During the preparation of this paper within the present stringent financial climate in the industry I have been deeply conscious of time and cost, since it is much more difficult these days to give the time and also to justify the cost of an activity of this nature.

Initially it was intended to examine the contribution of the aircraft designer to the improvement of those phases of the total journey over which the designer could have a direct influence. However, the organising committee had other thoughts and has requested that I should point up those aspects where, despite the efforts of the aircraft manufacturers to improve their product by reducing airborne times and real costs, many of the resulting benefits appear to have been frittered away and lost within the surface phases of the total system.

The problem of maintaining a satellite in a fixed orientation relative to the earth has led to the investigation of several methods of attitude control. In particular, the one involving passive stabilisation using gravity-gradient torque has aroused considerable interest. However, a major limitation of this manner of stabilisation is its inability to achieve station keeping to a high degree of accuracy. Furthermore, some form of external damping is necessary to recover an equilibrium configuration in a reasonably short period of time. Modi and Brereton investigated the energy dissipating mechanism which was an extension of the model proposed by Paul The numerical analysis of the system with small damper mass showed limit cycles associated with the system to be identical with one of the periodic solutions of the undamped case.

A few years ago when high–speed aircraft were mentioned, speeds of 300 to 400 m.p.h. came to mind. The advent of jet propulsion has made those figures 100 per cent, out of date and today speeds are discussed more and more in terms of Mach number; for example, high–speed subsonic aircraft fly at Mach numbers of 0.85 to 0.90, aircraft are flying in the transonic region and supersonic guided missiles are proposed for speeds anywhere between M=1.5 and 2.5, i.e. ground level speeds up to 2,000 m.p.h.

It is proposed to review very broadly the suitability of propulsion units for these transonic and supersonic applications. What is the difference between ordinary power plants and those for high speed? The answer might be contained in another question—why are supersonic aircraft different from conventional types? The aerodynamicist will give an involved explanation concerned with compressibility, drag rise, shock waves, and so on.

An analysis is presented for the non-linear vibrations of an elastic rectangular plate resting on a viscoelastic foundation. Hamilton’s principle is used for obtaining coupled non-linear partial differential equations of the system. These equations are uncoupled with the help of Berger’s approximation and the Galerkin method is used to obtain the solution of the resulting equations. Particular cases of the plates on an elastic foundation are also discussed.

The plane free jet is a difficult flow in which to make accurate measurements because of the high intensity of the turbulence. Nevertheless, a reasonable agreement might be expected between comparable measurements of a quantity such as growth rate.

As can be seen in Table I, however, a variation of 10% exists in measurements made by various experimenters in fully-developed jets (x/b>100). If the results are grouped according to the value of (x/c)max,where c is the width of the wall in the x = 0 plane (see Fig. 1), a consistent variation can be seen, with the rate of growth for x/c<1, being 10% higher than for x/c>l.

A considerable amount of material has been produced over the past few years on the subject of heliports and therefore it is proposed to make only brief reference to general heliport requirements and the national and international activity in this field. The application of these requirements to the proposed heliport at Penzance will then be discussed.

Kites are currently used in a number of applications (anemometry, aerial platform, traction), but very little information is available for the systematic design of kite systems. An experimental technique based on an instrumented tether for single-line kites is described. This was used to measure the performance of a variety of single-line kites. The analysis techniques are briefly outlined, and incorporate allowances for kite unsteadiness, the displacement of the kite from the anemometers, extrapolation of the line tension from the tether to the kite, and the kite’s velocity relative to the ground. The results are correlated with aspects of kite design, and specific recommendations for kite applications are made.

Analytical studies involving the pressure on inclined surfaces in hypersonic flow are made difficult by the lack of an explicit and simple relationship connecting the pressure p with the flow deflection angle 8. The various existing relationships are either too complicated or valid only over a very limited range.

With all transport vehicles a light structure weight is of prime importance. Light weight vehicles require less power to accelerate, less braking to stop, less power to climb hills. The power /weight ratio broadly determines the ability of a vehicle to get out of difficulties, avoid collision and, generally speaking, settles the vehicle's performance characteristics.

This is particularly true of the aeroplane where, with a third dimension of travel, the effect of gravity is present to a degree unknown to sea or land travel, even in mountainous countries.

Weight saving thus becomes of paramount importance in aircraft design and leads inevitably to the conclusion that nothing should be carried in the aeroplane to fulfil a service which can be satisfactorily and safely performed on the ground.

A further result, and one that most concerns us here, arises from this weight factor. In many trades a great deal of the technical execution of the work in detail is carried out in accordance with the superintendent's or foreman's knowledge and craftsmanship, and whether there is a little more—or less— material used is a matter for commercial considerations of cost, rather than one of necessity to save weight in order to fulfil performance.

The speaker has no specialist knowledge of agricultural aviation and will therefore briefly describe the aircraft, and provide thoughts on possible uses in aid of agriculture.

The ultra-light autogyro is probably the smallest practical aircraft of any type. Happily it does not need to be correspondingly fragile or delicate and it is little affected by turbulence or inclement weather, in the air or on the ground.

Some thought has already been given to an agricultural autogyro, although a somewhat larger machine than the Wallis autogyro was envisaged. While advantages would undoubtedly ensue from the larger size, such an aircraft would probably be in competition with comparable helicopters and fixed - wing machines. By the time development was complete there might be no great saving in first cost or maintenance.

When a turbulent fluid flows past a solid surface whose temperature differs from that of the fluid, the shear stress at the surface and the heat flow from it can be related by means of the Reynolds analogy. This analogy has been improved by Prandtl, Taylor, von Kármán and others, and its validity has been tested for flow through tubes and past flat plates by several investigators. In this note the analogy is checked against shear stress data and heat transfer data for a cylinder rotating in “still” air, when the flow is turbulent.

The Twelfth British Commonwealth and Empire Lecture “ Aeronautical Development in Australia and its Potential Contributions to the British Commonwealth ” was given by Mr. L. P. Coombes, D.F.C., B.Sc, F.C.G.I., F.I.A.S., F.R.Ae.S., Chief Superintendent, Aeronautical Research Laboratories, Melbourne, before the Society on 22nd November 1956 at the Institution of Mechanical Engineers. Mr. E. T. Jones, C.B., O.B.E., F.R.Ae.S., President of the Society, presided and introduced the Lecturer

MR. E. T. Jones: The British Commonwealth and Empire Lecture was given annually and normally alternated yearly between a resident of the United Kingdom and a resident of a member country of the Commonwealth. This year the lecture was to be given by a resident of Australia and it was his great pleasure to introduce Mr. Coombes. Mr. Coombes had long been a friend and colleague of many of them but as they had a fair number of the younger generation present he would introduce Mr. Coombes properly.

Mr. Coombes had served the profession of aeronautics since 1917 when he started as a pilot in the First World War. For ithese services he was awarded the Distinguished Flying Cross. He was a Fellow of the Society and a Fellow of the Institute of the Aeronautical Sciences. He was also a Fellow of the City and Guilds Institute. Mr. Coombes was elected Chairman of the Melbourne Branch of the Royal Aeronautical Society in 1953 and in 1956 he was elected President of the Australian Division of the Society. He was also a most active and enthusiastic member, or delegate rather, of the Commonwealth Advisory Aeronautical Research Council, a body to which he referred in the paper and which came into existence in 1946.

Mr. Coombes joined the Royal Aircraft Establishment in the Aero Department in 1924 and a year after transferred to the Marine Aircraft Experimental Establishment at Felixstowe. He was recalled to Farnborough in 1930 to take charge there of the seaplane testing tank which had just been erected and many would remember that Mr. Coombes and the late Mr. W. G. A. Perring worked side by side on that tank for many years. He thought it was about 1938 when he and his family left England when there were no facilities at all in Australia for aeronautical research. Indeed there was no organisation in Australia for aeronautical research and he thought that there was no need personally or professionally for Mr. Coombes to go to Australia because he had already assured for himself an eminent aeronautical career in the British Air Ministry. Mr. Coombes therefore was just as much a pioneer, aeronautically speaking, as those men of sail who set out from England two centuries before him. Mr. Coombes was both architect and designer of the Aeronautical Research Laboratories in Melbourne and was now the leader there of a strong team of scientists and engineers who had made quite a reputation in the aeronautical sciences for the high quality of their work.

He would like now to read a message from Australia from Mr. Isbister, the honorary secretary of the Australian Division, which said: “ Please convey to our President, Mr. L. P. Coombes, best wishes for a successful British Commonwealth and Empire Lecture. From Council and members of the Australian Division.”

It is with some misgiving that I come here this evening to lecture to this Society on the training of an aeronautical engineer. The subject is not one which I chose myself; indeed, I think that it is probably the very last which I should have selected to talk about, but the Council of the Society, for some reason which I have not yet been able to understand, invited me to deal with it. I rashly promised to do it, but now that the time has come to redeem that promise I feel that I ought to have refused and chosen a subject on which perhaps I could speak with a little more authority. I suspect, however, that the Council was anxious to obtain a discussion on a topic which to any Society is a very important matter and that I have been put up to serve as a target for your criticism in the hope that something useful may emerge from your comments rather than from my paper.

A successful project outcome requires that the ‘right’ product, (from an overall ‘performance’ viewpoint), should be available when the market place needs it, for a price it is prepared to pay.

To satisfy ‘performance’ requirements, (in the widest sense), the task is broken down into manageable elements, and requirements/specifications are formulated. As the design/development proceeds, progress towards achievement is monitored, with eventual verification through ground and flight testing. On ‘timescale’, we develop inter-locking ‘line of balance’ programmes covering all manufacture inputs, such that the effects on total programme achievement of local gains or shortfalls can be seen.

Barnes has said ‘simulation is like a meal in a restaurant —more depends on the way it is prepared and served than on the basic ingredients'. We know a good deal about the ingredients, the hardware, of the simulator meal but we are not yet particularly good cooks. The lore of cooking has largely been obtained by ad hoc experiments, and at its highest expression is an art; the same is still true, in the main, of simulation techniques. Simulation should come of age. The precocious youngster grew up relatively undisciplined using the sledge-hammer of technology in an endeavour to produce a ground-borne aeroplane, with little science used in identifying the requirements.

It is a commonplace of laboratory experience that one or two months' practice may be required to “get one's eye in” for an apparently so simple task as taking the readings of a polarimeter. But it does not seem to be so widely realised that similar practice is necessary to get one's eye in for seeing objects that are only visible for minute periods of time. Consequently, anyone who has had such practice is liable to incur criticism from those who do not realise its nature and value.

Colonel de Villamil is sceptical as to my statement that in certain cases the smoke issuing from a steamer funnel assumes the form of two vortex filaments lying side by side and rotating in opposite directions. The changes of shape of the smoke masses and their rotary movements are so rapid that they are by no means easy to recognise. I have seen the movements in question both on P. and O. steamers and on excursion steamers from Bournemouth. Mr. J. H. Field, of the Agra Aerological Observatory, kindly permits me to state that he has frequently seen the double spiral in steamer smoke as I have described it. His observations were ,made independently of mine and before he had seen my paper. The necessary condition for the formation of the spirals is that a strong wind should be blowing across the top of the funnel.

In recent years the advances in materials technology, coupled with the rising operating costs of conventional aircraft, have led to renewed interest in the airship as a means of fulfilling certain transportation requirements.

This brief paper does not attempt to retell the story of the airship or to try and justify its present day use, this being far better left to the experts in this field, but considers the requirements and considerations to be taken into account when selecting a propulsion device. The propulsion devices considered are limited to open propellers and very low pressure ratio ducted fans.

The Integral I occurs frequently in aerodynamics. To cite a particular case, Ward has shown that if S(x) is the cross-sectional area distribution of a slender body its wave drag D is given to a first approxition by D = qI/(2π), where q is the kinetic pressure. In this case, S(x) is often defined numerically, and the direct evaluation of I is then complicated by the presence of the logarithmic singularity. Several methods may be employed to avoid this complication. Legendre has recently suggested rewriting I in a non-singular form, which unfortunately is not well suited to numerical work. Here, a method for the evaluation of the unmodified integral is presented.

A detailed survey of a delta wing of 70° sweep has been performed at M = 2.5. The measurements include upper- and lower-surface pressure distributions, schlieren photographs, vapour-screen photographs and surface oil-flow visualisation. The results have been compared with thin-shock-layer theory and various other predictions.

The paper presents the results of an experimental study of the buckling of transversely stiffened shear webs when the stiffeners have a thickness less than that of the web-plate.

It is shown that the effectiveness of such stiffeners is greatly influenced by two factors, the ratio of the thickness of the attached leg to that of the web-plate and the position of the connecting rivet. An empirical design rule relating these two factors is presented.