I proprose to consider some of the problems which arise in fitting the hovercraft into our legal system and to suggest in a tentative way, not so much the solution to these problems, but rather the lines on which I feel that solutions should be approached. It is unnecessary to emphasise that the views I express are entirely my own; for whose else could they be?

Now it will be noticed that the title of this lecture, “The Development of Legislation for Hovercraft”, assumes that legislation will be necessary to deal with hovercraft; but a moment’s thought, or a single example, will show how well justified the assumption is.

I feel greatly honoured having been invited to deliver the Second Handley Page Memorial Lecture and, indeed, grateful for the opportunity to pay tribute to a great Englishman and aeronautical pioneer, who for 40 years was my personal friend and, for over 30, my Chief. As no other man, he has decisively influenced the course of my life.

The engines for the Concorde supersonic transport are being developed jointly by SNECMA and Bristol Siddeley Engines Ltd. The basic engine is derived from the Olympus engine and the responsibility for this part of the development will rest with Bristol Siddeley Engines Ltd., but the jet pipe, propelling nozzle, thrust reverser and noise suppressor will be the responsibility of SNECMA.

The casual reader might think that there is a mistake in the title of this paper, but the first authenticated descent by parachute was made in 1797 by Andre Jacques Garnerin in Paris. Subsequently, M. Garnerin also made the first parachute descent in England, in 1802, and some thirty-five years later Mr. Robert Cocking, then sixty-one years of age, made a descent in a parachute of a very different design. This descent resulted in his losing his life.

In the interim period between the two descents in England, considerable speculation arose about the designs. The authorities in “Aerostation” of the day put forward some remarkable hypotheses about the problems involved and it might perhaps be of interest to the many people who are now familiar with parachutes to read about them. It is no accident, of course, that the parachute first made a positive appearance at this time. Man had just learnt to free himself from the earth by means of hot air and gas balloons and thus the need for a means of escape was born.

Measurements of profile drag, base pressure, wake turbulence and vortex shedding frequency have been made on a 9 per cent thick aerofoil in the presence of a secondary air flow, ejected from the blunt trailing edge. It is shown that the decrease in profile drag caused by the base bleed is associated with a decrease in the strength of the vortex street. The initial formation of the vortices occurs further downstream as the bleed quantity is increased. As a result, a greater proportion of the shed vorticity is diffused before the street is formed.

Recently the use of Maclaurin’s series was illustrated for the analysis of orthotropic plates. Formulae connecting the deflection of orthotropic plates to that of the corresponding isotropic plate are established here, thus eliminating the need for solving the characteristic equations of orthotropic plates. Rectangular plates with two opposite sides simply-supported and one of the other two sides elastically restrained against rotation are considered.

Since I have not been concerned with matters thermo-dynamic for some years, I have hesitated to enter the lists on the recent discussions on “The Speed of Sound and Mach Number Effects,” but I cannot let the comments of Mr. Naylor (Journal, January 1964, p. 63) and the reply by Messrs. Bragg and Smith stand without further comment.

I am in agreement with Mr. Naylor in the specific circumstances with which he deals, but I believe his concentration upon the polytropic efficiency obscures the more fundamental approach.