The Twelfth Louis Blériot Lecture, “The Griffon Aircraft and the Future of the Turbo-Ram-Jet Combination in the Propulsion of Supersonic Aeroplanes” was given by General Noël Daum, Technical Director, Nord Aviation, on 12th March 1959 at the Institution of Mechanical Engineers, Birdcage Walk, London, S.W.I. Sir Arnold Hall, M.A., F.R.S., F.R.Ae.S., President of the Society, presided.

Before introducing the Lecturer, Sir Arnold presented the Society ̓s Gold Medal, the highest award the Society can confer, which the Council had awarded to Monsieur Marcel Dassault and which they felt it would be particularly appropriate to present on this occasion—their annual joint meeting with the Association Francaise des Ingenieurs et Techniciens de l ̓Aéronautique (A.F.I.T.A.)

The First Fairey Memorial Lecture, “Sir Richard Fairey— An Appreciation” was given by Mr. G. W. Hall, F.R.Ae.S., on 5th March, 1959 at the Feltham Hotel, Feltham, Middlesex. This was the 34th Main Lecture of the Society to be given at a Branch and was held under the auspices of the London Airport Branch.

Mr. R. L. Lickley, F.R.Ae.S., Chairman of the London Airport Branch, opened the meeting by welcoming the President of the Society, Sir Arnold Hall, M.A., F.R.S., F.R.Ae.S. This was the first Main Lecture of the Society to be held at the London Airport Branch and they were delighted to have the President with them to preside at the Meeting.

Of all those forms of corrosion with which the engineer must deal, such as atmospheric corrosion, galvanic and fretting, stress corrosion is perhaps the most difficult to understand, to predict and to prevent.

Unlike that other troublesome characteristic of metals, namely fatigue, which also defies exact analysis, it is caused by static tensile stress acting in a corrosive environment (in many cases, the atmosphere). This may be due to internal residual stress or externally applied assembly stress and under such circumstances the possibility of stress corrosion occurring is ever present and is not necessarily removed by the cessation of the working loads.

Most alloys are susceptible to some degree ranging from those which suffer in practice to those which only exhibit the phenomena under exaggerated laboratory conditions. Some examples are railway locomotive boilers, stainless steel construction, commercial spot-welded construction and, of course, aeroplane structures in light alloy.

Figure 1 illustrates a structural problem which occurs in naval architecture, and which may also be of interest in the structural design of aircraft. Compressive loading is applied to one transverse edge of a stiffened flat sheet and reacted, not by equal compressive loads on the opposite transverse edge, but by shear forces along the two longitudinal edges. These shear forces, and the complementary shear forces acting on the transverse edges, arise from the connection of the stiffened sheet to adjacent structure. This situation arises, for example, at a ship's transverse bulkhead. The lower edge of the bulkhead is subjected to vertical loads applied by the ship's bottom structure, and these loads are transmitted upwards and outwards to the vertical edges of the bulkhead, thence to be diffused into the side shell plating.

In a recent paper(1) Collar discussed some aeronautical applications of linear differential equations with variable coefficients. Part of the paper deals with the approximate solution:

of the differential equation

This asymptotic approximation, which dates back at least to Liouville, has an interesting history(2). It is widely known as the WKB approximation because of its use in quantum theory by Wentzel, Kramers and Brillouin. It has been applied to compressible flow by Imai(3).

While very useful it breaks down at the zeros of n(t) and there are problems in joining solutions passing through such points. Recently(2,4,5) extensions of the approximation which circumvent this difficulty have been developed. This note deals with the extension due to Bailey.

This approximation can be developed from the equivalence of equation (2) and the Riccati equation: —

The College owes its origin to the early days of NATO when the first Supreme Allied Commander Europe, General Eisenhower, was confronted with the problem of finding suitably trained staff to fill the posts in the NATO organisation. He therefore proposed to the Standing Group that a Defense College should be formed to fulfil this function. This proposal was agreed and the French Government set aside part of the historic Ecole Militaire building in Paris to house the college. The first course began in November 1951, some two years after the signing of the North Atlantic Treaty and since then fifteen courses have been held, each of approximately six months duration.

The first Commandant was Admiral Lemonnier of France, who was succeeded by Air Marshal Sir Lawrence Darvall, R.A.F., Great Britain, Lieutenant General Clovis E. Byers, United States Army, Lieutenant General de Renzi, Italian Army, and Major General Estcourt, British Army. The present Commandant is Lieutenant General Ariburun of the Turkish Air Force.

In his excellent review of the “state of the art” of effusion cooling (p. 73, February Journal, 1959), Dr. P. Grootenhuis clearly distinguishes the two mechanisms which contribute to the cooling effectiveness; namely, efficient abstraction of heat from the porous wall material by internal transfer to the effusing coolant, and reduction of the rate of external transfer of heat from the stream to the wall as a result of boundary layer injection. An observation that deserves emphasis, however, is that the first of these mechanisms is the predominant one. This fact is illustrated by the good agreement between the theory assuming laminar flow conditions (i.e. involving integration of the Navier-Stokes equations and the use of a one-parameter velocity-profile expression proposed by Schlich-ting for the laminar boundary layer with injection) and the various experiments, all of which involved turbulent stream conditions. This observed agreement indicates that the surface temperature is primarily controlled by the internal heat transfer within the porous wall and is relatively insensitive to the external heat-transfer conditions.