On July 29, 1944, B-29-5-BW serial number 42-6256 of the 771 BS 692 BG commanded by Capt Howard R. Jarrel was damaged by flak during a raid on the Showa steel works at Anshan in Manchuria. Unable to make the trip back to its base around Chengtu in China, the crew decided to divert to Vladivostok in the Soviet Union. Since the Soviet Union was not at war with Japan at the time, both the aircraft and Capt Jarrel's crew were interned.
On August 20, 1944, during a raid on Yawata staged out of the Chengtu bases, B-29A-1-BN 42-93829 commanded by R McGlynn of the 395 BS 40 BG was forced to divert to the Soviet Union. It crashed in the foothills of Sikhote Alin Range east of Khabarovsk after the crew baled out. The crew was interned.
On the night of November 10-11, 1944, B-29 42-6365 was damaged during a raid against Omura on Kyushu was forced to divert to Vladivostok. It was followed on November 21 by 42-6358. Again, both crews and both aircraft were interned.
The Soviets were now holding three intact B-29s and four B-29 crews. In January of 1945, it was arranged by the Soviets for these four crews to "escape" to the West via Teheran, but their B-29s remained behind.
World War 2 had been over only for a little over a year when an article appeared in the November 11, 1946 issue of the Berlin newspaper Der Kurier claiming that the Soviet Union was manufacturing a bolt-for-bolt copy of the B-29 in a series of factories located in the Urals. This report was widely disbelieved, since the Soviet Union was at the time thought incapable of manufacturing an aircraft as large and sophisticated as the B-29. However, the report was given more credence when it was revealed that some Soviet agents had been attempting to purchase B-29 tires, wheels, and brake assemblies in the USA.
During the August 3, 1947 Aviation Day parade over Tushino Airport, Moscow, three four-engined aircraft which were obviously B-29s appeared during a low-altitude flyover. It was at first thought that these three aircraft might have been the same 3 intact B-29s known to have been in Soviet hands, but a FOURTH aircraft appeared which was obviously a transport conversion of the B-29, leaving no doubt that the earlier report of B-29 manufacture in the Soviet Union was completely accurate. The transport version was designated Tu-70, but it was only revealed later that the designation of the bomber was Tu-4.
During the Great Patriotic War, Josef Stalin had allocated the highest priority to the development of a strategic bombing capability, and the presentation to the Soviet Union of three intact B-29s was extremely fortuitous, since the Soviet aircraft industry could now overcome the immense technological problems involved in the development of a strategic bomber in a fraction of the time it would have taken to develop an indigenous design from scratch. In May of 1945, Stalin ordered that the Soviet Union develop a copy of the B-29 for immediate manufacture. The design bureau of Andrie N. Tupolev was given responsibility for the airframe, while the engine bureau headed by Arkadii B. Shvetsov was assigned the responsibility of copying the Wright R-3350 Duplex Cyclone engine. The Soviet version of the B-29 was assigned the designation Tu-4. The Shvetsov Shvetsov ASh-73TK used to power the Tu-4 was actually a reverse-engineered version of the Wright R-1820 Cyclone, not the R-3350 Duplex Cyclone.
Two of the USAAF B-29s were disassembled for detailed evaluation, with the third being kept intact for flight testing. The go-ahead for the program was given before the end of 1944, and the Tu-4 project was well under way by the first quarter of 1945. A factory on the Volga was given the task of building 20 test and evaluation aircraft, and two factories behind the Urals were given the responsibility for full-scale production.
In spite of the end of the war, the Soviet Tu-4 program went forward with all deliberate speed. The first Tu-4 test aircraft was ready by the late summer of 1946. Early test flights turned up problems with the electrically-actuated undercarriage which forced several wheels-up landings. In addition, there were frequent runaway propellers. Lots of test pilots complained about the distortion of vision caused by the extensively-glazed nose.
Following the public debut of the Tu-4 in the Aviation Day parade on August 3, 1947, initial long-range trials began. Many teething problems with both the Tu-4 systems and the Shvetsov ASh-73TK engines still remained to be resolved. The Tu-4 begin to enter service with the Soviet strategic bombing arm, the Dal'naya aviatsiya (DA), in 1948, providing the Voennovosdushniye Sily (V-VS, the Air Forces of the USSR) with true strategic bombing capability. The series production Tu-4s suffered continuously from malfunctions in the remotely-controlled defensive armament system and in the crew cabin pressurization system. The reliability of the ASh-73TK turbosupercharged engines still left a lot to be desired. Quality control at the manufacturing plants had to be tightened up, and by early 1949, most of the more serious defects had been corrected. It was not until mid-1949 that the Tu-4s of the DA had achieved full operational capability. By the end of 1949, some 300 Tu-4s had entered service with the DA. In addition, a few Tu-4s entered service with the Aviatsiya Voenno-morskovo Flota (AV-MF, the Naval Air Force) as long-range patrol aircraft.
The Tu-4 was assigned the code name Bull in the NATO code naming system. The entrance into service of the Tu-4 threw the USAF into a virtual panic, since the Tu-4 possessed sufficient range to attack Chicago, Los Angeles, and New York with a worthwhile load on a one-way "suicide" mission. From seized airfields in Iceland, Soviet Tu-4s were even capable of hitting targets in New England, New York, Pennsylvania, and Ohio, and from bases in Greenland they could hit targets as far away as New Orleans or Denver. Since the Soviets now had a weapon capable of attacking North America, this forced the United States government to develop an extremely costly air-interception capability involving ground radar installations, a Ground Observer Corps, radar picket planes, Nike surface-to-air missiles, and a fleet of jet interceptor fighters. The development of the Soviet atomic bomb in 1949 gave the air defense program a new urgency, since the United States was itself now in danger of a nuclear attack.
Approximately 1200 Tu-4s are believed to have been built in the Soviet Union, with some going to China during the later 1950s. During the later 1950s, the Tu-4 was progressively withdrawn from operational service with the DA and replaced by more advanced types. These planes were then transferred to the air transport force, the voenno-transportnaya aviatsiya to supplement the short-range Li-2s and Il-14s. As the Antonov An-12 turboprop transport became available, the Tu-4 was progressively withdrawn from the transport role. By the beginning of the 1960s, the Tu-4 was essentially also out of the inventory of the shore-based maritime patrol force. A few Tu-4s had been provided to China to provide that country with at least a token bombing force, and some of these were reportedly still in service in China as recently as 1968.
Tupolev proposed the M-49TK-powered Tu-79 and TV-2 turboprop powered Tu-94 derivatives of the Tu-4, but these were never built (some Tu-4s in Chinese service were, however, re-engined with AI-20 turboprops). The People’s Republic of China also built an AEW derivative of the Tu-4 known as the KJ-1, which had four AI-20 turboprops (the sole KJ-1 is now displayed at the China Aviation Museum in Beijing).
Engines: Four Shvetsov ASh-73TK eighteen-cylinder air-cooled supercharged radials, rated at 2200 hp for takeoff, 2400 hp war emergency. Performance: Maximum speed 261 mph at sea level, 354 mph at 32,808 feet. 224 mph cruising speed Range 1927 miles at average cruising speed of 310 at maximum continuous power at 25,590 feet with 11,023 pound bomb load., 3107 miles at long range cruise power at 9845 feet with 11,023 pound bomb load. Range 4100 miles with 6614 pound bomb load and weapons-bay auxiliary tank. Weights: 135,584 pounds maximum takeoff weight.