Tanks in the form of a surface of revolution are sometimes employed for carrying fuel. The purpose of this paper is to show how the stresses, due to the internal hydrostatic pressure, in a shell of this kind can be calculated when the equation of the generating curve is given. The acceleration imposed on the shell and its contents will be assumed to be at right angles to the axis of revolution, hence shear as well as direct stresses are set up. It will be supposed that no longitudinal bulkheads are fitted, and the shell will be taken as very thin so that the bending stresses in it are negligible. No attempt will be made to examine the stress distribution in the neighbourhood of a relatively rigid supporting ring; as shown by Timoshenko these ‘ end effects ’ are appreciable only in the immediate vicinity of the support. Nor will the stability be considered of those portions of the shell which are subjected to compression. Thus attention will be confined to what are commonly described as the membrane stresses.

To claim that communications have unified our world is by now to voice a truism. Within the span of a generation we have thrust headlong into an age of transition and readjustment, the definitive trend of which is towards a world-wide mobility of goods, ideas, and the citizens who produce them. The role of the air route in this process is no longer a matter of dispute, and it is clear that the time has come to consider certain technical questions which underlie any detailed scheme for a truly international network of airways.

Earlier sections have dealt with engines which have been developed almost entirely with the object of war and destruction. The fighter engine has been pushed all the time harder and harder to obtain greater output, with increased rate of supercharge, higher critical altitude, and more power to manœuvre under all possible conditions and attitudes of the aircraft. Performance has been achieved at almost any expense, provided reliability was ensured for a given period; such items as the time between overhaul and fuel consumption have been secondary considerations. In a similar way bomber engines have been continually stepped up in power to give maximum output at rich mixture for takeoff, so as to project the greatest possible load of bombs into the air, and every attention has also been given to providing the highest weak mixture cruising power at altitude, in order to allow for the necessary power to maintain flight at a reasonable altitude during the early part of the mission, when the machine is fully loaded.

To the aircraft designer and contractor, those of us responsible for equipment may appear as arch-perpetrators of complex, bulky and weighty “ gadgets,” impossible to install and the source of all unsightly excrescences on the aircraft's skin.

Any aircraft, from its inception should be designed for some specific role, and its usefulness may well depend upon the availability or simultaneous development of equipment.

A structure with cut–outs or other discontinuities is generally considered to be more difficult to analyse than a similar structure without such features, although it is in fact less redundant. This is largely due to the special conditions which have to be introduced to allow for these discontinuities, tending to make the calculations less adaptable to routine computation . Another and very practical reason is that it is sometimes fairly easy to—dare we say it?—make a reasonable guess at the load distribution in a structure without cut–outs, whereas a much more critical approach is necessary for the treatment of structural discontinuities. Be that as it may, it will be assumed here that the structure without discontinuities, which will henceforth be termed the “original” structure, can be analysed exactly, in the sense that all the effective redundancies are taken into account. It will now be shown how these calculations may be modified to deal with the corresponding structure with discontinuities, which for this reason will be referred to as the “modified” structure.

When considering the engine programme for the 1927 Schneider Trophy Race, a study was made of the machines used in the race held in 1925.

There appeared to be a considerable divergence of opinion between experts as to the best form of engine to adopt. Some thought it would be essential to have a Vee type of engine. Some thought the “Lion” or “Broad Arrow” type to be suitable. This view was supported by Mr. Mitchell in the discussion on the paper on the 1925 race read before the Society by Major Buchanan in January, 1926. Others seriously considered the radial type of engine.

We of the Napier Company were, perhaps, a little biassed, but we thought the “Broad Arrow” type of engine would be best under all the circumstances, and in view of the accumulated experience we had of that type, it could be developed to a very high standard of mechanical performance and power output.

The introduction of German “Stukas“ has been one of the great surprises of the present war. By means of this weapon, daring men, with the true fighting spirit, have already obtained innumerable successes of the greatest importance on all fronts. These results could not have been achieved but for the conviction that German scientists, and engineers had so perfected the design of this divebomber that it could withstand the exceptional demands made on it—especially on the engine and airscrew.

On the assumption that for winged flight a man would have to rely on the phasic activity of his muscles (that is to say on an activity induced by nerve impulses from the brain at a rate of 50 per second, or thereabouts) it is easy to believe that for man such flight is impossible.