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The Yak-141 (a development prototype of the Yak-41) was, like the 1960s prototype Dassault Mirage Balzac/Mirage VIIIV, an attempt at a supersonic VTOL aircraft. The British Hawker-Siddeley P.1154 supersonic version of the Hawker Siddeley Harrier project was cancelled as part of the massive defense cuts of 1960s before a prototype could be built.
The Yak 141 gained VTOL ability through a combination of a lift and lift/cruise engines, as did the Balzac and earlier Yak VTOL designs. The two lift jets were mounted behind the cockpit. These contributed only to take-off and once in horizontal flight were switched off. The main engine was installed in the rear fuselage area, with a swivelling nozzle and an afterburner. For take off and hovering the exhaust from the jet was vectored downwards through 90° working in conjunction with the forward lift jets. To obtain sufficient power for vertical take off, the afterburner had to be used, which imposed serious limitations on the types of runway surfaces that could be used.
The Yak-141M was supposed to fly at speeds of Mach 1.7, but it was never able to fly supersonic, and was claimed to have had a maneuverability comparable to the MiG-29 'Fulcrum'. It was designed for the Soviet Air Force (VVS), not for the Soviet Navy (VMF), as was the original Yak-41.
The program was initiated in 1975 as the Yak-141, a development of the Yak-38. The first conventional flight of the Yak-41 was on March 9 1987, and the first hovering flight on December 29 1989. The Yak-41M designation was adopted around 1991 to reflect a shift to a multi-role configuration.
In August 1991 the program was stopped because of the shrinking military budget of the Soviet Union. The Yakovlev design bureau has attempted to generate interest in reviving the program, including the proposal for an advanced version known as the Yak-43, but has yet to find interest.
Related development
Yak-36 - Yak-38 - Yak-43
General characteristics
Crew: one, pilot
Length: 18.30 m (60 ft 0 in)
Wingspan: 13.97 m (45 ft 10 in)
Height: 5.00 m (16 ft 5 in)
Wing area: 31.7 m² (341 ft²)
Empty weight: 11 650 kg (25,680 lb)
Loaded weight: kg (lb)
Max takeoff weight: 19 500 kg (43,000 lb)
Powerplant: 1× MNPK Soyuz R-79V-300 turbojet, 108 kN (24,300 lbf)
Powerplant: 2x RKBM RD-41 42 kN (9,300 lbf) thrust each)
Performance
Maximum speed: Mach 1.7
Range: 1400 km (870 statute miles)
Service ceiling: 15 500 m (50,850 ft)
Rate of climb: m/s (ft/min)
Wing loading: kg/m² (lb/ft²)
Armament
1 x 30 mm GSh-301 cannon with 120 rounds
Four underwing and one fuselage hardpoints for 2 600 kg (5,500 lb) of external stores
Hope that helps
Source: Wikipedia
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