“Man's curiosity searches past and future
And clings to that dimension. But to apprehend
The point of intersection of the timeless
With time, is an occupation for the saint.”
The Dry Salvages—T. S. Eliot

Why include the topic of education and training, it could be asked, in a series devoted to predicting ahead to the Second Century of the Society. It is obvious that in the other fields covered there is bound to be great technological progress but men, it might be thought, will teach, and learn, and study much as they do today, and as they did yesterday. Thus we could advise our student engineer that “the acquirements which are necessary to enable the individual to distinguish himself, or even to practise his profession with a moderate chance of success are partly abstract and theoretical, and partly experimental or practical.

I am very conscious of the great honour of being invited to deliver this fourth Reynolds-Prandtl Lecture. At the same time, I am very pleased. As far as I am concerned, the spirit of these two great scientists is still alive. They are both with me every day—at least, I have pictures of them in my office and I look at them every day. As has been said before, their influence is as strong as ever and many of the problems that engaged their attention are even today only partially solved. However, there is more to it than that. Their example and their work have left me with many other problems to think about, which concern the kind of work we do and the aims we pursue. The present lecture gives me an opportunity to put before you some of the thoughts that occupy my mind and which I should like to be discussed. I feel quite strongly that these problems deserve our attention. It may even be vital for the survival of research in our field to find answers to them, which satisfy not only ourselves but also the society in which we live.

Development of the Buccaneer began in 1955, leading to the first flight of the Mark 1 in 1958 and of the Mark 2 in 1963. It was one of the first British aviation projects to operate the Weapons System Concept and to utilise the Development Batch principle.

Development specifically for the low-level high subsonic speed attack, with the requirement for maximum range very much to the fore, required a new approach. The flying qualities and structure produced for the initial design have been utilised with progressive developments in power-plant and equipment to give large improvements in performance, reliability and effectiveness at relatively low cost.

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).

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.

The term “All-Weather Systems for Helicopters” is capable of many different interpretations dependent upon operational requirements. Certainly there are no hard and fast rules laid down defining the equipment required to enable a helicopter to operate under adverse weather conditions. The accuracy to which the aircraft has to be flown under instrument conditions and the ability of the pilot to complete a given mission safely without undue fatigue are the prime considerations which need to be considered in determining the facilities and degree of sophistication necessary for a flight control system.

The theory of modal control is concerned with the design of control loops for systems with governing equations which can be adequately approximated by linear vector-matrix equations of the form

where x is the system state vector, y is the control vector, A is the matrix of the uncontrolled system, and B is the control matrix.

Although a numerical solution of the turbulent boundary-layer equations has been achieved by Mellor and Gibson for equilibrium layers, there are many occasions on which it is desirable to have closed-form expressions representing the velocity profile. Probably the best known and most widely used representation of both equilibrium and non-equilibrium layers is that of Coles. However, when velocity profiles are examined in detail it becomes apparent that considerable care is necessary in applying Coles's formulation, and it seems to be worthwhile to draw attention to some of the errors and inconsistencies which may arise if care is not exercised. This will be done mainly by the consideration of experimental data. In the work on constant pressure layers, emphasis tends to fall heavily on the author's own data previously reported in ref. 1, because the details of the measurements are readily available; other experimental work is introduced where the required values can be obtained easily from the published papers.