The theme of the meeting poses the question, “Is there a future for British Air Transport ?” I firmly believe that the answer to this question is “Yes, of course there is,” and that the only debatable issue is the size and vigour of the future British Air Transport Industry.

In all of the experimental and theoretical work done on wall jets(1-3), the flow always passed over a stationary surface. An exception to this is the theoretical analysis reported in ref. 4 in which a laminar axi-symmetric jet impinged on a rotating disc.

The present investigation aims to provide information on the flow of a turbulent jet over a rotating cylinder. The curvature of the wall, the jet slot width and the initial speed of the jet are kept constant. The speed of rotation is the important variable.

The design of a homing missile normally involves the incorporation of a dielectric window to form the nose region of the flight vehicle. Immediately this creates a situation in which a compromise is required between the conflicting needs of

1. (a) The aerodynamicist who requires a fairing of minimum drag, within the length limitations imposed, and which at the same time possesses a reasonably predictable shape. The shape must often satisfy rain erosion requirements.

2. (b) The heat transfer engineer who requires that the thermal load be spread as uniformly as possible over the fairing surface.

3. (c) The materials/structures technologist who requires the fairing to be manufactured from readily available material at reasonable cost.

4. (d) The microwave engineer who requires no fairing at all.

The equations defining compressible flow are sufficiently complicated to preclude general analysis, but, in particular cases, can often be simplified and manipulated into a form amenable to solution. Problems connected with aircraft have, in the past, usually fallen into this category, where the non-linear equations can be simplified to a linear form and reasonably accurate solutions deduced. At hypersonic speeds, however, the more usual assumptions become invalid, no reasonable simplification can be made, and, except in certain specialised cases, no solutions can be deduced. Hence the problem of deriving the flow pattern around some specified shape becomes, in general, insoluble. The simple caret wing was proposed seven years ago by Nonweiler to avoid such difficulty. His elegant idea was to reverse the normal process of deducing the flow field round a given body shape, and instead to deduce body shapes that would generate specific, simple, flow patterns. From known flow fields lifting bodies may be obtained, by replacing .streamlines with solid surfaces, and the caret wing is one example. Nonweiler’s original notion has sin:e been extended by a number of people.