Favourable interference effects

In supersonic flight the lift-to-drag ratio can be further refined by paying care­ful attention to the favourable interference which can be obtained between components such as wings and fuselage, and we will examine some particularly important applications of this principle when we look at hypersonic aircraft shortly.

Engine installation is another area in which careful attention to such inter­ference effects can bring great returns. An example of this is the positioning of the engines and intake system on the Concorde. The influence of the local flow field generated by the under-surface of the wing in the region of the intakes plays a very important role in this design (Chapter 6).

Hypersonic aircraft

In Chapter 5 we saw that the transition from supersonic to hypersonic flight is not sudden and dramatic as is the transition from subsonic to supersonic conditions. Hypersonic flight exhibits the same basic flow phenomena that are found in the supersonic regime but the problems of flow analysis become more difficult because of the breakdown of some of the assumptions we made at lower Mach numbers, and because of the increased importance of kinetic heating.

At the time of writing hypersonic flight has been the province mainly of missiles and re-entry capsules, together with what is really a hypersonic glider; the American space shuttle (Fig. 8.19).

In the following section we will consider the problems associated with atmospheric re-entry. We will also briefly examine the prospects for aircraft which may be able to operate in a more conventional way to provide regular passenger and freight services over long ranges.