The introduction to a book called “An Anthology of Partly Baked Ideas” states that it was compiled to provide an opportunity for the publication of ideas either half or partly baked, which might not otherwise be suitable for publication in established learned journals.

However, the Royal Aeronautical Society's decision to solicit articles on aeronautical achievement in the latter half of the twenty-first century is a direct invitation from a learned society to expound on, what at best, can only be some very partly baked ideas.

The author of this admirable anthology, I. J. Good, has defined partly baked ideas (PBIs) in some detail in the opening chapters where he gives a clear indication that reputable scientists and engineers should at very least endeavour to incubate their proposals to the point where the degree of “bakedness” should be greater than 0·5, i.e. better than half-baked.

In considering the spectrum of possibilities which advances in electronics offers during the next fifty years it is worth a short backward glance over an equal time span.

In 1918 the use of electronics was almost entirely devoted to developments in the radio frequency field, principally those of communication and sound amplification. Wireless telegraphy under pressure from naval and merchant marine requirements had reached the stage where it formed a dependable means of communication, albeit with the need for specialised human skills, for the world's modern shipping.

There had been a limited amount of aeronautical radio development during the war, to reduce the size and weight of wireless telegraphy and the later radio telephony transmitters; much of the later stages of this work was carried out at Biggin Hill. However, these developments had scarcely any influence upon either the design and construction of aircraft or perhaps more important only a small influence on their operation. It was to be sometime before the exploitation of the radio frequency spectrum on the ground and in the air contributed to increase greatly the operational capability of the aeroplane during the 1930's.

Orbital manoeuvres by means of impulsive thrusts, such as those available with chemical rockets, are well known, but a different treatment is needed for the small, continuous thrusts that are typical of electrical propulsion systems. It is shown that with the aid of these small forces it is possible to change independently all the orbital elements of a spacecraft, and thus to proceed slowly from a given orbit to any other. For each manoeuvre there exists an equivalent velocity which depends only on the initial and final orbital states, and which can be related directly to the spacecraft propulsion parameters.

For any form of propulsion where the propellent acquires some or all of its energy from a separate energy source, as in electrical propulsion, it is found that optimum time-varying relations exist between the flow of mass and of energy, which may also be expressed in terms of the exhaust velocity and the thrust. In particular, the optimum exhaust velocity is shown to be an increasing function of time, related to the way in which the energy is released.

The practical realisation of electrical propulsion depends on the development of efficient propulsion units and of lightweight power supplies; these and other spacecraft components are discussed, and a number of examples of orbital manoeuvres are given, including close-Earth, far-Earth and lunar orbits. The paper concludes with a discussion of these orbital transfers in relation to their possible uses, including communication satellites and a test of relativity theory

The design of aircraft subjected to kinetic heating is the same as any other structural problem. First, the loading condition must be determined, then the structure has to be designed to withstand that condition and finally the design must be confirmed by test. This lecture follows this pattern and does so in the same order.

The source of the energy that is transferred to the structure is the aerodynamic boundary layer and a study of the boundary layer forms the main part of the lecture. During the past few years a large amount of work has been done and the Society is proposing to issue Data Sheets this year to replace those issued in 1955. The same work forms the basis from which the present proposed values of heat transfer coefficients are obtained.

The Air Ambulance of New South Wales came into operation on Good Friday 1967. Less than sixteen months later as I write it has carried 2348 patients in 807 flights. Four hundred and eleven of these patients have been emergencies and it is highly probable that most of them would not have survived a long distance road journey. With few exceptions all patients have been sent in by country doctors for specialist treatment in the metropolitan area.

Introduced as an Air Arm to the excellent road ambulance service it was intended to avoid the road journeys for distances of more than 175 miles. In the first year it saved that service 932 760 road miles. The time that patients would have spent on the road was 16 201 hours, this was reduced by air to 3 094 hours.

It is hardly necessary to add what this means to a sick or injured person. Although deeply unconscious and in a state of shock patients have been transported without their condition deteriorating.

In delivering the 1968 British Commonwealth Lecture I am conscious of the honour bestowed upon me by the Council of the Royal Aeronautical Society and mindful of the responsibilities attached to addressing such an eminent body as are assembled here tonight.

My subject—The Development and Future of Air Cargo—is, I believe, worthy of our attention at this particular time, not only because it is in itself an interesting special aspect of the general history of civil and military aviation, but because we have reached a critical point in that development at the very moment when air cargo service is beginning to show its potential contribution to the expansion of World Trade, including the badly needed expansion of Britain's own export trade. As we proceed, we shall see that the big expansion in air cargo has only recently begun. The formative years of aviation were more concerned with development of the vehicle, in creating public acceptability of this new form of transport and in fostering the growth of the more immediately profitable passenger traffic.

This submission presents collated views of a representative cross-section of the members of the Royal Aeronautical Society. It is presented under the broad headings set out in a letter from the Committee of Inquiry into Civil Air Transport inviting the Society to forward any information or views that might assist them.

Approximately 80 notes or papers were received from the Society's members and Groups, and these have been augmented by specific invited opinion from known experts within the Society.

The Society members welcomed the opportunity of putting forward their views and hoped that the Inquiry's report would lead to more positive government action than has so far emerged from the Plowden report. Many members also felt that considerably more use should be made of the Royal Aeronautical Society as an advisory body particularly in view of its wide cross-section of interests.

Although it has been said that dynamic load factor is equal to 2, it became evident by the author's researches that this value is influenced by the dimensions of members and loading conditions and is very different from 2. However, the solid viscosities are neglected in all these researches. Previously, the author obtained the coefficients of viscosities from the experimental results of damped oscillation of a cantilever beam in a vacuum vessel and investigated the relationships between dynamic load factors and solid viscosities on the beam and the rod subjected to transverse or longitudinal impulsive loads. From these results, it was found that the effects of solid viscosities to dynamic load factors cannot be neglected.

To find out whether the same fact can be obtained for the higher dimensions or not, the ring and the hollow sphere subjected to uniformly distributed impulsive loads along the inner and outer edges are analysed. Since σθ, the direct stress to the circumferential direction, is the most important from the engineering point of view, the relationships between solid viscosities and dynamic load factors of σθ are investigated.

The basic theory for the new TUBA family of plate elements has been presented in ref. 1, but lack of space did not allow the inclusion of all relevant developments. This refers, in particular, to the kinematically consistent load matrices, the so-called initial loads due to initial strains, and the geometrical stiffness for the analysis of buckling phenomena. In view of numerous requests by readers of the JOURNAL, we complete in this sequel the presentation with a brief account of the information omitted in ref. 1. At the same time we reproduce a small number of examples which show the great power of the new elements. To facilitate the reader's task the numbering of the current sections, equations and figures follow on consecutively from ref. 1.

Every control system employs some computing elements and it is customary to designate systems after the type of computing predominantly used in them. Thus, we have hydromechanical systems, pneumatic systems, fluidic systems, analogue electric systems, and so on. Traditionally, as described by Watson, the aircraft gas turbine has used hydromechanical control (see Fig. 1). The diagram does not depict any particular engine component but illustrates some of the principles used in a variety of present-day systems. A mixture of bellows, springs, cams, orifices, etc, compute according to their particular arrangement; frequently the fuel itself is used as the computing medium. Essentially such systems compute continuously using physical representations of the measured parameters. They are, therefore, of analogue form.

As a result of the failure of parts of the airframe on several types of aircraft having high intensity acoustic environments, the military and civil certification authorities are requiring assurances that new designs have adequate strength to resist the acoustic loads. In most cases failures have been detected early enough to prevent serious impairment of the aircraft's structural strength. In some cases this has led to unsatisfactory maintenance and inspection requirements and there is also the possibility of more serious failures arising from the extension of undetected damage. The purpose of this paper is to review the test data available and to present a design procedure for structures in the region of high noise levels. As it is impractical to apply the full theoretical treatment in design because of computational complexity, an approximation is presented and the predicted results are compared with the experimental values.