Tupolev Tu-4

Tu-4
Tupolev Tu-4 at Monino Central Air Force Museum, Moscow
Role	Strategic bomber
Manufacturer	Tupolev
First flight	19 May 1947
Introduction	1949
Retired	mid 1960s (Soviet Union)
Primary users	Soviet Air Force PLA Air Force
Produced	1949-1952
Number built	847
Developed from	B-29 Superfortress
Variants	Tupolev Tu-70 Tupolev Tu-75 Tupolev Tu-80 Tupolev Tu-85

The Tupolev Tu-4 (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.-made Boeing B-29 Superfortress.

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 B-29 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.

The Soviet Union used the metric system, thus 1/16 inch (1.6 mm) thick sheet aluminum and proper rivet lengths were unavailable. The corresponding metric-gauge metal was thicker; as a result, the Tu-4 weighed about 3,100 lb (1,400 kg) more than the B-29, with a corresponding decrease in range and payload.

Tu-4 engineers were under very heavy pressure to achieve an exact clone of the original B-29. Each minute alteration had to be scrutinized and was a subject to a lengthy bureaucratic process. For instance, because 1/16 inch nominal sheet thickness equals 1.5875mm, no industry in the USSR was willing to take the responsibility to produce sheets with such accuracy. Engineers had to lobby high-ranking military officials even for the most basic common sense decisions. In another example, the Soviets reverse-engineered and copied the American IFF system and actually had it installed in the first Tu-4 built. As yet another example, Kerber, Tupolev's deputy at the time, recalled in his memoirs that engineers had to obtain an authorization from a high-ranking Air Force general in order to use Soviet-made parachutes for the crew.

The dismantled B-29 had a small flaw in one wing - a small rivet hole that was drilled mistakenly by an unknown Boeing engineer. Given Stalin's order for preciseness, all Tu-4's had this same hole drilled in the same location on the wing.

Another item that ended up going all the way to Stalin himself were the markings to be used on the Tu-4. As Stalin had directed an exact copy to be made, that would naturally mean copying the U.S. markings, but Tupolev knew that Stalin and the NKVD could view that as disloyalty to the USSR. The placing of Soviet red stars could also be interpreted as a willful disobedience of Stalin's directive to have an exact copy of the B-29 made. In the end Tupolev went to Stalin and presented the dilemma as a joke. Stalin was reported to have laughed, then approved having Soviet markings applied to the Tu-4.

The Tu-4 first flew on 19 May 1947, piloted by test pilot Nikolai Rybko. Serial production started immediately, and the type entered large-scale service in 1949. Entry 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 City with a worthwhile load on a one-way mission, and this fear may have informed the maneuvers and air combat practice conducted by US and British air forces in 1948 involving fleets of B-29s. Some limited attempts to develop midair refueling systems were made to extend the bomber's range, but these were fitted to only a few aircraft.

Public display surprises the West

The aircraft was first displayed during a flyover at the Aviation Day parade on 3 August 1947 at the Tushino Airport in Moscow. Three aircraft flew overhead. It was assumed that these were merely the three B-29 bombers that were known to have been diverted to the USSR during World War II. Minutes later a fourth aircraft appeared. Western analysts then concluded that the Soviets had the capability to reverse-engineer the B-29. The appearance of an obviously Superfortress-derived Tu-70 transport over the crowd removed any doubt about the success of the reverse-engineering task.

People's Republic of China

China Aviation Museum, Tupolev Tu-4.

In 1967, China attempted to develop its first Airborne Early Warning aircraft, based on the Tu-4 airframe outfitted with turboprop engines. The project was named KJ-1, with a Type 843 rotordome mounted on top of the aircraft. However, the radar and equipment was too heavy and the KJ-1 did not meet PLAAF's requirements, thus the project was cancelled in 1971. That aircraft is now on display at the PLAAF museum north of Beijing.^{[citation needed]}

Operational history

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.

Variants

Tu-4

Main production version.

Tu-4K

Anti-naval version, armed with KS-1 Komet missiles.

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.

Tu-85

Bomber derivative, never reached mass production.

Operators

Soviet Union

Soviet Air Force

The Soviet Air Force operated 847 Tupolev Tu-4 bombers between 1948 and early 1960. They were initially used as long range bombers. In 1954 the Soviets began phasing out the Tu-4; units upgraded to Tupolev Tu-16 bombers and, beginning in 1956, to Tupolev Tu-95 bombers. Tu-4s withdrawn from front line units were used for transport duties.

People's Republic of China

People's Liberation Army Air Force

On 28 February 1953, Joseph Stalin endowed China with 10 Tu-4 heavy bombers. These Tu-4's were refitted with AI-20K turbopropellers in 1966. In 1967 China attempted to develop its first airborne early warning aircraft, based on the Tu-4 airframe. The project was named KJ-1 and mounted a Type 843 rotordome on top of the aircraft. However, the radar and equipment was too heavy, and the KJ-1 did not meet PLAAF's requirements. The project was canceled in 1971. All Tu-4 bombers of PLAAF retired in 1988.

Survivors

Tu-4 4114 (c/n 2805601), ex-KJ-1 AEWC, "4114"

Stored at Datangshan, China

Tu-4 4134 (c/n 2205008), "4134"

Stored at Datangshan, China

Tu-4 unknown (c/n 2805103), "01"

Stored at the Central Air Force Museum, Monino, Russia

Specifications (Tu-4)

Data from

General characteristics

• Crew: 11
• Length: 30.179 m (99 ft 0.1 in)
• Wingspan: 43.047 m (141 ft 2.8 in)
• Height: 8.46 m (27 ft 9 in)
• Wing area: 161.7 m² (1,741 sq ft)
• Empty weight: 36,850 kg (81,240 lb)
• Gross weight: 47,850 kg (105,491 lb)
• Max takeoff weight: 55,600 kg (122,577 lb) - 63,600 kg (140,214 lb)
• Powerplant: 4 × Shvetsov ASh-73TK 18-cyl. air-cooled radial piston engines, 1,790 kW (2,400 hp) each

Performance

• Maximum speed: 558 km/h (347 mph; 301 kn) at 10,250 m (33,629 ft)
• Range: 5,400 km (3,355 mi; 2,916 nmi) at 3,000 m (9,843 ft) with 63,600 kg (140,214 lb) take-off weight including 3,000 kg (6,614 lb) of bombs and 10% fuel reserves
• Service ceiling: 11,200 m (36,745 ft)
• Rate of climb: 4.6 m/s (910 ft/min) at 1,000 m (3,281 ft)
• Time to altitude: 5,000 m (16,404 ft) in 18.2 minutes
• Wing loading: 400 kg/m² (82 lb/sq ft)
• Power/mass: 0.11 kW/kg

Armament

• Guns:
  
• 10 × 23 mm Nudelman-Suranov NS-23 aircraft cannon, two cannon in each of the four turrets and two cannon in the tail barbette
• Missiles:
  
• 2 × KS-1 Komet standoff missiles (Tu-4K only; these anti-ship missiles resembled a scaled-down MiG-15)
• Bombs:
  
• 6 × 1,000 kg (2,205 lb) bombs

or

• 1 x RDS-1, RDS-3 or RDS-5 nuclear fission bomb (Tu-4A only)

See also

Related development

• Boeing B-29 Superfortress
• Tupolev Tu-70
• Tupolev Tu-75
• Tupolev Tu-80
• Tupolev Tu-85
  

Aircraft of comparable role, configuration and era

• Avro Lincoln
• Consolidated B-32 Dominator
• Messerschmitt Me 264
  

Related lists

• List of bomber aircraft
• List of military aircraft of the Soviet Union and the CIS
  

References

Notes

Bibliography

• Bowers, Peter M. Boeing B-29 Superfortress. Stillwater, Minnesota: Voyageur Press, 1999. ISBN 0-933424-79-5.
• Duffy, Paul and A. I. Kandalov. Tupolev: The Man and his Aircraft. Warrendale, Pennsylvania: SAE, 1996. ISBN 1-56091-899-3.
• Gordon, Yefim and Vladimir Rigmant. Tupolev Tu-4: Soviet Superfortress. Hinckley, Leicestershire: Midland Counties Publications Ltd., 2002. ISBN 1-85780-142-3.
• Hess, William N. Great American Bombers of WW II. St. Paul, Minnesota: Motorbooks International, 1999. ISBN 0-7603-0650-8.
• Nowicki, Jacek. B-29 Superfortress. Gdansk, Poland: AJ Press, 1994. ISBN 978-8386208098.
• Pace, Steve. Boeing B-29 Superfortress. Ramsbury, Marlborough, Wiltshire, UK: Crowood Press, 2003. ISBN 1-86126-581-6.
• Rigmant, Vladimir. B-29, Tу-4 - стратегические близнецы - как это было (Авиация и космонавтика 17 (Крылья 4)) (in Russian). Moscow, Russia, 1996.

External links

• Tu-4 Photos at airliners.net, including PLAAF examples.
• Tu-4 "Bull" entry at the FAS.org website