This paper is intended to supplement a part of the paper by Mr. F. W. Armstrong on ‘The aero engine and its prospects—fifty years after Griffith’. It deals in more detail with Dr. A. A. Griffith's early ideas on the aerodynamic aspects of turbomachines.

Even with reasonably optimistic use of materials and operating temperatures it was essential in 1926 that very high component efficiencies were obtained to make the gas turbine competitive with the piston engine on fuel consumption. Griffith believed that efficiencies of over 90% could be obtained for the compressor and turbine components, if the correct attention was given to the aerodynamic design of the blades. His 1926 report on ‘An aerodynamic theory of turbine design’ showed how such high efficiency designs should be carried out and gave appropriate formulae for the compressor and turbine efficiencies.

Three qualities come to mind as seeds for success in civil aircraft engine design over the next two decades—care, optimism and judgement; care to exploit and extend the technology of the high bypass ratio fan engine, optimism to continue to seek apparently unconventional concepts, and judgement to identify the opportunities when each should be applied.

This paper accepts this definition of the engine designer's choice and reviews a range of possible trends, some more likely than others. It is in two parts. The first, entitled ‘Conventional Engines', concentrates on the family of high bypass ratio single stage fan engines which has become established as the preferred design for application to aircraft cruising at high subsonic Mach numbers.

The purpose of this paper is to provide a view of air freight developments over the next decade.

Before we try to do that, it might be very useful to look back over the past 10 or 15 years to see where we are and to develop some understanding of how we got into the position that we find ourselves in today. Therefore, we are going to go back over the past 15 years and review the economic situation and assess the impact of selected air freighters in an attempt to develop some guidance in forecasting what we might look forward to in the next 10 years.

There can hardly have been a time in the history of Britain where a national consciousness of the importance of design to the future economic health of the nation can have been more needed. More investment, more wage restraint, a ‘fair day’s work’ and all the other matters about which we are exhorted would be of little avail if the products which we must sell to the world if we are to survive are not better, in the broadest sense of the word, and how can a product be made better if not by design?

Opinions have been expressed in the past by such eminent people as the Duke of Edinburgh and E. A. Gibson and the NZ Civil Aviation Authority to this Society that there is a need throughout the world for an airborne equivalent of the tractor, or Land Rover. Current observations and market survey confirm that there is an expanding market in which this new aircraft has a huge role to play in agriculture and general land development because the existing specialist crop sprayers and converted conventional aircraft can only play but a part.

The purpose of this paper is to describe a new component for spacecraft. The subject is not quite new in that the author presented a paper (Ref. 1) on the subject this year.

The original idea for the device came from thoughts about an extension beyond the terms of reference of a study contract. After a proposal had been made it became apparent that Cloutier of Hughes Aircraft had made a remotely similar proposal, but apart from its mention in some letters, no publication has been seen by the author.

This paper can be divided into four parts; firstly, a tribute to R. K. Pierson, then a brief historical survey of events that have affected the RAF and industry, leading up to where we stand today; and finally, some thoughts on the future based on the twin aims—which I am certain you will endorse—of maintaining a healthy and viable aircraft industry in the United Kingdom, and of satisfying the future needs of the Royal Air Force at the lowest possible cost. I am going to concentrate on the military side.

Airline efficiency is not a simple concept which can be measured by a single parameter. It is an amalgam of complex relationships which are in turn the results of many different activities. Probably because of this, efficiency criteria are mostly looked at in isolation which results in the overall concept of airline efficiency remaining nebulous. In fact the airline efficiency concept possesses a number of different but inter-related aspects. Figure 1 is a diagrammatic representation of the airline efficiency concept and depicts the various aspects and relationships which go to form it. This diagram portrays, in basic form, the major forces involved.

My experience qualifies me only to discuss maintenance aspects of our operation, and I feel very strongly that we in British Airways Helicopters have been forced into developing major design modifications in the past and that insufficient time and experience has been left over to devote to improving our maintenance philosophies and systems.

This was inevitable in the early days, but I now wish to make our position perfectly clear. We, in engineering, are predominantly in the maintenance business and our development and research time will become more and more biased towards maintenance problems.

Since the advent of air transport half a century ago, safety has been a dominating influence in aeroplane design. It is by no means the only factor. The successful designer is one who uses his talents to arrive at the best balance between the competing demands of speed, reliability, comfort, and cost, while satisfying the demands of safety.

The fundamental reason why the aeroplane places high demands on the designer, perhaps to a greater degree than is the case with surface vehicles, is that the aeroplane proceeds on its way in defiance of gravity. It has to be light enough to fly, and it cannot stop for running repairs. Working within the limitations of available materials and fuels, it took mankind a long time to discover how to make an aeroplane light enough to fly at all. It is a near miracle that some 70 years later, today's aircraft carry large loads for long distances with remarkable safety.

This paper is intended to illustrate some of the new features of design management which are likely to be particularly important for the large, high technology organisations.

The two subjects that have been chosen for discussion are co-operation, both national and international; and diversification. The need to consider both of these subjects arises from the same cause; the general economic climate and the increasing complexity and cost of high technology projects. The complexity and more particularly cost mean that no one organisation or even country will tackle them alone—hence the need for co-operation.

Many investigators have studied the rolling-up of the vortex wake behind a wing of finite span. The earliest step in this study was the work of Kaden who found an analytical solution for the rolling-up with time of a semi-infinite, straight, two-dimensional vortex sheet. This solution must represent the situation very close to the edges of a finite-span vortex sheet of zero thickness, in two or three dimensions, during the initial stage of the rolling-up process. An important result following from Kaden’s work is that, from the very onset of rolling-up, due to the infinite velocity at the sheet edge, a spiral of near-axi-symmetric form, with an infinite number of turns, is established at the edge. This is a consequence of the assumption of zero thickness for the sheet.

Over the years, the evolution of legal and contractual relationships between the suppliers of equipment and their customers has been fragmentary. Fiscal incentives for the supply of economical equipment have been rare, while incentive contracts for developing military equipment have been the cause of some controversy, particularly as regards allowances for inflation.

Immediate interests have tended to take precedence over longer term characteristics, which are often of more importance to customers. Relative merits of rewards, penalties and other motivating factors have received little attention in the literature, and philosophical considerations have been neglected.

The small deflection/initial buckling behaviour of elastic, homogeneous plates is characterised by the absence of coupling between in-plane and out-of-plane quantities, i.e. stress couples, shear strains etc. By contrast, heterogeneous plates, of which generally laminated plates are an example, exhibit ‘shell-type’ behaviour in as much as in-plane and out-of-plane quantities are coupled. Reissner and Stavsky were the first to correctly formulate the field equations for such plates. Since that time a large number of papers on the influence of coupling on the behaviour of many different types of laminated structural elements, such as beams, plates and shells have appeared in the literature. However, it appears that until quite recently, the analysis of these structural elements in the presence of a general (Winkler/Pasternak) elastic foundation has not been undertaken.

It is now over twenty years since the first experimental inertial navigation system was built and tested in America, by MIT. Over that period inertial navigation has come of age as a technology, and many thousands of inerital systems are in service in civil and military aircraft.

Ferranti Limited have been active in this field over 15 years, developing and producing both the basic inertial instruments and complete systems for a range of aircraft and space applications. The first system was produced for the TSR-2, which was cancelled at the prototype stage. But a first generation production system has now been in RAF service for some time. A second generation system, now at an advanced stage of test and development, will equip the European Multi Role Combat Aircraft (MRCA). A version of the same system has been adopted in Japan.

This paper deals with two operational aspects of civil aircraft design of major interest to Operators and Pilots,

1. (i) Flight Control Systems and

2. (ii) Information Requirements.

The first of these describes the problems encountered in our 10 years experience of autoflight, and the operational requirements arising from this, while the second describes the problems caused by the limitations in the availability and display of information to the pilot, and proposes improvements in three areas.

The aim of this paper is to trace the evolution of the flight documentation of Concorde, with special emphasis on crew operating procedure, and to make some generalised predictions of the impact of recent technology on the methods of operating aircraft in the future.

The overall process of Concorde certification has been described elsewhere, the aspect with which we are concerned here being the approval of the aircraft’s operating procedures. The generation of these procedures is an involved process, one which started for Concorde in December 1967, with many possible difficulties foreseen in the aircraft operational sphere and neither of the prototypes having flown.

The preceding symposium papers have indicated the saleable developments on offer in the constituent parts of the civil transport system and their collective impact in aircraft project terms is covered in the paper by Brown and Lawson.

As the aircraft industry matures performance gains come less readily and costs have become a much greater determinant of progress. This paper therefore considers some of the fundamentals of cost reduction. This topic cannot be considered in isolation; cost reductions must be balanced against product effectiveness and there are major interactions between possible cost levels and sales volume. Thus, it is necessary to treat the subject in the broader framework of commercial viability. This paper attempts this task. It starts with the more direct cost questions, considers market interaction factors and concludes on a positive note by a critical review of the investment decisions needed, many of which are urgent and of critical importance to the future of the industry.

It is only fifteen years since the hovercraft principle and early configurations were first described in Ref. 1. Since then, we have seen the development of a wide range of craft and many applications in both civil and military roles.

This paper gives a brief review of the performance capability of the Mountbatten Class SR.N4 amphibious hovercraft which are currently operating on the English Channel ‘short sea’ routes and indicates the improvements anticipated from a simple but substantial lengthening of the craft. A contract has now been signed with British Rail to lengthen both of their craft, and design and manufacture work is now in progress. The first craft returns to BHC in December 1976 and will be back in service in its modified form by December 1977.