A meeting of the Royal Aeronautical Society was held in the lecture hall of the Institution of Civil Engineers at Great George Street, Westminster, London, S.W.1, on Thursday 5th December 1946, at which a paper by Mr. J. K. Hardy on “ The Protection of Aircraft Against Ice,” was presented and discussed. In the Chair, the President, Sir Frederick Handley Page, C.B.E.

A meeting of the Royal Aeronautical Society was held at the Institution of Civil Engineers, Great George Street, Westminster, on 11th December 1946, at which a paper, “ Lofting and Template Reproduction,” by Mr. S. P. Woodley, was read by Mr. L. G. Burnard. In the Chair, Sir John Buchanan, F.R.Ae.S.

In this paper an explanation is furnished as to why linear simultaneous equations arising in structural problems are, in certain circumstances, sensitive or “ill-conditioned,” and an indication is given concerning the physical significance of this sensitivity. Means are also discussed whereby difficulties of this kind may be overcome.

The title of this paper is the result of practical experience in the maintenance of aircraft, combined with a view to trying to improve the design standard in future aircraft. In the past, engineers, especially aircraft engineers, have put up with a considerable amount of poor maintenance design and have gone on improvising time and time again as the only solution to their problems. As a result of this improvisation it is probable that those concerned with the actual design do not realise many of the difficulties experienced in the maintenance of their aerodynamically efficient aircraft.