On the 1st November 1944 the delegates of 52 States met at Chicago at the invitation of the United States Government, and, on the 7th December, the Convention on International Civil Aviation (the Chicago Convention) was signed. It came into force on 4th April 1947. Today, there are 117 States parties to the Convention, albeit representing, in the main, the same territories.

To mark the achievement of 25 years of international co-operation through ICAO, I had personally hoped that it might be possible to get the President of the Council, Mr. Walter Binaghi, to give an up-to-date account of ICAO’s work. This not being possible, I have been asked to take his place, and I must make it clear that I cannot attempt to do the same thing. This is not a history of ICAO. I speak only from the point of view of my experience in the first 10 years. I hope to show the origin of some ideas and actions and trace certain changes in thinking and attitudes. I must apologise in advance if, in doing so, I seem to give undue attention to matters in which I have taken part and to ignore so much else that has been done. How much that is was impressively borne in on me, when I recently received the ICAO Bulletin for September 1969. For an authoritative and complete (though summarised) account of what ICAO is and what it has done, I commend this admirable review, and I wish to pay my tribute to those who have contributed so much to what there is recorded.

It is to be noted that this Annual Report covers the Calendar Year and not the year between Annual General Meetings, and consequently the rnonths from January to April 1970 will be included in the Report for next year.

The activities of the Society do not lessen, but rather do they increase imperceptibly from year to year. The Air Transport Group has now become operational, and should, in the future, make an increasing contribution to aviation. During the year a second Air Transport Course was held at Bournemouth; this was the result of popular demand, for the Course during Easter was very heavily oversubscribed. This would indicate that Air Transport is looming larger and larger in the aviation picture, and receiving more and more attention.

Early in May 1785, Mr. Vincent Lunardi, famous for the first balloon ascent in England on 15th September 1784, announced that he would ascend again, in his new balloon, on 13th May, this time accompanied by his friend Mr. George Biggin and a lady.

For the occasion a stipple engraving (Fig. 1) was published, entitled “V. Lunardi, Esq., Mrs. Sage, G. Biggin Esq.”, showing these individuals in the balloon’s car. On the engraving, the date of publication is given as 13th May, the date fixed for the ascent, Mr. Bovi is named as the publisher, F. Bartolozzi as the engraver and Rigaud as the artist who had painted the picture from which the engraving had been made.

It can be said that the main cause of premature failure or malfunction of any engineering component is attributable to the design being below the standard required for the environment in which it had to exist. This idea is neither surprising nor new, and applies throughout the whole field of engineering, especially in the aircraft industry which is extremely conscious of the need to design and develop its systems to suit the environmental conditions of flight.

In the air-breathing engine industry this need has been recognised almost from the inception of flight. For the successful development of an aero engine there is, therefore, the need to use all the resources of past flight experience to provide initial design information for the engine and its components, and then to test the engine or components to determine that the requirements have been fulfilled.

Before considering the techniques used for in-flight thrust measurements, it is important to understand fully the basic reasons for such measurements.

For without this understanding it is difficult to assess the benefits to be gained from making accurate thrust measurements. Those readers who are actively involved in performance prediction and measurement on new aircraft will already be aware of many good reasons, but a brief review of the situation will help to set the scene.

Of the two main finite element approaches, the displacement method has progressed more rapidly than the force method in the area of element representation. Many authors have contributed to the displacement method with both static and dynamic stiffness matrices for beam elements, plane stress elements and plate bending elements. The plane stress and bending elements being rectangular, triangular or quadrilateral in form. A dynamic stiffness matrix consists of a static stiffness matrix and a mass matrix. In the force method, .static flexibility matrices have been developed for beam elements and plane stress elements. However, static flexibility matrices for plate bending elements have only recently been published (Kaufman and Hall, Morley, Robinson, Przemieniecki). For the past few years, the author has been investigating the rank force method for structural vibration analysis. In ref. 6 a dynamic flexibility matrix is presented for a beam element. This matrix consists of a static flexibility matrix and an inverse mass matrix. Ref. 5 contains the derivation of a dynamic flexibility matrix for a rectangular plate element in bending, twisting and shear. The author, in collaboration with Petyt, demonstrated how a dynamic stiffness and flexibility matrix can be extended to include material damping.

The equations governing the flow in a boundary layer are a simplified form of the full Navier-Stokes equations; the simplification being based on the argument that within the boundary layer the velocity gradients normal to the solid surface are much larger than those parallel to the surface so long as the boundary-layer thickness is much smaller than (a) a representative streamwise length of the surface and (b) the principal radii of curvature of the surface.

It is undoubtedly true to say that with the death of Archibald Reith Low on the 21st January 1969, there departed from the scene the last of the early pioneers of British aviation.

Born in Aberdeen on 31st December 1878, he was brought up with four brothers and three .sisters at the Manse at Fountainbridge, Edinburgh, where his father was Minister of the Church of Scotland. His mother was Jane Stuart Reith, aunt of the present Lord Reith, who was thereby his first cousin.

The equations defining compressible flow are sufficiently complicated to preclude general analysis, but, in particular cases, can often be simplified and manipulated into a form amenable to solution. Problems connected with aircraft have, in the past, usually fallen into this category, where the non-linear equations can be simplified to a linear form and reasonably accurate solutions deduced. At hypersonic speeds, however, the more usual assumptions become invalid, no reasonable simplification can be made, and, except in certain specialised cases, no solutions can be deduced. Hence the problem of deriving the flow pattern around some specified shape becomes, in general, insoluble. The simple caret wing was proposed seven years ago by Nonweiler to avoid such difficulty. His elegant idea was to reverse the normal process of deducing the flow field round a given body shape, and instead to deduce body shapes that would generate specific, simple, flow patterns. From known flow fields lifting bodies may be obtained, by replacing .streamlines with solid surfaces, and the caret wing is one example. Nonweiler’s original notion has sin:e been extended by a number of people.