When the Council invited me to read a paper before the Society they suggested as the subject, “ The Use of Steel in Aircraft.” After some consideration, I came to the conclusion that there was not very much new and interesting to say on the use of steel in structures, but that there was a good deal to say concerning the use of light alloys in special constructions. Not that I claim that what I have to say is new, but the particular use of light alloy sheet to be described certainly merits more consideration than it has so far received in England. It is not to be inferred that I think that the use of steel is likely to decline rapidly, on the contrary, I am of the opinion that it will always be widely used. Everyone seriously, engaged in the technical side of the industry knows that steel of various grades has been used in aircraft from the beginning of aviation amd has been the subject of intensive studies during the last fifteen years. It was obvious from the first that if high stresses could be realised with fair uniformity in the finished structural members—say 35 tons per sq. inch or higher—more economical use of steel on a weight-strength basis could be made than of any other material. However that may be, I shall only touch on steel and its uses in construction at one or two points in the course of the lecture.

A method for predicting the flutter boundaries of a helicopter rotor blade is developed which is intended to provide

1. (a) an illustration of the effects of fundamental characteristics of the blade on the flutter boundaries, e g, mass axis location, flexural axis location, stiffness of control circuit, etc

2. (b) a basic approach which may be developed and expanded to provide more detailed representation of any particular blade problem For example, in addition to giving the flutter boundaries for the blade, the equations in the form presented could be used to determine the response of the rotor blade to force distributions which are simple harmonics of the rotor angular velocity Another example is given at the end of this report in which the familiar blade resonance diagram is obtained for the torsion and flapping modes considering dynamic and stiffness properties only, and then again for the blade including the effect of aerodynamic damping

It is shown that when heavily curved circular beams of constant cross section are subjected to a compressive load along the “open” diameter, the load for the start of significant deformation as indicated by the reduction in diameter along the line of action of the load, may be estimated by the use of rectangular plastic stress blocks based on the yield stress of the material. Comparison of the experimental values obtained on specimens of duralumin and mild steel with those predicted theoretically are, on the whole, only slightly underestimated.

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.”

This paper is concerned with the rolling resistance, or drag, of an unpowered pneumatic-tyred wheel rolling at high velocities in soft soil. Its application is to undercarriage design for aircraft intended to operate from unsurfaced airfields, and to the inverse problem of predicting the performance of existing aircraft in such conditions.

The idea of using engine power directly to provide the lift required to sustain flight has recurred frequently throughout the history of aviation. Most of these proposals have concerned some form of helicopter, but in a few cases methods of changing the line of action of the normal propulsive thrust to assist the landing and take-off manoeuvres have been suggested. Few, if any, of these schemes were ever successfully put into practice, one of the main difficulties being the excessive weight and bulk of the power plant, but with the development of the jet engine with its compactness and low specific weight this objection largely disappeared and the idea was brought nearer the realm of practical realisation.

An Address by the President, Sir George Edwards, C.B.E., B.Sc, F.R.Ae.S., was given before a large and distinguished audience of members and their guests at Church House, Westminster, London, S.W.1, on 26th February 1958. Lord Hives, C.H., M.B.E., B.Sc, LL.D., Honorary Fellow, presided. At the end of the Address the second part of the Shell Petroleum Company’s film “High Speed Flight—Part II. Transonic” was shown for the first time.

Following the Presidential Address a Reception was held by the President and Lady Edwards at the offices of the Society, 4 Hamilton Place, W.1, which was attended by over 500 members and their guests.

Numerical results are presented for two-dimensional vortex-aerofoil interaction using a grid-free discrete vortex method. The effects of the passing vortex on the surface pressure distribution and hence the aerodynamic force and moment of the aerofoil are examined in detail for a variety of interaction geometries. For some head-on interaction cases, vortex-induced local flow separation is also predicted on the aft part of the aerofoil surfaces. Extensive comparisons are made with other numerical results and the results from the Glasgow University BVI wind-tunnel test, which show good agreement.

The world of hearing is made up of two types of sound— on the one hand, that which provides communication, be it in the form of speech, music or the noise of a car or dog; on the other hand, a noise which interferes with that message, or a sound consisting of an unwanted message, intruding upon a person's thought processes or sleep. It is always difficult to separate these two functions, since one man's noise is another man's message, and this is particularly so for quiet noises heard at night or occurring sharply to frighten and alarm. It is for this reason that the law regarding noise has been less specific than in other fields and it is for this reason that seldom have any clearly defined limits been specified.

The beam on elastic supports is often considered as a beam on a continuous elastic medium. This method can be applied only to a large number of equally spaced supports having equal rigidities. The method proposed by the author, giving the solution in the form of rapidly converging series, is not bound by this restriction, and when applied to the problem of beams supported by cross-girders reduces it to a system of linear equations, their number being equal to the number of cross-girders, while the existing approximate method leads to the same number of simultaneous differential equations.

Expressions are obtained for the radial and tangential bending moments in a circular plate under the combined action of (a) a lateral load concentrated on the circumference of a circle and an end tension or compression, and (b) a uniformly distributed lateral load, having a diameter less than the diameter of the plate, and an end tension or compression. For both types of loading, solutions are obtained for plates which are simply-supported and for plates with an arbitrary end rotation.

In addition, the following limiting cases are considered: (i) concentrated lateral load with end tension or compression, and (ii) an infinite plate under the simultaneous action of an end tension and a lateral load concentrated on the circumference of a circle of finite diameter.

It is a remarkable calibre of man who is attracted to aviation. Those enthusiasts who formed Britain's Aeronautical Society 100 years ago were optimistic visionaries. For they had to wait 37 years before man's first controlled powered flight. Very few of the members then, in 1903, are alive today. And this is also true of those other optimists who, inspired by the Wrights’ great achievement, have led the world during the past 63 years into the astronautic age.