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IN Aeronautics as in other branches of science, applications of the “theory of dimensions” have been of great assistance, as the customary use of coefficients, which are in effect non‐dimensional variables, testified. In most text books of physics rules are given for obtaining dimensional relationships in any problem, but in practice the methods recommended are seldom used. The procedure suggested by the text books is recapitulated in Bairstow's Aerodynamics (p. 380), but the author adds, “After a little experience in the use of the method … it is possible to discard it and write down the answer without serious effort.”

THE aim of aviation engine research is to produce engines of higher power‐weight ratio, and of lower specific fuel consumption. To enable the full benefit of the power to be obtained when the engine is installed in an aeroplane, the shape of the engine must permit of a well streamlined cowling, and the means of cooling must provide the required heat dissipation with a low attendant drag. Finally, the running time between overhauls must be kept in view, and there must be good reliability, and good facilities for inspection and maintenance.

Every organisation invests in design to create and develop distinctive products and services. The development of a coherent design and marketing philosophy is essential to the achievement of a longer‐term competitive edge. However the marketing literature hardly refers to design and where it does so there is a great deal of confusion as to what design means. Design is taken to encompass styling, fashion and product development and innovation. Key findings of a major study recently undertaken by the Design Innovation Group (DIG) are reported here. The research investigated the risks and rewards of investment in design by British companies participating in the Department of Trade and Industry/Design Council′s Funded Consultancy Scheme and subsequent Support for Design Programme. The study showed that investment in design does pay. But design effort could be more fully exploited if marketing practitioners as well as other managers acquired design management skills.

IT has been the practice at the official Air Ministry Testing Establishments at Martlesham and Felixstowe to issue with each complete performance report an analytical picture of the performance. This picture is commonly called “Figure 4” because it appeared as Fig. 4 of R. & M. 1140. It is reproduced in Fig. 1. Its physical significance is by no means apparent, and to the practical engineer who appreciates physical significance mainly through his visual imagination it must sometimes have been more mystifying than simplifying. But, as is shown in what follows, the physical significance can be explained naturally and elegantly in terms of the “unit plane” of unit size and wing loading.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the U.S. National Advisory Committee for Aeronautics, and publications of other similar research bodies as issued

THE flight of a formation of seaplanes to America and back, recently completed by the Italian Air Force under the personal leadership of the Secretary of State for Air, Air Marshal Balbo, is one of those performances which can be accorded wholehearted approval.

In estimating the change of performance of an aircraft resulting from a change in the airscrew‐engine unit—for example, in considering the possible improvement of performance clue to an alteration of gear ratio or to fitting a variable pitch instead of a fixed‐pitch airscrew—the selection of appropriate characteristics and the estimation of the resulting performance is frequently rather troublesome. The absence of airscrew data in a form convenient for immediate application generally makes the computations lengthy.

AIRSCREW noise, engine noise and aerodynamic noise combine to produce the high noise level of an aeroplane. Much information has been obtained experimentally concerning these noises and the loudness level they produce when occurring together. The possibility of applying this information, to predict the noise level of projected aircraft, recently promoted a further review of the data, and some new expressions were framed, which, together with other older and well‐tried formulæ, linked together tolerably well the results of the several experiments. These empirical laws, which have proved of considerable value in several problems relating to the improvement of aeroplane noise, are now put forward. At the same time the basic experiments are outlined so that those who may use the expressions will be aware of possible limitations.

AN interesting feature of modern aeroplane design is the growing use of duct systems. The low drag and heat regeneration obtainable from a cooling duct is now an accomplished fact. Ventilation systems for cabin aircraft have been introduced. In the future we may see duct systems used in connexion with the control of the boundary layer. As aeroplane design is improved, new applications of duct systems continue to appear.

THE influence of the surrounding atmospheric conditions on the power developed by an internal combustion engine has been the subject of a number of experimental investigations and theoretical discussions. The mass of experimental data dealt with and the rather involved arguments employed have, in some instances, tended to obscure the main issues of the problem.