The experimental work described in this paper, which was divided into two sections, was done to determine the usefulness of photoelasticity as a method for analysing fuselage frame problems. In the first part, a series of tests was made by the photoelastic method on models without any supporting shell, which were in equilibrium under the applied i loads, to determine the bending moment distribution in various types of frames and rings.

In all cases the theoretical bending moments were calculated from the principles of minimum strain energy. The experimental results agreed with theory to within 5 per cent, except close to the null points and joints.

The second part was devoted to shell-supported models, and the shear loads were reacted out through the skin to firm supports at the end of adjacent bays. Again the bending moments were determined for the entire frame from the isochromatic fringe pattern.

The shell-supported tests proved to be of considerable interest when compared with the theoretical curves of Ref. 4 for the corresponding relative stiffness parameters. In some cases agreement was good but in others there were marked differences. A possible reason for this was that compression effects in the skin were altering the distribution and value of the bending moments in the frame.

It was felt that there was plenty of scope for more interesting work on fuselage frame analysis, from the standpoint of shear flow determination, intermediate frame reaction, and skin-to-frame relative stiffness effects. All of these might feasibly be examined photoelastically with a certain degree of advantage over lengthy and laborious theoretical investigations.

Before making an appreciation of present knowledge about a single metal, it is not inappropriate to say something of all metals, for the ever-increasing tempo of material civilisation has largely depended on man's increasing knowledge of these constituents of his World. His first discovery in this field was copper. To it and to its alloys he gave an exclusive allegiance for some 100 generations, then about 3,000 years ago iron became, and still continues to be, the predominant metal of his needs.

In the eighteenth century, when alchemy finally gave way to the logic of scientific thought, the metals employed by man for purposes other than currency and decoration were practically confined to iron, copper, tin, zinc, mercury and lead. Today, when over seventy metallic elements are known, only a small number of these are used by the engineer.

On June 5th 1783, one hundred and seventy years ago, almost to the very day of the Coronation of Queen Elizabeth II, the first public “aerostatic experiments” were made which were to herald the dawn of a diuturnity of human endeavour.

In the Hodgson-Cuthbert Aeronautical Collection the Royal Aeronautical Society possesses a direct link spanning those one hundred and seventy years, a link which joins those wondrous days of long ago when people cried “What on Earth in Heaven is that?” with the present welfare days in which many have learnt how to move Heaven and Earth simultaneously atomically.

About twenty years ago I was invited by the Council to read a paper before the Society, the title suggested being "The Use of Steel in Aircraft Structures." At that time steel, as the material for important parts of main structural members, was giving place to the then new and stronger aluminium alloys, and I decided that the lecture should be on something of growing, and not diminishing, importance; therefore in a paper entitled “ Some Developments in Aircraft Construction ” (March 1934) stiffened sheeted structure in aluminium alloy was chosen as the theme of the subject. The paper was as up-to-date as possible, but it contained no pictures or descriptions of British aeroplane structure of that type because in this country no aeroplanes (except the odd one in which fabric had simply been replaced by aluminium alloy) designed basically in that way had been built.

The problem of determining the distribution of stress over the various components of a structure such as an aircraft frame is one which has always presented considerable difficulty. For a large proportion of the components calculations of the stresses can only be carried out on the basis of assumptions and approximations, the effects of which cannot be estimated with any degree of accuracy and, since considerations of size and weight impose limitations upon the employment of a large safety factor, there has always existed a need for some practical means of checking the results of calculations or of obtaining more reliable estimates of the stresses.

West Africa, particularly British West Africa, has been one of the last areas to be opened up to Air Transport and because of physical and financial difficulties, progress has been slower than in most other parts of the Empire.

As West Africa, even today, is not very well known in other parts of the Empire, it will be useful to give a brief description of the territory and the early history of aviation there before dealing with the special problems encountered in the development of air transport. While the particular territories dealt with in this lecture are the four British West African Colonies and Protectorates of the Gambia, Sierra Leone, the Gold Coast and Nigeria, it will be necessary, from time to time, to make passing reference to the adjacent French territories and even to the Anglo–Egyptian Sudan. The four British territories, unlike those in East Africa, are not contiguous but each is surrounded on the land side by the intervening French territories of Senegal, Guinea, Ivory Coast, Dahomey, Volta, Niger, Chad and the Cameroons.

A simple formula is presented for the safe life of an aircraft under reasonably good operating conditions from the standpoint of wing fatigue. Gusts are treated as the main factor in determination of fatigue life, though other factors are allowed for as being secondary. Before the formula can be used a simple fatigue test is required on critical components, and is repeated several times to establish variation of nominally identical specimens. The loading cycle for this test corresponds to a sequence of up and down gusts of 8 ft./sec. equivalent velocity. The life obtained is termed the “Standard Life” and corresponds to normal operating conditions on European air lines. Reservations in the use of the formula and correction for other operating conditions are discussed in general terms.

I consider it a great privilege to have been chosen to give the first Rex Pierson Memorial Lecture, as not only is he an outstanding figure in British Aviation, but he was also one of my close friends.

Reginald Kirshaw Pierson was born in February 1891 at Fransham, Norfolk, his father being the rector there. He was educated at Felsted School. On leaving he was destined to enter the Bank of England, but at the last moment, mainly due to the untiring efforts of his mother, he was allowed to follow his natural bent, and take up engineering instead.

In 1908, therefore, at the age of 17 he entered the Erith Works of Vickers Ltd., as an engineering pupil-apprentice, passing through the various departments and, while there, taking his Bachelor of Science Engineering degree the hard way, from evening classes.

The 882nd Lecture to be given before the Royal Aeronautical Society was held under the auspices of the Glasgow Branch on 23rd April 1953. Professor W. J. Duncan, F.R.S., F.R.Ae.S., President of the Glasgow Branch, welcomed the visitors. He expressed regret that the President of the Society, Mr. G. H. Dowty, F.R.Ae.S., was unable to be present and welcomed Mr. N. E. Rowe, C.B.E., F.R.Ae.S., Chairman of the Branches Committee, and the Secretary of the Society, Dr. A. M. Ballantyne, T.D., A.F.R.Ae.S.

Mr. Rowe, taking the Chair for the rest of the meeting, said how much the President regretted not being present; as they knew, he had shown the liveliest interest in the Branches and had made many visits to them during his year of office. This was the twelfth Main Society Lecture to be given at a Branch meeting; the holding of Main Lectures at the Branches had proved a great success and he was sure that the present meeting would be a success also, because their lecturer had been doing pioneering work for the past three years on the development of the Comet. After graduating from Cambridge in 1940 Captain Majendie joined the R.A.F. and served as an instructor for several years; he served with Coastal Command in 1943 and was mentioned in despatches, then served on ferry duties, and in 1946 joined British Overseas Airways. He held a Pilot's “B” Licence, a Navigator's Licence and a Wireless Operator's Licence. Before being appointed to work on the Comet he had been engaged in helping Mr. E. S. Calvert at the Royal Aircraft Establishment to develop the high intensity lighting system. Captain Majendie was one of those rare people who combined a scientific and a really practical ability.

The Sixth Louis Bleriot Lecture was given in London by General Guy du Merle on 19th March 1953 at the Institution of Mechanical Engineers, Storey's Gate, S.W.I. Mr. G. H. Dowty, F.R.Ae.S., President of the Society, presided and welcomed particularly M. Jules Jarry, President of the Association Francaise des Ingenieurs et Techniciens de l'Aeronautique, and members of A.F.I.T.A., who had come over from France for the occasion.

Introducing the Lecturer, the President outlined his career. After leaving school General du Merle went into the corps of aeronautical engineers, which was then of civil status but had since been militarised. He spent two years at the Ecole Nationale Supérieure de l'Aéronautique, graduating in 1932, and obtained his certificate as a pilot of military aircraft including seaplanes. For the next two years he served as an engineer pilot at the Centre d'Essais en Vol (Flight Testing Centre) testing prototype aeroplanes at Villacoublay, during which time he flew both French and foreign aircraft. He next became Engineer at the Technical Department of Aeronautics at the Air Ministry and then Director of the Department. While a professor at the Ecole Nationale Supérieure de I'Aéronautique he had published a book on the construction of aeroplanes, a copy of which was in the Library of the Society. Upon being attached to civil aviation at the Ministry of Public Works and Transport, he founded and directed for two years the National School of Civil Aviation at Orly. General du Merle was then appointed Director of Navigation and Air Transport at the same Ministry, and represented France at a number of international meetings on Civil Aviation. Appointed Ingénieur Général de l'Air, he had regained for a short time his original Ministry, which he now represented on the Interim Committee of E.D.C. He had been on missions to England a number of times since the end of the war, and in 1947 had flown several British aeroplanes, including the Sea Fury, the Meteor and the Vampire. He was a Fellow of the Royal Aeronautical Society, and was also an Officer of the Legion d'Honneur and held the Medaille de l'Aéronautique. General du Merle was at present Commandant des Ecoles et Stages at the Ministere des Travaux Publics et des Transports (Officer in charge of Schools and Courses).

Most sections of the Aircraft Industry with something to make, something to describe or something to sell will doubtless find much to take issue with in what is about to be said. No apologies are forthcoming, however, since it is proposed to speak about, and of, aircraft as found and experienced by pilots and operators.

Along with Lease-Lend the North American idea of high pressure salesmanship appears to have permeated British aeronautical matters together with all the superlatives ending in " ER." Of all mankind's ingenious devices probably none are more full of compromises than aeroplanes, therefore adjectives describing one or more of their aspects may be noteworthy but, when they tend to overflow, a sceptical eyebrow may well be raised.

In 1951 the Ministry of Civil Aviation made an investigation into the acoustic screening offered by the use of a running-up pen. Tests at London Airport in which a Viking was run up behind an experimental wall constructed of corrugated cement asbestos sheeting fixed to a scaffolding of steel tubing showed that a reduction of some 25 phons could be obtained throughout most of the geometrical shadow of the wall and over a range of distances probably exceeding one mile. Unexpected acoustic characteristics of the experimental wall precluded the collection of the full design data on running-up pens that were sought, but did not detract from the efficacy that was demonstrated. Auxiliary tests suggested that little noise abatement can be achieved by the use of trees or buildings. A prototype running-up pen is now being built at London Airport to find what operational problems are associated with the use of running-up pens and, if possible, the design data still required.

Because of the limited nature of its application the wind tunnel balance has never been the subject of steady development along well defined lines such as are discernible in the development of most other mechanisms of comparable size and complexity.

The diversity of types and forms of balance which have been constructed in the past, reflect the wide range of tunnel sizes, financial resources, and personal preferences which are characteristic of some laboratory equipment.

The design and construction of a balance suitable for use in a medium–to–large industrial wind tunnel is a relatively costly undertaking, and the problem of providing such equipment is made more difficult by the paucity of published information, of a sufficiently detailed nature to be of assistance in making a decision on either a suitable specification for this class of machine, or the practical means by which a specification can best be met.

As part of the modernisation of the Blackburn and General Aircraft Aerodynamics Laboratory at Brough, a new six–component balance was installed, some few years ago, in a 7 ft. x 5 ft. wind tunnel having a maximum speed of 300 ft./sec. A detailed description of this balance is given.

It is of cardinal importance that the facts of aeronautical history should be placed on record.

The stirring stories of these tremendous first fifty flying years must be told where and when and how they can, but should be told quickly before the mists of time and memory lose them for ever.

Here is set down the story of the unprecedented achievement of the Wright Brothers, their impacts on, and relationships with, those members of the one-time Aeronautical Society of Great Britain who knew them and were aware of the reality of their genius. It is a story of some importance and one which it is fitting should be on record in the Society's own publication, for all to read who may. It is told by the brothers themselves, and by members of the Society.

In a previous paper it has been shown that a general method may be developed for calculating the various changes which take place in a flowing gas. The changes considered were the addition and extraction of heat in a subsonic flow, the addition and extraction of heat in a supersonic flow and sudden changes, such as shock waves. The changes were considered to be stationary and to take place in a parallel pipe. It was of interest to see if a similar approach would produce a general treatment for moving waves. The investigation was limited to moving shock waves and detonation waves.

The problem of symmetrically loaded circular plates of constant thickness is covered adequately in several of the standard textbooks on the strength of materials. Formulae are derived enabling the deflections and stresses to be readily calculated in any portion of the plate. The problem is complicated by the introduction of a variable thickness and by a variation of material properties due to a temperature gradient down the radius of the plate; conditions such as are encountered in gas turbine wheels, bearing support diaphragms and flexible disc couplings. Methods exist whereby the plate can be solved if the thickness is a simple function of the plate radius, but in practice this is not always so, the profile often being complicated by flanges and spigots.

This is a discussion of the various types of flow which may occur on thin swept wings when the air stream is not attached to the wing surface everywhere. In particular, the behaviour of vortex sheets which arise from such mixed flows is examined.

Fatigue of aircraft parts due to small but numerous vibrations has been known about for some time, but in 1944–5 cases of structural fatigue were found which were thought to have been caused by loads greater, but less frequent, than the usual vibration loads. Such loads could be ground loads due to taxi-ing, take-off and landing or they could be air loads caused by gusts and manœuvres.

A general study of the fatigue properties of typical structures was made in the laboratory and it became apparent that the loads likely to do the most damage were those occurring about a million times in the life of the aircraft.