YAK-40
| Yak-40 | |
|---|---|
 |
|
| Volga-Dnepr Yak-40 | |
| Role | Regional jet/ VIP transport |
| National origin | Soviet Union |
| Manufacturer | Yakovlev |
| First flight | October 21, 1966 |
| Introduction | September 1968 (Aeroflot) |
| Status | In service |
| Primary user | Aeroflot (Former) |
| Produced | 1967–1981 |
| Number built | 1,011 (according to some sources, 1013) |
The Yakovlev Yak-40 (Russian: Як-40), NATO reporting name: Codling) is a small, three-engined airliner. It is the world's first commuter trijet. The maiden flight was made in 1966, and it was in production from 1967 to 1981. Introduced in September 1968, the Yak-40 has been exported since 1970.
By the early 1960s, Soviet international and internal trunk routes were served by Aeroflot, the state airline, using jet or turboprop powered airliners, but their local services, many of which operated from grass airfields, were served by obsolete piston-engine aircraft such as the Ilyushin Il-12, Il-14 and Lisunov Li-2. Aeroflot wanted to replace these elderly airliners with a turbine-powered aircraft, with the Yakovlev design bureau being assigned to design it. High speed was not required, but it would have to be able to operate safely and reliably out of poorly equipped airports with short (less than 700 m or 2,300 ft) unpaved runways in poor weather.
Yakovlev studied both turboprop and jet-powered designs to meet the requirement, including Vertical Take-Off and Landing designs with lift jets in the fuselage or in wing-mounted pods, but eventually they settled on a straight-winged tri-jet carrying 20 to 25 passengers. The engines were to be the new AI-25 turbofan being developed by Ivchenko at Zaporozhye in Ukraine.
The Yak-40 is a low-winged cantilever monoplane with unswept wings, a large T-tail and a retractable tricycle landing gear. The passenger cabin is ahead of the wing, with the short rear fuselage carrying the three turbofan engines, with two engines mounted on short pylons on the side of the fuselage and a third engine in the rear fuselage, with air fed from a dorsal air-intake by an "S-duct", as is an auxiliary power unit, fitted to allow engine start-up without ground support on primitive airfields. The three AI-25 engines are two-shaft engines rated at 14.7 kN (3,300 lbf). The engines have no jetpipes, and initially no thrust reversers.
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