The Tupolev Tu-28 (NATO reporting name 'Fiddler') was developed by the Soviet Union in the 1960s as a long-range interceptor aircraft. Also known as the Tu-128, it remains the world's largest fighter aircraft.In 1955 the PVO issued a specification for a long-range interceptor aircraft to defend the vast territory of the Soviet Union, which was so extensive that even with a far richer economy it would have been impossible to provide comprehensive air defense. To provide the necessary range and ability to carry a powerful radar and air-to-air missiles, Tupolev developed an aircraft similar to the Tu-105 (Tu-22) bomber. The Tu-102 development aircraft first flew in 1959, with the initial operational version, the Tu-28P ('Fiddler-A'), entering production in 1963. This was replaced in production by the definitive Tu-128 ('Fiddler-B'). Based, like the Tu-22 bomber, on the unsuccessful Tu-98 supersonic bomber, it had a broad, low/mid-mounted swept wing carrying the main landing gear in wing-mounted pods, and slab tailplanes. Two Lyulka AL-21F-3 turbojet engines were mounted in the fuselage. Unlike the Tu-22, there is no internal weapon bay. Weapons were carried on wing pylons, with the fuselage used for enormous fuel tanks. The Tu-28P seated two crew in tandem, with separate canopies.