A Meeting of the Society was held in the Lecture Hall of the Institution of Mechanical Engineers, Storey's Gate, St. James's Park, Westminster, London, S.W.I, on Tuesday, February 20th, 1945, at which a paper by Air-Qommodore F. R. Banks, O.B.E., F.R.Ae.S., on “ The Importance of Power Unit Development,” was read and discussed. In the chair, the President, Sir A. H. Roy Fedden. The CHAIRMAN: Air-Commodore Banks had played an active and important part in engine development during the period between the two world wars. He had filled various positions successfully during the present war at the Air Ministry and the Ministry of Aircraft Production, holding at the moment the key position of Director of Engine Development at M.A.P.

A meeting of the Royal Aeronautical Society was held in the lecture hall of the Institution of Mechanical Engineers, Storey's Gate, St. James's Park, Westminster, London, S.W.1, on Thursday, March 1st, 1945, at which a paper on “Control Surface Design in Theory and Practice ” was read by Mr. M. B. Morgan, M.A., F.R.Ae.S., and Mr. H. H. B. M. Thomas, A.F.R.Ae.S.

This paper discusses the static longitudinal stability of an aircraft in the simple case when the aerodynamic derivatives are independent of speed. An outline of the basic theory of static stability is given, accompanied by a working document, giving suitable forms for the estimation of neutral points from wind tunnel tests. A worked example is included for a typical case. No attempt is made to interpret the results, but the conclusions include a note on the C.G. margin. Loss of stability stick free, and scale effect are commented on briefly in the appendices.

A meeting of the Royal Aeronautical Society was held in the lecture hall of the Institution of Mechanical Engineers at Storey's Gate, St. James's Park, Westminster, London, S.W.1, on Thursday, March 8th, 1945, at which a paper on “Electrics for Aircraft,” by Mr. C. G. A. Woodford, A.M.I.E.E., A.F.R.Ae.S., was read and discussed. The President, Sir Roy Fedden, in the Chair.

The well-known maxim “ know your enemy ” is as sound in aircraft design as it is in war. Application of this, doctrine might perhaps modify the conclusions in Mr. Tye's interesting paper, “ Factors of Safety –or of Habit? ” published in the November issue of the Journal. He discussed design factors and strength requirements from the aspects of V-g records and of structural variation. The V-g records with very few exceptions have been obtained from aircraft which have not broken up.

To claim that communications have unified our world is by now to voice a truism. Within the span of a generation we have thrust headlong into an age of transition and readjustment, the definitive trend of which is towards a world-wide mobility of goods, ideas, and the citizens who produce them. The role of the air route in this process is no longer a matter of dispute, and it is clear that the time has come to consider certain technical questions which underlie any detailed scheme for a truly international network of airways.

A meeting of the Society was held in the lecture hall of the Institution of Mechanical Engineers at Storey's Gate, St. James's Park, Westminster, London, S.W.1, on Thursday, April 5th, 1945, at which Dr. A. G. Pugsley, F.R.Ae.S., presented a paper entitled “Modern Experimental Work on Aeroplane Structures.”

Test Flying should not be confused with Flight Testing. There is a very large difference between the two. Flight Testing covers the work of an infinite variety of people, while Test Flying is done by pilots and observers only. It is with the work of the pilots that this paper will deal.

A Test Pilot is presumably a pilot who tests aircraft, but it is a very loose, term. Out of the multitude of pilots engaged on test work in aircraft, only a small percentage actually test the aeroplane itself, while the remainder may be divided into two classes: those who do flight inspections, and those who use the aircraft merely as a vehicle for the testing of equipment and engines.

The Journal of the Royal Aeronautical Society, in one form or another, is the oldest aeronautical publication in the World, with a continuous record of publication.

The Aeronautical Society of Great Britain was founded on January 12th, 1866, and the first report of the proceedings of the Society was published in 1867 by the firm of Cassell, Petter and Galpin, of Ludgate Hill, E.C., price Is. 6d.

It was a bold venture to start an aeronautical society in those days, and it is worth while recalling the year 1866. It was the year Prussia became head of the new German confederation which was the beginning of modern Germany, and it was the year that the first treaty of alliance was signed between Italy and Germany.

In those days Dickens, Browning, Tennyson were the giants of their time. Women wore crinolines, shawls and poke bonnets, and men light trousers with frock coats and top hats.

The general recognition of the importance of vibration study, as a specialised branch of engineering science, is clearly reflected in the fact that each year sees the publication of a great number of papers on all aspects of vibration theory and practice. The theoretical papers most commonly describe new methods of analysis and calculation, and it is becoming increasingly difficult for the general engineer, who has neither the time nor the inclination to follow in great detail the development of all the specialised subjects, of which vibration study is only one, to retain in his mind a clear picture of the general strategy applicable to the attack on vibration problems, and to fit into this strategical scheme the tactical operations represented by the new methods.

The differential equation for the deflection of a tapered strut cannot usually be solved by formal methods; we propose to attack the problem in the reverse direction; given the deflection-curve as a polynomial, we find the shape of the longitudinal section for struts of given strength. It will appear that the shapes so found are quite different from those for struts “ of uniform stress ” yet it is possible to get substantial saving in weight for a given strength (for some of the examples up to 11 per cent., the theoretical maximum being 13.4 per cent.

In this lecture the aim is first to establish of position of “airworthiness” in the field of “safety”. To draw a comparison, airworthiness is but one element of a complex jigsaw puzzle in which all the pieces must properly interlock in order to produce a satisfactory safety picture. This parallel applies too in the sense that if the shape of one of the elements is altered, all the adjacent elements must be altered to maintain a perfect fit. Arising from this, it is clear that, if safety and efficiency of air transport are to increase, then airworthiness provisions must be ever more closely linked with the conditions under which the aeroplane operates. The second aim is to draw attention to those airworthiness matters to which the designer could most profitably direct his efforts.

All aircraft engineers profess a belief in the importance of low structure weight. To implement this belief our efforts must be comprehensive and consistent and in the search for sound method it is important that we review, from time to time, familiar habits that are based on compromise. In the past the comparative merit of a particular aircraft structure has depended on a series of individual assessments, many of them semiarbitrary.These assessments have covered the whole field from the choice of the initial design load factors and the valuation of the working stresses right up to the ultimate maximum permitted all-up weight.

It cannot be denied that many of the prewar valuations were haphazard, usually conservative. This is demonstrated by the successful types of aircraft operating in service at weights considerably in excess of their original design estimate. Although this state of affairs proved highly fortunate it is a method that should not be perpetuated.

The simple ring frames which are a common feature of metal fuselage construction are being superseded in some large aircraft by more complicated frames in which one or more cross members are added to stiffen the frame. The stress distribution in simple rings is readily analysed by the standard methods for redundant structures, but the direct extension of these methods to more complicated cases leads normally to the solution of a number of simultaneous equations. The method now proposed avoids this difficulty by breaking down the calculation into a number of simple steps and then applying the principle of superposition to combine the results so obtained. In this respect it is equivalent to the Hardy Cross moment distribution method (1) or to Southwell's method of the systematic relaxation of constraints (2) though in many applications the final superposition of loadings is so simple that the full moment distribution or relaxation procedure is not required.