There is no question that the distinguished Rumanian inventor and aircraft designer, Henri Coanda (1886—1972), was a highly gifted and creative man. Many called him a genius. There have been at least five lengthy feature articles in various aeronautical or true adventure magazines extolling his remarkable career and bearing such flamboyant tides as, ‘The Jet-Propelled Genius and His Mighty Blow’ (True, December 1956); ‘The Amazing Dr. Coanda’ (Air Progress, August/September 1965); and ‘The Prowling Mind of Henri Coanda’ (Flying, March ] 967). These articles rightly praise Coanda’s multi-faceted pioneering achievements in pre-fabricated houses, soil regeneration, sea-water desalinisation, solar energy, the discovery of the ‘Coanda Effect’ which is well-known to aerodynamicists, his highly innovative aircraft designs such as a twin-engined machine of 1911 (also proclaimed by some as a world’s first), a vertical take-off aircraft, the 1934 ‘lenticular aerodyne’ (otherwise known as a flying saucer), and so on.

Traffic growth and the replacement of the older, less efficient and noisier aircraft—60% of Western World capacity may be regarded as in this category—provide the opportunity for applying new technologies to subsonic commercial transports. Reduction of operating cost continues to provide the major incentive, though increasing emphasis is being placed on low fuel consumption and low noise.

In this paper, the term ‘advanced technology’ is taken to embrace significant engineering advances which are not commonplace on aircraft flying today. In general, it is wrong to think of such advances as new inventions. Almost without exception they have evolved over the years, with few quantum jumps. There are, of course, exceptions to this and a recent example as regards engine development might be the introduction of high bypass ratio engines in the late 1960s, which brought about a 25% improvement in specific fuel consumption. However, even this major step could be regarded as an evolutionary development from engines of bypass ratio about 1·0, which themselves had conferred significant gains relative to the straight turbo-jet engines of the late 1950s.

Multiple redundant flight control systems have been the subject of continuous development since the 1950s. Early examples include the automatic landing systems of the BAC 1–11 and the VC10; these were followed by the full flight envelope control systems fitted to the Concorde and Tornado. These examples all use analogue computing techniques, with redundancy levels appropriate to the individual fail-passive or fail-operational requirements of each system.

However, recent advances in digital technology have enabled highly sophisticated flight control systems to be implemented which would be wholly impractical using analogue computing methods. Furthermore, digital computing is amenable to self-monitoring techniques which can be used not only to improve system maintainability, but also to augment the cross comparison or majority voting algorithms which have been developed on analogue systems.

Although hundreds of moving base simulators exist in the world today, there is a paucity of objective and quantitative methods of assessing the necessity for, and the effectiveness of the motion provided. This paper describes a quantitative method of assessing the effects of motion on an aircraft simulation when there is short-term interactive control of the aircraft by the pilot.

The author and colleagues at the University of Sussex have been investigating technical problems related to the production of moving colour pictures representing real scenes in real-time. The object is to produce a visual system suitable for vehicle simulation. Flight simulation is generally the most difficult to achieve because of the need for freedom of movement and orientation in three-dimensional space coupled with a rapidly changing scene.

Such a system must therefore show smooth motion and reasonable realism. These factors imply a picture update rate of around 25 frames per second, the use of a wide range of colours and textures, a large terrain model, a picture generator capable of representing surfaces and a good mathematical aircraft performance model.

The title of this presentation is, perhaps, wider than the title of the section of the symposium within which it is placed. It is intended to move from the general aspects of aerial photography and other airborne remote sensing devices to the particular aspects of pest forecasting and control using this technology.

The quality of aerial photography has doubled every 10 years since the technique was first introduced, and it is believed that this improvement may well continue for the remainder of this century. It is probable that multispectral photography and improved photographic representation of near and far infra-red imagery will greatly improve during the coming decades. As more research is done on more freely available material, so shall we find more applications for it, including, without doubt, those in the field of pest control.

The scope of the subject is a challenging, if not a forbidding, one. It is to trace the evolution of routes, capacity, charters, designation and rates from Chicago to the present day. Collectively, these issues encompass the question of governmental regulation of the international air transport market and embrace the total air transport system. However, there is no attempt to catalogue the specific of these policy developments worldwide. Rather, it is attempted to analyse the foundations of international aviation policy, in a shorthand steeplechase through the past, present and into the future and, in this way, to offer some interpretations of the developments over the past thirty years. In so doing, it is hoped to place in perspective the complexity of the international system and the many interrelated factors which must be taken into account by those who bear the heavy responsibility of determining national policies.

The keynote address given by Mr. Chouffot to this convention summarises the reasons for the growing concern of the airworthiness authorities and industry alike for the structural integrity of ageing civil transport aircraft and the measures taken to ensure their continued safety.

This paper explains in greater depth the background for these concerns and the actions taken.

I would like first to briefly review the airworthiness philosophy underlying the structural development of presentday aircraft.

Structural integrity is a key ingredient of aircraft design. It takes its place alongside flight performance, operational effectiveness, reliability, maintainability and economy in determining, or contributing in very large measure to, the success of a project in service.

What is expected from the contractor for a new project in respect of these qualities is set down by the customer in a specification which includes reference to a set of mandatory design requirements. Thus, flight performance parameters such as speed, range and payload, are defined in the specification : there too is to be found a description of the sorties to be flown, numbers and types of manoeuvres and their severity (conventionally including the levels of normal acceleration) and the regions in which the aircraft is required to operate. Sufficient detail is given to establish, as the process of design evolves, the loading and environmental conditions to which the structure will be subjected.

In this paper, the various facets of Kron’s eigenvalue method which have been developed over the past decade by the present writer are drawn together for review purposes and to provide solution algorithms for large scale eigenvalue and response problems which arise, for example, from the need to study large order finite element models in the frequency analysis of ship equipment raft structures. Also included are considerations of eigenvalue sensitivities which are found to be readily calculable by means of simple modification of the basic eigenvalue method. These sensitivities are of importance in the study of vibration transmission paths and hence in the design and positioning of optimum anti-vibration mountings (AVMs).

Although the latest aircraft flight simulators incorporate much recent technical development and are becoming increasingly accepted by the world's airlines, government regulatory agencies and air forces for pilot training and checking, there does not exist any completely satisfactory objective method for assessing their realism. If an objective method of measuring the realism of an aircraft simulator could be developed, it might be possible to reduce the often lengthy period needed by the simulator manufacturer in making final adjustments (tweaking) before customer acceptance, or to monitor the realism in service (15 year service life being typical), or to achieve the same degree of realism with equipment of a significantly lower specification and therefore much lower cost.

No eighteenth century designer of flying machines surpassed Melchior Bauer in imagination and aerodynamic insight. Born on 19th October 1733 at Lehnitzsch, a village near Altenburg, he was the son of a gardener, Hans Bauer'1'. Little is known of his life, but in 1763 he went to London, where he sought patronage from the recently crowned King George III for the construction of a man-powered aircraft. According to his own account, he got no further than the official scribe who refused to copy out the submission, saying that even if he were offered £500 he would never agree to send such folly to the Court. ‘If you could do all that you claim,’ said the scribe, ‘you would certainly be the foremost and greatest man on earth.’ [1 r](2).

Nobody would deny that a major objective of the peoples of the world is to improve standards of health and hygiene and an essential part of this must be to increase the quantity of food produced. To do this it is essential to use supplementary nutrients and exercise effective pest management. It has been shown that the yields of basic foods, such as rice, can be doubled by using the right seed strains, fertilisers and crop protection techniques. Crop yield losses because of insects alone are estimated at 5% in Europe where insecticides are used widely and as much as 21% in Asia where insecticides are used only in a few of the better organised cultural areas.

Experiments in the wake of a circular rod at a Reynolds number Re=5·104 have shown that single vortex-like structures can leave the wake and may be detected in the ambient potential flow. This experimental finding suggested the theoretical investigation of the interaction between a vortex and a shear flow. Lin has calculated the average acceleration acting on the vortex at the time t = 0. In the following a finite-difference scheme is described which, in detail, determines the local components of the acceleration and the temporal development of the flow.

During the past decade the UK Accidents Investigation Branch has been involved in the investigations into three major accidents to public transport aircraft, each caused by catastrophic structural failure in flight. During the same period other accidents involving structural failure with less structural damage, but with potentially equally serious consequences, have been investigated.

As early as 1714, when he was 26, Emanuel Swedenborg (1688-1772) showed an interest in the possibility of building a flying machine. Writing from Rostock on 8th September 1714 to his brother-in-law Erik Benzelius, he ambitiously listed 14 inventions which he had under way and about which he had prepared manuscript notes. The projected inventions included ‘a kind of flying chariot, or the possibility of being sustained in the air and of being carried through it’. Two years later, in 1716, Swedenborg founded Sweden's first scientific journal, Daedalus Hyperboreus, in the fourth number of which he anonymously published a short article entitled ‘Utkast til en Machine at flyga i wädret’ (Sketch of a Machine for Flying in the Air).

An experimental study was undertaken to measure the instantaneous lift and propulsive forces generated by a rigid, sinusoidally flapping wing at Reynolds numbers ranging from 72 000 to 120 000. The wing was flapped about a fulcrum at the root at frequencies of 2.55 Hz and 3.30 Hz. Instrumentation and a data reduction system were developed to provide quick and reliable assessment of the effects of changes in flapping amplitude, flapping frequency, flapping plane angle, wing incidence, and windspeed. In this way it was attempted to model, however crudely, the forward flapping flight of birds.

The instantaneous values of lift coefficient and thrust coefficient were plotted against position in the cycle while the average CL and CT were plotted against advance ratio (ratio of the windspeed to the maximum tip speed velocity). The experimental results were compared to the theories of Walker(e) and Hoist ' Kuchemann(4) both modified to correspond more closely to the experimental conditions.

The relevance of this subject to the theme of today’s discussions lies in the fact that the universities play an important part in aerospace research and that significant research in the field of flight simulation can easily lead to the requirement for rather costly equipment which universities usually find difficult to obtain. This may well have been one of the major stumbling blocks preventing the universities from taking a more active part in flight simulation. The outsider may perhaps wonder why it seems to have been possible in the past to avoid some of these difficulties in the Netherlands.

Twenty-one years ago, a small group of people who were very dissatisfied with the state of the art of aerial crop spraying, met over coffee in the sitting room of Mr. Foster's home near Heathrow. Inevitably, one of the topics discussed was the need for better crop spraying aircraft. The most important outcome of that (and several subsequent meetings) was the formation of the Agricultural Aviation Group of the Royal Aeronautical Society, now celebrating its majority. Of that group I was, and still am, the one who knew least about aerodynamics or aircraft design. However, as the last remaining founder member of this Group, perhaps it is not entirely inappropriate that I should take one last look at the future of spray aircraft design, before removing myself from the scene.

The general theory and formulation of Part 1 can be applied to a whole family of element shapes. However, quadrilaterals and triangles which are compatible with each other are found to be most useful in idealising general structures. The lowest order polynomial shapes of this kind which are generally curved are the ‘biquadratic’ quadrilateral and the ‘quadratic’ triangle. These have nodes (or nodal pairs for the sandwich elements) situated at the corners and the mid-sides of the ‘parent’ elements. The quadrilateral therefore has eight nodal pairs.