P-400 American fighter

The P-400 was the American redesignation for the export model of the P-39 Airacobra, intended to be sent to Britain and other Allies. It was equipped with a 20 mm Hispano cannon in the nose, rather than the typical 37 mm of other models. Britain ordered 675 P-39s (redesignated as the "Airacobra Mk I") starting in September 1940; however, once they began to arrive in September 1941, it was quickly found that they had inadequate climb rate and high-altitude performance, and only 80 were operated.