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. The interceptor made its initial public appearance in the 1961 Tushino air parade. Western experts, unaware that the bulge on the belly carried testing instruments, mistook it for 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, having 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 missiles (known as K-80 during development; NATO reporting name AA-5 'Ash'). Usually two of them were R-4Rs with semi-active radar homing and two were R-4T infrared-homing missiles, 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 a total of 198 aircraft having been built.