THE CHAIRMAN, introducing the author, spoke of the great work which is being done at Yeovil by Westland Aircraft Limited on helicopters, and of the close association of Mr FITZWILLIAMS with this work He felt sure that Mr Fitzwilliams would agree with the opinion that his paper would give us a peep into the future Papers of this kind were fully in accord with the general activities of the Helicopter Association—not over-optimistic but nevertheless having a firm eye on the future

Mr FITZWILLIAMS gained his B A at Cambridge, and later spent many years with the Autogiro department of Messrs G & J Weir In the year 1940 he joined the Ministry of Supply and was engaged for some time on military projects being concerned with the development of gliders and rotary wing parachutes with Dr BENNETT and Mr HAFNER at the Airborne Forces Experimental Establishment

For the second occasion during the 1951/52 session of lectures, this Association has been honoured by the presence of an eminent member of the United States aircraft industry, since this evening we have Mr FRANK PIASECKI as our lecturer

You all know Mr PIASECKI very well by name In 1940 he founded an engineering group known as the P V Engineering Forum This later became the Piasecki Helicopter Corporation, and today he is Chairman of the Board of Directors In 1943 the first single rotor helicopter designed by that small band of people emerged, it was the PV2, and was flown successfully by Mr PIASECKI himself Quick to appreciate the military possibilities of a helicopter capable of carrying a large load and with ample cabin space, he initiated and led the development of the big PV-3 tandemrotor helicopter, and the United States Navy, recognising the merits of the design, awarded a contract for the supply of a quantity of machines of this type

THE CHAIRMAN: This afternoon I take the Chair with great pleasure for the occasion is marked by the presence of our friend, Major G. P. BULMAN, President of the Royal Aeronautical Society, and also other .members of the Society, who have come along to hear Captain LIPTROT. I know that you will support me in extending to Major BULMAN a very warm welcome. It is the second occasion on which we have been able to meet on common ground, and I know that we shall enjoy listening to Captain LIPTROT on this particular subject.

We have been told that certain of our lectures in the past have been far too technical and above the understanding of some of the more youthful of our membership, and I must say that sometimes even I have viewed with apprehension the mass of mathematical formulae presented by some of our more advanced lecturers, but today I am heartened because our old friend Captain LIPTROT is the lecturer and he is one of those who, although accomplished technically, is able to present his subject in an exciting and yet easily understandable manner, having a style which brings the subject well within my own comprehension.

The CHAIRMAN, introducing the author, said Mr HAYWARD IS a member of the Helicopter Association of Great Britain He is a Bristol man, having been educated m that city, and later he served a five-year apprenticeship with the Bristol Aeroplane Company, Limited He served for some time on the technical staff of D Napier & Son, returning to The Bristol Aeroplane Company in 1945, and from there joined the Fairey Aviation Company as Patent Engineer

The title of Mr Hayward's paper is, I think, deceptive, for not only does he give a comprehensive review of the helicopter patent situation, but m addition almost a complete history of the helicopter through the ages, from Leonardo da Vinci to present day developments in the propulsion of helicopter rotors by jet motor

This paper examines the problems involved in designing the combustion system of a ram-jet motor for mounting on the tips of helicopter blades. Although sufficient knowledge is not yet available for such a motor to be completely designed on the drawing-board, a principle of construction is suggested which should require the minimum of experiment and development. The principle is illustrated by consideration of a 60 h.p. motor for a tip-speed of 650 ft./sec.

In studying the aerodynamics of rotor blades we are often uncertain how far we may apply quantitatively the data obtained from wind tunnel tests of aerofoils Of course, the rotor blade behaves qualitatively like an aerofoil, but I sometimes feel doubtful about calculations of the effect of detailed changes in blade design, say for example, the effect of taper on performance, and wish to stress the desirability of wind tunnel tests by which some at least of these questions could be settled more easily than by flight tests

I have found in preparing this lecture that covering the whole field would be impracticable I intend to concentrate mainly on the compressibility problem which, closely associated with stalling, seems to me to be the principal aerodynamic problem facing the blade designer today