Shadow test model of Tu-4, c 1950.

Model of USSR Tupolev Tu-4 aircraft, internal aspects only. To assess optimum angle of attack. NATO code name Bull. Unlicensed copy of Boeing B25.

Model of Soviet Tupolev Tu-4 aircraft, internal aspects only. To assess optimum angle of attack. NATO code name Bull. Unlicensed copy of Boeing B29. Researchers at the Royal Aircraft Establishment in Farnborough, Hampshire, illuminated this model with a beam of light to find angles at which they could attack it. As the model cast a shadow on a screen behind it, they could see its most vulnerable areas. Built in the Soviet Union, this aircraft (a Tupolev TU-4) is an unlicensed copy of an American Boeing B29 'Superfortress'. The Soviets captured three B29s and copied their design, when the aircraft made forced landings in Siberia in 1944.