Tupolev Tu-70

Tupolev Tu-70

Company type	Passenger aircraft prototype
Industry	Aerospace
Founded	1946
Headquarters	Soviet Union
Products	Passenger aircraft

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The Tupolev Tu-70 (Russian: Туполев Ту-70; NATO reporting name: Cart) was a Soviet passenger aircraft developed as a derivative of the Tu-4 bomber, itself an unlicensed reverse-engineered version of the Boeing B-29 Superfortress. Conceived shortly after World War II, it incorporated several components salvaged from Boeing B-29s that had made emergency landings on Soviet territory during their bombing missions over Japan. Distinguished as the first Soviet aircraft to feature a pressurized cabin, its maiden flight occurred on 27 November 1946. Although testing was successful and serial production was recommended, the project was ultimately halted due to higher priority military requirements and lack of demand from Aeroflot. A cargo transport military variant was developed as the Tupolev Tu-75.

Design and development

Following completion of initial design work on the Tu-4 bomber, Tupolev initiated development of a passenger model featuring a pressurized fuselage, internally designated Tu-70. The design aimed to maximize use of existing Tu-4 parts to minimize costs and shorten development time. The aircraft was configured as a low-wing cantilever monoplane with tricycle landing gear and powered by four Shvetsov ASh-73TK radial engines. Mockup construction began in February 1946, with the Soviet Council of Ministers approving production of a single prototype in March. Final decisions on serial production, under the designation Tu-12, were deferred pending test results.

To accelerate prototype assembly, multiple components were sourced from two B-29 aircraft. These included outer wing panels, engine cowlings, flaps, landing gear assemblies, tail sections, and certain internal systems. The wing’s center section was redesigned and extended in span. The newly designed pressurized fuselage repositioned the wing from mid-wing to low-wing placement. The cockpit windshield adopted a more conventional stepped design. Three cabin layouts were proposed: a VIP government configuration, a mixed-class arrangement seating 40–48 passengers, and an airliner setup accommodating 72 seats. Evidence suggests the prototype was built with the mixed-class interior, although this remains unconfirmed.

Although construction completed in October 1946, the first flight took place on 27 November. Manufacturer trials began in October but were interrupted by an engine fire during the fourth flight that forced an emergency landing. Investigation revealed a flaw in the American-made supercharger control system; diagnosing and resolving this issue extended testing through October 1947. The aircraft received its official designation Tu-70 during State acceptance trials concluding on 14 December. Despite fulfilling all design criteria, production was not authorized due to existing factory commitments to higher priority projects and Aeroflot’s satisfaction with its current fleet of Ilyushin Il-12 airliners.

In December 1951, the Tu-70 was transferred to the NII VVS (Russian: Научно-Исследовательский Институт Военно-Воздушных Сил – Scientific Research Institute of the Air Forces) for evaluation as a military transport aircraft. It subsequently served various test roles before being dismantled in 1954. Its design was adapted into the military transport variant Tupolev Tu-75, which also did not enter production.

Specifications

File:Tupolev Tu-70 3-view line drawing.svg