When you heard the title of my paper you were probably disappointed. Indeed, other lecturers have already discussed very similar subjects on this same occasion. To recall the most recent:

• I. G. Bloch in 1963: “The Aeronautical Industry in the Europe of Tomorrow”

• Mr. Handel Davies in 1968: “Some Thoughts about the Future of European Aeronautics”.

• M. Louis Giusta in 1969: “European Co-operation in the Aviation Industry and its Future Development”.

On reading again these three papers, I was struck by the pertinence of most of the points which were made. In that case, one may ask, why refer to them again? The reason is that many predictions have failed to materialise and many warnings do not seem to have been sufficiently heeded.

The testing of model rotors in closed throat wind tunnels is known to present major problems in the form of tunnel wall interference when operating at low speed. However, it is precisely this region of the aircraft's flight envelope which is of prime importance when investigating areas such as transitional flight, hovering in winds and tail rotor performance and handling qualities. Although much work has been carried out in the past to determine wall interference factors for various model and tunnel configurations, there still exists a problem of flow breakdown due to the presence of tunnel boundaries, for which no corrections are possible. The aim of this experiment was to conduct a short and simple investigation, first to identify the flow breakdown condition for a finite sized rotor in a closed tunnel, then to assess the feasibility of at least delaying the onset of this limiting condition by selectively removing panels from the walls of the working section. Since the experiment was designed only to study gross flow effects, no attempt was made to include wall interference factors.

For years, the development and testing of aero gas turbines has been hampered by the inability of development and test engineers to perceive and readily measure the positional changes of static and moving components within the engines due to the opaque nature of the engine casing walls. ‘Touch’ or abradable probes have been used but require special engine builds to employ them.

With the introduction of high strength materials and the thinning of engine structures and as the performance requirements have become more demanding, small component movements during engine handling have become more important. This is particularly true in areas where the airflow has the greatest work potential such as the tip and root seals of the high pressure turbine and the root seals of the final compressor stages.

The subject of this paper is the interaction between airborne and ground attack missions by aircraft, and the defence systems now available to deny or counter such attacks. I should like to make it clear from the start that I am restricting myself to air operations in a non-nuclear land battle scenario and I speak not as an expert in attack missions, but rather in a historical and speculative fashion, as one who has been concerned with some of the techniques concerned with air defence.

You may, from me, expect a highly biased approach to the subject of the paper and probably you are right, but I should warn that if you expect me to conclude that the aircraft is doomed then I must reassure you that I believe that the aircraft remains a most flexible instrument of warfare and will for the foreseeable future exercise an extremely important position in the land and air battle.

Since 1946 I have been convinced, from the viewpoints of safety, economy and simplicity (facilitating calculations and development) that the most rational solution to nearly all aircraft propulsion problems is the Fixed Shaft Constant Speed Variable Torque Turbine.

But as the engine manufacturer is not the only judge of the propulsion systems adopted by the airframe manufacturers, I have been and still am therefore obliged to manufacture engines, the technical and commercial success of which I do not deny, while being convinced that more rational solutions exist. Because of this Turbomeca has manufactured, and continues to manufacture—alone or in co-operation with other engine manufacturers—free turbines, pure jets and twin shaft by-pass jets, engines which I do not propose to discuss today.

Flight Simulation has made good steady progress over the years, and is now being given significant credit for its ability to reproduce aircraft flying qualities in a device on the ground. However, the simulator world is tending to claim too much credit for its present level of achievement. This talk is an attempt to review the present state of the art against an accurate comparison with aircraft flying qualities, to highlight the deficiencies and to appeal to the users of simulators to consolidate their present gains before proceding further. This paper deals only with civil fixed-wing transport aircraft above 20 000 kg maximum weight.

In giving this paper, my aim is to give an outline of the practical aspects of flight tests performed with a Bo. 105 helicopter, in the speed range of 100 kt to 220 kt, rather than to dwell on theoretical explanations for the results obtained, which have been dealt with in Refs. 1 and 2. In a short paper of this nature it is not possible to deal in detail with all aspects of such a test programme, so I have selected some results which I hope will be of interest. A number of similar investigations have of course been performed with other helicopters during the past, albeit not with this type of main rotor system, and to those who are familiar with these flight programmes I must apologise for not bringing any startling new discoveries.

The greatly increased cost of fuel has intensified the need for the manufacturer to increase operating efficiency in the aerodynamic, structural and propulsion fields. These aspects have already been highly refined and further improvements will be more and more difficult to realise. However, DOC is also equally affected by equipment and crew costs and this paper therefore attempts to examine the potential for improvements to the flight deck that will determine the most cost-effective combination of crew and equipment required for the safe operation of relatively large transport aircraft.

In the past, design effort has, very logically, been concentrated on those fields that could be shown to give an obvious economic return, and since investment in new instrumentation, flight deck workload analysis and system automation showed less tangible results than increases in speed, range, payload, etc, there was no great incentive to allocate money and effort to “human engineering”.

If I may I will begin with a few words of explanation and apology. It is always difficult to talk about helicopters to an audience not familiar with their peculiarities and it is doubly difficult to do so in a Memorial Lecture. For, although the helicopter industry has and has had its great men, they are few in number compared to those who made their names in the traditional field and it is not easy to find a direct connection. Indeed it is not unknown for the leaders of the fixed wing industry to be violently opposed to the helicopter in any shape or form. Fortunately I have not been able to discover such antagonism on the part of J. D. North; equally I have been unable to find that he was a supporter of the helicopter. Therefore I cannot begin in the traditional manner of a Memorial Lecturer by showing some sketch or brief excerpt written by him which will illuminate precisely the points it will take me ten pages to say. But I have been made very conscious of North's abilities and hope to pay some respect to him indirectly by laying emphasis on helicopter control.

Many thousands of words have already been spoken and numerous papers written extolling the virtues of fly-by-wire and the control configured vehicle. Most of these issue from control system specialists and avionics engineers anxious to sell their new technology. Aircraft designers and development teams, including test pilots, must adopt a cautious approach to these new developments and ask the questions “What has it to offer?” and “What's the catch?”.

We must always balance performance rewards against development risks, ensuring that the risks are carefully evaluated and that we do not suffer from what the Americans call “Second Degree Ignorance” (we don't know what we don't know). If we can define the development problems, we are well on the way to solving them; if they remain obscure then the benefits will elude us. If the risk outweighs the reward a conservative solution must be adopted; it is this consideration that so often makes us, like Hamlet, “rather bear those ills we have, than fly to others that we know not of”.

It is shown that the trailing vortex wakes generated by large aeroplanes can cause serious upsets (loss of control) to smaller following aircraft that may encounter them and may damage buildings near an airport. The increase in separation behind big aircraft imposed as a safety measure leads to a serious loss of runway capacity.

After discussion of the nature of wake vortices, it is demonstrated that they may be attenuated, so avoiding unnecessary separation between aircraft at an airport and, at the same time, obviating ground damage.

Discussion of alternative devices available for moderating the vortex wake indicates that practical solutions may be confidently expected.

This is a story of trouble and action—of an industry's trouble—of a company's, and in particular a division's actions, to ensure that there would be, in fact, a path to the future. The future, it turns out, probably will never be quite the same as the past—and I will cover some of that too. I have titled the three parts of the story Reduction in Cost, Increase in Sales, and Results and Comments.

Part of the material contained in this paper was originally written in early 1972 when I was Vice-President and General Manager of Boeing's largest commercial division, the one with which the paper is primarily concerned. The material was written for presentation to the management of another company in serious trouble. The story is that of a traumatic series of years in the life of one of the world's major companies. It is viewed of necessity from my position at that time as head of the company's largest division and does not constitute an official history of that period of life of The Boeing Company, even though some of the charts apply to the company as a whole rather than to just the division involved.

Occasionally, in the midst of satisfying customer requirements, we have to assess whether or not we are really making progress in terms of achieving more effective helicopters. We should identify both the areas which offer the greatest potential for improvement and those in which improvement is the most required. Then, we must decide on the amount of effort we will put into improving these areas.

The purpose of this paper is to record the structural design experience obtained during the construction of the Puffin aircraft. The paper starts with some fundamental considerations, follows by outlining the specific solutions adopted on the Mk I and Mk II versions of the Puffin, and concludes with some suggestions on future structural development possibilities.

I am breaking new ground—new ground to me—in addressing the Institution of Engineers and Shipbuilders in Scotland, since I am a dyed-in-the-wool aeronautical engineer and my professional contacts with your part of the world have been largely with Scottish aeroplane and missile activities; I know less than I should about your shipbuilding and general engineering scene apart from occasional excursions to the NEL at East Kilbride.

Non-destructive testing (NDT) is not a new procedure and it is not intended that, by choosing the thirty odd years since the War, the impression should be given that before 1945 little or no attention was paid to determining component, system or structural quality by non-destructive means.

Archimedes, having discovered the principle of flotation, applied it as a means of determining whether his King's new crown had been unduly alloyed with silver. He is therefore probably the first on record to practise what is now known as NDT.

The noise nuisance caused to communities around airports is one of the greatest problems besetting present-day civil aviation. Considerable effort is being expended to meet the challenge of lessening the nuisance without impairing the continued development of air transport. Governments, operators, manufacturers and research institutions are all playing a part. In addition to local regulations designed to control noise near specific airports, legislation based on international agreements has for some years required new types of subsonic jet airliner to be certificated as meeting given noise levels. Currently, the successful development of “hushkits” is enabling many older types to be brought within these levels. At the same time, it appears likely that still more stringent limits will be set for new types as the future unfolds.

I would like to begin by suggesting a small but important correction to the title of this Symposium. We must not refer to “the UK”, which infers the islands and surrounding coastal waters, but to the entire area for which the United Kingdom has search and rescue responsibilities.

The ICAO Convention, to which we were signatories in Chicago 1947, laid down that “Contracting States, separately or jointly, shall delineate Search and Rescue Areas for which they will be responsible, and establish one Rescue Co-ordination Centre in each”.

This Agreement went on to recommend that the areas might extend beyond national boundaries, by agreement with neighbouring States, and, as the Search and Rescue Services were to operate in close conjunction with the Air Traffic Services, there would be mutual operational advantages in having the Flight Information Regions and Search and Rescue Areas co-extensive.

The subject of the quiet helicopter is receiving increasing attention throughout the world because it is now established that a helicopter can be made quiet. Quietening is also needed as more helicopters are being used over cities and residential areas. To date, little attention has been paid to helicopter quietening because the emphasis has been on achieving maximum payload and other performance. Now that the basic helicopter design has been established, refinements for quietening are becoming practical. The comparison is much like the evolution of the automobile and the truck in the city. Initially these vehicles were noisy. As their number increased and their design evolved, mufflers and sound-deadening materials were skilfully applied to reduce their noise to more acceptable levels for each type vehicle.

The ideal of high speed centre-to-centre inter-city air transport remains unrealised with the problems of poor economics and excessive noise dominant and still largely unsolved.

Economics hit particularly hard at VTOL aircraft. Thrust/weight ratios in the order 1·15:1 are necessary with the result that total installed thrust is much larger than is required for the cruise condition and payload and range suffer. It is therefore tempting to compromise and go for a STOL solution and current trends are in this direction.