The 777th Lecture was read before the Royal Aeronautical Society on 7th April 1949 at the Institution of Civil Engineers, Great George Street, London, S.W.1. Dr. H. Roxbee Cox, D.I.C., F.R.Ae.S., F.I.Ae.S., President of the Society, introduced the Lecturer, Air Commodore Vernon Brown, C.B., O.B.E., M.A., F.R.Ae.S., Chief Inspector of Accidents, Ministry of Civil Aviation.

The 778th Lecture to be read before the Royal Aeronautical Society (the second main Society Lecture to be given at a Branch centre) was read under the auspices of the Portsmouth Branch, at the Portsmouth Municipal College, on 21st April 1949, by R. R. Duddy, B.Sc., A.F.R.Ae.S., on “ High Lift Devices and their Uses.” Sir John Buchanan, President-Elect of the Society, presided over the meeting with Mr. E. C. Green, Chairman of the Portsmouth Branch.

The Aerodrome, as the point of contact between the aircraft and the world of reality, has to a large extent been taken for granted. The designer regards it as the base for prototype tests and the airline operator as his aerial railway station. It is my intention to show that aerodrome development is at a critical stage of evolution on this side of the Atlantic, that many of the related problems do concern the aircraft designer and operator, and that if these problems are not given consideration, difficulties will be encountered in civil operations.

To quote an example; the optimum aircraft type to serve a system of air routes can be worked out taking into consideration the range required, payload and speed, but if the aircraft ultimately ordered and produced cannot safely operate from the aerodromes to be served because of the runway length and approaches, then the operations will either have to be reorganised or continued without due regard for safety.

Although floatplanes were not popular during the war years, new types have made their appearance since, and presumably, for certain classes of work, more will be seen in the future. With this in mind, this paper is presented in the hope that it may help in assessing the float weights on any new designs that are contemplated. Some suggestions are included concerning geometry and design which, if adopted, may help to show a higher weight efficiency than existing practice.

The paper is based upon an analysis of the weight and geometrical data relating to a large number of floats, although since the number built during recent years is small, a certain amount of data, which might possibly be considered old by some standards, has been incorporated. As will be seen by the curves, recent practice shows no radical departure from earlier years and the inclusion of the early data to establish design trends would appear to be warranted.