bluuebunny/crossref_metadata_2025 huggingface dataset:
The Problem of Vertical Flight
Authors: Crowe J.H.
Published: November 2014

THERE is, however, one method of considering the problem theoretically which is given tentatively here. Assuming the helicopter has its blade angle reduced so that it will auto‐rotate, the power required to sustain the screw is given by equation (10). This power must be precisely the same as that expended in dropping at its normal velocity Vv because, considering an interval of time t, there is a certain difference of potential energy between the two machines—one hovering, the other descending. In the same time t, therefore, there must be an equivalent input of energy to sustain the helicopter to balance the difference in potential energy. We are considering now only airscrew horse‐power, not engine horse‐power. The power expended in dropping at Vv is WVv. Therefore we have or Put in another form by means of the previous equations:
Colloidal Graphite in Oils
Authors: Higinbotham H.
Published: November 2014

IN order to discuss the manner in which colloidal graphite aids lubrication it is necessary to consider a piece of metal, the surface of which has been recently finished by some machining process. A material is only held together by reason of the attraction that the atoms of which the material is composed have for each other. In the body of the material each atom is surrounded by several other atoms to which it is attracted, but it cannot move under the influence of these attractions, because they balance. The atom at the surface of metal, however, has attracting atoms on the material side only; consequently there is a tendency for such an atom to be pulled inwards. The state of stress produced in this way is known as surface tension. This explanation could perhaps be better followed by picturing the atomic structure of a material in which two atoms only go to form the molecule, as in salt, where each atom of chlorine has its corresponding or companion atom of sodium, as pictured in Fig. 1.
Freezing In Carburettors
Authors: Swan Andrew
Published: November 2014

ICE formation in the carburettor or induction system of an aircraft engine may cause a serious loss of power, and if the ice continues to build up it will eventually cause complete failure of the engine. In consequence of this possibility the Air Ministry undertook, at the Royal Aircraft Establishment, a comprehensive investigation to determine the conditions under which ice is formed and to find means to prevent or remove it. The research has been attended by marked success, and the present article deals with the more important features of the work with particular reference to the practical considerations arising from it. The full results of the research are given in a paper by W. C. Clothier on “Ice Formation in Carburettors,” published in the Journal of the Royal Aeronautical Society, No. 297, Vol. XXXIX.
Shear Stresses in Hollow Sections
Authors: Goodey W.J.
Published: November 2014

THE shear stress distribution in hollow sections subjected to bending and torsion is a subject about which there does not appear to be much information in standard text books, and a knowledge of the theory and its numerical application is becoming important to the aircraft designer in view of the increasing popularity of the stressed‐skin type of construction.
The New Altitude Record
Authors: Weir R.H.
Published: November 2014

A study of the world altitude records for heavier‐than‐air aircraft homologated by the Fédération Aéronautique Internationale is interesting, and yields the information that from 1909 to 1914 the mean rate of increase of ceiling was almost 4,500 ft. per year, while from 1920 to 1936 the mean rate dropped to 1,000 ft. per year. Slumps, depressions and other financial phenomena must obviously have a repercussive influence in this particular field of aircraft development, and a pertinent example of their effect is provided by the unfortunate hiatus which occurs from 1914 to 1920, and obscures the height at which the change in rate takes place. It has been shown by Mr. McKinnon Wood, in an unpublished paper on the design of an aeroplane to reach a great height, written in November, 1931, that the power which the engine must develop at ceiling increases as the ceiling is raised, and that, in the case of a supercharged engine, the difference between the supercharged height and the ceiling of the aircraft decreases as the ceiling increases. Thus, to maintain the initial rate of increase of ceiling an accelerating rate of progress in engine design was necessary, but unlikely in view of the increasing number and difficult nature of the problems to be encountered and solved.
Some Notes on Tapered Wings
Authors: Irving H.B.
Published: November 2014

THE change from the parallel wings of the now obsolescent biplane to the tapered wings of the monoplane, usually fitted with flaps, raised a great number of problems, both aerodynamic and structural. Work on these has been pursued vigorously during the past few years, but the designer is still some considerable distance from having all his questions answered. For instance, further information is required as to the relation between wing thickness and profile drag before it can be decided what is the maximum thickness which can be used, taking both aero‐dynamical and structural considerations into account. This question is complicated by the fact that, so far as the tip sections are concerned,. the indications are that the thickness ratio has important effects on the nature of the stall, violent or gentle. So, too, will such factors as centre line camber and position of maximum ordinate affect the nature of the stall in greater or Jess degree. Added to these factors there is, of course, the important one of the taper itself, including—as is now realised—the question as to the way in which the tapering is done, that is, whether by sweeping the trailing edge forward or the leading edge back, or, as is more usual, a combination of the two.
Longitudinal Stability
Authors: Crowe J.H.
Published: November 2014

THE basic theory of stability has undergone no important modification since the publication of Professor G. H. Bryan's book on Stability in Aviation in 1911. The stability equations derived therein serve to‐day with the difference that axes and symbols have now been standardised and with the additional refinement of a non‐dimensional form of the stability equation introduced by H. Glauert. Due to the vastly increased knowledge of aerodrynamic characteristics, however, the stability derivatives are more readily assessable in any particular design case. This applies more particularly to longitudinal stability calculations which may, and indeed often arc, carried through with no wind tunnel tests available apart from a lift and drag curve for the aerofoil section used. There has also been some extension of the use of stability charts for deriving an approximate knowledge of the behaviour of the aeroplane when it receives a disturbance. These charts are exceedingly useful for obtaining periodic time and damping factor, but the assumptions on which they are based should be clearly realized.
Composite I‐Section Beams
Authors: Dudley Leslie P.
Published: November 2014

IT is shown in the present paper that a beam may be constructed, consisting of a steel section securely bolted to a lower section of high‐tensile aluminium alloy, having a weight much lower than that of a plain steel beam of equal strength. This is frequently desirable when the weight of a steel beam would be excessive, but the cost of a section constructed entirely of aluminium alloy is unwarranted.
The First Chinese Wind‐Tunnel
Authors: Wattendorf F.L.
Published: November 2014

THE 5‐ft. wind‐tunnel of the National Tsing Hua University in Peiping was the first wind‐tunnel to operate in China. The erection of the tunnel was a project of the Aeronautical Institute, established in 1933 as a division of the Mechanical Engineering Department. The organisation of the Institute at that time was carried out under the direction of Dr. Y. H. Ku, Dean of Engineering, and Prof. C. T. Chwang, in charge of the Mechanical Engineering Department.
Cutting Small Sheet‐Metal Blanks
Authors: Willis J.G.
Published: November 2014

IN the recent lecture on U.S. Methods of Aircraft Production given by Mr. T. P. Wright before the Royal Aeronautical Society the methods shown for cutting duralumin plates will be of interest to many people. Perhaps a brief description of a simple arrangement for cutting small blanks, which has been much used in America, will also be of interest and use to some readers.
Models in Structural Research
Authors: Williams D.
Published: November 2014

THE general use of monocoque structures for the wings and fuselages of modern aeroplanes has undoubtedly given rise to a crop of problems in stress distribution which are still far from a complete solution. Theoretical solutions are nearly always confined to simplified structures that are seldom met with in actual practice so that before a designer can apply a theoretical method He has first to convert the actual structure into one of the standard “simplified” structures. When, however, the actual structure is complicated by holes cut in the stressed skin covering and by other discontinuities no theoretical method can be relied upon for estimating the strength with a satisfactory degree of accuracy. The consequence is that the designer is driven either to piling on weight so as to be on the safe side or to checking the strength of the structure by some kind of test. To reduce the expense of such a test it is very desirable to carry it out on a small model of the actual structure, if it is at all possible to construct such a model with the necessary degree of similarity. Assuming for the moment that true similarity can be attained we shall here examine the relations connecting the behaviour of the model to that of the full‐scale structure.
Planning Fire Insurance—I
Authors: Gribble F.H.
Published: November 2014

THE rapid growth and development of the aircraft industry has necessitated prompt decision and action in handling the many problems in connexion with the erection and equipment of aerodrome buildings, hangars, workshops and factories. In the urgency of providing the industry with all its varied requirements, it is not surprising that lire insurance planning has to a very large extent been crowded out. There are, no doubt, several reasons for this and in the welter of plans and designs that have been drawn and re‐drawn, the necessity of complying with the clients' requirements, numerous rules and regulations of local authorities and Acts of Parliament, etc., the benefits which accrue to wise planning from a fire insurance point of view have not always been fully appreciated. The need for increased output has in many cases pressed very heavily on those making the necessary preparations, and frequently no serious thought has been given to fire insurance planning. There are some persons who are under the impression that, having conformed with the numerous rules and requirements, they have carried out all that can be done in this direction.
The Modern Twin‐Fin Tail
Authors: Shenstone B.S.
Published: November 2014

THERE are several reasons why so many of the newer aeroplanes are equipped with twin‐fin tails such as those shown in Fig. 1 (p. 312), the fins being disposed as end plates on the tail plane:
China's Large Wind Tunnel
Authors: Wattendorf F.L.
Published: November 2014

THE Tsing Hua 15‐ft. wind tunnel, with interchangeable 18‐ft. section for full scale engine and airscrew tests, was recently erected in Central China. It was planned as the central organ for aerodynamic research in China and, as such, was subject to interesting design conditions. The main features of the tunnel design, as well as the considerations underlying their choice, are described in this article.
Torsion and Flexure
Authors: Gurney C.
Published: November 2014

A SERIOUS difficulty in engineering is the bridging of the stream between the mathematician and the engineer. They have been from the start, to a large extent, on opposite sides, for whereas the mathematician is wholly a rationalist, the engineer is largely an empiricist. This empiricism of the engineer is not due to any innate dislike of reason, but rather to the inadequacy of reason to forecast experimental facts. In general, facts are discovered and are then shown to be rational; but once the reason underlying a known fact is produced, it furnishes a means of prediction in matters far beyond existing experience. The inability of the mathematician to produce a design technique as soon as it is required has led to some disparagement by the engineer, so that some engineers scorn to use any but the simplest formulaæ and base their design almost entirely on experience, even when adequate mathematical treatment is available. Others, who have little time for mathematical study, hesitate to use the results of the mathematical theory of elasticity because of their ignorance of the derivation of a formulæ and the consequent danger of misapplying it.
Rotary‐Wing Aircraft
Authors: Bennett J.A.J.
Published: November 2014

THE direct method of take‐off which has been successfully applied in the last few years to the rotaplane, commonly known as “jump‐off,” is achieved by setting the blade angle at a lower value than that required for flight and driving the blades to a high rotational speed, thereby storing kinetic energy in the rotor. This energy is partly transformed into potential energy whenever the blade angle is suddenly increased and the blades swing upwards about their horizontal hinges. If the excess of rotational speed above normal is sufficient, the aircraft is projected off the ground and rises until the excess kinetic energy has been absorbed.
The Prediction of Performance
Authors: Stepniewski Wieslaw
Published: November 2014

The aim of this article is to determine the simplest and clearest relations existing between the principal characteristics of aeroplanes and their performances.
Performance of a Jettison System
Authors: Brennan M.J.
Published: November 2014

IN the design of long range aircraft, the high percentage weight of fuel carried lias always tended to necessitate the provision of a system by means of which this fuel could be rapidly jettisoned, in the event of forced landing or continued flight on partial power. The provision of such a jettison system is now an important problem in ancillary design.
Thermal‐Air Jet‐Propulsion
Authors: Gohlke
Published: November 2014

EVERYBODY travelling in air or water by its own power applies the reaction or “repulse” principle, that is to say, it either takes up parts of masses contained within itself or, by means of suitable organs, gathers up parts of the surrounding fluid medium and accelerates these masses at a speed greater than its own travelling speed, and this generally in the direction opposite to that in which it desires to travel; whilst in certain cases, in addition to the force produced by the repulse, a further force is obtained through the forward suction of the fluid medium. Devices intended to utilize only the negative pressure produced by suction, e.g. through lateral ejection by means of radial surfaces running at very high (five‐figure) r.p.m. have not, in spite of repeated endeavours, proved successful.
Air‐line Engineering Management
Authors: Lusty Ivor
Published: November 2014

PROBABLY the most outstanding in‐dustrial tendency of recent years is the mechanization of production. In quantity production, machines have replaced men.
Rectangular Plates with Stiffeners
Authors: Ratzersdorfer J.
Published: November 2014

The Differential Equation of the Problem and the Solution. A RECTANGULAR plate of length a with simply supported edges is reinforced by equal longitudinal ribs at equal distances b and is submitted to the action of uniformly distributed compressive forces N along the x‐axis (Fig. 1). For every strip b we have the differential equation for the deflection w
Built‐in and Continuous Beams
Authors: Dudley Leslie P.
Published: November 2014

PROBLEMS relating to built‐in or rigid‐end members under transverse loading are frequently encountered by the aircraft engineer. In the following paper discussion of relevant theorems leads to the development of Clapeyron's Theorem of Three Moments. The latter is particularly valuable in, for example, estimating the crankshaft bearing loads in a non‐radial engine. Attention is also drawn to Wilson's method of solving continuous beam problems. This simple method produces results identical with those given by the Theorem of Three Moments and deserves wider recognition.
Kinetic Energy in Partial Climbs
Authors: Hurn A.G.
Published: November 2014

PARTIAL climbs are usually done at constant A.S.I, readings. In order to maintain constant A.S.I.R. during a climb, the true forward speed of the aeroplane must increase. Thus there is an increase in the kinetic energy of the aeroplane as well as an increase in the potential energy.
Two‐Spar Wing Stress Analysis
Authors: Goodey W.J.
Published: November 2014

IN an article in the June, 1941, number of AIRCRAFT ENGINEERING, the writer gave an approximate investigation into the stress analysis of a two‐spar skin‐covered wing, the basis of the method being the determination of the moments and shears induced in the spars by the skin covering. These moments and shears are then superimposed on the moments and shears which would occur in the spars were the skin covering to be removed, this latter loading system being statically determinate.
Fluid Flow Through Restrictions
Authors: Greenland L.S.
Published: November 2014

IN view of the extensive employment of fluids in the operation and control of modern aero‐engines and aircraft equipment, it is essential that a clear understanding of the laws governing the motion of such fluids is possessed by those interested in the design of the systems involved. In the various applications normally encountered in aeronautical work, such as the induction system of an engine, or the hydraulic circuit of a control system, the type of problem which arises most frequently is that dealing with the effects on flow produced by restrictions in the path of a fluid. It is obvious that there can be no limit to the variety of forms these can assume and one need only contemplate the fuel system of, say, a four‐engine aircraft to appreciate that a detailed analysis of the eifects produced by the numerous restrictions and changes of passage form is beyond the scope of an article of this nature. In fact, many such, cases can only be completely solved by experimental determination, since the flow characteristics depend entirely upon the conditions that prevail and for which no previous data of similar conditions may exist.
The Lateral Stability of Aeroplanes
Authors: Price H.L.
Published: November 2014

THE STABILITY CHARTS THE numerical results representing one of the primary aims of this paper are embodied in the 24 charts reproduced on pp. 282–4. These, while possessing some measure of generality, may readily be extended if desired so as to include a wider range of incidences, of inertia coefficients and of t. It is suggested that whenever a lateral stability investigation is made for any particular aircraft, the charts be used for a first approximation, and that this be followed by the construction of fresh E and R curves using the known values of the inertia coefficients and t. For this purpose all that is required is the filling in of one line of a table similar to Table II of Article II, and the drawing of a straight line and a hyperbola by a rapid and accurate method.
Rectangular Tubes under Torque
Authors: Ratzersdorfer J.
Published: November 2014

LET us consider a tube of length L of doubly symmetrical rectangular cross section, built‐in or simply supported at one end and free at the other. The tube is affected by uniformly distributed torques along the length and by a tip applied torque and torques at intermediate points.
A Philosophy of Strength Factors
Authors: Pugsley A.G.
Published: November 2014

IN aeronautical work the general engineering outlook in regard to the specification of strength factors has been supplemented by an appreciation of the unusually variable nature of the loads coming upon the aeroplane structure. The two questions have generally been treated as separate ones, and it is only recently that efforts have been made to bring them together by relating both to accident rates. In doing so we have on the one hand to allow for the frequency of occurrence of loads of different magnitudes and on the other hand to allow for the variation in strength among aeroplanes produced to a given design. The purpose of this report is to try, in a preliminary and elementary way, to weld these various aspects of the design of aeroplane structures into a logical and consistent whole—a philosophy of strength factors —and, by so doing, to reduce accident rates, to bring into better perspective some of our past problems, to point to ways of further development, and to prepare for making the fullest use of the speed and acceleration loading statistics now accumulating.
Rigidity of Wing and Tail Surfaces
Authors: Beilschmidt J.L.
Published: November 2014

IN an earlier article dealing with the general aspects of clastic distortion phenomena, which appeared in an issue of Aeronautics, mention was made of the various factors which tend either to promote, or to damp out and eliminate the onset of the aerodynamic inertia elastic vibration phenomena known as flutter, and it was pointed out that in this respect the provision of an adequate measure of rigidity, both as regards to twisting and flexure of the wing or tail surface structure is one of the most effective safeguards against the occurrence of torsional‐flexural flutter.
The Stalling of Airscrew Blades
Authors: Naylor V.D.
Published: November 2014

IN a recent article by the author, reference was made to the stalling of airscrew blades and to some of its effects. It seems worth while to examine more closely the kinematics of stalling. In some cases the thrust coefficient graph for a chosen value of p/D indicates a marked drop in kT at a certain value of J, this drop being attributed to stalling of the blade; point ? on ABC (Fig. 1) is such a point. It seems certain that the effect of stalling is complete at C when the kT graph is practically parallel to the J axis, but where the effects of stalling first come into play is not so clear. In other cases, especially for lower values of p/D, the kT graph has the shape DE, from which it is not clear whether or not any stalling at all has taken place.
A Russian Aero‐Engine
Authors: Mote Lionel
Published: November 2014

SINCE so little information has been made available in this country with regard to Russian aero‐engines, it was thought worth‐while to attempt to compile a description of this engine, although it was first produced at least fifteen years ago. This description is necessarily incomplete and to some extent disjointed because most of it is based on references contained in the book Aero‐Engines—Design and Detail Calculations, edited by A. E. Zaikin, of the Joukowsky Military Aviation Academy of Kiev, and published in 1941 by the State Publishing House of the Defence Industry. This book was not intended to describe any one engine but rather, to indicate the merits and demerits of various components of many engines including English, American, French and German products. It is known that most of the aero‐engines produced in Russia are of foreign origin and for this reason it was assumed that interest would be taken in the AM.34 which does appear to be of Russian design.
Photo‐Elasticity and Design Problems
Authors: Heywood R.B.
Published: November 2014

PHOTO‐ELASTICITY is not a new subject. In recent years much progress has been made towards a simplified technique, so that this method of stress analysis is now becoming popular in industry, and is giving valuable information about the failure of engineering parts. There is no mystery about the method; the application of photo‐elasticity is found to require not so much the learned scientist for its satisfactory execution, but rather the man with a sound common sense and a knowledge of the fundamental principles underlying engineering problems. It is found, too, that if the method is intelligently applied it is comparatively cheap and can well repay itself by saving thousands of pounds worth of damage caused by failures under service conditions. To the practical designer photo‐elasticity provides him with one of the most powerful weapons by which he may analyse the stresses existing in complicated engineering parts. In effect the responsibility of a design is passed from the intuitive thought within a designer's mind to the certainty of facts.
Airscrew Torque‐Coefficient
Authors: Naylor V.D.
Published: November 2014

THERE are reasons for believing that in certain states of working, the resultant aerodynamic force on a blade element of an airscrew is normal to a helicoidal surface. The object of the present inquiry was to see to what extent this is borne out by experimental results. It is found that between no‐thrust and maximum efficiency, the hypothesis is confirmed by experimental results for a certain set of helicoidal airscrews. In the course of the inquiry, a method of evaluating the torque coefficient! over the same range, is indicated—the method giving good accuracy.
The Strength of Alclad D.T.D. 390
Authors: Bowen I.G.
Published: November 2014

DATA are available in References 1 and 2 for the study of the frequency distribution of strength of Alclad sheet to specification D.T.D. 390. Before proceeding with the analysis it is important to ascertain how far this sample is representative of the whole universe of data for the material. The following points are relevant:—
Wing Tips for Tailless Aeroplanes
Authors: Weyl A.R.
Published: November 2014

THE study of the flight of birds has provided and will still provide much valuable information for tiie progress of human flight. Many suggestions for the improvements of wings by the use of special wing tips owe their existence to the observation of nature. In spite of such suggestions, free‐flight experimentation—as far as published work goes—is still rather rare and restricted in scope. This reluctance may be due to practical design considerations (handling) as well as to the necessity of making the conventional aileron as efficient as possible; it may also be caused by the impression that experiment in this direction is not worth the effort.
A Buckling Problem
Authors: Ratzersdorfer J.
Published: November 2014

LET us consider a continuous beam with an even number of spans. The spans are each of length l, a constant cross‐section of area A with a constant moment of inertia I about the axis of buckling and are subjected to the compressive force P. The elastic stiffnesses of all intermediate supports are equal and the elastic stiffnesses of the two end supports are also equal but generally different from those of the other supports. We set out to determine the buckling condition for the beam and the relationship between the critical load and the elastic stiffness of the supports. E is Young's Modulus of the material of the beam or the momentary modulus corresponding to the stress at the buckling load.
The Specification of Test Loads
Authors: Pugsley A.G.
Published: November 2014

STRUCTURAL engineers have always been accustomed to think of the strength of a structure in terms of gradually applied, or “static”, loading. It was natural, therefore, that when strength tests were first made on aeroplane structures, the primary object was to find the load that, when gradually applied to the structure, just broke it. This “ultimate” load was easy to determine, because when it was reached the structure collapsed and refused to carry any more load. At a later stage attempts were made to define a “proof” load at which the structure, because of its deformation or other damage, just ceased to be regarded as airworthy. This proof load was a much vaguer load to determine experimentally; how long should it be left on the structure, should it be applied more than once, who should be regarded as competent to pronounce on the airworthiness of the deformed structure, and should the airworthiness be judged when the structure is actually underload or after the load is removed, were all difficult questions to answer. As a result, in spite of an increasing realization of the relatively greater importance of the proof load, or at least of some comparable concept, in practice reliance has continued to be placed on measurements of ultimate load.
Termites and Timber
Authors: Fitzgerald‐Lee G.
Published: November 2014

TERMITES, or as they are commonly and erroneously called, “White Ants”, belong to the zoological class “Insects”. Insects are characterized by having in the adult state three distinct parts to the body: the head, with one pair of feelers and usually three pairs of jaws; the thorax, bearing three pairs of legs and at most two pairs of wings; and the abdomen. The class is divided into three sub‐classes, of which the termites belong to the exopterygota: insects which change, mainly by enlargement, their appearance each time they moult, the wings developing outwardly, and thus visibly, throughout the process until they are fully winged at maturity. Of the many orders of this sub‐class the termites belong to the isoptera, having two similar and almost equal pairs of wings, large heads, and powerful jaws. The order is sub‐divided, as is common in zoology, into families. There are four families of termites, one, the mastotermitidæ, is purely Australian; the other three are common throughout the tropics and named according to their degrees of development. The most primitive of the three tropical families is the protermitidae (known as kalotermitidæ in the U.S.A.); rather more advanced, the mesotermitidæ (rhinotermitidæ in the U.S.A.); and the termitidæ, the most highly developed of all. True ants belong not only to a different order, but to a different sub‐class, the endopterygota, in which the development is quite different from the termite type, they are allied closely to bees and wasps, whereas the termites are allied to cockroaches.
Design and Production Technique
Authors: Schroeder A.J.
Published: November 2014

To ascertain the various diameters of drawing (d1, d2 … dn=d) for round bodies to be produced by several operations (Fig. 73) (22)
The Calculation of Frequencies of Vibration of a Truncated Cone
Authors: Conway H.D.
Published: November 2014

THIS paper is intended as a sequel to a paper by Dr. J. F. C. Conn entitled “Vibration of a Truncated Wedge” (AIRCRAFT ENGINEERING, Vol. XVI, April 1944, pp. 103–105). The three modes of vibration—longitudinal, flexural and torsional—of a truncated cone encastré at one end and free at the other are considered separately. Special attention is given to the vibration frequencies of the cone and uniform cylinder.
Fluid Power Transmission in Aeroplanes
Authors: Rendel D.G.A.
Published: November 2014

IT is probably true to say that the opinion most widely held about aircraft accessory power systems is that they are a necessary evil about which nothing very much can be done. This attitude is induced in practice by the following facts: (i) most aircraft will not operate satisfactorily without an accessory power system; (ii) the accessory power system is normally only re‐sponsible for a very small proportion of the major failures of the aircraft and is, in any case, only an accessory and not fundamental to the design of the machine; (iii) more maintenance hours are spent putting the accessory power system right than on almost anything else.
Stress Diffusion Problems
Authors: Goodey W.J.
Published: November 2014

THE case to be investigated is shown diagrammatically in fig. 8 (a). In practice, it represents the top or bottom panels of a two‐spar skin‐covered wing, where the front and rear spars have different flange areas. Using the notation of FIG. 8, we take for our basic solution the expression w=(P sinh λks + Q cosh λks)cos λz…F(1) A rigid‐body rotation may be imposed on this, if desired, to make the displacement at the point s=a, z=0 the same as at the origin, but as this will not affect the stresses it need not be included in equation F(l). It has, however, been found necessary to include such a rotation if it is required to find the final expression for the displacement w, in order to make the integral (which represents w) convergent. The present investigation has, however, only been carried as far as the determination of the end loads in each flange, since this information will in practice be sufficient for the design of the panel, as regards riveting of flanges to skin, and the skin reinforcing required.
Glauert Loading of Wings with Discontinuities of Incidence
Authors: Falkner V.M.
Published: November 2014

THIS report gives a general solution of the problem of the calculation of the Glauert loading of wings with discontinuities of incidence. The three existing variations of the original theory, the Glauert solution, the Gates' least squares solution, and the Lotz' solution, are not entirely satisfactory and may involve a considerable amount of labour. The present solution divides the Fourier series representing the circulation into two parts: (a) a standard solution representing the discontinuities, which includes the slowly convergent part of the solution, and which is expressible as a precise infinite series dependent only upon the position of discontinuities along the span, and (b) a secondary solution due to plan form, aspect ratio, slope of section lift curve, and so on, which is the quickly convergent part of the solution and usually requires a terminated scries of only from four to six terms. Once the standard solution has been computed, the remaining work is little more than for the standard Glauert solution for a flat wing.
Analyses of High‐Speed Crankshaft Loads
Authors: Binding J.E.
Published: November 2014

THE advent of higher engine operating speeds and output, has made it increasingly difficult to assess the strength of crankshafts of modern internal combustion engines by analytical methods. Nevertheless, the evaluation of a reasonably accurate estimate of the loads acting on this component is of immense importance to the engine designer, and in this paper the writer reviews suitable treatment for application to the crankshaft of an in‐line and a radial engine.
Stress Diffusion Problems
Authors: Goodey W.J.
Published: November 2014

THIS problem is similar to that treated in section C, but now the stringers will be treated as discrete members separated by panels of skin which transmit only shear stress. The method of solution is quite different from that hitherto employed, it having been found that the result was most conveniently obtained by the principle of minimum strain energy. The problem is shown diagrammatically in FIG. 16, where the notation to be used is also given.
Analyses of High‐Speed Crankshaft Loads
Authors: Binding J.E.
Published: November 2014

In the design of an articulated connecting‐rod system for a radial engine, certain conflicting desiderata have to be fulfilled, which of necessity dictate recourse to compromise. Considerations of strength, weight, a small overall diameter, component interchangeability and satisfactory combustion in all cylinders, often mean irregular disposition of the wrist‐pin centres on the master rod and variations in the stroke of different cylinders; consequent on which small differences occur in compression ratio, leading to dissimilar combustion conditions between the cylinders.
Some Aspects of the Repair of the de Havilland Mosquito
Authors: Brant A.J.
Published: November 2014

THIS article is prefaced by a few notes of an historical nature which should assist the reader to appreciate some of the background aspects involved in the creation of an organization to undertake the vast job of returning damaged Mosquitoes to warlike operations in the shortest time and most economical manner possible.
Choice of Fin Area and Dihedral
Authors: Baker F.B.
Published: November 2014

THE choice of nv and — lv for a new aircraft is not simply a matter of chance; nor can it be decided entirely by considerations of stability. Below are given certain working rules, which should act as a useful guide.
Conics in the Lofting of Streamlines
Authors: Campbell T.C.
Published: November 2014

THE increase in aircraft sizes which is envisaged in the next few years, raises the question of adequate lofting space where the traditional method by fairing by eye is still used. This problem can be met by the adoption of a mathematical technique which not only eliminates the need for considerable space but also provides close and accurate control of the body form. Whilst the size factor may make the lofting problem more acute and so lead to a better appreciation of a mathematical method, the use of such a method is equally valuable in the case of smaller aircraft in that it enables the loftsman to blend all parts of the body form together and to provide the layout draughtsman with accurate shapes for all parts which contain part of the body contour.
Aeronautical Research in Australia
Authors: Coombes L.P.
Published: November 2014

AERONAUTICAL research is now firmly established in Australia. Nevertheless, many people, including a large proportion of Australians, may well wonder why a country which derives the major part of its wealth from primary products should expend large sums on an activity apparently unrelated to its economy. Thus it will not be out of place to begin with some of the relevant background.
Some Aspects of Propeller Fatigue Testing
Authors: Gardiner G.C.I.
Published: November 2014

THE problems of fatigue testing are usually associated with the testing of specially machined specimens in a reverse loading machine such as the Whöler. Tests of this nature are designed to disclose the characteristic fatigue curve of the material freed from all imperfections necessitated in a mechanical structure by machining or design. The usual presentation of the results is, of course, in the form of the familiar S/N diagram, where the number of cycles required to produce a failure are plotted against the magnitude of the applied stress.
The Stress Analysis of Simplified Structures
Authors: Rice G.E.H.
Published: November 2014

THE first practical application of a simplified form of aircraft structure was made by the Republic Aircraft Corp. in their production of the Seabee. This machine dispensed with conventional ribs and used external chordwise corrugations instead. These were found to be perfectly satisfactory; they resisted the air loading and were stiff enough to prevent undue distortion of the cross‐section of the structure. For machines of higher speed, however, these corrugations, or ‘beads’ as they were called, would be objectionable and would have to be replaced by internal stiffeners fixed to the skin. This is the type of structure it is now proposed to analyse—a general view is shown in FIG. 1.
The Elementary Theory of. Stressed‐Skin Construction
Authors: Hemp W.S.
Published: November 2014

AIRCRAFT wings, tail planes, fuselages and control surfaces have to satisfy certain mandatory requirements of stiffness. These requirements arc designed to ensure the absence of aero‐elastic troubles. They all take the form of a minimum specified limit to a stiffness, calculated or measured under the application of a definite force and constraint system. A ‘stiffness’ may be defined as the ratio of a force to its ‘corresponding’ displacement (see 5.2) and so the calculation of stiffnesses reduces itself to a ‘deflection problem’(1.1 (2)).
The Identification of Plastic Materials
Authors: FitzGerald Lee G.
Published: November 2014

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.
The Analysis of Structures Consisting of Curved Members of Variable Section
Authors: Saravanos B.
Published: November 2014

THE analysis by the Hardy‐Cross moment distribution method of structures consisting of curved members of variable section involves modifications to certain processes of the method as used for straight, uniform‐section members. These modifications are considered in the present work.
The Filtration of Fine Particles
Authors: Cranston R.W.
Published: November 2014

In this analysis or the action of fine particle filters and the discussion of methods of test, the following principal conclusions are reached:
Some Design Considerations on Powered Flying Controls
Authors: Bradbury F.J. , Parker S.M.
Published: November 2014

Powered flying‐control systems are a comparatively recent addition to aircraft and, to date, have been devised to modify as little as possible existing piloting technique. At the present time there is a basic similarity in most of the designs being used, and it is the purpose of this paper to consider the reasons for this and to examine the suitability of these systems for such future requirements as can be foreseen. Little has been published about the difficulties encountered in the installation of such systems, particularly of relation to stability and reliability, but some account is given in the paper of experience with one typical system which has been used in a number of aeroplanes of widely differing types. Whilst the scope of this paper is not intended to cover a detailed comparison of the minor features of various designs, some reference is made to those details which have a prime influence on performance. Finally, consideration is given to the extremely important question of pre‐flight rig testing, which is necessary to secure adequate reliability in services so vital to the safety of the whole aeroplane and its occupants.
Cross‐Flow Heat Exchangers—Part II
Authors: Reid J.K.
Published: November 2014

AS the rate of heat transfer by forced convection from a fluid to a metal surface is relatively low, it is necessary to provide a large area of metallic surface while keeping down the overall volume of the exchanger. One design of exchanger which meets this requirement very effectively is the honeycomb type of construction shown in FIG. 11.
Post‐War Trends and Developments in British Aircraft
Authors: Newell A.F.
Published: November 2014

THE purpose of this article is to indicate the developments in aircraft that have appeared since the first post‐war S.B.A.C. Display of 1946. Now is perhaps the time to pause and consider progress in British aviation, particularly as the first turbo‐jet air liner, the Comet, has entered service, the first turbo‐propeller aircraft, the Viscount 700, is being manufactured in quantity, and production orders have been placed for the Hawker Hunter swept‐wing fighter and the Gloster G.A.5 Delta. These aircraft represent a few of the British types evolved in the post‐war period and demonstrate aeronautical advancement.
Progress in Two‐Seater Sailplane Design
Authors: Shenstone B.S.
Published: November 2014

THIS article attempts to summarize the technical development of two‐seater sailplanes during the past thirty years. There is no attempt to contribute anything new to the art, but only to bring together information from various sources. It is also hoped that the data collected will be found useful to designers.
The Transition from Prototype to Production
Authors: Hollyhock W.S.
Published: November 2014

THERE are various approaches to the problem of the evolution of a line of production aircraft from the basic prototype machine and the merits and demerits of each will depend to some extent on the kind of aircraft, the local conditions and the magnitude of the production order.
Simplified Numerical Integration
Authors: Shue G.L
Published: November 2014

TO facilitate the solution of differential equations by approximation methods, the writer has developed a simplified method of numerical integration.
The Problem of Thermal Stresses in Aircraft Structures
Authors: Loveless E. , Boswell A.C.
Published: November 2014

THERMAL stresses in aircraft structures arise from the long established fact that most of the common engineering materials expand with increase of temperature. The subject has become a problem due to the fact that increases in aircraft performance arc resulting in much greater variations and rates of variation of temperature than have hitherto been experienced. One solution to the problem would be to use only materials which do not change their physical dimensions with temperatures. However, although such materials do exist, it is probably asking too much of the metallurgist to expect him to produce alloys possessing this property in addition to the many others demanded by the aircraft structural engineer.
Flexure‐Torsion Failure of Panels
Authors: Argyris John H.
Published: November 2014

FAILURE of panels under static compression, or for that matter under any loads, involves a vast array of problems ranging from properties of material to initial instability and post‐buckling phenomena as occurring in various types of panels. It is not intended here to do justice to all these aspects of the subject but to select a single—but at the same time very important—topic, develop its analysis as fully as possible, and present the results in a readily applicable form. The structure investigated is the single skin stiffened panel under compression and the mode of failure considered, denoted by flexural cum torsional failure, involves predominantly flexure and torsion of the stringer with a wavelength of greater order of magnitude than stringer height and pitch. By torsional deformation of the stringer we understand a rotation of its undistorted cross‐section about a longitudinal axis R in the plane of the plate, the position of which will be selected later on (see FIG. 1b). The panel may, of course, also fail in a local mode of stringer and plate with a short wave‐length of the order of magnitude of stringer height and pitch, but the analysis of this case is not included here (see, however, Argyris and Dunne). Note that a local mode of deformation of a stringer formed by straight walls is commonly defined as a distortion of the cross‐section in which the longitudinal edges where two adjacent walls meet remain straight (see FIG. 1c).
The Elementary Theory of Aero‐Elasticity
Authors: Broad bent E.G.
Published: November 2014

IN Parts I, II and III of this series we have discussed the physical nature of divergence, control reversal and various forms of flutter, and have seen how these phenomena can be predicted by theory. The flutter problem is so complicated, however, that the aircraft designer needs the assistance of certain guiding principles; otherwise he may find when the aircraft is ready to fly that the flutter calculations which are just completed show that drastic modifications to the aircraft are necessary. These principles form the basis of this concluding part of the series and have two main objects: first to avoid large changes in design on flutter grounds and secondly to obtain a high efficiency from the flutter calculations.
Current Development of Aircraft Production Processes
Authors: Connolly J.V.
Published: November 2014

A CRITICAL stage in the process of making aircraft occurs with alarming frequency in the history of aviation.
The Spinning of Modern Aircraft
Authors: Kerr T.H.
Published: November 2014

SPINNING is a rather complicated subject but it is possible to present quite a broad view without going into too much detail so that one can appreciate the way in which the various characteristics of the aircraft can affect the motion both during the spin and in the recovery from the spin. In the following notes an attempt has been made to do this in a way which, it is hoped, will be helpful to the designer and the flight technician and pilot.
Rationalizing Aircraft Secondary Controls and Systems
Authors: Hollyhock W.S.
Published: November 2014

IT is an accepted principle that primary controls should have full consideration during the initial design of an aircraft but there is a general tendency to ignore secondary controls and systems, such as electrics and hydraulics, until all other requirements have been satisfied, basic shapes and sizes determined and structural members laid out.