to AGR: 2d rate? I seem to recall that the Allison Mustang was designed to be superior to the Curtiss Tomahawk/Kittyhawk series, which the RAF was buying in large numbers because it was SUPERIOR to any ground attack a/c being built in Britain at the time.

I know it was superior to the P-40, but that isn't saying much. I don't know why the RAF wanted to buy those two anyway. I suspect it was more to do with British production capacity than any enthusiasm for the aicraft. However, it would be more accurate to say that the Allison Mustang was a second-rate fighter that was restricted to ground-attack and recon. I was really making the point in response to Shooter's comments about the supposed advantages of the Allison over the Merlin, not to disparage the Mustang which was one of the all-time great fighter aircraft once the British engine was installed. http://www.globalsecurity.org/military/systems/aircraft/p-51.htm

Re: my last post, by "those two" I mean the two Hawk models, not the Hawk and the Mustang.

.... have the British order them from North American, then instead agree to have North American design the P-51 because the P-40's were crap, then install a British Merlin engine because the American Allison engine was crap, then when the USAF finally wakes up to the great fighter that they accidentally got thanks to British forsight and engine design, melt down your remaining P-40's to build more P-51's.

Just substituting the historically accurate acronym USAAC for USAF, from my last post. ".... have the British order them from North American, then instead agree to have North American design the P-51 because the P-40's were crap, then install a British Merlin engine because the American Allison engine was crap, then when the USAAC finally wakes up to the great fighter that they accidentally got thanks to British forsight and engine design, melt down your remaining P-40's to build more P-51's."

the design couldn't have been that defective ;) - the spit holds the record as the allied fighter that fought at the highest recorded altitude of the war - and that was a mod Mk IX. which other fighter aircraft in the allied stable was recorded as fighting at 43,000ft? Nada, zip zilch.

Actually, correct would be: USAAF as the Army Air Corps became the Army Air Force about the end of '41. The RAF bought the Curtiss's because they needed ground attack a/c that could defend themselves and had NOTHING as capable or effective. At low altitude, (which is what they were designed for) the P40s weren't at all bad. The version with the Merlin engine (P40F) actually had little improvement in performance. They were much tougher a/c than even the Hurricain, carried more useful armament (the Hurri IIs 4 x 20mm had a mere 90 rds per gun) anc carried heavier external load. They also had much more range than either. And the Mustang was better than the 'hawks. Also, there was nothing basicly wrong about the Allison that a decent two-stage blower wouldn't have fixed. Much is made about the engine failures in the P38 over N Europe, but that was mostly a result of supercharger problems, and low quality fuel. The problem was that, like the Soviets, the pre war USAAC felt that nearly all fighting would be at fairly low levels, near the ground troops, where the fighting that really matter, would be going on. The a/c (and engines) were designed with that in mind, hence the lack of concern about high altitude performance. The P38 was originally a low priority, 'insurance' project in case of attack by high altitude bombers. The P39 prototype had a supercharger, but it was removed to save weight, and improve low altitude performance. The Soviets were right in their estimate, the US Army wasn't. But for ground support, the 'hawks were in their element. Poor kill to loss ratio against '109s was partly poor air combat tactics by the RAF, partly the result of almost always being attacked from above. The P40 wasn't a bad a/c, but it was badly mis used. Even then, it could be an effective medium altitude interceptor. You just needed time to get above your enemy, and fall on him. It couldn't handle maneuver combat at medium altitude, but with an altitude advantage, it was quite effective using 'hit and git' tactics, as the AVG proved.

Please give details of Spitfire combat at 43K, how and why. I'm very interested. With the thin wing, the Spit just wasn't suited for maneuver in thin air. My reasons posted earlier. I do know that P38s could operate in flight formations above 42.5K, but it had both a turbo-charger and a much better airfoil shape for high altitude, and there wasn't much for them to fight up there anyway. As German ftrs rarely went above 30K (the B17s usually operated at about 24K and above 25K the performance advantage of the P47s increased sharply) there wasn't normally much reason to be fighting up there, except perhaps chasing a single recce a/c.

"Please give details of Spitfire combat at 43K, how and why" The highest air combat during the second world war took place 12 Sept 1942 when in a unique action both contestants reached altitudes above 43,000ft. Spitfire IX piloted by Pilot Officer Emanuel Galitzine of the Special Service Flight vs Ju-86R of the Hohenkampfkommando piloted by Oberfeldwebel Horst Goetz and Navigator Leutnant Erich Sommer (now living in Australia) Ref "Skies of Fire, Dramatic Air Combat" by Alfred Price. ISBN 0-304--35947-5. Chapter 7 Page 78-83. The whole book is a good read. Worth getting if you're interested in personal story books. Both lots of aircrew are interviewed.

Thanks for the tip on the USAAF, though the period we are talking about spans both acronyms. "The version with the Merlin engine (P40F) actually had little improvement in performance." One important feature of a well designed aircraft like the Spitfire or Mustang, was the ability to make use of better engines when they became available. The fact that the P-40 couldn't simply shows that it was an inferior design. "Also, there was nothing basicly wrong about the Allison that a decent two-stage blower wouldn't have fixed." Why would a blower on the Allison have made any difference for the P-40, if fitting a Merlin which already had one didn't? In any case, at that stage US manufacturers weren't up to designing decent two-stage blowers. That was a British specialty, on the Allied side at least. "Poor kill to loss ratio against '109s was partly poor air combat tactics by the RAF, partly the result of almost always being attacked from above." Surely a reason to build an aircraft that can do the job at altitude, so that it isn't attacked from above. As for the P-40 being ok at its designated role, that may be the case but you could argue that the Spitfire was (well and truly more than) ok at what it was designed for, that being to quickly get to altitude and nail high-flying threats. Shooter's arguments about range are irrelevant in this context, as long-range bomber escort wasn't in the equation when the Spitfire was built. In every other respect it matched or beat the best US aircraft in performance and was carrying a pair of cannon into battle before the P-51A even made its combat debut, armed with 4 x 50 cals.