With the exception, possibly, of the detective thriller most stories are best enjoyed by starting at the beginning. My story is no exception and, if i am to give you some feeling for the accomplishments in aeronautical research in my Country during the past ten years, I must refer briefly to what had been done already in Canada during the earlier years of this century.

Sir William Hildred, C.B., O.B.E., Director-General of I.A.T.A., in his Annual Report, which he presented at the I.A.T.A. Conference in Paris in the middle of September 1954, pointed out that there was an urgent need for a drive for greater efficiency to obtain a balanced airline economy. He quoted some interesting I.C.A.O. figures. These covered all the world's scheduled operators, both the profit-making and the loss-making companies. In 1951, the world's airlines showed that total operating revenues were 6 per cent, higher than total costs. In 1952, this figure was down to 3·6 per cent, and in 1953, down to 1·1 per cent., which represented $27-million profit on a total business of $2,500-million. It should be noted that this $27-million profit is arrived at after the pay-out of direct taxation by the profit-making companies to the tune of $69-million.

It has been adequately demonstrated that the reduction of structural and aeroelastic problems to a form suitable for computation is best done using a matrix formulation. The present paper outlines such a formulation of the aeroelastic problems on wings of arbitrary plan form and gives a method of solution which has been found satisfactory over a wide range of practical calculation. In the symmetric case the problem of manoeuvre margin due to aeroelastic effect is considered and in the anti-symmetric case the rolling effectiveness and the reversal speed for aileron controls are dealt with.

The effort required to produce very accurate supersonic nozzles has suggested the need for criteria from which the order of accuracy required for quantitative experiments can be deduced. The purpose of this note is to indicate a way of obtaining such criteria for measurements of aerodynamic forces, but also to point out that “ sufficiently accurate ” nozzles for such measurements are indeed very difficult to produce and to suggest that a remedy might first be sought in interference corrections.

From Mr. A. M. Dobson's Note (July 1955 Journal, page 506) which dealt with the stability of an axially loaded continuous beam, and other contacts we have had with the Aircraft Industry, it would appear that the very considerable developments of structural theory which have taken place in relation to continuous beams subjected to axial load, as employed in normal structural steel work, are not well known in aircraft stress offices. The list of references appended may then be found helpful.

A convenient method is pointed out for calculating the response of a damped linear system with one degree of freedom to harmonic excitation. Results of such calculations are usually represented by the familiar “ resonance curves ”—one curve being plotted for each intensity of damping. These curves are not particularly convenient to use and Yates has overcome several of their defects by throwing them into a nomographic form. Yates' nomogram is based upon the concept of viscous damping and it does not give the information of a conventional set of resonance curves in that it relates to the velocity of vibration. By changing over to hysteretic damping, a nomogram of somewhat similar form may be constructed such that it gives amplitudes and phase angles of displacements while retaining the advantages, over resonance curves, of this form of representation.

The effect of discontinuities on the analysis of structures is discussed by W. J. Goodey in a Technical Note in the October Journal. He quite rightly points out that a structure with cut-outs is more difficult to analyse (especially for routine calculations) than a structure without cut-outs. Subsequently he indicates a procedure for obviating the former complications by introducing fictitious members in place of the cutouts. Using then the variational method of arbitrary multipliers he derives the stress distribution in the structure with cut-outs from the simpler analysis of the structure without cut-outs.

The paper by Dr. A. H. Chilver (October 1955 Journal) purposed “ to present alternative theoretical approaches to the problem of local instability of a simple type of panel with unflanged stiffeners.”

Examination of these alternative approaches reveals that they are in fact identical and are based on the same approximate representation of the buckled form of the plate by sinusoidally varying lengthwise and transverse deflection, and of the stiffener by sinusoidally varying twist. The difference in the results obtained by Dr. Chilver is explained by the fact that whereas in the first analysis he uses plate theory correctly to express the strain energy in the stiffener, in his second analysis he omits entirely the torsion-bending energy.