The paper “Aircraft Servicing” by Norman and Wilkinson published in the November issue of the Journal demands the close attention of both operators and aircraft manufacturers. The suggestions made can be further developed.

There is little doubt that the attainment of higher utilisation rates is one, if not the ultimate, solution of the economic problems that face air transport. This is even more evident when the present–day capital cost per pound of complete but unladen weight of varying transport vehicles is compared.

One of the latest branches of scientific research in which aircraft have been employed is that of polar survey and exploration. It is well known how much time can be saved, and how much labour avoided by using aircraft for surveying large areas of difficult country. There is probably no part of the world more difficult of access than the regions surrounding the two Poles, and there is certainly no part of the earth where exploration and survey is harder to carry out.

In the Realm of stability and control, we are at present travelling headlong into a region of new problems. Besides tidying up the outstanding items on the types of aircraft we are used to seeing flying about to-day, a not inconsiderable task when one considers the troubles we encounter when we undertake the design of a new so-called “conventional” aeroplane, we have to tackle two major lines of research and development. First, the peculiar problems associated with the stability and control of aircraft of large size, both military and civil, into which difficulties associated with high Mach numbers intrude themselves but little; and secondly, the even more extensive problems associated with the stability and control of aircraft, both large and small, which are to fly at very high Mach numbers, not only at their design cruising and diving speeds, but also in the extremely important slow speed conditions. Mr. M. B. Morgan of the R.A.E. has dealt with some aspects of the second series of problems, so I propose to concentrate on some of the problems involved in the first series, that is those primarily associated with the increase of aircraft size.

In 1917–19, Barling and Webb, Berry, Cowley and Levy, and Webb and Lang discussed the elastic stability of struts of various tapers, but it appears to have escaped notice that one of the few cases in which formal integration is possible is that in which the tapered profile of axial longitudinal sections is part of a parabola; this gives a “ homogeneous linear “ differential equation, i.e., a linear equation of the form f (xd/dx) y = F (x).

It is now rather more than three years since I last had the honour of presenting a paper before this Society dealing with air-cooled aero engines. At that time the air-cooled engine had not fully won a place “in the sun,” which may be fairly stated to be the case to-day.

For some years after the war there was a considerable aversion towards the air-cooled aero engine owing to certain types which had been developed during the war which were supposedly air-cooled, but in reality obtained the greater portion of their cooling by means of exorbitant fuel and oil consumption. As lately as four years ago the practical advantages of the air-cooled engine were only tentatively appreciated by the aircraft constructor, and naturally, owing to his somewhat painful experiences in the past in respect of unreliability and high fuel consumption; it required some missionary work and proof in order to persuade him that the new family of air-cooled engines would really perform in the way their designers claimed for them.

The Focke helicopter presents the first successful solution of a problem which has occupied aeronautical science for a considerable time. Details of the record flights carried out last year caused a world sensation and with further development it is not too much to hope that this new type will open up fresh fields which up to now remained closed to orthodox aircraft.