An appropriate introduction to the topic of this lecture is the following comment taken from Cierva's third and last lecture presented before this Society in 1935:

“Perhaps the most irritating of the secondary difficulties met with in the Autogiro development have been those of a dynamical nature. The dissymmetry of speed on both sides of the rotor produces periodical variations in the lift and drag…“

The Fourth Cierva Memorial Lecture, which it is my privilege to present, is concerned with these periodic variations and their contribution to what remains one of the most irritating problems in rotary wing design.

The problem of air-breathing engines capable of flying at very high Mach numbers is described briefly. Possible performance of supersonic combustion ramjets is outlined briefly and the supersonic combustion process is described. Two mechanisms of combustion are outlined: one is supersonic combustion controlled by convection process, and the second is controlled by diffusion. The parameters related to the combustion process are discussed in detail. Data and analyses of reaction rates and mixing phenomena are represented; the flame mechanism is discussed, and experimental results are presented.

In looking through the list of British Commonwealth Lectures one finds that the great majority deal with the work or problems of a particular country. There are few which deal with the Commonwealth as a whole, the outstanding exception being the remarkable paper on Aviation and the Development of Remote Areas given by H.R.H. the Duke of Edinburgh in 1954.

This is a great occasion; I feel quite unworthy to do justice to this commemoration of a great man and a revolutionary event and to become one of the illustrious band who have so graced this occasion in the past. For the more one reads about the Wrights' achievements, the more one is impressed by them as men of stature—of great character, determination and intellectual strength with a most endearing modesty. They had too, such a sense of fun and there is a golden thread of family affection running all through the record. They were men of vocation just as their father, Bishop Milton Wright, and there is no doubt of the influence of the family ties on what they did. One senses how much home meant to them and how much they all turned to Katharine, the womanly stabilising element. A comment of Wilbur's in one of his letters to George Spratt commenting on a technical argument they had been having, is very revealing. "It is a characteristic of all our family to be able to see the weak points of anything", a vivid hint of most lively family discussions, and of course, this most rare combination of brothers must have been a fundamental element in all their work.

From some points of view this is a difficult time to be giving a general talk on supersonic civil transports. The pioneering period is over, and the really interesting lectures when bright new ideas and shapes were discussed have mostly all been given. The design of the Anglo-French “Concord” is now pretty well settled and a fair amount of information about it has been made public. The information which has not been made public is withheld for obvious reasons of commercial security, and I am therefore caught between not giving too much away on the present Concord and repeating a lot which has already been said.

From time to time in the course of my practice as a Solicitor I have the privilege of coming into contact with people who are concerned, as designers, engineers, pilots, operators, commercial and technical staff and insurance brokers and underwriters, with the actual business of designing, manufacturing, flying, operating and insuring aircraft.

Several of them have said to me that the Air Law Group of the Royal Aeronautical Society would fulfil a useful and worthwhile function, so far as they were concerned, if it would try to give them a basic but overall picture of what “air law” was and how their own day to day actions could be affected by it.

Some of the uses of ground based flight simulation as a research tool to aid the design of new aircraft and their equipment are described. The function of the simulator is to provide a method for investigating humon flying tasks in the laboratory, so that the relationship between the pilot's capabilities and the equipment's characteristics can be systematically studied. The paper is presented in two parts describing recent work on two research simulators at the RAE.

Part I deals with the use of simulation for studying aircraft stability and control characteristics. The equipment used at RAE for this work is described, with particular emphasis on methods of presenting to the pilot a simulated view of the outside world, and for reproducing some of the motion cues which he experiences in flight. Experimental evidence of the importance of these simulation cues when making aircraft control assessments is also presented. Several examples of simulation studies into the control of conventional and VTOL aircraft are given, to illustrate the type of research problems in this field which may be tackled and the techniques involved in solving them.

The past several years have seen a steady advance in the techniques employed in flutter and vibration analysis. At the same time aircraft performance has been improved on every front and margins have had to be reduced: it is only by making full use of these modern methods that the accepted margins of safety have been preserved.

The paper reviews the processes which are currently used in the prediction and prevention of aircraft flutter in contrast to those of a few years back. The more recent types of flutter which have had to be considered are discussed briefly in relation to the methods which have been developed to deal with them. Ground and Flight testing methods are reviewed together with the use to which the results are put.

Finally there is a discussion of the increasing need to predict sub-critical response. The methods employed are discussed in relation to the more important problems.

It is now 13½ years since turbine engines first began airline service with the Dart in the Viscount. It is 11½ years since the de Havilland Ghost jet engine went into airline operation with the Comet. Today there are some 2468 gas-turbined aircraft operating (or on order) on commercial service and it would be interesting to look back over those 13½ years and ask the question, “How do we apply this experience towards meeting the requirements of the future?”

I can only speak with first hand knowledge of that part of the operation associated with engines produced by my Company. However, this is a sizeable sample covering over 50 per cent of the “Free-World’s” civil aircraft including propeller turbines, jet and by-pass engines.

The noise radiated from the intakes of turbojet engines during landing is already causing a serious nuisance. This paper, which is largely based on the deliberations of an ad hoc working panel of academic experts formed by Rolls-Royce in 1961, describes the characteristics of the noise and discusses possible mechanisms of generation. The noise appears to be dipole in origin, and to come mainly from the first two compressor stages. It consists of a few discrete tone components, generated mainly by the interactions which occur when one row of aerofoils passes through the wakes of a preceding row; and broad band noise resulting from the turbulence in the wakes and the inherent instability of the boundary layer on the aerofoils.

Some discrete tones may be eliminated over part of the running range by suitable choice of blade numbers and disposition. The broad band noise is unlikely to be reduced without major design modifications involving either a reduction of the air speed relative to the front stage blades, or removal of the boundary layer at their trailing edges.

The Working Party considered the objects of professional training and of technical education and the parts played by both academic studies and by practical experience; these deliberations led them to a consideration of how the Diploma in Technology helped to achieve these objects. The content of both the academic studies and industrial training parts of the Diploma course was studied. Conclusions reached included the following:—

1. (a) Close liaison between lecturing staff and professional engineers is vital.

2. (b) Standards of supervision and staff engaged in industrial training should be similar to those found in academic studies.

3. (c) The Training Boards should initiate bodies in which the industry and the professional institutions co-operate with colleges in the maintenance of standards of industrial training.

4. (d) Attempts to assess and grade students on their industrial training should be approached with caution.

5. (e) Suggestions are made as to the form of projects to be undertaken by Diploma Students.

6. (f) It is neither necessary nor practical to integrate each part of the studies and practical training in detail.

7. (g) The Working Party is whole-heartedly in favour of the sandwich arrangement of courses and makes suggestions for the best lay-out.

8. (h) Recommendations are made concerning the qualification to be given for successful completion of the Diploma in Technology course; it is concluded that this should differ from that given for the normal full time degree course.

The Working Party concludes by making recommendations for further action.

I feel greatly honoured having been invited to deliver the Second Handley Page Memorial Lecture and, indeed, grateful for the opportunity to pay tribute to a great Englishman and aeronautical pioneer, who for 40 years was my personal friend and, for over 30, my Chief. As no other man, he has decisively influenced the course of my life.

In this paper an experiment is described in which a detailed study was made of the flow field associated with a slender sharp-edged delta wing which was rolling steadily at zero angle of attack to an air stream. The investigation was made by performing two pressure surveys: first , one of the static pressure acting on the wing’s surface and second by measuring the total-head distribution in the neighbourhood of the wing. From the former the local rolling-moment coefficients, Clp, are evaluated and these are compared with the predictions for attached flow, thus assessing the contributions to the forces acting on the wing which arise as a consequence of the leading-edge separations. The second set of surveys is used to construct a picture of the flow-field details and this is compared with that known to occur on a similar wing when it is set at an angle of attack to the airstream. One interesting finding is that the secondary separation which appears to cause the discrepancy between the theoretical predictions and the measurements made on slender wings at incidence, is absent in this configuration and thus it is concluded that these data could be used for a more meaningful test of the theory.