I feel deeply honoured to have received the Society's invitation to deliver the 46th Wilbur Wright Memorial Lecture. I undertook the task with humility in the light of the illustrious company who have preceded me but, more particularly, because of the greatness of the contribution of Wilbur Wright whom we honour tonight which, together with that of his brother Orville, continues to provide a tremendous inspiration to all concerned with aeronautics.

In preparing this lecture I was conscious of the fact that there were many phases of the development of a modern fighter which I had not covered, and which would possibly be of greater interest to the specialists on that particular subject than those that I did include. To them I offer my apologies, however, this lecture is not intended to be a handbook or reference on the design of all-weather fighter aircraft, but was prepared more or less as a chronicle of the main events leading up to the current development flying of Canada's newest defence weapon system, the supersonic all-weather CF-105, or Avro Arrow, and its associated equipment and environment (Fig. 1).

Now that major space flight operations are under way in Russia and America there is a natural interest in such topics in this country among those working on aeronautics and guided missiles. At present one can only speculate on how this country will eventually contribute to space flight. As the Duke of Edinburgh has remarked, the difficulty is not due to lack of scientific talent but to the absence of surplus funds. Even so, we can make effective contributions in many ways and we should not lack boldness in seeking out possible ways of doing this. In the meantime, however, there seems to be a place for a review of the present technical situation and prospects for the near future, as seen from the standpoint of one in the British Aircraft Industry. As the majority of interplanetary flights will begin through the Earth’s atmosphere and many will finish by way of the same medium, the Royal Aeronautical Society can claim a special and legitimate interest in these matters. Ever since its inception the Society has encouraged the discussion of new technical advances, although its ability to do this has sometimes been hampered by the requirements of security. The same restrictions apply to this paper with the result that I have chosen to draw upon published material throughout, and to review the subject on a broad basis. I hope the work will not be less acceptable on these grounds.

Until recently, aircraft cooling requirements were met by direct heat transfer to free stream. Flight at high subsonic speeds brought forth a need for crew compartment refrigeration. Supersonic flight may result in an extension of this technique to a wider field, particularly the cooling of equipment and temperature-vulnerable functional materials.

This state of affairs has arisen from two major factors. Firstly, the hot boundary layer which surrounds the aircraft and would ultimately soak it to maximum boundary kinetic temperature. Secondly, ducted air either for the engine, equipment cooling, or crew conditioning, is received at nearly stagnation temperature. This temperature increases rapidly with Mach number and reaches its first unacceptable level, i.e. for crew cooling, at low altitudes in the transonic range.

Tension bolts are widely used in engines, in machinery of various kinds, and in structures. They have unique advantages in their contribution to ease of assembly and dismantling. They also give a comparatively rigid and compact joint, and from the standpoint of static strength are extremely efficient. Unfortunately they have not got a good reputation from the standpoint of fatigue. Some designers go to considerable trouble to avoid them. Others accept their limitations and ensure safety by care in detail design and by adopting conservative figures for design stresses. Where necessary, a limitation is placed on working life, at the expiration of which the nut and bolt are replaced by new ones.

The present time, when the prospect of high speed flight often seems to recede, not to approach, may well be a good occasion to review the ram-jet, an engine whose main use is at high flight speed. We owe the succinct name “ ram-jet” to the Americans and the original idea to the French. But despite the admirable efforts abroad this paper is most concerned with British ideas, especially and naturally with those conceived and prosecuted at the National Gas Turbine Establishment. At the outset it is appropriate to acknowledge all the separate personal contributions to the subject of this paper and the assistance of my colleagues in preparing some of the information presented.