world, and I believe him.

There is considerable evidence that the P-39 also had a very good rate of roll, and we ALL know the late-model P-38s were strong in roll. Everyone wishes they were stronger in turning ... but let's all recall that the highest-scoring American ace flew a P-38. Couldn't have been all THAT bad, huh?

All that being said, the graphs I have seen from WWII show the P-40 with the best roll rate of all .... American, that is.The makers of these graphs are careful to not show everything in one graph.

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