Saab 21

The SAAB 21 is a Swedish single-seat low-wing monoplane fighter and attack aircraft designed and manufactured by SAAB. Its twin boom fuselage with a pusher engine gives the aircraft an unusual appearance.
Work began at SAAB following a Swedish Air Force decision to embark on a major expansion programme in preparation for the possibility of being drawn into the Second World War. The company designed a monoplane twin-boom aircraft, powered by a single Daimler-Benz DB 605B engine that was positioned at the rear of the fuselage nacelle, driving a pusher propeller. This arrangement allowed guns to be carried in the aircraft's nose while providing the pilot with good visibility. An ejection seat was adopted to enable the pilot to bail out without hitting the propeller.
On 30 July 1943, the 21 performed its maiden flight and on 1 December 1945, the first examples of the J 21A-1 were introduced to service. It was quickly followed by the improved J 21A-2, which featured heavier armament, and the J 21A-3 fighter-bomber.
With jet-powered aircraft rapidly overtaking piston-powered aircraft, in 1947 SAAB produced a conversion of the 21 using the British de Havilland Goblin jet engine, the resulting...