The
Bell P-39 Airacobra was one of the principal American fighter aircraft in service when the
United States entered
World War II. The P-39 was used by the
Soviet Air Force, which scored the highest number of individual kills attributed to any U.S. fighter type in the Eastern European theatre. Other major users of the type included the
Free French, the
Royal Air Force, the
United States Army Air Forces, and the
Italian Co-Belligerent Air Force.
Designed by
Bell Aircraft, it had an innovative layout, with the engine installed in the center fuselage, behind the pilot, and driving a tractor propeller via a long shaft. It was also the first fighter fitted with a
tricycle undercarriage. Although its mid-engine placement was innovative, the P-39 design was handicapped by the absence of an efficient
turbo-supercharger, preventing it from performing high-altitude work. As such it was rejected by the RAF for use over western Europe and passed over to the USSR where most air combat took place at medium and lower altitudes.
Together with the derivative
P-63 Kingcobra, the P-39 was one of the most successful fixed-wing aircraft manufactured by Bell.