| Tu-85 | |
|---|---|
 | |
| General information | |
| Type | Heavy bomber |
| National origin | Soviet Union |
| Manufacturer | Tupolev |
| Status | Cancelled |
| Number built | 2 |
| History | |
| First flight | 9 January 1951 |
| Developed from | Tupolev Tu-4 Tupolev Tu-80 |
TheTupolev Tu-85 (Russian:Туполев Ту-85;USAF/DoD reporting name: "Type 31",NATO reporting name:Barge[1]) was aSoviet prototypestrategic bomber based on theTu-4, an unlicensed,reverse engineered copy of theBoeing B-29 Superfortress. It was the ultimate development of the B-29 family, being over 50% heavier than its progenitor and had nearly double the range. Only two prototypes were built before the program was cancelled in favor of the turboprop poweredTupolev Tu-95 bomber which could cover the same range at a far higher speed.
Neither the Tu-4 nor theTu-80 were true intercontinental strategic bombers 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 thelift/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-cooledASh-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 unsuccessful GermanJunkers Jumo 222. Both proposed powerplants were giventurbochargers and power-recovery turbines to turn them intoturbo-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 withTsAGI. It had anaspect ratio of 11.745 and a taper of 2.93 for optimum lift at high altitudes.[2] The Tu-85 carried 63,600 litres (16,800 US gal) of fuel in 48 flexible tanks.[3]
Much of the armament and equipment was derived from those of the late-model Tu-4, including the four remotely-controlleddorsal andventralgun turrets and the tail turret, each with two 23 mm (0.91 in)Nudelman-Rikhter NR-23 cannon. But the Tu-85's tail turret had an Argon range-onlyradar and each of the two bomb bays was enlarged to hold a 9,000 kg (20,000 lb) FAB-9000 bomb.[2]
Actual design work began in August 1948 and was ratified by a directive from theCouncil 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.[4] It first flew on 9 January 1951 and the manufacturer's tests lasted until October. On 12 September the first prototype flew 9,020 km (5,600 mi) with a bombload of 5,000 kg (11,000 lb) which it dropped en route,[4] landing with enough fuel remaining to have covered a total of 12,018 km (7,468 mi).[3] 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.[4]
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 cancelled; during theKorean War SovietMiG-15s brought down many American B-29s, showing that there was no longer a future in aerial combat for piston-powered aircraft. Priority was given to the higher-performanceturbopropTu-95 'Bear',[4] as its own turboprop powerplants, the TV-12 prototype series for theKuznetsov NK-12 turboprops that power the Tu-95 to this day, were already generating 12,000 shp (8,900 kW) as early as 1951.[5]
Data fromOKB Tupolev: A History of the Design Bureau and its Aircraft[6]
General characteristics
Performance
Armament
Related development
Aircraft of comparable role, configuration, and era