The P-39 was designed around a 37mm automatic cannon. This cannon fired through the propeller hub and this layout required the engine to be located behind the pilot.
The aircraft was also the first single engine fighter to feature tricycle undercarriage.
The prototype first flew in April 1938. It did not perform as expected and the aircraft was sent to NACA for evaluation.
During these tests a speed increase to 690Kph was achieved however the original turbo charger was replaced with a single stage supercharger.
The aircraft went into production in this form but was found to have reduced performance at high altitudes. As a consequence most Airacobras supplied to the UK were transferred to the Soviets where air combat generally occurred at lower altitudes.
In all, 9558 Airocobras were built of which 4773 were supplied to the Soviet Union under the Lend Lease program.
Academy 1/72 kit completed by Steve Pulbrook in 2013.