Looking back at the pioneering period of aviation one is struck by the almost complete lack of mechanical components in the early aeroplanes. Besides the single primitive engine there were no more than about a dozen hinges on control surfaces which, together with a few pulleys and levers, formed the entire mechanical system of the aircraft. As flying speeds increased, however, the need for mechanisms grew; retracting gear for the undercarriage became necessary, wings had to be fitted with flap gear, and engines and propellers received reduction gears and pitch varying mechanisms. The advent of the turbine opened further avenues for development; thus for flight at great heights cabin pressurisation became necessary, and supersonic flight demanded powered controls and flight stabilising mechanisms. Finally, a large family of VTOL aircraft, including the helicopter, came into existence.

Fretting is examined in its engineering aspects and then considered on a more theoretical basis. The mechanism of fatigue initiation by fretting is discussed, and also some of the methods proposed for the prevention of fretting. Some attention is also given to the fatigue life of joints when fretting does not occur. The difficulties that have been encountered in understanding fretting and assessing its consequences are thought to have a rather special significance. It is considered that there is now sufficient knowledge to put the whole subject tentatively on a rational basis, but more research is required to remove some of the uncertainties that still remain.

The title of this lecture is “The Operation of Naval Aircraft and Aircraft Carriers”, but its sub-title should be “New Aircraft into Old Carriers”, because I am going to talk about just one phase of the Aircraft and Carrier problem: that of converting our wartime designed Carriers so that they can operate our new Aircraft coming into service, particularly the Scimitar, Sea Vixen and N.A.39.

Those who have followed a career similar to mine have generally displayed an interest in things mechanical from an early age. I was true to type in this respect, and showed my liking for making things from as early as I can remember. This was not because I was taught to do so, for my father died when I was only six. However, I inherited a fine kit of tools which I had seen him use, and I taught myself to use them.

As early as 1910 I constructed some balloons, one about 15 ft. in diameter which rose fully 1,000 ft. and drifted miles over the countryside. I made large kites and some model aeroplanes with elastic motors which flew short distances.

An Annular Fairing can be used to control the flow through an airscrew, which is then generally referred to as a ducted fan. There are obvious affinities between such a fairing and the fairings used to control the flow through turbo-jet engines, but there are certain significant differences which have to be recognised when such fairings are designed. In particular, a fairing for a ducted fan is usually much shorter than one for a turbo-jet engine. Whereas it is usually convenient and justifiable to treat the internal and external flows of a turbo-jet nacelle separately and to consider the interactions between the intake and nozzle to be small, a short fairing must be treated as a whole. The simple calculations made in this note may give some indication of the order of fairing length where this becomes necessary.

The Farnboro Indicator gives a large permanent pressure-time diagram with a linear time base and pressure scale. In its latest versions accurate diagrams can be taken over a wide pressure range. The major disadvantage is that it can only be used for cyclic repetitive processes such as those occurring in engines or specially designed machines. During the course of an investigation of pressure wave phenomena in an exhaust pipe of a high-pressure-charged two-stroke cycle engine model the Farnboro indicator was used to record shock waves travelling along the pipe and to measure the total head pressure downstream of a nozzle placed at the end of the pipe and hence to calculate the transient velocity. In this note some of the pressure records taken in the investigation are presented.