[1] Tupolev's team designed a twin-engined all-metal monoplane with a corrugated Duralumin skin — based on Tupolev's earlier work utilizing the all-metal aircraft design techniques first pioneered by Hugo Junkers in 1918 — powered by two Napier Lion engines, and named the ANT-4.[2] The first prototype was built during 1925 on the second floor of Tupolev's factory in Moscow, it being necessary to knock down a wall to allow the aircraft to be taken out of the building in pieces.Production was delayed, however, by shortages of aluminium, and by the need to find a replacement for the expensive imported Lion engines, the BMW VI (and later the Soviet licence-built version, the Mikulin M-17).The first production aircraft was completed as an unarmed civil aircraft, named Strana Sovyetov (Land of the Soviets) for a propaganda flight from Moscow to New York, taking an eastward course via Siberia, reaching its destination on 3 November 1929, flying 21,242 km (13,194 mi) in 137 flying hours.One Avia Arktika ANT-4, flown by Anatoly Liapidevsky, played a key role in the rescue of the crew of the steamship Chelyuskin, which sank on 12 February 1934 after being trapped in ice near the Bering Strait.