Tupolev Tu-85

Tu-85
Role	Heavy bomber
National origin	Soviet Union
Manufacturer	Tupolev
First flight	9 January 1951
Status	Prototype
Number built	2
Developed from	Tupolev Tu-4

The Tupolev Tu-85 (USAF/DoD reporting name 'Type 31',NATO reporting name Barge) was a Soviet prototype strategic bomber based on the Tu-4, an unlicensed reverse engineered copy of the Boeing B-29 Superfortress. It was the ultimate development of the B-29 family, being over 50% heavier than its ancestor and had nearly double the range. Only two prototypes were built before the program was canceled in favor of the Tupolev Tu-95 bomber which was much faster and had the same range.

Neither the Tu-4 nor the Tupolev Tu-80 was a true intercontinental strategic bomber as they both lacked the range to attack the United States from bases in the Soviet Union and return. The Tu-85 was designed to achieve the necessary range by use of more powerful and fuel-efficient engines, a redesigned wing to increase the lift/drag ratio and the addition of more fuel. A large number of engines were considered before settling on the 4,500-horsepower (3,400 kW) Shvetsov ASh-2K, essentially two air-cooled ASh-82 radial engines paired together and the liquid-cooled 4,300-horsepower (3,200 kW) Dobrynin VD-4K six-bank inline engine, similar in configuration to the failed German Junkers Jumo 222. Both engines were given turbochargers and power-recovery turbines which converted them into turbo-compound engines. The Shvetsov design was preferred, but was not yet mature enough for use, and the VD-4K was selected. A lot of effort was put into refining the design of the wing in collaboration with TsAGI. It had an aspect ratio of 11.745 and a taper of 2.93 for optimum lift at high-altitudes. The Tu-85 carried 63,600 litres (16,800 US gal) of fuel in 48 flexible tanks.

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