The theme of this symposium is “Inter-Relations and Inter-Face Problems.” It is suggested that what are called “inter-face problems” are sometimes no more than symptoms of a failure to get priorities right. There is, presumably, an “inter-face” between a dog and its kennel. But if the dog owner wants a kennel then he gets one of the right size. The dog takes priority and no inter-face problem arises. Similarly, if someone owns a car and wants a garage for it then he has one built to the appropriate dimensions. It is only if he already has a garage that cannot be enlarged and buys a car too big for it that he is confronted by an inter-face problem but there would have been no problem had he, in this case, given first priority to the garage and bought a car to fit it.

The first drawing showing a recognisable Harrier-type configuration was produced in the Project Office at Hawker Aircraft Limited, Kingston, in October 1957 (Fig. 1).

During the next year the design of this P1127 project was refined by detailed study and the final BE53 engine configuration was settled between the Hawker Team led by the late Sir Sydney Camm, and the Team at Bristol Aero Engines Ltdf led by Dr. S. G. Hooker. Hawker worked on a private venture basis and Bristol proceeded, on manufacture as well as design, with 75% backing from the USA by the Mutual Weapons Development Programme Agency in Paris.

Some people claim that there is nothing new under the sun. Certainly incentive contracting is not new. The Navy Department boasts of Pepys using delivery incentives in the form of penalties and bonuses in ship contracts 300 years ago. In America, the War Department included a performance incentive in the Wright brothers' aircraft contract in 1907, providing for a 10% bonus for each mile per hour the aircraft would perform in excess of 40mph(18m/s).

The engine parameters which most obviously must improve to contribute to the continued lowering of aircraft Direct Operating Costs are those of prices, weight, volume and fuel consumption. These affect the base-line performance characteristics of the aircraft and in any formula for estimating Direct Operating Costs they will appear in the general cost of flying a load of passengers or freight from A to B.

First, let me say what a great honour it is to be asked to take part in one of the Society's symposia, and particularly one on as wide and important a subject as this. Before I start to consider the particular aspects of this subject I must make three points clear.

The first is that, since airports range from primitive landing strips to multi-runway complexes covering ten or more square miles (26 x 106 m2), I should be foolish if I made sweeping statements that might be taken to apply to any one of them. So let me narrow the field to major international airports and dismiss the rest with the generality that transport aircraft today demand airport facilities that are expensive to provide and operate and that if an airport is not supported by a strong and growing demand for air services it is irrelevant and will eventually be put to other uses. I realise that in the USA large airports may handle little international traffic, but my concern is with Europe.

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.

Our previous speaker, Mr. Blyth, in his paper on the Design of Incentive Contracts, has given us a lucid explanation of the basic principles of incentives and examples of cost, performance and delivery conditions which could be used as incentives and the objectives to which they could be directed.

Following on this paper, one could initiate a discussion on the basic philosophy behind the use of incentives, whether the incentives as stated are likely to be achieved, and propose various alternative methods of achieving these objectives without using contractual conditions. I have no doubt that many points such as these will be raised later during the discussion.

In recent years many methods have been proposed for the measurement of the frequency response of linear systems but the method most often used in the study of structures is the steady state vector response method, the natural frequencies and damping ratios being measured from the resulting vector diagrams. This method is tedious and time consuming and often cannot be readily applied outside the laboratory. Some effort has been directed in the past to employ quasi-steady state methods such as the slow frequency sweep technique but errors are introduced because the response at resonance is less than the steady state maximum and the frequency at which the maximum occurs is shifted in the direction in which the excitation frequency is changing. Additional errors are introduced in the analysis of the system response because of the necessary averaging time of the function analyser used to derive the vector diagrams. Some refinements in technique have been proposed by Reed who developed the “λ Law” frequency sweep in which the percentage change in frequency per cycle is constant. This offers some reduction in test time when compared with logarithmic and linear frequency sweeps but a knowledge of the minimum damping likely to be encountered at any resonant frequency within the sweep range is essential so that the method may be employed advantageously.

The North Atlantic is increasingly developing into the main trade route of the age. Shipping, the pioneer along this highway of commerce, in the past decade has been joined by air traffic displaying a striking growth rate. Not only is the number of aircraft simultaneously plying the Atlantic routes constantly on the increase, but also the volume of passengers and freight transported on each flight. The question, whether such flow of traffic in the air and on water could be dealt with in future with the safety to which it is entitled, has led to world-wide discussions over the past few years concerning the necessity for an air traffic surveillance system for the North Atlantic area. A further question, whether one should not include also sea traffic in such a system suggested itself. The initiative for holding such discussions naturally proceeded less from air and shipping undertakings, but rather from those committees who are entrusted in supervising the safety in the conduct of man and merchandise.

If maximum gas temperatures aire to rise appreciably above 1500°K, the value currently achieved in advanced aero-engines, alternatives to the present internal convective methods of air-cooling the first-stage turbine blades will have to be sought. One of the most promising developments lies in the use of porous blade materials, through which cooling air can be “effused” or “transpired”. In a recent paper Bayley and Turner have shown that by the combination of high heat transfer coefficients within the interstices of the porous material, and a reduction in heat transfer rate by injection into the boundary layer on the hot-gas side of the blade, effective cooling rates can be achieved.

The method of finite elements is in certain cases advantageous when dealing with flow problems in a finite domain. This is particularly so when attempting to include subcritical compressibility effects.

In the present note we first consider the two-dimensional flow using TRIC and TRIM-like triangular elements in conjunction with the concept of the stream function, which is assigned to the nodal points of the elements. The application of the stream function allows a direct and exact satisfaction of the boundary conditions. Strictly the elements in question could also be used in conjunction with the potential function but the observance of the boundary conditions is then cumbersome.

The title proposed to me for this paper is not very suitable, as it suggests that I should cover two subjects, one of which, Present Supersonic Travel, is nonexistent, and the other, Future Supersonic Travel, is ,so vast that I could not possibly explore it fully in the time available.

Therefore, to clarify tonight's discussion, I shall define present and future supersonic aircraft as follows:

1. (a) Those aircraft now under construction and due to go into commercial service in the early seventies. This is primarily Concorde (if we leave out Eastern Europe).

2. (b) Those aircraft that will enter commercial service in the late ‘seventies and be flying in the ‘eighties, although I will discuss briefly the last decade of this century.

For many people Stansted represents the best example of the relationship between air transport and regional planning. The public inquiry at least showed up the fact that, although both are subjects with a growing body of knowledge, the interaction between the two is less well known. This is not to say that work of this kind is absent, e.g. the studies undertaken for the Port of New York Authority (PNYA) into the siting of a fourth major airport for that city, the symposia and studies of the Institut de Transport Aerien in Paris or the work of Stratford and others in this country, all pay attention to the relationship. The real crux of the matter is that both air transport and the development of our cities and regions are undergoing rapid change.

Immigration control is an expression of national interest. The objective is to ensure that, of all those people who wish to come from abroad to work and settle here, we should accept only those whom it is in the national interest to accept. The process of selection must be operated in a way which does not delay or inconvenience the great generality of travellers.

In more detail, the current objectives of the UK immigration control are: —

1. (a) to prevent the entry of people who are personally unacceptable, for example, because of criminal record;

2. (b) to protect and supplement the resident labour force;

3. (c) to prevent immigration of a type, and on a scale, which might give rise to serious social problems.

Within the framework of this broad subject, the paper focuses on some of the intra-mural technical and operational planning activities of an airline resulting, directly or indirectly, from airport restrictions of one form or another. While some of the overall problems discussed are, by their complexity, not within the powers of the airline industry on its own to solve, examples are given: (a) of the actions which an airline can take to minimise the effects of a given problem, and (b) of the contributions that an airline can make to solution of that problem. Attention is drawn to conflicts and anomalies in some of the limitations imposed on the airlines by the airports. Several cases in which airport restrictions are beginning to impose new burdens on the aircraft designer are cited.

A VTOL aircraft which is in a state of hovering flight possesses no inherent stability of its own, consequently it may be found necessary to introduce some artificial form of control of the aircraft in both rolling and pitching motion. Such a control device may consist of an auto-stabiliser which enables the pilot to maintain the aircraft in a state of stationary hover, or to perform some manoeuvre by rolling or pitching the aircraft. This paper investigates the wing vibration problems associated with the roll attitude control of a transport aircraft in which the jet-lift engines are mounted in pods situated on the wings. Fig. 1 illustrates diagrammatically a typical transport aircraft configuration in which there are sixteen jet-lift engines mounted in two pods, one on either wing, each pod containing eight lift-engines.

Although difficulties had been experienced for many years in preparing initial estimates for major defence development projects and in the control of subsequent expenditure, they did not become a matter of serious concern until the second half of the 1950's. Then, at a time when the Government was seeking to stabilise defence expenditure, a series of cases came to light where final costs were, or seemed likely to be, substantially higher than the estimates at which they were first approved. Some of these projects attracted the attention of the Public Accounts Committee and led to considerable public criticism.

The instrument described here is designed to measure mean flow directions and velocities in the three-dimensional boundary layer. Its particular advantage is the small amount of interference it introduces, while allowing measurements to be made close to the surface and providing an acceptably large traverse distance normal to it. In its present form it is restricted, however, to flat surfaces where space beneath the surface is not at a premium.