The McDonnell Douglas-led JAST team has unveiled a near-tailless aircraft, using main-engine thrust-vectoring to achieve pitch, roll and yaw control.
In 1995, it dropped the gas-driven lift-fan concept for a lift-plus-lift/cruise short take-off and vertical-landing configuration. In this, a forward engine being developed by General Electric/ Allison provides vertical lift, while the Pratt & Whitney F119 provides rear lift and conventional forward thrust.
The lift engine, generating about 70kN (16,000lb) of thrust, is mounted behind the cockpit and replaced by fuel or a second cockpit in the conventional take-off and landing variants.
The lift engine will operate up to an altitude of 6,100m (20,000ft) and aircraft speed of 250kt (465km/h).
In vertical-lift mode, a blocker/diverter valve redirects the main-engine exhaust outwards to nozzles either side of the rear fuselage. Movable flaps and nozzle rotation, coupled with vanes in the lift-engine exhaust, provide flight control in the hover.
Source: Flight International
