First flown in , the Tu entered service with the Long-Range Aviation of the Soviet Air Forces in and was first used in combat in It is expected to serve the Russian Aerospace Forces until at least A development of the bomber for maritime patrol is designated the Tu , while a passenger airliner derivative was called the Tu The aircraft has four Kuznetsov NK engines with contra-rotating propellers.
It is the only propeller-powered strategic bomber still in operational use today. The Tu is one of the loudest military aircraft, particularly because the tips of the propeller blades move faster than the speed of sound. The Tu is the only propeller-driven aircraft with swept wings built in large numbers. The design bureau, led by Andrei Tupolev , designed the Soviet Union's first intercontinental bomber, the Tu , a scaled-up version of the Tu-4 , a Boeing B Superfortress copy.
Other goals included the ability to carry an 11, kg 24, lb load over the target. Tupolev was faced with selecting a suitable type of powerplant: the Tu-4 showed that piston engines were not powerful enough for such a large aircraft, and the AM-3 jet engines for the proposed T-4 intercontinental jet bomber used too much fuel to give the required range.
Turboprops were also initially selected for the Boeing B Stratofortress to meet its long range requirement, [ 5 ] and for the British long-range transport aircraft, the Saunders-Roe Princess , the Bristol Brabazon Mk 2 and the Bristol Britannia. Tupolev proposed a turboprop installation and a Tu design with this configuration was officially approved by the government on 11 July It used four Kuznetsov [ 6 ] coupled turboprops , each fitted with two contra-rotating propellers with four blades each, with a nominal 8, kW 12, hp power rating.
The engine, advanced for its time, was designed by a German team of ex- Junkers prisoner-engineers under Ferdinand Brandner. The fuselage was conventional with a mid-mounted wing with 35 degrees of sweep, an angle that ensured that the main wing spar passed through the fuselage in front of the bomb bay. Retractable tricycle landing gear was fitted, with all three gear strut units retracting rearwards, with the main gear units retracting rearwards into extensions of the inner engine nacelles.
