Six years ago the present authors read a paper on “Aviation Spirit, Past, Present and Future.”

At that time the subject of special interest was the possibility of finding substitutes for petroleum spirit and a variety of alternative volatile combustibles was described.

Six years ago there happened one of the periodical scares regarding a possible world-famine in petroleum and naturally the chemist at that time was anxious, to find substitute fuels.

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.

Physical–chemical study of light fuels and of lubricants in Aeronautics. (M. Moutte, La Technique Aeronautique, Sept.–Oct., 1926, pp. 279-281 and 305-319) (8.51/5096 France)

Systematic tests of fuels in an engine on the test bench were commenced in 1917, in conjunction with a systematic determination of physical properties, and as far as possible of chemical composition. It was found that homogeneity, volatility and high latent heat of evaporisation were the most desirable qualities. In agreement with Ricardo, the aromatic compounds of hydrogen are found to be the least amenable to propagation of explosion, then the saturated cyclic compounds, and lastly the saturated acyclic compounds. In identifying fuels use is made of characteristic curves of distillation:—

Temperature—Volume Distilled, Density;—Volume Distilled.

Temperature—Density, Temperature—Solubility.

Temperature of distillation plotted against critical temperature of solubility in aniline gives highly characteristic differences, and is considered a fundamental method. Optical methods are also used for approximate quantitative determination. The formation of clouds of condensed drops affords another method of determination. The mechanical conditions were also examined:—Variation of inlet pressure, condensation, centrifugal separation.

The subject of the carburettor as opposed t o fuel injection is one which has created much controversy in aero engine design and development. Current opinions both in this country and abroad are many and varied and it would be presumptuous to forecast which will eventually predominate. The object of this paper is to present an unbiased review in the hope of provoking a useful interchange of opinions and experiences.

It might be argued that claims for one system can be countered by claims for the other and to be impartial it is necessary, therefore, to be familiar with as many facts and as much published information as possible. Owing to the meagre amount of information available on fuel injection, the paper is not as complete a review as the authors would wish, but it is hoped that sufficient material has been presented to be helpful to those who are interested in the subject.

A general expression is obtained for the potential of sound or aerodynamic disturbance from a source moving with variable vector velocity, based on linear theory. Knowing the space time curve for the source, the Doppler frequency corrections and intensities can be determined. If in any part of its trajectory the aircraft exceeds the velocity of sound, the number of sonic bangs and the times of occurrence can be calculated. A numerical example is given. The following conclusions are deduced: (i) If at any point of its trajectory, the component of the aircraft velocity in the direction of the observer is equal to the velocity of sound, a sonic bang is propagated to the observer with the velocity of sound. This has been previously postulated by C. H. E. Warren. (ii) A bang as determined by conclusion (i) comprises two components and in certain circumstances the components in some of the bangs may be acoustically separable, thus giving rise to double bangs.

The importance of healthy relations between the sporting and the scientific sides of gliding is very great; and the fact increases the responsibility of my task this evening as well as the honour that the Council of the Aeronautical Society have done me in asking me to undertake it. The history of gliding on the continent shows that at times when financial or other difficulties have given cause for anxiety, some development suggested on the scientific side has rekindled enthusiasm and given the movement a new vitality. Change is as essentially connected with a healthy sport as with a living organism. Nobody can visit the Wasserkuppe without being impressed by the zeal which prevails there; it is almost religious in its fervour, and although some of the neophytes of the hierarchy may be mere gymnasts fired with the team spirit, its bishops and its missionaries are inspired by their determination to advance knowledge.

The purpose of this paper is to illustrate the research and development work necessary to improve existing products and to anticipate demands for new products facilitating the advance in efficiency and performance of aircraft. The experience of Thornton Aero Engine Research Laboratory, in which the author has worked since it came into operation in 1941, has been drawn on almost entirely.

Recent developments in the design of rigid airships, as commercial air liners in England and Germany, and for military purposes in America, show a demand for greater lifting capacity, cruising range and speed. The increase in size is mainly responsible for radical changes in the structural arrangement of the transverse frames, introduced by the designers of the British airships, R.100 and R.101.

The buckling of skewed plates with clamped edges and under externally applied shear, and skewed plates with simply-supported edges but with both externally applied axial and shear loading have been considered previously. It is the purpose of the present note to consider the buckling of simply-supported rhombic plates under externally applied shear as shown in Fig. 1.