10.05.2009, 04:25
From aviation-history.com
The prototype XP-40, the Curtiss Hawk Model 81, owed its origin to the earlier Model 75 of 1935 vintage. With the standardization of the Allison V-1710 , the P-36 design was reworked to incorporate this engine, becoming the XP-37 which was equipped with a General Electric turbo-supercharger, and featured numerous other modifications, including a rearward positioned cockpit. Thirteen YP-37s were built for service evaluation; but, with increasingly ominous signs of an approaching war, development of this fighter was abandoned in favor of a less complex and more direct conversion of the P-36 for the Allison engine, the XP-40. This was, in fact, the tenth production P-36A with an integrally-supercharged 1,160 hp Allison V-1710-19 (C13) engine, and first flew with its new power plant in the autumn of 1938. Successful in a US Army Pursuit Contest staged at Wright Field, in May 1939 it was awarded what was at that time the largest-ever production order for a US fighter, totaling nearly thirteen million dollars.
I also note the existence of a YP40F, no doubt to prove the installation of a Rolls Royce Merlin. Incidentially, the P40A was never built and seems to have been intended as a recconsaisance variant
The prototype XP-40, the Curtiss Hawk Model 81, owed its origin to the earlier Model 75 of 1935 vintage. With the standardization of the Allison V-1710 , the P-36 design was reworked to incorporate this engine, becoming the XP-37 which was equipped with a General Electric turbo-supercharger, and featured numerous other modifications, including a rearward positioned cockpit. Thirteen YP-37s were built for service evaluation; but, with increasingly ominous signs of an approaching war, development of this fighter was abandoned in favor of a less complex and more direct conversion of the P-36 for the Allison engine, the XP-40. This was, in fact, the tenth production P-36A with an integrally-supercharged 1,160 hp Allison V-1710-19 (C13) engine, and first flew with its new power plant in the autumn of 1938. Successful in a US Army Pursuit Contest staged at Wright Field, in May 1939 it was awarded what was at that time the largest-ever production order for a US fighter, totaling nearly thirteen million dollars.
I also note the existence of a YP40F, no doubt to prove the installation of a Rolls Royce Merlin. Incidentially, the P40A was never built and seems to have been intended as a recconsaisance variant