bluuebunny/crossref_metadata_2025 huggingface dataset:
Non‐Ferrous Metals for Aircraft
Authors: Hanson D.
Published: November 2014

THE rapid development of the social structure of the world during the past century is due, in no small measure, to improvements in communication. In certain ways we have annihilated distance completely, through the invention of telegraphs, telephones, and more recently and more wonderfully, of wireless telegraphy and telephony, and we are on the verge of another annihilation through the perfection of television. We have not yet discovered the magic carpet that will do for more material substances what these inventions have done for writing, speech, and vision. Nevertheless, transport by water is more rapid and more certain then ever before, while the motor vehicle has given us, during the last thirty years, a remarkable improvement, in rapid and reliable communication on land. The most recent and most spectacular development is that of aerial communication, which has given us a speed quite unattainable in any other form of transport. Metals are essential to the development of modern aircraft, if only for the reason that the motive power cannot be generated without their use. It would be incorrect to claim that the conquest of the air has been dependent on the use of non‐ferrous materials in substantial proportions, and indeed the first aeroplanes contained them only in small amounts, but it is certainly true that the present state of air communications is in large measure due to the development of non‐ferrous alloys, and their use in aircraft construction in large quantities.
The Range of Aircraft
Authors: Coales J.D.
Published: November 2014

A GREAT deal of research and experiment is at the present time being carried out with the object of producing a light‐weight compression‐ignition or Diesel aero‐engine burning heavy‐oil fuel, which shall replace the petrol engine and free aviation from the ever‐present danger of petrol fires. It has often been pointed out that, although the specific weight of the Diesel engine is considerably greater than that of the petrol engine, its greater fuel economy so reduces the amount of fuel required, that for certain aircraft ranges the complete power unit will have the same weight, whichever type of engine is used.
Aerodynamics for Engineers
Authors: Piercy N.A.V.
Published: November 2014

Each form of normal, steady aeroplane flight dictates a particular setting of the control surfaces and engine throttle. In whatever circumstances a desired steady motion may be pre‐arranged in this way, a completely stable aeroplane will establish of its own devices the speed and other conditions necessary for equilibrium. No help is demanded from the pilot, or from automatic operation of the controls, which are supposed to remain fixed, but only a sulficient space for transitional manoeuvring. It follows that if the aeroplane be subsequently disturbed, whether by accident or design, left to itself it will return to its arranged motion.
Experiments in Lateral Control
Authors: Jennings W.G.
Published: November 2014

WING tip automatic slots have proved an effective device for providing increased lateral stability at the stall and many service aircraft of the two seater and larger types have been fitted with them. In the case of single seater fighter aircraft, where manoeuvrability is of primary importance, it is desirable that adequate control at the stall should also be provided and the plain automatic slot does not, in general, supply this need. Certain aircraft fitted with the interconnected slot and aileron type control have shown satisfactory control characteristics at the stall but little or no increase in stability.
Safety in Spinning
Authors: Irving H.B. , Stephens A.V.
Published: November 2014

Experiments with Modified Tail Units.—Experiments have been performed with 1/15th scale models of the original single‐seater fighter and 1/20th scale models of the Bristol Fighter with a view to improving their spinning properties by redesigning the tail unit. The experiments with the fighter models were mainly directed at investigating the spinning characteristics of the original and deepened models to see whether the overall effects of the deepened fuselage and raised tail plane would bear out the encouraging conclusions drawn from the wind tunnel work. The scope of the experiments was somewhat limited, but all results indicated that slower and steeper spins and very much more rapid recoveries might be expected from the deepened fighter.
Research Equipment in Canada
Authors: Parkin J.H.
Published: November 2014

IF the most effective use is to be made of aircraft in Canada in the future, adequate research facilities must be provided to assist designers and the industry to develop improved aircraft, suited to the conditions and requirements of the country, and to solve the problems arising in Canadian aviation. The National Research Council has, therefore, with the approval of the Sub‐Committee of the Privy Council for Scientific and Industrial Research, undertaken to provide, in the National Research Laboratories now being established in Ottawa, facilities for aeronautical research.
Drop Forgings and Stampings
Authors: Thain W.A.
Published: November 2014

THE growth in recent years of drop forging and stamping is recognised as being fundamentally linked with the history of the development of high‐speed transport.
The Estimation of Performance
Authors: Clarkson Richard M.
Published: November 2014

PART II.—PERFORMANCE ESTIMATION (a) Absolute Ceiling.—This will be dealt with first, as it is, in many respects, the most fundamental and the easiest to deal with of all items of aircraft performance, being a simple function of Z only.
Anti‐Knock Qualities in Fuels
Authors: Morley A.W.
Published: November 2014

A PRECISE value cannot be given to the anti‐detonation property of a fuel unless very exact conditions of test are specified. A method of rating is required which will apply with sufficient accuracy to aero‐engines. Some aspects of the problem are discussed below.
The Design of Valve Springs
Authors: Nixon F.
Published: November 2014

NO component of the modern aero and automobile engine has been more uncertain in action and more troublesome in service than the valve spring.
The Aluminium Bronzes
Authors: Marsh E.C.J. , Mills E.
Published: November 2014

THE demands of modern engineering employing machinery that has to operate at high power, and to include rapidly‐moving units, has forced the metallurgist to depart from the old‐established alloys and to introduce new mixtures to which it is possible to impart specific or enhanced properties by thermal treatments. This aspect of metallurgy has also been given impetus by the demand for reliability, whether in factory plant or the fabricated product. This becomes obvious when it is realised, on the one hand, that the basis of all systemised workshops is the maintenance of continuity in output and an ever‐increasing production; and, on the other, that the failure of even a minor accessory may cause disaster with loss of material, labour or human life. Thus, it no longer occurs that one regards the ferrous metals only as being manipulable by selected heat treatments, and, in the non‐ferrous scries, annealing to be the only means of modification by heat. To‐day, various copper‐rich alloys are available that are susceptible to hardening and tempering processes closely similar to those long since employed for steels. Those containing beryllium and aluminium have been the most exploited. However, the reluctance with which the engineer accepts the advantages offered by these developments is understandable, because the information appertaining to the subject is not always available in a form which enables him to appreciate the economies to be accrued. Further, he often prefers production to be straightforward, using raw materials in the “as‐received” condition, rather than to introduce processes, the value of which has not been elucidated. Yet this is a situation that cannot be tolerated indefinitely, if economies in material weights and dimensions and increased service life are mutually to be secured. It is, therefore, from this angle that the study and comprehension of the properties and possibilities of aluminium bronze cannot be ignored.
Furnaces for Heat Treatment
Authors: Thain W.A.
Published: November 2014

IN modern aircraft a large percentage of the parts and details which make up the complete structure require heat treatment at some stage of fabrication. The heat‐treatment requirements necessitated by any particular design, and hence the furnace equipment of the factory requisite for dealing with the manufacture of a given machine on a production basis, is, generally speaking, a function of:—
A Note on Interference
Authors: Ower E.
Published: November 2014

THE term interference in its aerodynamic sense is generally associated with an effect that spoils the performance of an aeroplane mainly by increasing its drag at a given lift. While there are good grounds for this outlook, it is of some importance to remember that it by no means represents the whole truth. Interference effects are not confined solely to changes of drag or lift: they often play a material part in many other properties of a complete aeroplane such as its stability, its spinning properties and in the phenomenon known as buffeting. Further, it is not correct to assume that interference always works against the designer; it may quite well assist him in certain cases, and the better he understands its causes the more chance he has of designing combinations having favourable interference.
A Design for an Air Port
Authors: Cousins H.G.
Published: November 2014

IT has been considered essential to segregate the various types of aircraft using the aerodrome from the beginning of its development. In view of this and the number and size of the aeroplanes to be housed, it has been found most convenient and economical to construct three hangars. These consist of:
The Problem of Vertical Flight
Authors: Crowe J.H.
Published: November 2014

MUCH time and money have been devoted to the development of the helicopter, but the achievement of a practical machine is apparently not yet in sight. Some of the problems, indeed, have been solved; others await solution. In any discussion of the helicopter the subject naturally divides itself into five headings. First, there is the problem of the provision of adequate lift. This has for many years been solved, and an airscrew can now be designed that will give its predicted lift with a certain degree of confidence. On the practical side, helicopters have demonstrated that they can be built with a sufficiently light structure weight that modern power plants are adequate to lift the aircraft vertically upwards. The problem has also been investigated theoretically, and a relationship between disc loading and pounds per horse power established which should permit of any designer producing a helicopter that will lift itself. This fact cannot be too strongly emphasised in view of the fact that many inventors consider that the major problem is one of lift.
Education in Aeronautical Science
Authors: Sutton Pippard A.J.
Published: November 2014

IT is with some misgiving that I come here this evening to lecture to this society on the training of an aeronautical engineer. The subject is not one which 1 chose myself; indeed, I think it is probably the very last which I should have selected to talk about; but the Council of the society, for some reason which I have not yet been able to understand, invited me to deal with it. I rashly promised to do it, but now that the time has come to redeem that promise I feel that I ought to have refused and chosen a subject on which perhaps I could speak with a little more authority. I suspect, however, that the Council was anxious to obtain discussion on a topic which to any society is a very important matter and that I have been put up as a target for your criticism in the hope that something useful may emerge from your comments rather than from my paper.
Divided‐Axle Undercarriages
Authors: Rees H.S.
Published: November 2014

THE most difficult problem in an analysis of a split axle type of undercarriage is the proper division of the moments which must be carried by the axle and radius rod. These moments are due to wheel overhang and braking torque. It has been found that most of the methods so far devised have resulted cither in a mass of very ponderous calculations based on strain‐energy or, owing to simplifying assumptions, in an erroneous answer. The correct and probably the easiest way is to resolve these external moments into and normal to the plane of the axle, radius rod, and hinge line (hereafter called the plane of the “vee structure”). In order to avoid finding the complicated and numerous equations of a line normal to this plane, and of lines in this plane normal and parallel to the hinge line, as well as equations of the resultant loads and moments required for resolution, the method of rabattément has been developed.
The Heavy‐Oil Aero‐Engine
Authors: Chatterton E.
Published: November 2014

IN the year 1890, Herbert Akroyd Stuart took out a British patent in which, for the first time, mention is made of an engine which may be said to bear some resemblance to the modern compression‐ignition engine.
A New Form of Biplane
Authors: Irving H.B.
Published: November 2014

THE outstanding property of the biplane to be described, as determined from model tests, is stability in roll up to angles of incidence in excess of 40 deg. (Fig. 8). This is achieved without any additional mechanism or parts, simply by the form and disposition of the wings. Maximum lift is slightly increased (Fig. 6) and there are minor advantages as regards coming in to land, aileron control and spinning.
Skin Friction Drag
Authors: Vessey H.F.
Published: November 2014

DURING the past year the increase in performance shown by certain American and Continental aircraft has merited the attention of all aircraft technicians. The performance is, of course, partly due to increase in horse‐power, but this is a small factor compared with the advance shown in the reduction of drag. Now that it has been shown that it is possible to build aeroplanes of low form‐drag and with little interference, the drag due to skin friction is becoming of great importance, and it will probably be of advantage to outline the methods of estimating skin friction, and discuss what information is now available on the effect of surface finish and protuberances.
Stressed‐Skin Structures
Authors: Lockwood Taylor J.
Published: November 2014

ONE of the outstanding problems in design of stressed‐skin structures is that of ensuring adequate rigidity to guard against instability failure or buckling of the parts of the structure which have to carry compressive loads. Such structures consist usually of a scries of longitudinal members or stringers with intersecting transverses or frames. Apart from the waving of the skin itself in the panels thus formed, which must usually be tolerated and which remains modcrate in extent so long as the stiffening members themselves do not deflect, and docs not impair the ability of the structure as a whole to continue to take increasing load, there are two possible forms of buckling. The stringers alone may bow between adjacent frames, which remain fixed, or longer waves involving both stringers and frames may occur. The strength to resist the first type of failure can be estimated with reasonable accuracy by treating the stringers as struts of length equal to the frame spacing, and gives a design criterion for the stringers. It is fairly evident that for this rather elementary treatment of the stability problem to be adequate it is necessary that the frames themselves should have a certain minimum rigidity. It is in determining this minimum rigidity that the question arises of the possibility of the second type of buckling, which will be specially considered here. Whether this will, in any practical case, be sufficient to fix the size of frame required, cannot of course be stated in general terms, as this will depend on the local loads which the various frames may have to carry. Fig. 1 shows the type of deformation involved, for the special case of the side of a monocoque fuselage, which may be subjected to compression due to lateral bending under the action of rudder and inertia loads. The mode of waving is specified by the longitudinal wave‐length (two frame spaces in the illustration) and by the transverse wave length, which may be the full width of the panel or something less than this.
Problems in Engine Research
Authors: Capon R.S.
Published: November 2014

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.
Load Factors and Stability
Authors: Crowe J.H.
Published: November 2014

THE major problems connected with the development of satisfactory structural strength requirements have long since been solved. We have, in this country, an empirical system of specification which fulfils the fundamental criterion of any strength system, namely, that failures in the air through lack of adequate strength of any component of an aircraft are extremely rare. An analysis of civil accidents (Ref. 1) shows that about 6 per cent are due to this cause. This does not imply any reason for regarding even this small number with complacency, rather the reverse.
Drag Analysis of Civil Aeroplanes
Authors: Crowe J.H. , Wood W.E.
Published: November 2014

THE increasing speed of modern aircraft has brought to the forefront the necessity for making a careful drag analysis of all aircraft in order to separate out the essential drag, that is to say the drag that is unavoidable, from the non‐essential drag. Most designers, we believe, now do this in order to see what progress is being made in the streamlining of their products. By this means we are enabled to see the relative importance of the drag terms and to arrive at a figure of merit. The ideally‐streamline aeroplane, though not at present a precise proposition, is like other ideals unattainable. It is the standard to which designers may aspire, but which they cannot achieve.
Loss of Momentum and Drag
Authors: Serby J.E.
Published: November 2014

IT has for a long time been realised that if a complete exploration is made of the wake behind a body and the loss of momentum suffered by the air flowing past it measured the drag on that body can be deduced. In 1925, Betz suggested a method whereby this principle could be conveniently applied to the measurement of the drag of wings in flight and a little later, in 1926, Schrenk published results obtained by the method. At that time interest in wing profile drag was not great and the results Schrenk obtained for wings covered with surfaces of different roughnesses were mainly of academic interest. At the time when aircraft had overall drag coefficients (CD based on wing area) of 0·040 to 0·050 a change of wing profile drag coefficient of 0·002 meant only 4 per cent or 5 per cent change in total drag or 1·3 per cent to 1·6 per cent change in the top speed of the aircraft. With the rapid improvement of performance which has taken place in the last 5 to 7 years due to a general “cleaning up” of fuselage shapes, elimination of strut and undercarriage drag, overall drag coefficients of 0·015 have been achieved and a saving of 0·002 in wing profile drag now means a 5 per cent increase in top speed. For this reason designers are now much more interested in accurate data regarding the effect of wing thickness and surface roughness on profile drag.
Generator Regulating Systems
Authors: Sykes B.
Published: November 2014

IN this article it is proposed to deal with the broad principles of operation of the various systems of control of aircraft electrical generators which are in common use, rather than with the detail design features and the many minor variations adopted by different manufacturers of this type of equipment.
Down Gusts
Authors: Crowe J.H.
Published: November 2014

IT is shown that the down gust requirement is open to the objection that heavier loads may be taken by the front spar at lightly loaded weight than those for which the spar was designed. This is normally covered by the factor of safety of 2, but the method of calculating the loads on a basis of all up weight is not very rational. Some available data concerning the magnitudes of down gusts are reviewed and the sharp‐edged gust hypothesis briefly examined. The British requirement is compared with those of the I.C.A.N. and the U.S.A. The conclusions are that there are no very practical alternatives to sharp edged theory and while the estimate of the magnitudes of normal down gusts at 25 f.p.s. appears satisfactory and British standards of strength in this respect need not be tightened up, a modification to the requirement to meet the above objection is desirable. A suggested alternative is put forward.
Combined Stresses
Authors: Parkinson H.
Published: November 2014

In all drawing offices “labour‐saving” methods of making approximate preliminary calculations are in use. Here the author renders useful service in throwing open to others charts he has himself developed for rapid selection of appropriate sizes of tubes and bolts, etc., for components and fittings.
Some Books Recently Received
Authors: A.N.B.  , F.C.S.  , A.F.
Published: November 2014

These companion volumes are designed to cover a university engineering course in mechanics, but they will have a welcome extending outside university circles. The needs of the engineer have been kept in mind throughout, with the result that important subjects such as frameworks, and especially space frames, in statics, and vibrations in dynamics, receive especially full treatment. The examples, too, of which there are more than three hundred in each volume, have been carefully chosen, not only to illustrate the theory, but also to have a practical interest. Students often find that their greatest difficulty in solving problems lies in marshalling the known facts in a mathematical form suitable for solution; and in the many worked examples the authors have taken great care to explain this process. The worked examples have also been used to introduce subjects which are later fully developed in the text, or which are not of sufficient importance to justify special treatment.
The Stressing of Rotor Blades
Authors: Morris J. , Tye W.
Published: November 2014

NUMEROUS difficulties are encountered in any attempt to ascertain the loads which come into action on a gyroplane rotor blade, and the stresses which these loads impose on the blade. The loads are not steady but variable, complicated and subject to intractable fluctuations. In consequence the blades are in a continual state of agitation. Even when various simplifying assumptions are made the resulting differential equations of motion do not readily yield to conventional methods of treatment. So far as the modes of free vibration are concerned the analysis is relatively simple, but so far as the stresses in forced vibration are concerned the difficulties are formidable. In this paper it will be assumed that the loading over the blade is steady at any instant of a given flight condition. Subject to this restriction, the stresses in the blade may be found to any required degree of approximation by the generalised theorem of three moments suitably modified. In addition the gyroscopic moments of a blade and its frequency of “Happing” vibration will be found on the assumption that the blade is rigid and regard being had to imposed rotation.
Pilot's View in Cabin Aircraft
Authors: Serby J.E.
Published: November 2014

TEN years ago most aeroplanes, certainly nearly all those of the R.A.F., had open cockpits and pilot's view was not the problem it is to‐day. Occasionally a pilot would be heard to murmur that “in a so‐and‐so you couldn't see a thing straight ahead when you were on the ground,” but apart from a few such complaints very few were made about the view once the aeroplane had got into the air or when it was flying in bad weather. The pilot might complain if he had to move his head out of the shelter of the front screen when travelling at, say, 70 m.p.h., but he could at all events do this when wearing goggles and thus safely approach the aerodrome and land.
The Continuous Beam
Authors: Moyes S.J.E.
Published: November 2014

THE problem dealt with in this article has been solved before by various methods such methods involving the necessity of dividing an irregularly lateral loaded beam into a small number of bays in order to represent with fair accuracy the lateral loading by preconceived laws for which solutions are available.
Modern Diffuser Design
Authors: Patterson G.N.
Published: November 2014

ONE of tin: most important causes of low efficiency in duel systems is tin; large loss which accompanies a transformation from kinetic energy to pressure. The exit cones of wind tunnels and turbines and the expanding entries to cooling duets and air‐intakes on aircraft are some of the duct systems which lvcpiirc ellicient expansions of the flow.
Air Transport as a Public Utility
Authors: Spaight J.M.
Published: November 2014

THE decision to con ne Imperial Airways and British Airways in a kind of public utility corporation is a curious instance of the adoption by a Government of a proposal made by the Opposition some time before and then rejected. When the Air Navigation Bill was under discussion in the House of Commons, Mr. T. Johnston (Labour) proposed, on May 19th, 1936, that civil air transport should be nationalised, or at any rate that the State should acquire ownership or control to the extent of the subsidy given. This proposal was repeated with more precision by Mr. F. Montague on the third reading of the Bill on July 1st, 1936. Imperial Airways, he urged, should be turned into a “public utility concern, more directly responsible to this House.” “It should belong to the whole community and should be developed for public purposes by the public.” A monopoly fostered by subsidies should not be allowed to create vested interests. The fact that at that time the £1 shares of Imperial Airways were quoted in the market at over 50s. was a pointed reminder that there was some substance in this fear.
Recent Airscrew Research
Authors: Perring W.G.A.
Published: November 2014

THE increase in aeroplane speed, brought about by improved aerodynamic design and higher engine powers, together with the design restriction on airscrew tip speed resulting from efficiency considerations, has reacted on the airscrew performance during take‐off, and has made the take‐off more difficult.
Recent Aero‐Engine Research Work
Authors: Mansell H.C.
Published: November 2014

DURING the past few years the aeroplane has increased in performance to such an extent that normal machines of to‐day have speed, climb, load capacity, economy, and reliability characteristics, combined, only considered possible from individually specialised record making designs of ten years ago. Both airframe and engine are concerned in these gains, and the two now require to be such close partners that apportioning of credit is scarcely possible and research on both components has to proceed in step.
Modern Aluminium Alloys
Authors: Handforth J.R.
Published: November 2014

IN replying to the discussion on one of his many excellent papers to the Institute of Metals, the late Dr. Rosenhain once made a statement to the effect that it took industry approximately ten to fifteen years to develop for commercial use the advances in knowledge which resulted from the researches of such Institutions as the National Physical Laboratory. Whatever may have been the shortcomings of industry ten years ago, the outstanding feature in the world of light alloys during the past two or three years has been the tremendous increase in manufacturing capacity and the modernization of all methods of production. This has been a necessity, caused on the one hand by the progressive increase in size of engines and planes, and on the other hand by the Rearmament Programme, which has been necessary owing to the unsettled condition of world affairs.
Aeroplane Design For Production
Authors: Davies S.D.
Published: November 2014

THE last five years have seen enormous changes in the size and national importance of the British aircraft industry. From the position of Cinderella we have jumped overnight to that of mother's darling of the longer suffering taxpayer; new schemes of factory expansion, for which the only recognized unit of currency appears to be £1,000,000, have been announced with almost startling frequency, but, nevertheless, it will be no infringement of the Official Secrets Acts to say that the increase in output has been very disappointing to the customer.
Torsion of Tapered Tubes
Authors: Hanson J.
Published: November 2014

THE stiffness of an aeroplane wing is usually considered in terms of its torsional and llexural stiffnesses as measured at the “mid‐aileron” and “equivalent tip” sections(1), (2). It appears at present that the stiffness in torsion is more significant than that in flexure, partly because high torsional stiffness is necessary to prevent not only flutter but also reversal of aileron control and divergence(1), (2), both of which are independent of llexural stiff‐ness ; and partly because it is found in practice that when a wing is designed to meet minimum existing strength requirements alone, its torsional stiffness may be inadequate whereas its llexural stiffness is commonly sufficient. The more important of the two torsional stiff‐nesses (“mid‐aileron” and “equivalent‐tip”) is that at the “mid‐aileron” section. The present paper examines the effect of the various parameters on the torsional stiffness of a tapered rectangular tube of proportions representative of an aeroplane wing under a con‐centrated torque applied at a section equivalent to the average “mid‐aileron” section. The analysis of the problem is based on the stress distribution in an axially constrained tapered tube given by Williams in R. & M. 1761(3), and the stiffness obtained is compared with that for a tube with the simple shear stress distribution of the Bredt‐Batho type for a tube with free ends. The similar problem for a uniform tube has already been solved from the equations of reference (3) in R. & M. 1790(4).
Structural Research in Aeronautics
Authors: Pugsley A.G.
Published: November 2014

AERONAUTICAL research has until recently been conducted by men trained in other and varied branches of science and engineering. Mathematicians and physicists, civil and mechanical engineers, have all taken part from time to time, and their work has naturally borne the imprint of their several outlooks. Structural research, which has hitherto been largely overshadowed by aerodynamic and engine work, has suffered particularly from a continual changing of personalities and a confusion of interest. As a result it has in many respects failed either to adopt the traditions of the general body of structural engineers or to build up a fully ordered tradition of its own. And so we may sometimes see on the one hand, for example, the anomaly of an approach to the local buckling problems of monocoque construction as though Stephenson had never built and experimented upon his Britannia Tubular Bridge; and, on the other hand, a growth of stressing methods inadequately linked by generally accepted basic principles.
The Formation of Cracks after Welding
Authors: Bochenek Bronislaw
Published: November 2014

SOME kinds of chrome‐molybdenum steels widely employed in the construction of aeroplanes, the chrome‐manganese‐silicon steels introduced comparatively recently and even some carbon steels with a higher content than 0·2 per cent. carbon show minute cracks after welding with oxy‐acctylene, even when the actual operation of welding is carried out faultlessly. This tendency is described as “weld‐crackability,” cracking occurring at high temperatures. At first, micro‐fractures form, causing in turn the formation of cracks that are visible at a temperature still high enough to cover their surface with a dark bluish flux. These cracks occur not only in the weld itself but also in the whole of the region affected by the thermic influence of the flame. It is characteristic that welding by an electric are does not produce this phenomenon.
The Modern Twin‐Fin Tail
Authors: Shenstone B.S.
Published: November 2014

AS in the case of end‐plate fins, inset fins have the effect of increasing the effective aspect ratio of the tail plane, but to a somewhat less extent. The tail with fins will be compared with an untwisted elliptical tail without fins, because this method of comparison is very clear and being also used to compare wings of different shapes is familiar to people concerned with aerodynamic problems.
Steel and Duralumin Beams
Authors: Dudley Leslie P.
Published: November 2014

ALTHOUGH it is common knowledge that a steel beam may be replaced by a geometrically similar duralumin beam, with a resultant saving in weight, it is not so generally known that such a procedure invariably involves the use of an unnecessarily large quantity of the light‐alloy, and is, therefore, wasteful. The reason for this is that adherence to geometrical similarity, when changing from steel to duralumin, accords the same proportional increase in thickness to all parts of the beam, thus giving uneconomical distribution of metal. It seems, therefore, that some notes showing how more efficient metal distribution may be achieved by departure from geometrical similarity may perhaps prove of interest.
Tricycle Undercarriage Design
Authors: Walker P.B.
Published: November 2014

THE General Problem.—The inertia loading of a tricycle undercarriage presents a problem of considerable difficulty to designers. The type of tricycle under consideration has a pair of wheels not far behind the centre of gravity and a single wheel a considerable distance in front. Although such an undercarriage has special characteristics not possessed by an orthodox undercarriage with two main wheels, it has the same essential duties to perform: namely to absorb the kinetic energy associated with velocity of descent and to transmit the vertical retarding forces which reduce this velocity to zero. For these purposes, however, it has in the front and rear wheel units two distinct and in many ways independent shock‐absorbing systems, and the special problem is to assess the contributions made by each.
Solid Organic Materials
Authors: de Bruyne N.A.
Published: November 2014

CELLULOSE is a polar material held together by the strong secondary forces emanating from its OH groups. It can be swollen, dissolved or cemented together (according to circumstances) by a polar liquid like water or alcohol, while it is unaffected by non‐polar liquids such as benzene or toluene. It is rigid and relatively inextensible and strong.
The Prediction of Performance
Authors: Stepniewski Wieslaw
Published: November 2014

IN the early stages of design, when the general conception of the aeroplane is discussed, it is important for designers to realize the numerical influence of changes in the design parameters (characteristics) upon the performances.
Tapered Spar Frames
Authors: Kittelsen H.M.J.
Published: November 2014

THE methods and formula outlined below are applicable to any shape of fuselage, but an elliptical one is assumed to serve as an illustration.
Two‐Spar Wing Stress Analysis
Authors: Goodey W.J.
Published: November 2014

THE mathematically exact determination of the stress distribution in a two‐spar skin‐covered wing is, in the present state of knowledge, an impossibility, and is in fact quite unnecessary, since only a reasonable approximation is required. The theory outlined in this article will, it is hoped, give a reasonable approximation for a reasonable amount of work, while taking into account as many variables as possible.
Fabricating Fittings by Bronze Welding
Authors: Christie E.
Published: November 2014

THE need for skilled workers in Aircraft Production is a source of continual difficulty, and a severe strain has been put on the Ministries of Labour and Aircraft Production to find suitable labour to satisfy the increased demand. It is, therefore, essential that other ways and means must be investigated to help to speed up and meet the great demand required. Improved methods of production can be utilized to a far greater extent, with the object of reducing the amount of labour required, and there is a tremendous scope in the production of aircraft component parts, particularly in connection with the welding processes and the adaptation of “Sifbronzing.”
Oxygen Breathing Systems
Authors: Weyl A.R.
Published: November 2014

THE partial pressure of the oxygen content in the atmosphere decreases directly with the atmospheric pressure, i.e., with the altitude, the proportion of oxygen in the atmosphere (about 20·9 per cent) remaining practically constant in the substratosphere.
Remote Controls for Aeroplanes
Authors: Hadekel R.
Published: November 2014

OWING to the growing multiplicity of services and the increasing size of aircraft the problem of remote control is assuming considerable importance.
Fluorescent Lighting
Authors: Jenkins H.J.
Published: November 2014

THE property possessed by certain discharges of radiating relatively large proportions of their energy in the visible part of the spectrum is well known. Thus efficiencies of the order of 50–70 lumens per watt are obtained from high pressure mercury vapour and sodium vapour discharges.
Boost Controls for Aero‐Engines
Authors: Ramsay D.
Published: November 2014

THE power output from an engine is roughly proportional to the absolute pressure of the charge mixture in the induction system. If we take a normally aspirated engine, the maximum power output is obtained when the induction pressure is raised to atmospheric pressure by opening the throttle to wide open. The power output may be lowered by reducing the induction pressures by part closing the throttle. The power output could be increased by supplying the induction gases at a pressure higher than atmospheric. This can be done by attaching a supercharger to the engine which, drawing air at atmospheric pressure, will deliver it to the induction system at a pressure higher than atmospheric, and the greater the pressure of delivery, the greater will be the power output.
The Value of Literary Research
Authors: Mote Lionel
Published: November 2014

IN modern times, increasing emphasis is being laid on specialization and there is so much research being made into the many intricate details of the most abstruse problems that members of one group of engineers are too often unaware that their own problems, or others closely related to them, have already been investigated.
Quality Control in Production Engineering
Authors: RISSIK H.
Published: November 2014

THE first part of this article, published in last month's issue of AIRCRAFT ENGINEERING, laid stress on the importance of the technique of quality control to modern production engineering processes, and discussed the basic principles of this technique. The present issue describes the practical applications of quality control and the use of control charts.
Vibration Resistance of Engineering Materials
Authors: C.W.
Published: November 2014

This is a paper read before the North East Coast Institution of Engineers and Shipbuilders on May 15, 1942, and is reprinted from its Transactions.
The Lateral Stability of Aeroplanes
Authors: Price H.L.
Published: November 2014

The following series of articles presents a new geometrical system of determining the lateral stability of aeroplanes. The method is intended to appeal particularly to engineers on account of two advantages: it is simple and rapid in operation, and gives a clear insight into the several factors governing the stability. Thus, whereas in the classical method stability calculations entail the drawing and analysis of quartic curves, the results are here obtained, and with greater generality, merely by the use of curves of the second degree. Furthermore, the effects of typical changes in design characteristics may easily be assessed with the minimum of effort. The fundamental analysis is essentially mathematical and follows the treatment first laid down by G. H. Bryan in 1911 and since developed by Bairstow, Glauert, Jones and Bryant. Physical explanations are included where possible to amplify the underlying principles.
Aircraft Engineering
Authors: Lockwood Marsh W.
Published: November 2014

DURING 1943, we published two papers, both from foreign sources, on electric gauges to measure the strains in aeroplane structures. The second of these, which logically should have come first, appeared in our April issue and was an MAP. translation from the German which covered the theory of electric resistance strip and ring gauges. The other, which had appeared earlier, in‐our February issue, was an S.A.E. paper by MR. C. R. STRANG dealing with practical technique in the application of strip gauges as developed by the DOUGLAS AIRCRAFT COMPANY. Owing to the limitations on paper the February issue is now completely out of print—not, perhaps, a matter of great moment since the article is now mainly of academic interest—and there are only two or three copies of the issue containing Mr. STRANG'S most interesting account still available. We mention this to save disappointment on the part of those who may be led by the further article on the subject in this, issue to wish to obtain them. MR. KING now to a large extent completes the picture and rounds off what may be considered a series by giving information on the form in which the gauges should be applied and the method of interpreting the resulting readings.
Vibrations in Aircraft
Authors: Manley R.G.
Published: November 2014

THE general properties of the resonance phenomenon, described in Part I, in connexion with the simple system consisting of a concentrated mass on a cantilever spring, pertain also to all the types of vibration possible in complicated structures.
Roots of Frequency Equations
Authors: Manley R.G.
Published: November 2014

THE “escalator” method of solving frequency equations, developed by Morris and Head (Ref. 1), and the natural extension of a Lemma by Professor Temple, together enable simple proofs to be given of two important fundamental theorems:
Designing for the Customer
Authors: Willis J.G.
Published: November 2014

IN betting out to design an aeroplane for the commercial or civil market most designers have primarily thought of their aeroplane as a machine whose first and last function was to fly at the highest cruising speed for the least power; its structural form usually fitting in with personal whims on wing‐body combination, undercarriage type, tail location, type of spars and formers and so on.
Stability of Tailless Aeroplanes
Authors: Weyl A.R.
Published: November 2014

IN a series of articles entitled “Tailless Aircraft and Flying Wings”, concluded last month, the evolution of the tailless aeroplane and the flying wing was treated. The different trends of the development were classified, and a short discussion of the difficulties which had been experienced during experimental work given.
Stability of Tailless Aeroplanes
Authors: Weyl A.R.
Published: November 2014

THE complexity of the problems which are associated with the lateral stability and directional control of tailless aeroplanes was not realized until rather late.
Descriptive Geometry in Engineering
Authors: Orloff G.
Published: November 2014

ORTHOGONAL projections are commonly used for representing three dimensional figures on a sheet of paper, and their object is usually that of conveying shape and dimensions to craftsmen, in order to permit manufacture of mechanical parts.
Adiabatic Air Flow
Authors: Saksena G.B.
Published: November 2014

IN most aerodynamical problems it is convenient to consider the aircraft to be stationary and the air to be flowing with a speed equal to the flight speed in a direction opposite to the direction of the flight. This practice simplifies the investigation of the motion of the aircraft and is perfectly legitimate from the mathematical point of view. Thus, if the flight speed is v, the kinetic energy or the dynamic head, q, of unit mass of air is ½ρv2. It the air is allowed to flow through a restriction, for example, a radiator or an air intake duct, the velocity of flow is reduced, and the dynamic energy thus lost is converted into the pressure energy. In most problems it is sufficiently accurate to assume that air is an incompressible fluid so that the density remains constant, and the flow changes can be investigated by applying the well‐known Bernoulli's Equation, viz., p+½ρv2=constant. This assumption is not strictly true, as the flow changes are usually brought about very quickly and there is little chance for the heat generated to be dissipated. However, the error made by this simplified assumption is not very large if the flight speed is fairly low. But in the case of high‐speed aircraft, e.g. a fighter aircraft, the above assumption involves a considerable error. To make a due allowance for the suddenness of the change, it would be necessary to discard the notion of the incompressibility of air and to use the adiabatic law between the pressure and the density of air. Thus, a better and a truer picture of the actual state of affairs would be obtained by assuming the air to be compressible and to investigate its effect on the pressure, density, and the temperature of the air. It is proposed to make a theoretical investigation of this problem on these lines and to present the results in the form of tables, graphs, and nomograms which could be easily applied in the solution of any practical problem on the flow changes.
Serviceing Advantages of the Jet‐Propulsion Engine
Authors: Cooper F/Lt. S.
Published: November 2014

SOME literature on the subject of jet‐propulsion power units for aircraft is now available. These have, however, in the main, been primarily concerned with the description and performance of these units. Little, if anything, of the serviceing and serviceing requirements of the gas turbine has been written.
Evolution of Energy in Jet and Rocket Propulsion
Authors: Bielkowicz P.
Published: November 2014

THE task of any recoil engine consists in transforming the chemical energy of fuel into the kinetic energy of gases leaving the nozzle. This article gives a brief survey of problems connected with transformations which the energy undergoes on the way from the fuel containers to the end of the nozzle. I have simplified as far as possible the problem, examining only the conditions in a rocket engine, without a gas turbine. Even in these simplified schemes the phenomena inside the combustion chamber and the nozzle are rather complicated and require careful examination.
Stress Diffusion Problems
Authors: Goodey W.J.
Published: November 2014

THE case now to be considered is shown diagrammatically in FIG. 12, which also gives the additional notation required. The problem is to determine how a bending moment, applied at one end to the longer‐ons only, is diffused into the whole section, being finally distributed according to the usual beam theory of bending. The differential equation to be satisfied by the displacement w is equation B(2), and if we take the origin at the centre we may take s=Rψ, h=r, x=R sin ψ and y=R cos ψ. Equation B(2) then becomes:
Rate of Roll of Aeroplanes
Authors: Thomson William T.
Published: November 2014

ELASTIC deformation of the wing in relation to divergence and loss of aileron control has been studied by a number of investigators. Much of the previous investigation is based on the equivalent two‐dimensional wing, the success of which depends on the proper choice of a representative wing section. The three‐dimensional analysis requires a knowledge of the torsional deflexion mode, which in general necessitates an iteration process for evaluation.