The 909th Lecture to be given before the Society and the 16th Main Lecture at a Branch, was held under the auspices of the Chester Branch of the Society on 8th April 1954. Mr. K. G. Hancock, Chairman of the Chester Branch, expressed the pleasure of the Branch at having a Main Meeting of the Society at Chester and welcomed the visitors, particularly the officers of the Main Society. He then asked the President, Sir William Farren, to preside for the rest of the Meeting.

Gliding as a sport dates from the early nineteen twenties when German pilots, banned by the Treaty of Versailles from constructing or flying powered aircraft, turned their attention to constructing sailplanes. Their progress was remarkable and, after visits by some of their best pilots to England in 1929, many clubs were formed here together with an association of clubs, the British Gliding Association. Many of these clubs lasted only a few months but by 1937 a few were in a strong position and in November 1937 Squadron Leader (now Group Captain) Buxton gave a lecture to the Society reviewing developments up to that date. Developments in gliding are well recorded in the Journal of the B.G.A., Gliding, and in the other aeronautical periodicals, but it is proper that the Society should record periodically progress made in this branch of flying.

The 902nd Lecture to be given before the Society, which was also the 15th Main Lecture at a Branch of the Society and the First Barnwell Memorial Lecture, was held under the auspices of the Bristol Branch on 4th March 1954. The Lecture was delivered by Major G. P. Bulman, C.B.E., B.Sc, F.R.Ae.S., Director of Construction and Research Facilities, Ministry of Supply and a Past President of the Society.

Dr. A. E. Russell, F.R.Ae.S., President of the Bristol Branch, opened the meeting and then invited Sir William Farren, C.B., M.B.E., M.A., F.R.S., M.I.Mech.E., F.R.Ae.S., President of the Society, to preside.

The 893rd Lecture to be given before the Royal Aeronautical Society was held under the auspices of the Belfast Branch on 10th December 1953. Rear Admiral M. S. Slattery, C.B., President of the Belfast Branch, presided, and welcomed the visitors. He expressed the regrets of the Branch that the President of the Society, Sir William Farren, C.B., M.B.E., M.A., F.R.S., F.R.Ae.S., was unable to be present, but welcomed the Secretary, Dr. A. M. Ballantyne.

The Branch President, introducing the lecturers, said: —Mr. Ringham is the Manager and Chief Engineer of the Flight Similator Division of Redifon Ltd. He has been connected with the design and development of communication and electronic equipment for over 25 years. He joined Rediffusion (now Redifon Ltd.) in 1939, and worked extensively on the development of navigational training aids during the war years.

His co-lecturer is Dr. Cutler, Chief Designer of the Flight Simulator Division of Redifon Ltd. He worked on naval navigational aids with the Admiralty Signal Establishment during the war, returning to the development laboratories in Haslemere at the close of the war in Europe. He re-entered Nottingham University later and obtained his B.Sc, Special Physics, and then did research work and was granted his Ph.D. in 1952.

Following the Lecture Rear Admiral Slattery said that it was the practice in the Belfast Branch to present a small memento to lecturers who did them the honour of coming to Belfast and he had much pleasure in presenting the lecturers with a small memento each of Irish linen.

The Lecturers presented their paper and then showed a film depicting sections of a simulated flight from Rome to London.

The Seventh Louis Bleriot Lecture was given in Paris on 10th March 1954, by Mr. Raoul Hafner, F.R.Ae.S., under the auspices of the Association Française des Ingenieurs et Tèchniciens de L'Aèronautique (A.F.I.T.A.)

The Lecture was attended by the President, Sir William S. Farren, C.B., M.B.E., F.R.S., F.R.Ae.S., and several members of Council of the Royal Aeronautical Society, by the Secretary, Dr. A. M. Ballantyne, T.D., A.F.R.Ae.S., members of the Society and of the British Aircraft Industry, and by a large and distinguished French audience.

Monsieur Jules Jarry, President of A.F.I.T.A., presided at the meeting and welcomed the guests before introducing Sir William Farren, President of the Society.

The 887th Lecture to be given before the Royal Aeronautical Society was held at the Institution of Mechanical Engineers, Storey's Gate, London, S.W.I, on 29th October 1953, and was presided over by Sir William Farren, C.B., M.B.E., M.A., F.R.S., F.R.Ae.S., President of the Society. Sir William said that this was the first main lecture of the session. In one paragraph of his paper Mr. Mercer said that those who were specialists in fields of a highly specialised kind should get together with their friends in other branches of aeronautics, otherwise they might all go on in ignorance of what was being done by others; he hoped therefore, that there were a number of specialists present who would join in the discussion.

Introducing the Lecturer, Sir William said that he had known Mr. Mercer for many years; Mr. Mercer had joined the Blind Landing Experimental Unit at Martlesham Heath when it was formed and it was there that he had done the work described in the paper. The President said he had always felt that one of the things most needed for the real development of aviation was a means of landing in bad weather. He hoped that Mr. Mercer's paper was a contribution towards that end; it was concerned with one phase only of blind landing—approach—but he hoped there would be other papers on the subject. He now called on Mr. Mercer to give his paper.

In presenting this paper an attempt has been made to examine the development of current propeller theory and practice to cover the range of aircraft speeds between 450 and 550 m.p.h., which at 36,000 ft. represents a flight Mach number range of about 0.68 to 0.83. Inevitably in such a discussion it has been necessary to peep over the wall into the realms of higher speeds, but no serious attempt has been made to cover such a controversial region because of the lack of experimental data.

Since the advent of the aircraft gas turbine engine, various ways have been employed for feeding the fuel into the combustion chambers in the most advantageous manner. Perhaps the most commonly employed method has been the use of swirl atomising nozzles, and in this group is the spill type which has been used successfully for many years in industrial oil burning furnace equipment.

Arising from the general review of burner nozzles made for the aircraft gas turbine engine in its early days, spill burners were used experimentally on the W2/700 engine. Among the problems encountered was that of achieving suitable flow matching characteristics between the several burners of a set and also, that of arranging a satisfactory control system. The knowledge gained by this early work has been made available and has proved helpful to those who chose to carry on with this particular type of fuel nozzle.

During the past few years, the introduction of the large jet air liner has introduced new noises into the sky which has caused the public to be more aware than ever of the increasing nuisance value of aircraft taking off, landing, or on the ground. Much of this is being blamed unfairly on the jet air liner but the problem in any case remains with us.

For example, recent measurements given before the Society of Automotive Engineers are very revealing; here Baranek plotted the maximum noise levels on the ground when aeroplanes took off with a 5° take-off path.

The title of this paper could cover a number of interesting problems ranging from the ultrasonic scream from compressors and its (alleged) effect in producing “jet sickness,” to the noise from supersonic propellers but, since it is “in particular Jet Noise” which is under discussion, this paper deals entirely with that subject. Some new facts are presented, mostly obtained at my own firm, with the active encouragement of the Ministry of Supply, and some of their implications are discussed.

For US in the early evening of life, who have witnessed the development of aviation since the Wright brothers flew in 1903, for us, it is hard—and a little sad—to realise that some of our great pioneers are already becoming almost mythical characters. They were our personal friends with whom we worked most happily; yet, to the young men of today, who are now carrying, or are about to don, high responsibilities in the aeronautical world, they are indeed just names. And so it is fitting that the Royal Aeronautical Society should have inaugurated these Memorial Lectures, of which this is the third. I am deeply sensible of the honour and responsibility which have fallen to me by the choice of the Bristol Branch to pay this first tribute to Captain Barnwell. May I say at once how indebted I am for so much of the detail of this appreciation to Mr. C. W. Tinson, who served with Barnwell for most of his career at Bristol; to Mr. C. H. Barnes, who has written the history of the Bristol Aeroplane Co.; and several other “ old hands.” It is significant that in all my conversations with them, they referred always with obvious affection and deep respect to “the old man.”

Compared with the general advance of aeronautics in the past decade, or indeed with sailplane development in the 20's and 30's, progress in sailplane design has recently been very leisurely. This is due in part to the fact that there is less scope and partly because little effort has been expended. The most important advances in the art have been in the understanding and use of meteorological conditions which make soaring flight possible; sailplanes good enough for the purpose have existed.

Before the Second World War the main design impetus came from Germany and Poland and in most current designs the German influence is still strongly evident. Since the war there have been outbreaks of activity in Switzerland (W.L.M.I., Moswey), Canada (where Shenstone and Czerwinski have inspired designs at Toronto) and in the United States. The total effort has not added up to that in pre-war Germany.

In the design of high-speed aircraft the problem of relating structure loads to a prescribed flight envelope leads very often to the necessity of airframes being considerably stronger than past experience would tend to suggest, due to the methods used in calculating the loading.

Hitherto, when dealing with subsonic flight, it has usually been sufficient to determine structural loads in manoeuvre on the basis of a rigid aircraft. That is to say, the influence of structural distortion upon the aerodynamic derivatives, which enter the load calculations, is neglected. That this assumption becomes untenable as the speed is increased is clear when it is realised that, for a given fixed loading on the wing, the distortion is fixed; whereas the incidence necessary to produce the loading is approximately inversely proportional to the square of the flight speed.

Although columns built almost 5,000 years ago still stand in Egypt, the first theoretical calculation of the load-carrying capacity of columns was published by Euler only 209 years ago. The classical theory established in this publication is still the foundation of all stability analyses and is likely to remain so in the future. It was derived for perfectly elastic columns and for specific end conditions. These end conditions are not realised in the ordinary column test nor do they correspond exactly to the conditions prevailing in an aeroplane wing when it is subjected to a gust or to the shock of landing. They are not the same as the end conditions of a column in a building when it collapses during a tornado or an earthquake.

Quite often, those whose honour it has been to deliver the Wilbur Wright Memorial Lecture have used the occasion to present a survey of progress along a fairly broad front and thence to predict what the future holds in store.

It may be that the courage, insight in experiment, and skill in craftsmanship, which culminated in that successful demonstration of fifty years ago last December, have excited those whose privilege it has been to commemorate that achievement to undertake flights in the realm of prophesy. A time so near the fiftieth anniversary might be considered unusually appropriate to historical review and philosophic speculation, but since Sir Harry Garner's 1952 Lecture “Prophesy and Achievement in Aviation,” the Royal Aeronautical Society has been busily converting crystal balls into models of the Montgolfiere balloon.

I am very conscious of the privilege and honour of being asked to deliver the first R. J. Mitchell Memorial Lecture. The presence of such a distinguished audience, and the fact that I feel the subject is one to which it is difficult to do full justice, are factors which do not tend to fill me with confidence, and I hope you will forgive any inadequacies. From a mass of recollections arising as the result of fourteen years of contact with Mitchell, I hope to give you my impressions of the life and career of that great designer.