An-77 / An-170
The Antonov Design Bureau offered cooperation to the Shansiy aircraft building corporation to build a new airplane using Antonov An-70 as a basic model. The Chinese side left the offer unanswered, although the proposition was negotiated during Li Peng's visit to Ukraine in the middle of 2000.
According to Ukrainian sources, in 2003 the Antonov bureau proposed a radical development of its An-70 transport that would replace its current contra-rotating propfan engines with four turbofan engines, lengthen the fuselage and increase cargo capacity to between 50 and 60 tons. This would approach the 70-ton capacity of the Boeing C-17 and exceed the 50-ton capability of the Ilyushin Il-76MD. The Chinese military transport aircraft would adopt different design concepts and technologies than the An-70 transport aircraft designed by Ukraine and Russia, and will be powered by four jet engines.
The Antonov company was going to launch a transport aircraft to beat USA's C-17 Globemaster, a Ukrainian military web site has reported. Ukraine is going to develop the new plane together with Russia. Simultaneously, Antonov shelved the An-218 passenger plane project, but was successfully developing the An-148 mid-haul passenger plane project, the web site quoted Antonov's chief designer, Petro Balabuyev, as saying.
An unattributed report by Ukrainian Defense- Express web site in Russian on 14 March and published by the BBC Monitoring Service in English on March 15, 2003 provided some details. The Antonov aircraft design bureau is beginning a research on the C-17 Globemaster transport aircraft, challenging this unique and expensive machine worth 220m dollars. Defense-Express has learned this from the Antonov design bureau's chief designer, Petro Balabuyev. "This will be not a C-17, but our aircraft different from the American one," he said. Balabuyev refused to give more details about the plane, citing corporate secret.
However, he said that "we have begun joint work with the Central Airhydrodynamic Institute [Russia] to create an aircraft capable of carrying 60-80 tons. This will be a completely new aircraft, built according to a new scheme".
[Passages omitted: technical features of C-17 and An-124] The ability to deliver cargo to airfields that are poorly equipped and have short runways is a key factor, especially now when conflict zones are spreading across the world. Only C-17 can manage such tasks now. An-70 can land with 37 t cargo on earth runways up to 900 meters long. However, unlike C-17, An-70 cannot deliver T-84 or T-80UD tanks weighing around 56 t each, that are used by the Ukrainian armed forces.
By early 2007 ANTK Antonov set up a new VTL (Heavy Transport Aircraft) working group, to start developing a heavy transport with China using the existing designs for the An-77, a turbojet version of the An-70, which had earlier been put on hold. The take-off weight of the aircraft was increased from 132 tonnes to 187 tonnes, the maximum payload went up from 47 to 50 tonnes, and the volume of the cargo bay was increased by adding a 2-meter insert in the airframe in front of the center-wing section.
The original An-77 design relied on four CFM56-5A16 bypass turbofan engines; these were replaced by four D-30KP-2 bypass turbofan engines eventually used in the Y-20. The aircraft retained the ability to take-off and land using short landing strips, although the take-off length went up to 900m. The solution for increasing the thrust was the same as used in the An-77. First introduced in the C-17A Globemaster III, it directs the exhaust jet of the bypass turbofan engine at the high-lift flaps.
Major changes were made to the Y-20 design in 2010, with the entry into service with the Chinese army of the Type 99-IIA [aka Type 99A2] main battle tank. The combat weight of this tank, which has many similarities to German Leopard IIA6, is 58 tonnes. This imposed greater payload requirements for the aircraft, which was still expected to be able to carry the heaviest tanks in service with the Chinese Army. The project switched to a different variant of the An-70, the An-170.
Antonov worked on the An-170, a heavy operational-strategic transport, in the late 1980s and early 1990s. The project was in competition with the the Ilyushin Bureau's Il-106, which was announced the winner by the Soviet authorities. Owing to the crisis after the break-up of the Soviet Union, neither aircraft entered production. The An-170 is much larger and heavier than the An-70, with a take-off weight of 230 tonnes and a maximum payload of 60 tonnes. Another difference is the regular wing profile of the An-170, whereas the An-70 uses the so-called supercritical profile.
|Join the GlobalSecurity.org mailing list|