It has recently been decided by the Council that the newly elected and installed President may, if he so wishes, give an Address. While Presidential Addresses are not new to the Society this is now to be a part of its policy, although still voluntary. So, after some thought as to whether I should risk telling you much of what you already may know, I decided to give my views on this and that and also what I conceive to be the role of the Society in relation to the Aircraft Industry.

It is, and always will be, an honour to give the Handley Page Memorial Lecture, but for me the occasion has a special pietas because Sir Frederick Handley Page was a friend of mine for many years and I admired his extraordinary intelligence, pertinacity and independence of character. I had the honour to immediately follow him in two offices of high importance—as President of the RAeS and as Chairman of the Governors of this College, and as this is the last major lecture I intend to give, I am particularly happy that it is in his memory, just as the first major lecture I ever gave was in memory of that other great pioneer, Wilbur Wright.

It is a great honour for me to present this lecture as a tribute to the memory of La Cierva.

In my opinion, La Cierva was more than a pioneer who designed practical rotor-craft: he was, above all, the engineer who tried to understand how these machines worked and what is more remarkable, he sometimes succeeded! I am afraid that this attitude of mind has been somewhat forgotten since La Cierva, but the manufacturers willing to survive should now follow his example.

I have been asked to present the next generation of French helicopters but it would be more appropriate to speak of the next generation of Anglo-French helicopters. For, as you know, the models of the near future are being developed and produced under the terms of a co-operation agreement concluded between our two Governments. Other lecturers, with better qualifications, have already emphasised the “pros” and “cons” of these international programmes.

For the 22nd time we are here among friends of both sides of the Channel, meeting together for an annual celebration in the memory of Louis Bleriot, who achieved the first liaison by air between our two countries.

Last year's eminent lecturer, Mr. Handel Davies, delivered a brilliant and substantial lecture on world-wide aircraft market forecast and the future progress of technical development. In his conclusion, he stressed the necessity for European co-operation.

For many people Stansted represents the best example of the relationship between air transport and regional planning. The public inquiry at least showed up the fact that, although both are subjects with a growing body of knowledge, the interaction between the two is less well known. This is not to say that work of this kind is absent, e.g. the studies undertaken for the Port of New York Authority (PNYA) into the siting of a fourth major airport for that city, the symposia and studies of the Institut de Transport Aerien in Paris or the work of Stratford and others in this country, all pay attention to the relationship. The real crux of the matter is that both air transport and the development of our cities and regions are undergoing rapid change.

The development of carbon fibres which exhibit high strength and stiffness raises many problems in the design of such fibre reinforced structures. One such problem concerns the optimum arrangement of fibres to support a given load system or load envelope, and this has been treated by Harris for planar load envelopes bounded by given values of applied stresses σX, σY and τXY. Here we consider a problem of optimum fibre arrangement to transfer a torque T across an annulus bounded by inner and outer radii r0 and kr0, respectively. This problem is much simpler than Harris', insofar as only one load system is considered, but it differs insofar as the stress pattern is not isotropic.

The success of the TUBA plate elements, has not only engendered the development of the SHEBA elements but has also lead, nolens volens, to the consideration of folded plate structures (Faltwerke), which are of considerable practical importance. A little thought shows that a consistent theory of such systems requires that the kinematic representation or interpolation rule of the membrane state is identical to that for the bending state laid down in the TUBA analysis. Moreover, the membrane modes must be effectively the same as the ones adopted for the SHEBA element.

In a recent discussion on measurements made by Quarmby in fully-developed turbulent flow in concentric annuli, Quarmby has made several statements which are incorrect and need to be clarified.

Quarmby states that the pitot displacement corrections measured by MacMillan are those solely due to the shear and that they do not take account of the effect due to the presence of the wall. This is not so. Fig. 9 of MacMillan's original paper shows the total displacement effect. It is this total displacement effect which was used in my paper on the calibration of Preston tubes to relate the calibration curve to the inner-law velocity distribution. It is quite obvious that a Preston tube will be influenced both by shear as well as the wall and it would have been pointless to attempt to correlate its calibration with the velocity distribution using pitot displacement corrections unless these corrections included the rather important influence of the wall.

It is quite true that MacMillan gave corrections for both the wall effect and the shear effect. I did not say that MacMillan gave no results for the wall effect but it appears, however, that Patel took notice of a correction which did not include the wall effect.

Thus Patel puts the effective centre of the pitot tube at a distance from the wall y=½Kd and by consideration of a model consisting of a linear sublayer, a transition zone and a fully turbulent region derives a value for K of 1·30 and values for the constants in the logarithmic law profile, A= 5·5 and B=5·45.

Application of a method suggested by my technical note on equilateral and semi-equilateral triangles has yielded values for the buckling coefficients for isosceles triangles which in some cases differ appreciably from those given on Data Sheet 02.04.06.

The technical note quoted gives exact solutions in the form of a terminating trigonometrical series. When the triangle becomes isosceles, the series no longer terminates, but the infinite series solution, on insertion of the boundary conditions, gives an infinite determinant for the buckling load or eigenvalue.

Evaluation of the determinant, or of a sufficient number of terms, was computed on a Univac 1107, with the following results, which have been converted to the notation of Data Sheet 02.04.06.

The problem of the prediction of wall and fluid temperature with a turbulent boundary layer can appear in two forms:

1. (a) the prediction of wall heat transfer with specified wall temperature;

2. (b) the prediction of wall and fluid temperature with specified wall heat flux.

Because the differential equations governing heat flow in the turbulent boundary layer are linear, it is sufficient to be able to predict theoretically either the heat transfer rate consequent upon a step function of temperature or the temperature distribution following a step function of wall heat flow rate. Such predictions will then permit the treatment of the more general situations (a) and (b) by superposition.

In ref. (1) Pope presents a theoretical analysis of the buckling of rectangular plates tapered in thickness under uniform load in the direction of taper. An experimental investigation into the end load buckling problem for a plate having simply-supported edges with the sides prevented from moving normally in the plane of the plate is described in ref. (2). For these boundary conditions the theoretical solution is exact. However, the compatability equation is not satisfied exactly when the sides are free to move in the plane of the plate. This experimental investigation demonstrates that the buckling load is nevertheless adequately predicted by the analysis in these circumstances.