It is my privilege to present to the Royal Aeronautical Society a brief summary of the work done and the results achieved in developing the autogiro in the last few years. Many fundamental improvements have been the product of that work, but of still greater importance is the considerable progress in the knowledge of the aerodynamics, dynamics and engineering requirements of the new aircraft. The improvements in the formula have been made possible or practical only because of the painfully acquired technique, which, as is the case in all new arts, is a compound of theoretical developments and empiricism.

Tetraethyl lead is a constituent of most fuels of high anti-knock value, but such fuels cause serious corrosion of magnesium-base alloy tanks and may completely penetrate them in a few months. No work on the mechanism of this attack has been published and no satisfactory method for protection exists, so that magnesium-base alloy tanks cannot be used for leaded fuels. Since tanks constructed from an ultra-light alloy would be of advantage for aircraft, experiments have now been carried out to elucidate the mechanism of their corrosion, this work representing the first stage of an attack on the problem of providing protection against such corrosion.

Problems involving discontinuous aerodynamic twist, as for a flapped wing, are not readily soluble for wings having a rectangular plan form or straight taper. Lotz's method (B.Ae.S. Journal, May, 1934) has been stated to be particularly suitable, but a recent American report used in preference a direct method of successive approximation. In either case a fair amount of labour is involved, and the final results are only approximate. The exact solution for a wing of elliptic plan form, whilst no-t directly applicable to the usual type of tapered monoplane wing, is readily obtainable, and should give a good idea of the lift distribution and induced drag due to a flap on an actual wing.