The successful development of the gas turbine for aircraft propulsion stimulated much thought, some serious and a great deal speculative, on the possibilities of even more advanced forms of propulsion. The ramjet and the rocket immediately sprang to mind. The former was a natural development of the turbo–jet. It could extend the useful field of the turbo–jet but the bounds of that extension could be clearly seen. On the other hand, the rocket was not restricted by the same fundamental limitations and its eventual, although still somewhat remote, exploitation in wider spheres could be prophesied with some confidence. Before the 1939—45 War, the stage of development of the rocket motor was comparable with that of the internal combustion engine a century ago. Pioneers like Tsiolkovski in Russia, Esnault–Pelterie in France, Oberth in Austria and Goddard in America had laid down the basic theory and made some small scale experiments in support, but the first major practical steps came from the Germans during the war.

Before the 1939-45 War, the stage of development of the rocket motor was comparable with that of the internal combustion engine a century ago. Pioneers like Tsiolkovski in Russia, Esnault-Pelterie in France, Oberth in Austria and Goddard in America had laid down the basic theory and made some small scale experiments in support, but the first major practical steps came from the Germans during the war.

My pleasure in accepting your invitation to lecture, which I treat as a great honour, has been somewhat overshadowed by doubt that I shall do justice to the occasion. This is but the second lecture to commemorate Captain Frank Barnwell. I am fully alive to the fact that the members of this Branch of the Society, many of whom were Captain Barnwell's personal friends, are very desirous of establishing, in these early lectures, a standard which is a worthy memorial.

Captain Barnwell was one of a small number—I suppose they can be counted on the fingers of two hands —who, by their courage and ability, made the barely flyable contraptions of 50 years ago into the aeroplanes we know today. The changes in aeronautical engineering have been so great that it is not easy to realise in 1955 the problems Barnwell and his colleagues faced in 1905, the year of the first Barnwell designs.

During the past few years numerous developments in the hydrodynamic design of flying-boats have been brought about mainly by systematic model research. Although Germany deserves the credit for initiating research on the forces on planing plates and Vee wedges, we are indebted to various estabhshments in the U.S.A. for the multiplicity of data on both flying-boats and simple planing surfaces, which are now available.

The Classical Kirchhofif–Love Theory for the deflection of thin plates leads to fourth order Lagrange's differential equation,D△4w — q = 0 for which a general solution is not always possible. Exact solutions are known so far only for a few special cases and, therefore, numerical solutions have often been tried. The advantage of numerical solution is that it can be applied easily to any plate plan form which is in marked contrast to the analytical method where, for mathematical reasons, definite restrictions have to be imposed on the geometrical shape of the plate. Among the various numerical methods, relaxation is the easiest, but when applied to solving a biharmonic equation, the process becomes extremely difficult and laborious as convergence is very slow and the unit relaxation operator cumbersome to deal with.

When tip–mounted engines are employed on a helicopter rotor, such as lightweight turbines, ram-jets or pulse-jets, the action of the fuel flowing along the blade gives rise to a power loss. For a ramjet helicopter this is of the order of 6 per cent, of the total power requirement of the rotor system. In addition, if the fuel injection nozzles in the combustion chamber face upstream this leads to an additional power loss of 1-6 per cent, of the total power, and it is evident that these effects should be allowed for in helicopter performance calculations. It is shown for a ramjet helicopter that the total spraying and centrifugal pumping loss is of the same order as the total transmission and tail–rotor power loss for a conventional shaft-driven helicopter. The same effect can be demonstrated for pressure-jet rotors, where it has an even greater magnitude.

The Paper by A.C.Nicholls in the October 1954 Journal (p. 724) describes two empirical equations neither of which possesses the first essential of an acceptable strain hardening function, namely that the stress attained in a preliminary straining operation shall become explicitly the threshold stress at which subsequent deformation begins. Eight years of study and the analysis of hundreds of published curves have convinced me that the exponential function put forward in 1948 faithfully reflects the strain hardening process. Far from being empirical, it can readily be deduced from a few simple and credible assumptions, and has counterparts in many branches of physics.