It was a reverse-engineered copy of the U.S.-made B-29's.
Design and development
Towards the end of World War II, the Soviet Union saw the need for a strategic bombing capability similar to that of the United States Army Air Forces. The U.S. regularly conducted bombing raids on Japan, virtually in the Soviet Union's backyard, from distant Pacific forward bases using B-29 Superfortresses. Joseph Stalin ordered the development of a comparable bomber.
The U.S. declined to supply the Soviet Union with Boeing B-29 Superfortress heavy bombers under Lend Lease. However, on three occasions during 1944, individual B-29s made emergency landings in Soviet territory after bombing raids on Manchukuo and Japan. In accordance with the Soviet–Japanese Neutrality Pact, the Soviets were neutral in the Pacific War and the bombers were therefore interned and kept by the Soviets, despite American demands for their return.Stalin tasked Tupolev with cloning the Superfortress, and Soviet industry was to produce 20 copies of the aircraft in just two years. The three B-29s were flown to Moscow and delivered into Tupolev OKB. One B-29 was fully dismantled, down to the smallest bolt, the second was used for flight tests and training, and the third one was left as a standard for cross-reference.
The Soviets used a different engine, the Shvetsov ASh-73, which had some parts in common with the Superfortress' Wright R-3350 but was not identical. The remote-controlled gun turrets were also redesigned to accommodate Soviet Nudelman NS-23 23mm cannon.
Eight hundred and forty-seven Tu-4s had been built when production ended in the Soviet Union in 1952, some going to China during the later 1950s. Many experimental variants were built and the valuable experience launched the Soviet strategic bomber program. Tu-4s were withdrawn in the 1960s, being replaced by more advanced aircraft: the Tupolev Tu-16 (starting in 1954) and the Tupolev Tu-95 (starting in 1956). By the beginning of the 1960s, the only Tu-4s still operated by the Soviets were used for transport or airborne laboratory purposes.
Tu-4 Main production version.
Tu-4 AWACS Chinese prototype with KJ-1 AEWC, "AWACS" radar and powered by Ivchenko AI-20K turboprop engines.
Tu-70  Airliner derivative, never reached mass production.
Tu-75  Cargo aircraft derivative, never reached mass production.
Tu-80  Bomber derivative, never reached mass production.