Tupolev Tu - 28 The Tupolev Tu - 28 ( NATO reporting name Fiddler ) was a long - range interceptor aircraft introduced by the Soviet Union in the 1960s . The official designation was Tu - 128 , but this designation was less commonly used in the West . It was the largest and heaviest fighter ever in service . Background . In the 1950s , the Soviet Union sought the means to defend against the nuclear - armed American bombers possibly penetrating its borders ( especially its long and vulnerable northern border ) . Contemporary interceptors , even the Yakovlev Yak - 28P , were able to cover a radius of a few hundred kilometers ; the newly developed surface - to - air missile s had even shorter range . Considering both , the sheer numbers required to defend a 5 , 000 km air front were economically impossible to maintain . This left the Soviet Union able to provide a modern air defense only for selected valuable areas . The PVO decided to cover the entire territory , but with a more loose defense . In 1955 it placed a requirement for a large area - defense interceptor , that would achieve it with sparse airbases . The PVO requirement called for a supersonic aircraft with enormous fuel tanks for both a good patrol time and a long range , a capable radar , and the most powerful air - to - air missile s possible . The first attempt , although an unsuccessful one , was a 30 - tonne Lavochkin La - 250 prototype , the last of the Lavochkin design bureau ' s aircraft . Design and development . Iosif Nezval of Tupolev Design Bureau led development of the new interceptor aircraft . The work began in 1958 , based on an existing single prototype of the unsuccessful Tu - 98 supersonic bomber . The military designation of the interceptor was at first Tu - 28 , but it had been changed in 1963 to Tu - 128 , identical to the designation used by the OKB . The Tu - 128 had a broad , low / mid - mounted swept wing carrying the main landing gear in wing - mounted pods , and slab tailplanes . Two Lyulka AL - 7 F - 2 turbojet engines were mounted in the fuselage . The two - man crew of pilot and navigator were seated in tandem . The Tu - 128 , with its maximum weight of 43 tonnes , was the heaviest fighter ever to enter service . It was a pure patrol interceptor , and with its high wing loading , unsophisticated but reliable avionics , and poor visibility , was not an agile aircraft . It was intended to only combat NATO bombers like the B - 52 , not to dogfight with smaller aircraft . The Bureau managed to make the initial public appearance on the 1961 Tushino air parade . Western experts , being unaware that the bulge on the belly carried various testing instruments , suspected the existence of a large ventral radar for a mixed interceptor / AWACS role . The production version lacked the bulge and had a large nose radome housing a radar , known as RP - S " Smerch " , with a detection range of about 50 km ( 31 mi ) and a lock - on range of about 40 km ( 25 mi ) . Armament of the Tu - 128 was four Bisnovat R - 4 air - to - air missile s ( known as K - 80 during development ; NATO reporting name AA - 5 ' Ash ' ) . Usually two of them were R - 4R with semi - active radar homing and two were R - 4T infrared - homing missile , with the former on the outer pylons and the latter on the inner underwing pylons . There was no internal weapons bay . Production of the Tu - 128 ended in 1970 with total 198 aircraft built . Development of various projects designated Tu - 28A , Tu - 28 - 80 , Tu - 28 - 100 , Tu - 138 , and Tu - 148 were attempted by the Tupolev Design Bureau but all became abandoned . Operational history . The Tu - 128 ' s only publicly reported combat operation was destruction of NATO reconnaissance balloon s . The aircraft was long - lived , remaining in service until 1990 . Through the 1980s , units armed with the Tu - 128 were being converted to the Mikoyan MiG - 31 .