The one-thousandth-and-fourth Lecture to be given before the Society, " London Airport," by Air Marshal Sir John D'Albiac, K.B.E., C.B., D.S.O., was given on 6th November 1956 at the Institution of Mechanical Engineers, London, S.W.I. Mr. E. T. Jones, C.B., O.B.E., F.R.Ae.S.. President of the Society, presided. Introducing the Lecturer, Mr. Jones said that they were to hear from the most competent man in England to give it, a talk on what he would say was the finest airport in the world. He did not think they had had a lecture on a modern airport before and it was worth while reflecting on previous means of transportation. Every previous vehicle of transport before the aeroplane had had to have tracks made for it to take it from one place to another, as well as terminal stations built for it on long distance journeys. Soma people commented on the costs of airports, the amount of concrete, etc., but when one realised that the air was provided free of charge and itself provided the means for the aircraft to go from one concrete patch to another, one appreciated that the airport was cheap compared with previous forms of transport. Air Marshal Sir John D'Albiac had, he thought, possibly one of the most interesting jobs in London; he met all the personalities, film stars, and so on. He had been there since 1946 when London Airport was converted from a small airfield. He therefore knew every little bit about it, control, runways, buildings and everything. Sir John started his career in the Army. He found that a little too slow for him and so he transferred to the Royal Naval Air Service. Whether he found that still not quite fast enough he did not know, but he later transferred to the Royal Air Force and he remained in that Service until about 1946 when he retired with the rank of Air Marshal.

It is well known that the performance at high subsonic and transonic speeds of a swept-back wing-body combination in which the wing is untwisted and has the same section at all stations along the span and in which the body is not specially shaped to allow for the presence of the wing, falls far short of what would be predicted for the corresponding infinite sheared wing. For example, with a sweep of 45° and a thickness/chord ratio of 6 per cent it has been found experimentally that a rapid shock-induced increase in drag occurs above a Mach number of about 0·95 and a peak value of CD is obtained at Mach numbers slightly in excess of 1·0, whereas it can be estimated that for the corresponding infinite sheared wing, sonic speed in a direction perpendicular to the isobars (the lines joining points where the pressure is equal) would not be obtained until a Mach number of 1·18 was reached. The poorer performance of the finite swept-back wing results principally from the fact that the pressure distributions for sections near the root and tip are distorted in shape from what would be obtained on an infinite sheared wing and, as a result, the isobars tend to lose some or all of their sweep. With a moderate aspect ratio such as 3, such effects extend over most of the span at high subsonic speeds.

In a recent publication the problem of denning the thrust of a jet engine, or the internal drag of a ducted body, is considered in some detail. This Report was compiled by a special Panel of the Aeronautical Research Council and, during its discussions, concern was expressed at the position regarding the definitions of certain quantities having the dimensions of pressure; in some cases the most widely-used definitions were not rigorous, in others a variety of names were in use. In addition, some quantities of considerable value in fluid dynamics were either unnamed or, had been given misleading names. This state of affairs was felt to be undesirable. As a result, the A.R.C. set up a small Panel to consider the matter more fully. The Panel contained representatives from both of the two important groups interested in obtaining uniformity in this field, those concerned with external aerodynamics and those primarily interested in internal flow problems.

It is shown that, on the basis of the data provided by two sets of influence coefficients for a wing (or other surface)–an “elastic” set giving deflections (and hence incidence angles) in terms of applied loads, and an aerodynamic set giving aerodynamic loads in terms of incidence angles (or other linear function of the displacements)–all “static” aeroelastic problems can easily and expeditiously be solved by the use of a digital computer. It is also suggested that the same method of approach may well be used for solving oscillatory aeroelastic problems such as flutter.

An estimate is made of the “ground” interference effect of the deck of an aircraft carrier. It is shown that in the extreme case of wing span equal to deck width the induced upwash is of the order of 20 per cent less than the usual ground interference value. Thus the landing characteristics of an aircraft should not be markedly affected.

It seems that there should be a difference between landing an aircraft on a stationary aircraft carrier and on the ground, due to modification of the ground-interference effect by the finite width of the carrier deck, particularly if for some reason large aircraft are to be used. In this note an estimate is made of the magnitude of this effect.

The turbulent boundary layer on an aerofoil is represented by simple distributions of velocity, so as to obtain approximate general formulae for the displacement and momentum thicknesses in terms of two ratios of local velocity to that at the edge of the boundary layer.

Optimum positions for the local velocity are calculated to be at 0·15 and 0·62 of the boundary layer thickness from the aerofoil surface. The accuracy of the formulae is closely examined. A rapid experimental and numerical procedure is given for estimating the displacement and momentum thicknesses within ± 2 per cent. A minimum of seven velocity measurements has been found satisfactory in practice.

An exact solution of the streamlines of the slow viscous motion inside a cylinder with partially moving walls has been obtained and verified experimentally. This problem has been treated by H. B. Squire for high Reynolds numbers.