In
the late 1930s, the U.S. Army Air Corps requested an fighter
aircraft to be powered by the Allison V-1710. Lockheed
responded with the Lightning and Bell with
the Airacobra.
First flown in 1938, the Bell Model 12
featured the engine mounted behind the pilot in order to mount a
37mm cannon and two .50 caliber machine guns in the nose.
Along with the P-40, the P-39 Airacobra was
the USAAC's front-line fighter when Japan attacked Pear Harbor in
1941. With insufficient power to be a successful fighter, the
P-39 proved to be a potent ground attack aircraft. Over 9,500
were built with almost 4,800 supplied to Russia.