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The Tupolev Tu-four (NATO reporting name: Bull) was a piston-engined Soviet strategic bomber that served the Soviet Air Force from the late 1940s to mid-1960s. It was a reverse-engineered copy of the U.S.-produced Boeing B-29 Superfortress.
Towards the end of Planet War II, the Soviet Union saw the need to have for a strategic bombing capability related to that of the United States Army Air Forces. The Soviet VVS air arm did have their personal-design and style Petlyakov Pe-eight 4-engined "heavy" in service at the start off of the war, but only 93 have been built by the finish of the war as the sort had been equipped with unreliable turbocharged V12 diesel engines at the start of its service to give it lengthy range. The U.S. regularly performed bombing raids on Japan, extremely close to the Soviet Union’s borders, from distant Pacific forward bases making use of B-29 Superfortresses. Joseph Stalin ordered the development of a comparable bomber.
The U.S. twice refused to provide the Soviet Union with B-29s under Lend Lease. Nonetheless, on 4 occasions for the duration of 1944, individual B-29s created emergency landings in Soviet territory and one crashed right after the crew bailed out. In accordance with the Soviet–Japanese Neutrality Pact, the Soviets were neutral in the Pacific War and the bombers have been as a result interned and kept by the Soviets. Despite Soviet neutrality, America demanded the return of the bombers, but the Soviets refused. Three repairable B-29s had been flown to Moscow and delivered into Tupolev OKB. A single B-29 was dismantled, the second was employed for flight tests and education, and the third one was left as a regular for cross-reference. With the Soviet declaration of war against Japan in accordance with the Yalta agreement to enter the war inside 90 days of VE day (to permit it time to move its forces from Europe to Asia) at about 11pm on August eight, 1945 — two days right after the U.S. bombing of Hiroshima and the subsequent entente with Japan ending, the fourth B-29 was returned to the US along with its crew.
Stalin tasked Tupolev with cloning the Superfortress in as short a time as feasible rather of continuing with his personal comparable ANT-64 or samolet (aircraft) 64, and Soviet market was to make 20 copies of the aircraft ready for State acceptance trials in just two years.
The Soviet Union utilized the metric system, therefore sheet aluminum in thicknesses matching the B-29’s imperial measurements have been unavailable. The corresponding metric-gauge metal was of distinct thicknesses. Alloys and other materials new to the Soviet Union had to be brought into production. Extensive re-engineering had to take spot to compensate for the differences, and Soviet official strength margins had to be decreased to stay away from additional redesign, however regardless of these challenges the prototype Tu-4 only weighed about 750 lb (340 kg) a lot more than the B-29, a distinction of significantly less than 1%.
The engineers and suppliers of elements have been beneath pressure from Tupolev, Stalin, and the government to create an exact clone of the original B-29 to facilitate production and Tupolev had to overcome substantial resistance in favor of employing equipment that was not only already in production but in some circumstances much better than the American version. Every single element created and every alteration was scrutinized and was subject to a lengthy bureaucratic method. Variations were restricted to the engines, the defensive weapons, the radio (a later model employed in lend-lease B-25s was utilized in location of the radio in the interned B-29s) and the identification friend or foe (IFF) system – the American IFF being unsuitable. The Soviet engine, the Shvetsov ASh-73 was a improvement of the Wright R-1820 but was not otherwise connected to the B-29s Wright R-3350. and the remote-controlled gun turrets have been redesigned to accommodate the harder hitting and longer ranged Soviet Nudelman NS-23 23mm cannon. Kerber, Tupolev’s deputy at the time, recalled in his memoirs that engineers necessary authorization from a higher-ranking common to use Soviet-created parachutes. Added modifications were created as a outcome of issues encountered during testing, associated to engine and propeller failures and gear changes had been created all through the aircraft’s service life. Despite the fact that it has been widely quoted, the Tu-four did not have a random hole drilled in the wing either to emulate a bullet hole or simply because a Boeing engineer made a error – the Russians had 3 complete aircraft and the wreckage of a fourth and the likelihood of all four possessing a hole in the very same spot is also small to be credible. The aircraft included 1 Boeing-Witchita −5-BW, 2 Boeing-Witchita −15-BWs and the wreckage of 1 Boeing-Renton −1-BN – 3 various models from two diverse production lines. Only 1 of the 4 had de-icing boots as utilised on the Tu-4.
The Tu-4 initial flew on 19 Might 1947, piloted by test pilot Nikolai Rybko. Serial production began quickly, and the variety entered huge-scale service in 1949. Entry into service of the Tu-four threw the USAF into a panic, given that the Tu-four possessed adequate variety to attack Chicago or Los Angeles on a one particular-way mission, and this may have informed the maneuvers and air combat practice conducted by US and British air forces in 1948 involving fleets of B-29s. Some attempts to develop midair refueling systems were made to extend the bomber’s variety, but these had been fitted to only a handful of aircraft.
The aircraft was 1st displayed for the duration of a flyover at the Aviation Day parade on 3 August 1947 at the Tushino Airport in Moscow. 3 aircraft flew overhead. It was assumed that these were merely the 3 B-29 bombers that have been recognized to have been diverted to the USSR throughout Globe War II. Minutes later a fourth aircraft appeared. Western analysts realized that the Soviets should have reverse-engineered the B-29. The appearance of an certainly Superfortress-derived Tu-70 transport over the crowd removed any doubt about the accomplishment of the reverse-engineering.
Eight hundred and forty-seven Tu-4s had been constructed when production ended in the Soviet Union in 1952, some going to China for the duration of the later 1950s. Numerous experimental variants have been constructed and the valuable knowledge launched the Soviet strategic bomber system. Tu-4s had been withdrawn in the 1960s, being replaced by much more advanced aircraft: the Tupolev Tu-16 (beginning in 1954) and the Tupolev Tu-95 (starting in 1956). By the starting of the 1960s, the only Tu-4s nonetheless operated by the Soviets were used for transport or airborne laboratory purposes. A Tu-4A was the 1st Soviet aircraft to drop a nuclear weapon, the RDS-1.
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