The aerodynamic characteristics of the jet wing and its application to high speed aircraft

Abstract

The slender wings and bodies suitable for supersonic flight have, in general, relatively poor aerodynamic characteristics especially at lay speeds. In order to improve their performance the use of edge blowing has been explored. In this scheme high velocity air jets in the form of thin sheets are used to fix separation lines on the wing or body and to favourably influence the external stream. Thus the equivalent wing, called here the

"Jet Wing” is composed of the wing-body itself plus the extended curved jet sheets which spring from its edges. A limited use of edge jets has been proposed in the 'Jet Flap' concept but the efficiency of this device fails off with decreasing aspect-ratio and the problem of trimming could be severe as most of the increased lift is generated near the trailing edge. At very law aspect-ratios a considerable part of the lift is contributed by the leading-edge vortices which dominate the flow field at moderate incidence. It follows therefore that leading edge blowing is particularly useful for small aspect-ratio wings and the trimming problem can be avoided by a suitable jet arrangement which does not disturb the conical nature of the flow. When sufficiently large auxiliary thrusts are available peripheral jet sheets can be deflected downwards close to the ground, the air craft becoming a Ground-Effect-Machine, with substantial reductions in both take-off and landing speeds and distances.