When delivering a Memorial lecture it is customary to open with a tribute to the one who is remembered. But the substance of my lecture is the rotor which Cierva evolved 50 years ago and I hope to sufficiently recognise his contribution during the delivery. Therefore with your permission I will content myself now with marking my deep appreciation of the honour done me by your invitation.

An informed layman reading past papers on rotors and rotorcraft would form the impression that each achievement was only a fleeting gain. The autogyro was to give way to the helicopter, the helicopter to the compound helicopter and the compound to the convertible rotorcraft. The rotor itself, it was argued, is ideal for hovering but hopelessly inefficient in forward flight. Hence the haste to get back to wings, a tendency much increased when fixed wing designers discovered how to use small, heavily loaded, rotors. But such is the lure of the rotor that even its detractors saw the case for its use in landing and take-off.

Successful man powered aircraft projects may be divided into three main stages:

(a) Design.

(b) Construction.

(c) Operation.

From a purely practical standpoint, this sequence represents the order of increasing difficulty. It is in the later stages of a project that the major problems of team management and of organisation arise. Indeed, many groups, having designed and built a machine, have encountered the utmost difficulty in flying with any regularity. As a result, relatively little has been recorded on the matters of operating methods or handling characteristics, although there has been much discussion on the theoretical aspects of flight under human muscle-power.

Stiffened panels usually consist of a skin of uniform thickness with several identical equally spaced longitudinal stiffeners. This paper demonstrates that the weight of a panel which is designed to have a specified initial buckling load, in uniform longitudinal compression, can be reduced by using more than one size of stiffener.

Initial buckling stresses quoted were all obtained using the computer program VIPAL, which is based on a recent “exact” method which allows for coupling between all possible modes. In this method the panel is considered as an assembly of thin uniform flat rectangular plates which are rigidly connected together along their longitudinal edges and are simply supported at their ends. The in-plane destabilising effects of the longitudinal compressive stress on the behaviour of these plates are included.

In presenting experimental results on turbulent wall jets, most workers have adopted as basic scales the slot height b and jet exit velocity Uj. Although this is a natural choice, experience with other flows like jets and boundary layers, where the details of the initial conditions are eventually (if not always rapidly) forgotten by the flow, prompts the question: cannot a gross parameter like the jet momentum flux Mj rather than Uj and b separately, suffice to determine the flow, at least in some region where the wall jet may be said to have attained a “fully-developed” state? If the answer to the question is yes, it would give a more compact and practically useful description of the flow than is currently available.

The A300B, otherwise known as the European Airbus, is an international collaborative project. Hawker Siddeley Aviation are under contract to Airbus Industrie to design and manufacture the wing. Manufacture is now well advanced, the first wing having been delivered to Toulouse in November 1971.

In describing the aerodynamic development of the wing for this aircraft, it is necessary to describe events before the advent of the designation A300B, as the aerodynamic design philosophy was established prior to that date. In particular reference will be made to the preceding paper project the A300 and to a lesser extent to projects being considered before the opening of technical discussions between Sud Aviation, Deutsche Airbus, and Hawker Siddeley Aviation.