Some concluding remarks

So far our discussion of aircraft with a subsonic cruising speed in the transonic range has been concerned a great deal with transport aircraft which are not required to indulge in violent manoeuvres and whose cruising altitude can, within the restrictions imposed by air traffic control, be selected to give the most economical performance. Before we leave the subject, it is, however worthwhile to remind the reader that other types of transonic aircraft also exist, with different design requirements.

One such aircraft is shown in Fig. 9.2. The Hawk is, for example, required to fly transonically at low altitude and to carry a wide range of under-wing mounted missiles and bombs for ground attack purposes. The requirement of high manoeuvrability means that a relatively stiff wing of restricted span is required. Another example of a military transonic aircraft having specialised operational requirements is the Harrier, which has been previously mentioned. The use of jet lift derived from the engine nozzles means that a comparat­ively small wing can be used since the landing requirement is no longer such a powerful influence on the design. The use of downward directed nozzles also dictates the high wing configuration.

Recommended further reading

Jenkinson, L. R., Simpkin, P. and Rhodes, D., Civil jet aircraft design, Arnold, 1999, ISBN 0340631708. An excellent account of the practicalities of transonic transport design.