Rapid developments in the use of the helicopter were made in the Korean War. These were taking place at the time when there was considerable urge to introduce the gas turbine engine into the civil aircraft market. It was also a time when much effort was being expended on various forms of reaction propulsion, mostly for missiles. A number of new helicopter projects were started, taking advantage of the new knowledge in propulsion engineering; some utilised new gas turbine designs and others various forms of tip jet reaction. Liquid fuel rockets, ram-jets, pulse-jets and air pressure jets were tried. However, the main line of development continued to be the gradual improvement of direct mechanical drive.

Since Korea the natural trend has been first to convert existing helicopters to turbine engines. When new helicopters were designed wisdom dictated mechanical drive pending the gathering of sufficient experience with other forms of rotor power, and so far the accumulated knowledge of the mechanical drive has proved of greater value to helicopter progress than the potential advantages offered by the alternative engine forms.

Results of an experimental investigation of the distribution of skin friction along the wall of a plane turbulent wall jet are presented. The measurements show that it is possible to describe the variation of skin friction coefficient by a formula similar to the Blasius formula which is based on experimental results of turbulent pipe flow. This is simply achieved by considering the inner layer of fluid between the wall and the position where the velocity is a maximum as a boundary layer with an outer uniform free stream of velocity equal to the local maximum velocity.

Other measurements of velocity distribution indicate that within the experimental range and accuracy, the velocity profiles in the jet are similar and that the rate of change of velocity and width of the jet can be expressed by simple power laws. These results are then partially compared with theory.

An appreciation is made of recent experimental and project work of relevance to the design of a very light weight aircraft capable of being taken off and flown by two men. The emphasis is on the aerodynamic problems involved. It is concluded that, although there are many difficulties still needing attention, all the information supports previous assertions that flight by muscular power alone is possible. The merits and de-merits of a particular projected design are studied, and its performance and stability assessed.

In considering this subject we should first briefly examine how guided missiles came on to the scene. Manned flight in heavier-than-air vehicles is some 50 years old and, once the early scepticism of sopie critics had been overcome, very large and highly successful efforts were made to use flying machines of this kind for direct military purposes. The scope of these efforts and the measure of success that attended them are well known and have been the subject of many of the papers and much of the discussion which the Royal Aeronautical Society has enjoyed in the past 50 years or so of its 90 years of active life. It is indeed significant that the two World Wars of the past 40 years have, by reason of the extra effort they focused on military aviation, been the cause of most of the advances in aviation and thus brought about commercially and economically successful civil aviation as we have it today.

Aircraft have been used for agricultural purposes for at least thirty years. Probably the first country to use them to any extent in agriculture was the United States where there are now probably some 7,000 or more aircraft in more or less continuous employment on some aspect of agricultural aviation.

Up to the present, although many countries, since the end of the Second World War, have employed aircraft on agricultural work, the total world employment of aircraft on this activity has been small in comparison to that obtaining in the U.S.A.

The First Trenchard Memorial Lecture, “Lord Trenchard,” was given by Marshal of the Royal Air Force Sir Dermot Boyle, G.C.B., K.C.V.O., K.B.E., A.F.C., Chief of the Air Staff, at the R.A.F. Station, Halton, on 20th February 1958. This was the 30th main lecture of the Society to be given at a Branch and was held under the auspices of the Halton Branch. The large and distinguished audience included The Dowager Viscountess Trenchard and the present Lord and Lady Trenchard, Sir John Nott-Bower, Commissioner, Metropolitan Police, the Mayor of Aylesbury, a number of members of Council of the Society, the Commanders-in-Chief of Fighter Command, Technical Training Command, Maintenance Command and Home Command of the Royal Air Force, the A.O.C.s of No. 24 and No. 41 Group, the Commandants of Andover, Bracknell, Cranwell and Halton, and many other serving officers of the Royal Air Force.

Kinetic heating, which is associated with supersonic flight, is probably the greatest challenge which has confronted the structural engineer, since the design and analysis of affected structures requires a radical extension of current practice. For example, the laws of heat transfer and the effects of high temperature on structural materials become important factors in structural analysis. To obtain a clear appreciation of the situation it is therefore necessary for the designers of the structure to become familiar with these factors, together with certain aspects of boundary layer theory.

In this short paper on the transonic jet-driven tunnel, I will place the emphasis on the word transonic and deal only with the jet drive as it affects the design or operation of the transonic working section. I also would like to say that, although a fair amount of the information discussed afterwards will refer to the D.H. transonic tunnel, the problems are more or less general to the jet–driven tunnel and some will even be applicable to electrically–driven transonic tunnels using diffuser suction.

In recent years there has been a rapid expansion of the ranges of speed and altitude that are of practical interest to aircraft and missile designers. In consequence, several new terms have been introduced to describe the new flow regimes that require to be considered and, at the same time the meanings of some of the older terms have undergone a measure of modification. The meanings attached to these terms by different workers have not always been consistent, differences have sometimes arisen from the differences of outlook between theoretical and experimental workers or between those concerned primarily with the motion of a fluid and those concerned primarily with the forces on a body in the fluid. To avoid the confusion that may readily arise if such differences become too well established it was felt desirable at this stage to attempt the formulation of unambiguous definitions of the more important terms in current use.

The advent of the high altitude supersonic aircraft has brought in its train a whole host of complex control problems. As far as the engine manufacture is concerned, these are perhaps best indicated in the diagrammatic layout shown in Fig. 1

It is not my intention however, to go into the question of multiplicity of controls and their proper co-ordination, nor will I venture into the abstruse province of stability. I should like instead to concentrate on the fuel system itself, i.e. the supply and control of fuel to the main engine combustion chamber.

The title of this paper is to be construed as primarily referring to guided missiles. Some of the principles have possible application to more peaceful purposes, such as aircraft flight, but the primary emphasis is towards weapon systems.

The principal guidance and control methods are discussed on a review basis but certain of them, which are particularly important or of which the author has special experience, are considered more fully. These are, in particular, guidance and control problems relating to homing missiles.

The first Sir Henry Royce Memorial Lecture described the work of a brilliant engineer, who was directly responsible for the design of a long series of great engines. As a contrast, I have been asked to tell you about the work, not of an individual, but of a team. A team, moreover, that has had no responsibility for the final product, but whose task has been that of attempting to clear the ground and make the engine designers’ work less difficult.

The year 1957 has a certain significance in gas turbine history, in that it is the twentieth anniversary of several important early events. It was in March 1937 that the Engine Sub-Committee of the Aeronautical Research Committee discussed the internal combustion turbine and as a result recommended “that the Air Ministry should take up the question of the development of the internal combustion turbine as a matter of urgency and make all possible arrangements for its production at the earliest possible moment …”

There is very little information on the stress concentration which is caused by a notch on one side of a plate in tension and the authors are not aware of any published data based on experiment. The theoretical solutions due to Neuber are for notches of hyperbolic or elliptic form and only give an approximate result for U-notches of varying depth.

Transition to turbulence in the boundary layer on an aerofoil may occur in several different ways, not the least important of which is by bubble separation of the laminar layer. Thus in establishing an empirical criterion for the limit of existence of a laminar boundary layer the necessary parameters must be able to describe separation and instability, as well as being physically reasonable and simple to calculate and use.

A number of airlines throughout the world will, in the near future, be reconditioning and testing Dart engines from Viscount, Friendship and Herald aircraft. In most cases the testing will employ a technique which has been in use at the Rolls-Royce Australian overhaul base at Sydney, N.S.W., since August 1954. This is based on the torque reaction of the engine to the propeller and is suitable for testing any comparable engine.

The science of aeronautics has developed rapidly in a very short space of time, when one reflects on the remarkable achievements which have been made since the advent of powered flight just over fifty years ago. This rapid advance has made the aircraft designer more keenly aware of any new design techniques which would assist him in his further understanding of the problems involved. In the pioneering days of aircraft development the aerodynamic characteristics were obtained largely at the flight test stage of a design. Through time, however, the designer learned that quite a lot of useful information could be obtained from ground tests in wind tunnels, and he therefore made use of an aerodynamic simulation in its broadest terms, in the form of a wind tunnel model. This was an important advance in design technique in that the concept was established of evaluating performance by means of a “model,” in the initial stages of a project design. A much later generation of aircraft resulted in the need for automatic and power control aids to flight. Further advances have resulted in completely pilotless and automatic flight.

Improvements made to the aerodynamic characteristics of the wing of the Avro CF-100 Mark 5 aircraft are discussed. Modifications to the wing included increase in aspect ratio, addition of vortex generators, and deflection of trailing edge plain flaps. The effect of flap deflection and addition of vortex generators on the aerodynamic characteristics of the wing are shown to be closely associated with interaction of the upper surface shock wave with the boundary layer. Performance gains were demonstrated at high subsonic speeds at high altitudes. Vortex generators improved the buffet boundary, whereas flap deflection both increased aircraft ceiling and improved buffet boundary.

The aviation industry has not yet given much attention to the development of rotary winged machines as specialist agricultural tools which would help to make farming easier, more efficient and more productive. The emphasis is, and naturally has been, on the development of the immediately bigger markets for military aircraft. It is understandable, if unfortunate, that the farmer has to wait his turn well down in the queue of various armed forces specialists. He is waiting for aviation to turn the focus, some day, of its technical knowledge and research resources onto the way that the versatility, manoeuvrability and usefulness of the helicopter can be used to grow more food, timber, wool and other natural products.

The Aircraft Research Association's tunnel was designed from the start as a transonic tunnel. Two important decisions were taken at the beginning of the design of this tunnel. First, that a separate auxiliary suction plant would be used to suck air out through ventilated walls of the tunnel instead of using diffuser suction for this purpose. This decision was taken mainly because the total power required with auxiliary suction is appreciably less than for diffuser suction. The plant is also more flexible and provides, for example, the possibility of running a smaller supersonic tunnel from the auxiliary suction plant.

Ten years ago take-off speeds rarely exceeded 130 m.p.h. and the maximum inflation pressure used in aircraft tyres was about 120 lb./in2. Today tyres have to cater for speeds up to 230 m.p.h. and pressures of 350 lb./in.2. The increased requirements have produced serious problems of heat generation within the tread and carcass of tyres, which, if not solved, result in disintegration. Fig. 1 shows the effect of speed on tyre temperature and also, the effect of lightening the tyre construction.

Beyond the speed range shown, the temperature rises rapidly and tyre failures would occur. To meet these conditions, improved materials with lower hysteresis losses, and capable of operating at higher temperatures, have been produced. Control can also be obtained by modifying casing cord angles, reducing casing and tread thicknesses and so on.