For types of structure where safety standards cannot be preserved by reliance on inspection, a permissible “safe life” has to be determined by relating the loads experienced by the aircraft in service to the fatigue performance of the structure, with due allowance for scatter in fatigue strength and in the frequency with which loads are encountered. This paper gives a working method for estimating the “safe life”—at which the risk of fatigue failure is negligible—of the wing structure of a transport aircraft, where the flight loads giving rise to fatigue are overwhelmingly due to atmospheric turbulence but where allowance has also to be made for “ground-to-air” loads.

The year 1868 was destined to be memorable and significant in the history of the Society. It was the year in which the first Aeronautical Exhibition in the world was held.

The Mechanics Magazine for 7th February 1868 said:

An All-Day Discussion on the Training of Guided Missiles Engineers was held by the Astronautics and Guided Flight Section of the Society in the Lecture Theatre on 16th March 1961. The Chair was taken by Mr. A. D. Baxter, M.Eng., F.R.Ae.S., M.I.Mech.E., F.Inst.P., Executive Director (Engineering), de Havilland Engine Co. Ltd.

Introductory papers were given by L. H. Bedford, C.B.E., M.A., B.Sc, A.F.R.AcS., Director of Engineering, Guided Weapons Division, English Electric Aviation Ltd.; Ian Dean, M.A., Education Officer, de Havilland Aircraft Co. Ltd.; F. G. Tarrant, Assistant Director, Guided Weapons (Engineering), Ministry of Aviation; Professor G. A. Whitfield, B.Sc, F.R.Ae.S., Professor and Head of Department of Aircraft Electrical Engineering, College of Aeronautics; Commander E. G. lege, Greenwich; Professor C. Holt Smith, C.B.E., M.Sc., M.I.E.E., Head of Department of Electrical and Instrument Technology, Royal Military College of Science, Shrivenham; and Wing Cdr. G. C. Wainwright, B.Sc, A.F.R.Ae.S., A.F.I.A.S., Chief Instructor, Weapon Systems Engineering Wing, R.A.F. Technical College, Henlow. The Discussion was opened by M. Armstrong, Chief Training Engineer, Bristol Aircraft Ltd.; Professor E. J. Richards, O.B.E., M.A., D.Sc, F.R.Ae.S., Professor of Aeronautical Engineering, University of Southampton; Colonel J. P. G. Lewis, War Office (Directorate of Equipment Production), and Colonel W. J. Mellors, M.B.E., School of Electronic Engineering, R.E.M.E. Twenty-three other speakers took part in the General Discussion.

The Oxford Dictionary defines the word responsible as, “liable to be called to account; of good credit or position; trustworthy;” this you will agree is quite a formidable definition.

Therefore, I have assumed the title of this paper to indicate that I should try to explain the abstract effects of this definition upon the individual Air Traffic Control Officer, rather than detail a list of the many and varied duties for which he is responsible.

It should not be necessary to explain the presence of a meteorologist at a symposium on any aspect of upper atmosphere research. Meteorologists understand their science to comprise the dynamics, thermodynamics and chemistry of atmospheres, wherever atmospheres occur. They are happy to have the facilities for observation and even experiment in the higher layers of the earth's atmosphere which rocket and satellite vehicles begin to provide, but can point to a considerable body of existing knowledge obtained by other means.

An important point to realise in the question of propulsion for aircraft of Mach 2 and upwards is that efficiency of the power plant is no longer a problem. Due to the high pressure developed from the intake the overall pressure ratio of the engine is high, and the aircraft forward speed being high the Froude propulsive efficiency is also favourable. Fig. 1 shows, in fact, that at Mach 2 overall thermal efficiency as high as 35 per cent is achieved which, of course, compares favourably with the best electrical power station generation. Indeed, it is one of the main reasons why economic transport at high Mach numbers is possible. The falling aerodynamic efficiency, as defined by lift/ drag ratio, is offset by this rising propulsive efficiency, so that a somewhat similar overall performance is obtained as compared with subsonic aircraft.

Solid propellant rockets are now being used in vehicles whose flight paths are mostly outside the atmosphere and need close control. Engines for such vehicles must not simply provide accelerating thrust but should also be capable of having the direction, magnitude and duration of this thrust altered at will. Some devices and methods for accomplishing such control have been described elsewhere, see Refs. 1, 2, 3 and 4. I shall attempt both to discuss these in more detail and to introduce others which I believe have not yet been mentioned.

The increasing importance of agricultural aviation can best be judged by a table setting out the area treated in the U.S.A., U.S.S.R., U.K. and other countries, which was compiled from recent publications. Fig. 1 shows how important a sector of aviation agricultural aviation has become.

Like other aircraft operations, agricultural aviation is not particularly profitable. Therefore a certain amount of work has gone into economic studies and into development work on methods for improving the service rendered to agriculture in order to improve the economy of aircraft operation.

The problem of determining the type of engine which best suits a particular application is not new to the engine designer, but the supersonic transport is perhaps unique in that a number of design criteria have been introduced which cannot easily be taken account of in the usual terms of engine weight, fuel consumption or even aircraft direct operating cost.

However, an examination of the effect of these standard criteria on different types of engines is a starting point in determining what engine will best match the supersonic transport requirement. A survey of a series of thermodynamic cycles both at Mach numbers in the region of 2.0 and at subsonic speeds typical of standoff or diversion suggests that two types of engine merit further study.

This paper deals primarily with Air Traffic Control in the European region and does not refer to problems specific to other areas. Nevertheless, most of these problems are common to all regions and differ only in degree. Their solution depends upon the existence of a properly organised and equipped Air Traffic Control Service and there is now world-wide recognition by users and providers alike that such a service is an essential element in the ordered development of aviation.

The difficulties of keeping the aeronautical infant alive were great. Few scientists or engineers could be persuaded to believe in heavier-than-air flight, although a number lent a readier ear to the possibilities of the airship.

The lecture theatre has now been opened, and I have taken it on myself to be the first to give an address in this newly-opened Theatre. I think this occasion is opportune to tell you something of its history and, in so doing, to demonstrate some of its facilities.

For many years the Council of our Society has considered the possibility of the Society having a Lecture Theatre of its own. Many of our Past-Presidents and Councils have expressed the desire and have made explorations but, though the wish was there, we did not see the means. Recent increases in the activities of the Society, the creation of Sections and Groups, each with its own Lecture Programme, added a new emphasis. Moreover, the problem of the hiring of halls has become increasingly difficult when one remembers that the Programme in London alone now includes more than 60 lectures.

In the Journal of the Royal Aeronautical Society, November 1959, the writer described an iteration process for the solution of the equations for plane oblique shock waves. Iteration methods avoid the difficulty of reading a solution from a chart; or, given a chart, provide a means of checking such a reading and, usually, of improving the accuracy to any desired degree.

As with plane oblique shocks, it is usual to use a chart to obtain the solution of a problem involving a Prandtl-Meyer expansion fan. The present note proposes an iteration process to avoid the use of a Prandtl-Meyer chart; or, given such a chart, offers the possibility of improvement in the accuracy of the solution obtained by reading from it, the limit being set by the accuracy of the trigonometric tables used.

As at present envisaged the man powered aircraft will more closely resemble the glider than any other type of flying machine. Because of this it was suggested that a paper on the relationship between gliding and man powered flight might be of value.

The papers which have been read to the Group have dealt with the aerodynamic, physiological and engineering aspects of the problem and they show that a man powered aircraft capable of flight just clear of the ground is a possibility.

Before undertaking the detail design a fourth aspect—pilotage—must be considered. It is in this field that the experience which exists in flying gliders is applicable and should be used.

“There was a considerable attendance of members,” says the Sixth Annual Report of the Society of the meeting held on 17th July 1871, with James Glaisher in the Chair.

The “considerable attendance” was not unexpected. The siege of Paris had drawn attention to the value of using the air for transport and mail in time of war. It was true that the besieged in Paris had to rely upon the way the wind blew and balloons, but enthusiasts of the Aeronautical Society were convinced that a heavier-than-air machine was not only possible, but would avoid all the drawbacks of the balloon being blown where the wind listeth. A large number of attempts had been made to make the balloon steerable, but with insignificant success.

When a Beam is subjected to a static transverse load acting through its flexural centre, the resulting deflection may be considered as the combined effect of the deflection due to bending stresses and the deflection due to shear stresses. In a majority of cases, where the span of the beam is large, or where the shear stiffness is large compared with the bending stiffness, the bending component only need be considered. However, for a short beam, the shear deflection can account for a substantial part of the total deflection. This is especially so in the case of a deep I section beam with a thin web, where the bending stiffness is large compared with the shear stiffness.

This note describes our recent attempts to apply the schlieren-interferometer to the study of supersonic flow around axi-symmetric bodies at zero incidence, and in particular shows how the density field distribution for a cone has been derived.

Various optical techniques, e.g. shadowgraph, schlieren and interferometric, have been used in the study of gas flows where density changes are significant. In some instances, however, a qualitative investigation is insufficient and although it is possible to obtain quantitative data from most optical methods, the interferometer has proved, so far, to be the most valuable in this respect.

As this is a wide subject area with many specialised fields, a broad review from a systems viewpoint would appear to serve the purposes of this Symposium best. Also, such a review may help to show that the importance of range instrumentation in upper atmosphere research is rather more fundamental and widespread than generally appreciated.