Tupolev TB-1

The Tupolev TB-1, developed under the name ANT-4, was a twin-engined all-metal monoplane heavy bomber that Andrei Tupolev's team designed for the Soviet Air Force and the first large all-metal aircraft built in the Soviet Union. Its corrugated duralumin skin followed the all-metal methods Hugo Junkers had pioneered, and the first prototype was flown from Moscow's Khodynka Aerodrome on 26 November 1925 with imported Napier Lion engines. Production was delayed by aluminium shortages and the need to replace those engines with the BMW VI and later the licence-built Mikulin M-17, and it began at the former Junkers factory at Fili in 1929, with 216 machines following two prototypes before production ended in 1932, among them 66 seaplanes. The TB-1 became the Soviet Air Forces' first standard heavy bomber, was fitted with floats as the TB-1P torpedo bomber, served as the first mothership of the Zveno project carrying two Tupolev I-4 fighters, and flew on as the G-1 freighter with Aeroflot and Aviaarktika until 1948. One survives at the Ulyanovsk Aircraft Museum.