The history of the Agena space vehicle starts in the years immediately following the Second World War, when the Rand Corporation under a contract with the U.S. Air Force examined the potential applications of satellites, recognising their technical feasibility as an additional bonus from an inter-continental ballistic missile development programme. The U.S. Air Force kept this concept alive throughout the development phase of the ICBM programme; the Lockheed Aircraft Corporation actually received its first contract, for detailed engineering studies, in 1955. The Agena space vehicle has grown from these beginnings and is now the vehicle selected for a large variety of U.S. space projects. Most of these are satellites, but they include a few space probes and moon explorers.

The 1172nd Main Lecture to be given before the Society and the 41st to be held at a Branch centre “Ballistic Research Rockets with Particular Reference to Black Knight” was given under the auspices of the Luton Branch on 1st December 1960. Mr. F. H. Pollicutt, F.R.Ae.S., Chairman of the Luton Branch opened the meeting by welcoming the President, Dr. E. S. Moult, C.B.E., B.Sc., F.R.Ae.S., M.I.Mech.E., the other members of the Council of the Main Society who were present, and representatives from the Bristol, Birmingham and Wolverhampton, Coventry, Christchurch, Derby, Hatfield, Halton, Henlow, Preston and Weybridge Branches. He then asked Dr. Moult to preside over the rest of the proceedings.

Dr. Moult expressed his pleasure at being present on this occasion–the second time a Main Society Lecture had been presented at the Luton Branch–and then introduced the Lecturer, Mr. D. J. Lyons. Mr. Lyons took his degree in Aeronautical Engineering at Queen Mary College and subsequently joined the Wind Tunnel staff at Farnborough. During the war he became a flying instructor in the R.A.F. and later rejoined the Aerodynamics Flight Section at. the R.A.E. For the next ten years Mr. Lyons was engaged in Flight Research on stability and control. In 1951 he was appointed Superintendent of the Experimental Projects Division in the Guided Weapons Department and in 1955 was promoted to his present position as Senior Superintendent of the Ballistic Missile Group of the Guided Weapons Department. He had been responsible from the Ministry aspect for the research and development connected with the Black Knight and Blue Streak Missile systems.

Skylark is an upper atmosphere rocket designed to carry a payload of 150 lb. to a height of 100 miles. The project was the outcome of discussions between the Royal Society and the Ministry of Supply which started in 1953 and were completed in 1955 when Treasury approval was given for a joint Royal Society-Ministry of Supply programme of upper atmosphere research using a vehicle to be designed by the Royal Aircraft Establishment. The programme was the responsibility of the Gassiot Committee of the Royal Society, matters of detail being agreed at a working party and endorsed by the Gassiot Rocket Sub-committee.

The Short SCI V.T.O.L. Research Aircraft, using four special Rolls-Royce RB.108 jet lift engines, which made its first flights in 1959 heralds a new method of taking-off and landing which may revolutionise the operational flexibility of aircraft of the future. The Short SC. 1 is the result of six years research and development by Short Brothers and Harland Ltd., who built and developed the aircraft, and Rolls-Royce Ltd. who designed and developed the special light weight turbojet engines which support the aircraft during the V.T.O.L. phase and which are shut down as soon as the aircraft has attained wing borne flight by the horizontal thrust from its separate propulsion engine. The SC. 1 is shown in hovering flight in Fig. 1.

An aspect of structural design which is becoming increasingly more important is the behaviour of a structure when it is subjected to random pressure loading. Random pressure fields can be encountered in several different ways, two of the principal sources of such fields being the noise emitted by a jet, and the fluctuating pressures in a turbulent boundary layer. Many jet-propelled aircraft have suffered secondary structure fatigue failures in those parts of their structures near to the jet stream, and it is not unlikely that certain failures of panelling in engine intakes have arisen because of vibrations set up by the turbulent pressure fluctuations in the boundary layers at the walls.

A summary is given of some of the more important experimental results relating to the noise radiated from a cold subsonic turbulent jet. These are then related to the predictions of Lighthill's general theory of aerodynamic noise.

My first illustration Fig. 1 shows how the World's very first powered flight was announced in this Country—and it had no more notice in any other—I cannot help feeling that the first manned space flight will cause a slightly greater fuss.

I suppose it really all began, so far as my urge to fly was concerned, in the summer of 1910. At that time I owned half a 166 ton schooner—the owner of the other half was my old friend Bill Eyre.

Incidentally, the engineer in charge of the auxiliary engine was Fred Sigrist. We were to remain in partnership through many varied experiences in aviation for the following 30 years.

We had left Le Havre and as we were becalmed in the Channel we put into Dover Harbour. There we heard that an American architect of Spanish descent, Johnny Moisant, was flying a Bleriot monoplane (Fig. 2) in a field nearby so we thought we would go and have a look.

Few things have given me greater satisfaction than the invitation to give the Seventh Barnwell Memorial Lecture, and tell the story of the early history of the Bristol Engine Department.

The Bristol Aeroplane Company which was founded by that great merchant venturer and pioneer of transport, Sir George White, has just passed its 50th Anniversary. I always look upon the 20 odd years spent with the Bristol Company as among some of the happiest and most stimulating in my engineering career.

While the subject of this paper is concerned with problems somewhat outside the scope of those which existed in the days of the late Roy Chadwick, nothing absorbed Chadwick's interest more than a seemingly intangible aircraft problem, and I am sure that had he been alive today he would have been deeply involved in the search for solutions to them.

He was without doubt a man of great talent, with an intuitive flair for design, and I join the many members of his staff who deem it a great privilege to have been associated with him for many years; and am honoured to have been asked to present this Memorial Lecture.

With increasing speeds of aircraft, problems arise over materials of construction, partly through kinetic heating effects which cause temperature rises and partly through rain erosion effects. Additionally, account has to be taken of a required life of 30,000 hours which is much longer than that over which most materials are normally evaluated.

For speeds of Mach 2.2, the maximum temperature attained will be of the order of 130°C, while for Mach 2.7 the corresponding temperature will be 200°C or higher. For the lower speed, it is probable that aluminium alloys will be satisfactory, although it must be emphasised that no information is yet available on the long-term behaviour of materials at the elevated temperatures likely to be experienced. Test programmes are in hand, but these will necessarily take considerable time for their completion. For speeds of Mach 2.7 or above, steel or titanium alloys will be required, but here again the necessary evaluation for long periods at high temperature has yet to be completed.

If man's desire to fly was not totally inspired by the flight of birds at least his early attempts at heavier-than-air flight were a direct imitation of birds. To the earliest known aviators two features seemed indispensable in any flying machine, wings that flapped, and wings covered with feathers. The former at least seems reasonable, but no attempt was made to discover the purpose of feathering a bird's wing and feathers were used simply to give the flying contraption the appearance of a bird. As we shall see later these factors probably delayed the advent of sustained flight—not necessarily powered—by many years.

Imagination has always, in the past, attributed the bird with greater powers than it really possessed. Many early flying machines were designed as chariots borne by as few as six doves—powerful indeed! Its powers to soar so high that it became lost to sight gave it the status of a semi-deity, from which came the mariner's faith in the albatross, perhaps.

I shall try to set the Air Traffic Control scene by describing how the responsibilities of States to provide Air Traffic Services are currently exercised in the United Kingdom, and by indicating some of the measures being taken to ensure that these services keep pace with the increasing demands of the air space users. Any opinions I may express are, of course, my own, and do not necessarily reflect the views of the Ministry of Aviation.

The invitation for this lecture requested “a review of missile structures from the viewpoint of an aircraft designer.” This is inevitable because most of the author’s experience has been associated with aircraft design. There are however many people actively concerned with missiles who have had considerable experience designing aircraft and would be better qualified to make a more realistic approach to the subject. The difficulty for an outsider making a review of missiles is justifying the “need to know” and then, having found out, or deduced interesting facts, he may be made aware that to publish them would contravene some security ruling.

Today we are Interested in the scope of the research programme rather than the actual details of the physics. Further I shall discuss space research rather than just upper atmosphere research, because we include astronomy and this will be discussed by others as well.

Now I have, in fact, a formidable task, because I find I have something like twenty-three experiments to deal with in twenty minutes. What I am going to do therefore is to list the experiments that are going on, to tell you whether they have been carried out successfully, or are awaiting completion, and thus to try to give you some idea of the scope of the work which has been undertaken.

When South Africa joined the Commonwealth Advisory Aeronautical Research Council in 1948 it was decided that the study of atmospheric turbulence was the first research project which could be undertaken. Equipment for the recording of aircraft accelerations was not then available commercially so an apparatus was assembled in the laboratory of the National Physical Research Laboratory, use being made of a commercial sensing head and an oscillograph galvanometer with photographic recording. The apparatus weighed about fifteen pounds so it was used on Douglas DC-3 (Dakota) aircraft which were flying for the S. A. Air Force on routes from Pretoria, to Durban, Cape Town and return. This apparatus recorded altitude and vertical acceleration of the aircraft. At a later date a lightweight commercial instrument was purchased and fitted into a Douglas DC-4 (Skymaster) aircraft flying on the routes of S. A. Airways. This instrument recorded altitude, air speed, and vertical acceleration.

“ God bless the Duke of Argyll!”

In the Lecture Hall at Hamilton Place, London, of the oldest aeronautical society in the world, that Duke of Argyll, who became its first President in 1866, looks silently down upon those members who, less than a century later, succeeded so noisily to fly faster than the sounds of their own triumphant cries of success.

A description is given of the distribution of vorticity in the surface of thin wings with large leading edge sweep. Although the delta wing is chosen as the basic plan form the deductions are general and applicable to other types of wing. The conclusions are illustrated with experimental evidence from a water tunnel.

The tailless aircraft configuration is relatively rare in the field of aircraft design and for many years was regarded as a “freak” design. It is intended to trace the development of tailless and flying wing aircraft and to outline the major problems in control and stability.

First it is necessary to arrive at an arbitrary definition of the term tailless aircraft. Later an attempt will be made to classify the different tailless types in detail, but for the moment it is sufficient to regard a tailless aircraft as “an aircraft having no auxiliary horizontal stabilising plane, deriving lift and controlling moment solely from the main plane.” This definition, as it stands, includes what are often termed flying wing aircraft.

For types of structure where safety standards cannot be preserved by reliance on inspection, a permissible “safe life” has to be determined by relating the loads experienced by the aircraft in service to the fatigue performance of the structure, with due allowance for scatter in fatigue strength and in the frequency with which loads are encountered. This paper gives a working method for estimating the “safe life”—at which the risk of fatigue failure is negligible—of the wing structure of a transport aircraft, where the flight loads giving rise to fatigue are overwhelmingly due to atmospheric turbulence but where allowance has also to be made for “ground-to-air” loads.