The Tupolev TB-3[b], OKB designation ANT-6, was a monoplane heavy bomber deployed by the Soviet Air Force in the 1930s and used during the early years of World War II.

[2][page needed] Despite obsolescence and being officially withdrawn from service in 1939, the TB-3 performed bomber and transport duties throughout much of World War II.

In 1925, the Soviet Air Force approached TsAGI with a requirement for a heavy bomber with total engine output of 1,500 kW (2,000 hp) and either wheeled or float landing gear.

[2][3] The Tupolev TB-1 was taken as the basis for the design and the aircraft was initially powered by 440 kW (590 hp) Curtiss V-1570 "Conqueror" engines,[4] with the intent of switching to Mikulin M-17s (modified BMW VIs) in production.

[6] The prototype was refitted with 540 kW (720 hp) BMW VIz 500 engines, larger radiators, and wooden fixed-pitch propellers of TsAGI design.

[2] The discrepancy was discovered to be due to high positive tolerances on raw materials which resulted in steel sheetmetal, pipes, and wires being much thicker than on the carefully constructed prototypes.

Any part of the aircraft could be walked on in soft shoes without damaging the skin, and the leading edges of the wings swung down to form walkways for engine maintenance.

The M-17 engines were tuned to provide a maximum theoretical range of 3,250 km (1,750 nmi; 2,020 mi) without spark plug or carburetor fouling.

Defensive armament consisted of light machine guns in five turrets — one in the nose, two on top of mid-fuselage, and one retractable "dustbin" under each wing between the engine nacelles.

[11] Stationed far from the USSR's western border, the ТB-3s avoided catastrophic losses during the first German air strikes, after which TB-3s from 3rd TBAP (Heavy Bomber Regiment) began flying night bombing missions on 23 June.

[citation needed] In recognition of the role TB-3 played during the war, three aircraft were included in the first post-war air parade on 18 June 1945.