GB1450028A - Aircraft - Google Patents

Abstract

1450028 S.T.O.L. aircraft HAWKER SIDDELEY AVIATION Ltd 5 May 1972 [5 May 1971] 13247/71 Heading B7G An aircraft with STOL capability has propulsion engines 11 mounted below the level of, and formed of, the wings 10 so as to discharge their effluxes into the forward ends of diffusers 19 which are slung under the wings 10, and in which the engine effluxes are mixed with cooling ambient air entering the diffusers 19 around the engine nozzles 13, the diffusers 19 in turn discharging their effluxes toward the undersides of slotted wing flaps 18. The diffusers 19 are in the form of augmentor boxes that can, at least in part, be folded or retracted for conventional flight. In one embodiment, the side walls of the augmentor boxes are formed by fixed vertical walls 15 of aerofoil section to give minimum drag in conventional flight, while the upper wall of each box is the undersurface of the wing 10. The bottom walls 16 are in the form of doors which, for conventional flight, are retracted into the vertical walls 15. When the doors are lowered for the STOL flight mode each first drops vertically, as indicated at 24, and then swings inward and upward while its outer or hinge end continues to drop, in a path that avoids the door entering the jet efflux. The augmented and cooled exhaust mixture issuing from the rear end of the augmenter boxes is diffused over the span of the slotted flap system and a substantial percentage of the impinging flow is deflected downwards, as at 20, to give a vertical lift component. A smaller percentage of the flow is directed through the slots 21, 22 and over the flap upper surfaces to induce a further lift component. In an alternative embodiment (Figs. 6 to 8, not shown),-the top wall of each augmenter box is formed by a movable element that retracts upwardly into the underside of the wing.