Tupolev Tu-85

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.

Development
Neither the Tu-4, nor the Tupolev Tu-80 were true intercontinental strategic bombers as they 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 4500 hp Shvetsov ASh-2K, essentially two air-cooled ASh-82 radial engines paired together and the liquid-cooled 4300 hp Dobrynin VD-4K radial. 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 63600 l of fuel in 48 flexible tanks.

Much of the armament and equipment was derived from those of the late-model Tu-4, including the four remotely controlled dorsal and ventral turrets and the tail turret, each with two 23 mm Nudelman-Rikhter NR-23 cannon. But the Tu-85's tail turret had an Argon ranging radar and each of the two bomb bays was enlarged to hold a 9000 kg FAB-9000 bomb.

Actual design work began in August 1949 and was ratified by a directive from the Council of Ministers dated 16 September that required the first prototype to be ready for manufacturer's tests in December 1950. Construction of the first aircraft began in July 1950 and was completed in September. It first flew on 9 January 1951 and the manufacturer's tests lasted until October 1951. On 12 September the first prototype flew 9020 km with a bomb load of 5000 kg and landed with enough fuel remaining to have covered 12018 km. The second prototype, sometimes referred to as the 85D (dooblyor) or 85/2, incorporated the lessons learned from the first aircraft, including revision and reinforcement of the airframe and a variety of changes to its equipment and systems. It was first flown on 28 June 1951 and its trials lasted until November 1951. Series production was approved on 23 March 1951 at three factories where it would succeed the Tu-4 on the production line, but this was reversed later in the year and the program was canceled - Korean War, during which the Soviet MiG-15 was successfully brought down the American B-29 showed that piston aircraft for military use is not perspective. Priority was given to the higher performance turboprop Tu-95 'Bear'.