# Showing papers in "Aircraft Engineering and Aerospace Technology in 1949"

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TL;DR: The introduction of statistical methods into the analysis of aeronautical experimental data, whether for quality control in production, for the interpretation of the results of structural and aerodynamic laboratory experiments, or for airline operation, has been brought about only in recent years, it may by now be fair to assert that their advantages are no longer in dispute.

Abstract: WHILE the introduction of statistical methods into the analysis of aeronautical experimental data, whether for quality control in production, for the interpretation of the results of structural and aerodynamic laboratory experiments, or for airline operation, has been brought about only in recent years, it may by now be fair to assert that their advantages and even their indispensability are no longer in dispute. Hitherto, investigations on these lines have usually involved, explicitly or implicitly, only the ‘normal curve of error’ and allied considerations; owing, it may be thought, to the controllability of the various manufacturing or laboratory techniques, but also perhaps to the scarcity of data hitherto available. It may well be, however, that with the accumulation of information arising out of investigations planned with particular reference to the statistical analysis of their results the whole range of the apparatus for statistical analysis, usually confined to such fields as those of biology or economics, will be called into full play.

350 citations

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TL;DR: In this paper, the problem was reduced to that of the construction and solution of two equations governing the variation of these parameters around the surface of the cylinder considered, and the second condition was selected.

Abstract: AN approximate solution of the boundary layer equations recently completed involved the assumption of a velocity profile through the boundary layerdepending on two parameters. As a result the problem was reduced to that of the construction and solution of two equations governing the variation of these parameters around the surface of the cylinder considered. Earlier solutions, such as Pohlhauscn's, have made use of a single parameter only and have employed Karman's momentum integral for its determination, but the additional, parameter now introduced necessitates the use of a further equation. It is the purpose of the present note to discuss and illustrate the properties of the second condition that was selected.

13 citations

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TL;DR: Armstrong Whitworth Aircraft Ltd. as mentioned in this paper took a serious interest in the design and development of tailless aircraft and today two types of aircraft are undergoing research flight testing, one of which is a Tailless Aircraft.

Abstract: SIX years ago Sir W. G. Armstrong Whitworth Aircraft Ltd. began to take a serious interest in the design and development of tailless aircraft and today two types arc undergoing research flight testing.

5 citations

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TL;DR: In this article, an investigation of the control and stability characteristics of a tailless aircraft was carried out in flight using a glider under the auspices of the National Research Council of Canada.

Abstract: FOR some years there has been proceeding, under the auspices of the National Research Council of Canada, an investigation of the control and stability characteristics of tailless aircraft. Because of the difficulties inherent in other methods of investigation, the work is being done in flight, using a glider.

3 citations

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TL;DR: This is the type of panel which has received most attention from investigators and the critical load for local wrinkling of a single skin of thickness t is most simply expressed as as mentioned in this paper.

Abstract: THIS is the type of panel which has received most attention from investigators and the critical load for local wrinkling of a single skin of thickness t is most simply expressed as

2 citations

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TL;DR: Gibrat, Divisia and Beckel as discussed by the authors showed that the summation curve of most skew distributions may also be represented as a straight line, if the argument x is traced as log (±x±a), where a is an arbitrarily chosen constant, which may, but need not, represent a physical condition.

Abstract: PROBABILITY paper was originally used to represent the summation curve of a Gaussian distribution as a straight line. Gibrat, Divisia in France and Daeves and Beckel in Germany have shown, that the summation curve of most skew distributions may also be represented as a straight line, if the argument x is traced as log (±x±a), where a is an arbitrarily chosen constant, which may, but need not, represent a physical condition.

2 citations

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TL;DR: In this paper, a new approximate solution of the boundary layer equations devised to meet difficulties that are encountered in applying earlier solutions to laminar flow aerofoils and similarly thin cylinders is presented.

Abstract: ANOTHER paper (Ref. 1) establishes a new approximate solution of the boundary layer equations devised to meet difficulties that are encountered in applying earlier solutions to laminar flow aerofoils and similarly thin cylinders. The advantage is in respect sometimes of accuracy, sometimes of applicability. The solution is a little unwieldy in its general form, however, and the present paper describes simplifications to facilitate rapid technical use. They are of two kinds, one being much more drastic than the other, and that first given, or both, may be used according to the nature of the problem and the accuracy required. Examples suggest that the resulting loss of accuracy and applicability will be small in most instances. This matter is described in Section I.

2 citations

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TL;DR: In a recent issue of AIRCRAFT ENGINEERING Mr R. H. T. Harper as mentioned in this paper gave an account of the design considerations which led his company into using composite wood and metal spars for the Hornet single-seater fighter.

Abstract: IN a recent issue of AIRCRAFT ENGINEERING Mr R. H. T. Harper, of Messrs de Havilland Aircraft Co. Ltd., gave an account of the design considerations which led his company into using composite wood and metal spars for the ‘Hornet’ single‐seater fighter. Such a method of construction was made possible by the development of the ‘Redux’ process for bonding metal to wood by Messrs Aero Research Limited, Duxford, and it was the first of a number of advanced designs made possible by this new process. They have already been described at some length in a number of articles in the technical press (see Bibliography), and it is only necessary to state here that when using the ‘Redux’ process for bonding metal to wood the strength of the bond is always greater than that of the wood itself even at 100 deg. C., and that the process can equally well be applied to the gluing of metals to metals (e.g. see the description of the use of ‘Redux’ on the de Havilland ‘Dove‘ given in The Aeroplane, September 20, 1946).

1 citations

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TL;DR: In this article, the authors present a procedure for the design of a redundant structure by assuming some initial distribution of material and then to stress this by strain energy methods, from the knowledge of the load distribution thus acquired, a second structure is designed and stressed and the process is repeated, if necessary, until a reasonably uniform stress is obtained.

Abstract: THE procedure usually adopted for the design of a redundant structure is to assume some initial distribution of material and then to stress this by strain energy methods. From the knowledge of the load distribution thus acquired a second structure is designed and stressed and the process is repeated, if necessary, until a reasonably uniform stress is obtained.

1 citations

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TL;DR: In this paper, the influence of the walls of a closed tunnel in increasing the velocity in the neighbourhood of a model under test is discussed. But the authors do not consider the effect of the boundary layer on the tunnel walls.

Abstract: THE paper reviews the problem of the influence of the walls of a closed tunnel in increasing the velocity in the neighbourhood of a model under test. It is shown that, for a perfect fluid, considerations of continuity suffice to establish an exact value of the mean interference velocity for any cross‐section of the tunnel. This mean interference velocity is expressed in terms of the perturbation velocity which would be caused by the same model in the absence of the walls. The linearized theory of subsonic compressible flow is applied and it is shown that the interference velocity for a small two or three dimensional model is increased in proportion to l/β3, where β=√(l—M2) and M is the Mach number. Interference caused by a body with a long parallel middle body, the influence of the wake from a model and of the boundary layer on the tunnel walls are briefly considered.

1 citations

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TL;DR: In this article, the importance of achieving a low structural weight is illustrated by simple estimates of the large decreases in aircraft gross weight and size made possible by conscientious weight saving in structural design.

Abstract: THE importance of achieving a low structural weight is illustrated by simple estimates of the large decreases in aircraft gross weight and size made possible by conscientious weight saving in structural design. A brief review is then made of the many variables in aircraft design which affect the weight of the structure. The review is made chiefly to emphasize the close interplay in project work between the structural and aerodynamic effects of changes of layout. Finally some remarks are made about comparative structural design efficiency. It is concluded that good weight prediction formulae are at present the best means by which the structural design efficiencies of different aircraft may be readily compared.

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TL;DR: The body temperature is the result of the automatic balancing of this heat production, which is more than the amount needed to keep the body warm, and the heat loss from the body.

Abstract: IN designing for passenger comfort in modern commercial aircraft, many laboratory tests and research investigations have shown that the fundamental requirement for human comfort is physiological, and can be summed up by saying that the optimum conditions for comfort are those existing when the body can maintain complete thermal equilibrium, with only minor adjustments in the heat regulating mechanism of the body. Heat is produced in the human body by the process known as metabolism, in which food is oxidized, or absorbed, by the cells in the body. The body temperature is the result of the automatic balancing of this heat production—which is more than the amount needed to keep the body warm—and the heat loss from the body. Heat is lost by radiation, convection, and evaporation. The radiation loss is dependent upon the skin, or clothing, temperature, and also the temperature of any surrounding surfaces. The convective heat loss is a function of air velocity over the body and a positive temperature differential between the skin, or clothing temperature, and that of the surrounding atmosphere. The evaporative loss is a function of temperature, velocity, and humidity, and takes place when the partial pressure of the water vapour in the surrounding air is less than the pressure of the moisture on the skin, or in the lungs.

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TL;DR: For the correct and intelligent use of plastics, it is just as important to identify each one as it is in metals to be able to tell aluminium alloys from magnesium alloys or mild steel from high tensile steel, or in timbers to discriminate between birch, spruce and mahogany.

Abstract: FOR the correct and intelligent use of plastics, it is just as important to be able to identify each one as it is in metals to be able to tell aluminium alloys from magnesium alloys or mild steel from high tensile steel, or in timbers to discriminate between birch, spruce and mahogany.

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TL;DR: The need for accuracy in estimating the component weights of project designs cannot be over-emphasized, forming, as they do, an important part of the stressing and performance calculations.

Abstract: THE need for accuracy in estimating the component weights of project designs cannot be over‐emphasized, forming, as they do, an important part of the stressing and performance calculations. Of the items controlled by the airframe manufacturer, the wing is not only the heaviest (often representing as much as 50 per cent of the structural weight), but is also the most difficult to predict. In order to arrive at a suitable figure, numerous formulae have been used in the past, these falling into two broad categories:

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TL;DR: It is paradoxical that we are endeavouring to supplant hydraulic power by other, alternative, media at a time when it is being successfully applied to purposes for which it is admirably, if not perhaps exclusively, suited.

Abstract: IT is paradoxical that we are endeavouring to supplant hydraulic power by other, alternative, media at a time when it is being successfully applied to purposes for which it is admirably, if not perhaps exclusively, suited.