AHC/WI: American Equivelant To The Merlin

[Gosing]

A defining character of most American aircraft (especially fighters) in the 1930s and early 1940s was the overall crappiness of their engines-the P-39, whose design was greeted with great enthusiasm, ended up off frontline service due to the lack of a good engine, and two of America's most famous WWII-era fighters (the P-51 and the later model P-40s) used an American-produced version of the famous Rolls-Royce Merlin, which was used in the Spitfire and Hurricane.

So, how could the US develop an engine that was about as effective as the Merlin in the 1933-35 time range? And what effect, if any, would it have on the course of American aircraft development, and the coming war? Any takers?