The Soko J-21 Jastreb (Hawk) is a Yugoslavian single-seat, light-attack aircraft designed by SOKO Mostar in the 1960s. The aircraft were built by SOKO Mostar until the 1980s. It was developed from SOKO G-2 Galeb (two-seater, training version of J-21 Jastreb).
The J-21 Jastreb is extensively used in the Balkan war during the 1990s, especially in Bosnia and Herzegovina. After the war Federal Republic of Yugoslavia has retired the remaining 66 Jastrebs. Still today fly only a few Jastrebs in the Republic Srpska J-21-RJ-1 version, and in the Libyan Air Force J-21E version.
The first flight on the prototype J-21 aircraft was made by the pilot Humar Rudolf 19 July 1965. The J-21 went into operational use on 26 September 1968. The first serial production aircraft J-21 has been put into operational use in the JRV (Yugoslavian Air Force) on 31 December 1968.
Compared to the G-2 Galeb, Jastreb due to strengthened structures and in accordance with its purpose, could carry more weapons. Besides the three machine guns (Colt-Browning M3 AN 12.7 mm cal., each with 135 bullets) mounted in the nose of the aircraft, Jastreb is able to carry up to 800 kg of cargo on under-wing hardpoint. Two internal under-wing hardpoints have a capacity of 250 kg for bombs, rocket launcher and additional tanks, while the two outer hardpoints provided for guided missiles HVAR (High Velocity Aircraft Rocket).
Maximum speed of J-21 Jastreb, at an altitude of 5,000 meters and without external load, is 819 km/h (509 mph or 441 knots), while at sea level, with two bombs per 250 kg, is 629 km/h (411 mph or 385 knots). Cruising speed is ranged from 650 to 680 km/h (420 mph). Service ceiling is 12,000 meters (40,000 feet). Range is amounted to 1,150 kilometers and combat radius is ranged from 270 to 360 km. Wingspan is 10.50 meters (35 ft) and length is 10.88 meters (35 ft 8.5 in). It is powered by one Rolls-Royce/Bristol Siddeley Viper Mk 531 turbojet (13.32 kN or 3,000 lb).