This lecture is an attempt to provide a general view of soaring, including the views of the pilot, the meteorologist, the engineer, and the club. If this can be done, it will be easier for each specialist to recognise how he can best contribute to the advance of the pastime.

I think that the technique to build a glider has been available for several hundred years, but the knowledge and desire have only recently grown. The present state of gliding is due to advance in two ways, in art and practice, and in organisation. Perhaps I should not leave out science which is the record of the practice and of the experiments which have been made to improve the practice.

The purpose of this paper is to attempt a broad review of some of the factors that influence the economic development of a country and to illustrate in general terms the importance and the application of airborne survey techniques, as a means of collecting the information on which any sound development must be based.

The industrial and agricultural revolution that is now taking place on a world-wide scale demands a completely new approach to the problem of economic development. When economic development was slow and confined to small areas it was sufficient perhaps to base that development on limited information. Today, however, the pace is quickening every year, but the speed with which we are obtaining the information, on which such development must be based, is lagging behind.

Why is the present position different from any other epoch in world history? The main cause is the industrial revolution, which has produced rapid means of communication, by air and by radio. The Twentieth Century now lives literally as neighbour to the Stone Age.

The stability of a uniform cantilever beam subjected to an articulated tip load has been analysed as an equilibrium problem of static elastic stability. It was found there that the articulation of the connecting rod applying the tip load introduced additional component forces during the process of beam deformation.

It is quite impossible in the scope of a single paper to deal with more than a small part of the vast subject of aeroplane design. What I have attempted, therefore, is to work out a few points which seem worthy of particular attention, and thence to suggest what would appear to be the best practice.

It is probable that what I have done has been done already by most people who have been engaged on designing work for the last few years, and probably done more fully and more accurately.

The use of machine vision to guide robotic spacecraft is being considered for a wide range of missions, such as planetary approach and landing, asteroid and small body sampling operations and in-orbit rendezvous and docking. Numerical simulation plays an essential role in the development and testing of such systems, which in the context of vision-guidance means that realistic sequences of navigation images are required, together with knowledge of the ground-truth camera motion. Computer generated imagery (CGI) offers a variety of benefits over real images, such as availability, cost, flexibility and knowledge of the ground truth camera motion to high precision. However, standard CGI methods developed for terrestrial applications lack the realism, fidelity and performance required for engineering simulations.

In this paper, we present the results of our ongoing work to develop a suitable CGI-based test environment for spacecraft vision guidance systems. We focus on the various issues involved with image simulation, including the selection of standard CGI techniques and the adaptations required for use in space applications. We also describe our approach to integration with high-fidelity end-to-end mission simulators, and summarise a variety of European Space Agency research and development projects that used our test environment.

For the definition of the acccuracy of an internal strain gauge balance no general agreement exists. So it is difficult or even impossible, to compare balances from different manufacturers or balances used at different places.

Since most wind tunnel tests at least in the aeronautical field are done on a reference basis i.e. the results are compared with earlier results achieved with a more or less different configuration, repeatability is at least as important as absolute accuracy or even more important. So also repeatability, which in a physical sense is quite different from accuracy, must be defined and proven for each balance.

With the examples of several balances manufactured for the DNW (Deutsch-Niederländischer Windkanal) and ETW (European transonic tunnel) accuracy and repeatability definitions are discussed.

A proposal for a generally binding definition of accuracy and repeatability is given.

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.

Let us first consider the oscillations, in still air, of a monoplane wing whose aileron is supposed locked to the wing in such a way that it behaves as though it were an integral part of the wing structure. When the wing is displaced from its position of equilibrium and released it will, in general, vibrate both in flexure and torsion. The initial displacement may be purely flexural, but if the inertial forces called into play, over any wing section, produce a twisting moment about the centre of twist (i.e., the centre about which the wing section twists on the application of a pure torque at that section) torsional as well as flexural oscillations will be set up. Inertia, in general, robs the two kinds of oscillation of their independence, and, when they are interdependent, we may conveniently speak of “inertial couplings” between the two motions. In still air these vibrations must, of necessity, die down. One part of the wing may gain energy at the expense of another, but the store of elastic energy given to the wing by the initial displacement must grow progressively less as the wing does work against the viscous air damping and structural hysteresis forces.

The purpose of this note is to present some recently acquired data showing the effects of variations in the open area of slotted liners on the pressures on a twodimensional aerofoil at sonic speed in the 36 inch X 14 inch transonic wind tunnel at the NPL. The basic slotted liners for this tunnel have eleven longitudinal slots, giving an open-area ratio (σ) of 0.091. Other slot openings are obtained by closing appropriate slots with “Sellotape.” Nine values of σ ranging from 0 to 0.091, were used in this investigation. A wall static-pressure orifice, sufficiently far upstream of the model to be unaffected by its presence (3-6 chords), was used as a reference pressure for tunnel speed. The relationship between the Mach number given by this reference pressure and the true tunnel Mach number (M0), at the model location, was obtained by careful calibration.

A Discussion on the Relationships between Government and Aeronautics was held at the Society on 4th November 1965 with the President, Sir George Gardner, KBE, CB, HonDSc, FRAeS, in the Chair. Short introductory papers were given by Mr. Denis W. G. L. Hayiland, General Robert Lecamus and Brigadier General Ake Sunden. Introducing these principal speakers Sir George said how fortunate the Society was to have persuaded three such eminent people to open this Discussion; they were particularly grateful to their French and Swedish colleagues. General Sunden had graduated as an engineer and had been a pilot since 1934. He had served in a number of commands and had been a flying instructor and a test pilot. He was now a member of the Board and Director of Aircraft, Royal Swedish Air Force Board, which included responsibility for aircraft, armament, aero engines, airborne electronics and test flying.

General Lecamus was also an engineer and a pilot; he had served as an engine specialist in various duties, including three years as Head of the Engine Test Section at the French Test Flying Centre at Bretigny. In 1948 he had joined Direction Technique des Industriel Aéronautiques (DTIA) (which later became DTCA—Direction Technique des Constructions Aéronautique) as Deputy Chief of the Development Department and later had served as Chief of Inspection Services in Toulouse for the South West of France. He was now Director of DTCA.

Mr. Haviland had served throughout the 1939-45 War in the Army but he also had learned to fly. After the War he had been Principal, Control Office for Germany and Austria, becoming Assistant Secretary; in 1951 he transferred to the Ministry of Supply becoming Under Secretary, and from 1959-64 was Deputy Secretary, Ministry of Aviation. In 1964 he had joined Industry and was now Chairman and Managing Director of Staveley Industries Ltd.

The rate of progress in most technical fields, and propulsion is no exception, has increased so rapidly during the past 50 years that it is becoming difficult to predict the trend of development for more than a few years ahead. On the other hand, there are fundamental limits to progress in certain directions and it is within these limits that this paper is written. One must, of course, devote some thought to the validity of the limit. Not so long ago it was thought that the speed of sound would be a limiting speed for aircraft, for instance. One cannot go far wrong with the basic laws of physics and the intention, at least, of this paper is not to transgress such laws.

In terms of cost, BEA estimate this to be worth over £3 000 000 a year or, putting it another way, 7% of the revenue we receive has to pay for unreliability.

No specific allowance is made for the rectification of defects in the scheduling of aircraft during its turn-round time and to cover this we aim to schedule two stand-by Tridents, two Vanguards, one Comet and three Viscounts for their respective fleet sizes, so that if the snags are anything but minor, the stand-by aircraft take over while the defective one is rectified.

The EEC Treaty gives a good deal of prominence to transport policy. Among the activities of the Community specifically listed in Article 3 is Article 3(e)—‘the adoption of a common policy in the sphere of transport’.

There is a whole Title devoted to it, consisting of 11 articles (Articles 74-84), and the title is included in Part Two of the Treaty which is entitled ‘Foundations of the Community’. Yet on 5th June 1973, speaking in the European Parliament, the Commissioner responsible for transport (Mr. Scarascia Mugnozza) said:

‘… without wishing to detract from the progress already achieved, particularly when it is viewed in relation to existing difficulties, we must nevertheless frankly and objectively admit that very few of the aims of the common transport policy have been achieved.’