At the first meeting of our Society in January 1866, James Glaisher advised us to “exclude any matter that may seem useless in forwarding the science, or that has the slightest chance of giving rise to ridicule …” this warning was timely and relevant to this theme for to consider the long-term future with as much rationality as is required for short-term forecasting and planning studies, is a valuable exercise in restraint as well as in imagination. So many avenues of possible development are technologically interesting, but in economic terms are sterile and unrewarding. One emerges with a deep conviction that certain areas of research and development may be in a dominant position in their influence on future aviation growth. Two of these are noise control and the evolution of composite materials. Although fairly obvious it seems important that they and some others be given the financial support which they deserve.

The disturbance due to aircraft noise which is being experienced in residential areas around the world's major airports is generally recognised as a serious problem. Indeed, the problem has reached the stage where public reaction is already influencing the development of future aircraft. Such influence may be seen in current international intention to include noise limitations in the certification of aircraft.

Limits imposed on the noise generated by aircraft engines should serve to prevent the problem from becoming catastrophic, but cannot be expected to provide a final solution. Aircraft manufacturers may seem confident that further improvements in performance could be achieved without corresponding increase in noise, but further increases in air traffic could cancel out these gains and still leave communities near airports excessively disturbed.

Requirements fall into two categories: —

(i) the demands of the market leading to a capacity requirement, which, dependent on the technical solutions, leads to a market requirement in terms of the number of aircraft.

(ii) the technical requirements in terms of the vehicle characteristics required to provide the most competitive aircraft to achieve maximum market penetration.

An appreciation of future civil requirements is presented as seen through the eyes of a project engineer rather than a market research economist. The title of the symposium suggests a focusing of attention on two main fields of air transport, namely, the successors to the supersonic long-range aircraft and the large subsonic short-range aircraft. It is, however, the intention to broaden the survey to cover the major areas of activity in civil aviation, since in many ways there may be inter-relations between the developments in different fields.

In this lecture I have tried to make a judicious selection of the aerodynamic problems involved in the design of future civil aircraft. The choice is necessarily restrictive because of the time limitations of the lecture, so it must be emphasised that the list of problem areas considered is by no means complete. Also, the choice is flavoured by my present field of activity in low-speed wind tunnel work, so some important areas will be excluded on this account.

An aircraft designer, working on one type of aircraft from inception to first flight, can now expect to be involved with only five different types in the whole course of his professional life. This is about 8 years per aircraft and explains why it is now timely and even popular to be airing views on the shape, manufacture, characteristics and operating requirements of the late 1970 civil air liners.

It is clearly unnecessary, before an audience with such experience of aeronautical matters, to explain why scientific, technical and technological research is a fundamental requisite for the growth of the aerospace industry, or why the growth of that industry is one of the factors vital to economic expansion. Nevertheless, I feel it would not be amiss to remind you of the great spur which the particularly advanced nature of the techniques involved in aeronautics provides for all the other industries (air and sea transport, communications, etc), which can often apply to problems closely affecting the general public, solutions which have been initially developed to meet the exacting requirements of aeronautical engineering.

The large displacement analysis of shells of arbitrary form is rightly considered to be a formidable undertaking. A purely analytical approach to the solution of such problems involving also initial buckling, post-buckling and secondary instability or snap-through is at the present state of knowledge impossible. However, with the advent of the matrix displacement method initiated in 1954 it became increasingly apparent that this method would prove in time the ideal tool for the solution of such complex structural phenomena. Nevertheless, all efforts in this direction were bedevilled until recently by the lack of suitable elements, satisfying all kinematic compatibility conditions. The major breakthrough came in this direction through the invention of the triangular shell element SHEBA, which admits an arbitrary variation of curvature. This again evolved from a natural extension of the plate element TUBA of TN 14. At the same time the SHEBA theory of ref. 1 was restricted to small displacements or linear behaviour. To generalise it to large displacements was not possible without an additional major conceptual progress. This was achieved within the Technical Notes 17 to 20, which introduced the idea of a local sub-element and showed how its geometrical stiffness could be used to deduce the geometrical stiffness of the complete element by a physically evident argument. The attentive reader will have noticed that the sub-element of an arbitrary beam in space discussed in ref. 3 is the obvious component block for our shell element. As a matter of fact, the technique is simply based on the representation of the SHEBA element by a grid of beam sub-elements running along the natural α, β, γ directions.

Operation of vehicles over dusty terrains and unprepared airstrips has highlighted the erosion problems incurred by ingestion of dusty air. Hibbert summarised the experience from British helicopter trials up to that date and drew attention to some of the factors that influenced the extent of erosion damage and to methods of minimising it. He cited a trial during 1963 in which a twin-engine Wessex Mk 2 helicopter having one intake protected by felt filters was tested in North Africa. Some idea of the severity of the problem may be gained from the fact that the unprotected engine surged after 3h 40 min while the other was found to have lost half its surge margin. However, operation can usually be arranged so that time spent in the dusty environment is minimised and service lives under desert conditions may be typically around 100h. In attempts to improve lives to a more acceptable level, different types of filtration have been investigated and the mechanism of erosion studied in some detail. This note describes some laboratory experiments to determine the influence of particle size on the erosion and attempts to relate this to filtration and engine life.

Vigilant is a man-portable, anti-tank guided weapon system primarily designed for infantry use but capable of being mounted on reconnaissance vehicles.

The system employs optical line-of-sight command guidance wherein the commands are manually generated by the operator and are transmitted to the missile by way of a wire link. The system has a maximum range of 1370 m with a time of flight of 12 seconds and can engage long-range targets with an angular coverage of ±39° about the line of fire with a lateral separation between the operator and the launcher of up to 30 m. The minimum range is 275 m with nominal separation and angular coverage.

The Matra 530 is currently called a second generation air-to-air missile. Indeed the first generation of air-to-air missiles was represented in France by the Nord 5103 which was command-guided, or the Matra 511 which was a semi-active, pure pursuit curve missile. In the second part of the 1950's the requirement was obvious for a sophisticated interception system capable of coping with the high and medium altitude threat represented by heavy and medium bombers. The destruction of this threat required a close link with an interception system composed of ground radars, ground control equipment, sophisticated high performance interceptor aircraft and, as a last link, a very high performance missile. From the French Air Force point of view, the two main characteristics of this missile as the last link of an interceptor system, were first its flexibility in different weather environment and counter measure environment; second, its capability to decrease to the maximum the penetration of the enemy bomber, which meant that the missile should be capable of attacking not only in the rear sector but also in frontal attack and in fact in all sectors around the attacking bomber.