bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strength of Screw Threads of Whitworth Form
Authors: Inglesby J. V. 
Published: August 2016

SummaryA Stress analysis of screw threads of Whitworth form has been performed.The critical stress in the threads is a shear stress, and this may be expressed simply in the form:–whereSmax=shear stress.f=distribution factor.= 1.0 when screw and nut are both in tension or compression.= 2.0 when screw and nut are in tension and compression respectively, unless specially designed for an improved distribution of load.k = coefficient, depending mainly on fit, but also on pitch of threads, L and D.<0.8 for close fit.<0.9 for medium fit.<1.0 for free fit.P=axial load.L=length of engagement.D=nominal diameter.
Analysis of Stress Strain Curves
Authors: Voce E. 
Published: August 2016

It is gratifying to learn from Mr. Nicholls (May 1955, p. 364) that he is favourably impressed with the exponential function, and it is to be hoped that he, and others interested in stress-strain relationships, may find it to be of practical value.While the modifications which he suggests are quite legitimate, they tend to mask the essential simplicity of the function. It would be difficult to obtain the asymptotic stress from his first equation. The second can be easily solved for strain, but the converse process is complicated by the fact that the current stress appears both inside and outside the exponential. It is surely much more straightforward, and infinitely quicker, to plot the stress-strain curve from the proof stress data and analyse it in the normal way.
Aeroplane Wheels and Tyres
Authors: Walters N. 
Published: August 2016

The first requirement in any manufacturing process is to secure a stable raw material, and to this end scientific control was essential, for it was found that the rubber obtained from trees on the top of a hill differed from the trees in the same field or plantation at the base of the hill. A process of blending was therefore essential.The pure rubber was rolled and crushed so that it became a “ flannelly ” sheet of crêpe rubber such as is used on tennis shoes, etc., but in this form the rubber becomes sticky when heated. Filling agents are therefore added, and colouring materials to give the red tint for inner tubes and grey for outer covers.
Practical Training of Aeronautical Engineers
Authors: Hahn J. M. 
Published: August 2016

The Men who could best lay claim to the title of “Aeronautical Engineer” were the early pioneers like Wilbur and Orville Wright. They were their own research workers, their own designers, their own draughtsmen, their own constructors, their own test pilots and, later on, their own salesmen. The Wright brothers carved and steamed the bamboo ribs and struts of their aeroplane themselves, brazed and spliced the wires and cables, while their sister Kathleen stitched the flimsy fabric. But the day of the craftsman-designer is gone.This paper is concerned with the present-day professional aeronautical engineer in industry and in particular, with the aircraft designer. A distinction must be drawn between the aeronautical engineer and the aircraft technician; both may be intimately concerned with the design of an aeroplane, but the technician—the stressman, the aerodynamicist, the draughtsman—is at the most an embryo aeronautical engineer.
The Military Aero-Engine-is it Suitable for Civil Aviation?
Authors: Bailey S. B. 
Published: August 2016

In the past, the majority of civil aircraft have been powered by engines which have been developed primarily for the Royal Air Force. Their development costs have been borne by the Service departments, and then they have been converted for civil use at comparatively small extra cost.It has always been questionable whether these converted engines have been really suited to their civil role, and it will become even more doubtful the farther the design and performance of civil aircraft depart from those of military aircraft.In this paper, an attempt has been made to coyer the more important requirements for the two kinds of engines, and to see how they compare. If it appears that too little has been said concerning the gas turbine, that is because there is as yet no experience of its commercial operation.The opinions expressed in the paper are the author’s and have no official significance.
Electric Resistance Welding and Its Use in the Construction of Aircraft
Authors: Sykes E. C. 
Published: August 2016

Designers and technicians pay a great deal of attention to the development of jointing methods for use in the construction of aircraft. A satisfactory method should be neat, economical in labour, flexible in application, and capable of yielding consistent results with a low weight penalty.Electrical resistance welding meets the above requirements and it is with this process that I shall deal.
Structural Features of German Aircraft
Authors: Leggett D. M. A. , Davison J. H. H. 
Published: August 2016

Although this paper is primarily concerned with the structure of current German military aircraft, no apology is needed in considering for a few moments some of the outstanding developments that took place 20 or 30 years ago.In the early days of any branch of engineering, there are always a few individuals in each country who stand head and shoulders above their fellow workers in the same field, and aviation is no exception. But, whereas in this country quite a number of people spring to mind as having made exceptional contributions to aeronautics, in Germany one name stands out pre-eminent— that of Junkers. Hugo Junkers was born in 1859 and soon showed promise as a scientist and engineer. His technical training was varied, and at the age of 36 he founded at Dessau the engineering firm which bears his name.
Evaluation of Aeroplane Metals
Authors: Van Den Broek J. A. 
Published: August 2016

The material herein presented was gathered as part of a research project for the Bureau of Aeronautics (Structures Branch) of the U.S. Navy on “Evaluation of High Strength Aluminium Alloys.” The Bureau has released this material for independent publication.In this paper the physical constants determined are limited to elastic limit, yield stress, ultimate stress, modulus of elasticity, weight and ductility. The materials tested are primarily the new aluminium alloys 75 ST, R 301 T, and R 303 T.To offer an immediate basis of comparison for aluminium alloys, the aluminium alloy at present in common use, namely 24 ST, was also tested. To extend the scope of the project still further, a few tests on magnesium alloy and stainless steel were included.
The Aerodrome Problem Related to Aircraft Design and Operation
Authors: Ayers R. H. 
Published: August 2016

The Aerodrome, as the point of contact between the aircraft and the world of reality, has to a large extent been taken for granted. The designer regards it as the base for prototype tests and the airline operator as his aerial railway station. It is my intention to show that aerodrome development is at a critical stage of evolution on this side of the Atlantic, that many of the related problems do concern the aircraft designer and operator, and that if these problems are not given consideration, difficulties will be encountered in civil operations.To quote an example; the optimum aircraft type to serve a system of air routes can be worked out taking into consideration the range required, payload and speed, but if the aircraft ultimately ordered and produced cannot safely operate from the aerodromes to be served because of the runway length and approaches, then the operations will either have to be reorganised or continued without due regard for safety.
The Problems of Blind Landing
Authors: Pritchard H. C. 
Published: August 2016

In being honoured by the request to deliver a lecture on “ The Problems of Blind Landing,” I am set to some extent a task different from that normally presented to the Society's lecturers. In general the results of successful research are presented to you, whereas I am merely asked to outline the problems — with the implication that constructive suggestions for their solution may result. Personally, I feel that this is a most appropriate type of lecture, particularly in regard to a problem which embraces specialist fields in radio and radar, in aerodynamics and aircraft instruments, to an extent that few can claim to be expert in all.The problem of blind landing can best be discussed after reviewing existing methods of blind approach and proposals now current for solving the landing problem.
The Development of the Spitfire and Seafire
Authors: Smith J. 
Published: August 2016

The object of this paper is to discuss the evolution of the wartime fighters the Spitfire and Seafire, designed by the Supermarine Works of Vickers–Armstrongs Ltd. In particular, it will be confined to the design and technical side of the problem. The production undertaking, which resulted in the manufacture of over 22,000 of these aircraft in 33 different types, would undoubtedly need a paper of its own.In order to make the matter clear it is proposed to begin with a brief history of the early development of high speed aircraft by the firm. The next logical step is to survey the Spitfire family as a whole and to trace the relative importance of the different types, giving some indication of their line of development. Finally, an attempt will be made to analyse the factors which maintained the efficiency of these aircraft at a high level for a period of ten years.
Progress Towards Electrical Serviceability
Authors: Woodall R. H. , Higgs V. A. 
Published: August 2016

The 820th Lecture to be read before the Royal Aeronautical Society, “Progress Towards Electrical Serviceability,” was given by R. H. Woodall, M.I.E.E., A.F.R.Ae.S., and V. A. Higgs, B.Sc., A.M.I.E.E., A.F.R.Ae.S., on 1st March 1951 at the Institution of Civil Engineers, Great George Street, S.W.I. Major G. P. Bulman, C.B.E., F.R.Ae.S., President of the Society, presided at the meeting and introduced the lecturers. Mr. Woodall is a Director and Chief Engineer of Rotax Ltd., and Mr. Higgs is Head of Technical Sales and Aeroplane and Automobile Sales of the British Thomson-Houston Co. Ltd.It is evident from remarks made in previous papers or in discussion on those papers, that the Aircraft Industry is not entirely satisfied with the electrical accessories available for use in aircraft.There may be some grounds for this dissatisfaction, but it is hoped to make it clear that the electrical equipment suppliers are very much alive to their responsibilities and that development on an ever-increasing scale is taking place in order to give the aircraft constructors the most reliable equipment possible.
Estimation of Cruising Air Speeds for Economic Analysis
Authors: Stratford Alan H. 
Published: August 2016

In the course of investigation into the operating economics of transport aircraft, the cruising speed arises as a fundamental variable and a rapid method of correction of speed for variation of power, height and weight is frequently required. Other problems present themselves, such as the estimate of cruising speeds in the course of a new type design study, or the correction of a “one–point” published performance of a new aircraft to a standard operational condition differing in specified weight, altitude or power output for cruising.In this note no account will be taken of the block speed correction arising because of the modification of true air speed by the various factors, such as wind, climb and glide which distort the optimum flight path. The principle of the method here suggested involves the unique relationship of p, the ratio of thrust power required at any speed (V) to the thrust power at the minimum drag speed (u) at the same altitude, and n the wellknown speed ratio V/u.
Fatigue in Engine Design
Authors: Owner F. M. 
Published: August 2016

The difference in outlook between metallurgist, physicist and designer on the problem of fatigue of metals is due not only to the differences in training and method but also in immediate objective, however closely their ultimate objectives may coincide.Physicists consider fatigue in terms of crystal structure and composition of the constituents of the crystal, noting in passing that certain types of crystal structures are associated with poor fatigue strength. The metallurgist's prime interest lies in the effect of surface finish, heat treatment, the physical condition of the surface, such as degree of cold work, the effect of carburised and nitrided cases having different hardness from the core. Both think in terms of controlled condition tests, with idealised test conditions such as cylindrical test specimens, close control of changes of section, polished surfaces of only a few micro-inches surface roughness, operating in a controlled atmosphere.
Aeronautical Research in the Netherlands
Authors: Van Der Maas H. J. 
Published: August 2016

It is a great honour to be invited to present a survey of the aeronautical research in the Netherlands to this distinguished audience and I wish to express my thanks to the Council of the Royal Aeronautical Society for giving me the opportunity to deliver this lecture. The more I appreciate it in view of the friendship between our two countries, between the Society and its Dutch counterpart and the personal friendship with so many present on this occasion.It is my intention to give a survey of some of the work performed in the Netherlands in the post-war period and to describe briefly the main installations which are now available or under construction. I hope that I will be able to give you an impression of the scope and the nature of the aeronautical research activities in the Netherlands. These activities are being directed in the first place by the immediate needs of the industry and the aircraft operators; and in the second place by the desire to contribute to the general development of the art, thereby also supporting the exchange of results on an international basis, even more essential than before, considering the rapidly growing importance of aviation in its broadest sense.Before entering into more technical matters it may be worthwhile to give very briefly an outline of the present organisation of aeronautical research and development in the Netherlands.
A Test Plant for Helicopter Engines
Authors: Walker A. 
Published: August 2016

This Note describes the design and construction of a “ Tilting Test Bed ” for helicopter engines for Alvis Ltd., for which some onerous requirements were laid down (Fig. 1). The most important of these were that:—(i)Readings of engine torque and b.h.p. must be given by a dynamometer, so as to provide accurate data.(ii)The engine, and therefore the complete test plant, must be capable of being tilted, while running, through 120°—from the horizontal to the vertical and 30° beyond.(iii)During the tilting process the engine throttle setting must remain unaffected and the readings of torque, b.h.p., fuel consumption, and so on, continue with unaltered accuracy.(iv)A powerful fan must be incorporated, for cooling certain types of engine not provided with selfcontained fan, and the air-blast must continue unchanged during tilting.
Problems of Servicing and Reliability
Authors: Buxton G. M. 
Published: August 2016

There are two parts of this paper, the first dealing with Servicing and the second with Reliability. Although they are connected in many ways, and indeed servicing has been taken to mean checking parts which might be unreliable, it is convenient to separate them.A practical factor of increasing importance is the burial of the accessory machines in modern aeroplanes.Compared with, say, a plough, the parts of Blériot's Anzani engine might be thought to be dangerously concealed; dangerous, that is to say, if its working depended on any condition of the internal parts which could be judged when looked at. But the Anzani engine was simplicity itself, compared with any modern machine, even an accessory machine, and these machines are usually covered by, or rather entangled in, the structure.
The Local Instability of a Simple Integral Panel
Authors: Chilver A. H. 
Published: August 2016

Summary:The local instability of a simple type of integral panel under uniform end compression is discussed firstly as a problem of interconnected flat plates, and secondly in terms of the torsional stability of the stiffeners. It is found that the second method under–estimates the “true” local buckling stress. This conclusion is in conflict with earlier work by Yusuff on closer study it is found that Yusuff's analysis involves two important assumptions which are generally unjustifiable. It is suggested that the collapse strength of a short compressed panel may be estimated with reasonable accuracy from a knowledge of the initial local buckling stress and the proof stress of the material of the panel.
The Pressure Distribution Due to Incidence on a Slender Elliptic Half–Cone
Authors: Taylor C. R. 
Published: August 2016

The slender–body solution for the flow about low aspect–ratio wings of non–zero thickness yields a pressure distribution which is valid in the vicinity of the leading edge and therefore suitable for comparison with measured distributions. In this note an expression is derived for the theoretical pressure distribution, due to small incidence, on a slender elliptic half–cone in uniform motion. It is shown that this distribution is additive to the zero incidence pressure distribution. A comparison with some low speed measurements shows qualitative agreement.The method can be simply extended to other bodies of elliptic cross section.
Graphical Analysis of Trans-Canada Airlines' Progress on the North American Routes 1946–1950
Authors: Jaworski Adam 
Published: August 2016

Progress of any organisation may be related either to an assumed basis within the organisation itself, or to some other organisations, preferably competitors in the same business. The second method is more realistic and by relating the corresponding data in ratios, it helps to eliminate to a great extent the influence of price changes, which distort yearly comparisons of revenues and expenses.In the United States the trunk lines represent over 95 per cent. of the total revenue ton-miles flown on the domestic routes and in international aviation, the largest system with the highest quality of service. Therefore, by comparing in Part I the domestic services of Trans-Canada Air Lines (T.C.A.) to corresponding services of the U.S. trunk lines, the most severe criterion was chosen.Part II contains an investigation of trends of particular expenses in relation to the total expenses for T.C.A's North American Services.
Certificate of Airworthiness Flight Testing
Authors: Davies D. P. 
Published: August 2016

Under the heading “C. of A. Flight Testing” many different subjects could be discussed; most of them, however, and particularly those concerning procedures and basic philosophies, are well understood and need little elaboration: the interest really lies in those items which regularly give trouble and, if I may borrow the current American expression, these “ problem areas ” form the basis of this paper.In the time available I cannot hope to cover the whole picture and must limit myself generally to the large transport aircraft and, apart from one or two divergencies, to qualitative handling. The paper is my own and I take responsibility for the opinions expressed in it.
Cumulative Damage in Fatigue—A Design Method Based on theS-NCurve
Authors: Levy John C. 
Published: August 2016

SummaryIt is suggested that a convenient way of presenting the results of fatigue tests in which two different stress amplitudes are applied alternately is to plot log N against log (n1/n) where N is the total cycles to failure and (n1/n) is the fraction of cycles run at the high stress.With these co-ordinates, a simple geometrical construction gives a safe design method for the two-stress level system using only the conventionalS-Ncurve and the value of (n1/n) expected to be encountered in service. IfN1andN2are the lives at the high and low stresses as read from theS-Ncurve, one point may be plotted at (log N1, 0) since this represents the programme when all cycles are at the high stress. On the assumption, shown to be justified, that less than one cycle of high stress per 10,000 total cycles would not significantly affect the life at the low stress, a second point is plotted at (log N2, 4). The straight line joining these two points is always found to predict safe values of N for any value of (n1/n).This conclusion is checked against a wide range of experimental results taken from six different sources in the literature covering rotating-bending and push-pull tests, ferrous and non-ferrous metals, any order of stressing and length of programme cycle from 50 up to 5 million. This last feature means that the length of the programme cycle in service need not be known. All that is required is the proportion in which the two stress amplitudes are mixed. The average value of the ratio (experimental life/predicted life) for the data examined is 1·8, the extreme values being 1 and 56. By plotting in three dimensions an equation is also developed for the three-stress level spectrum and a suggestion is made for an extension of the method to multiple stress levels.
A Method of Measuring Post-Yield Strain
Authors: Woodcock F. J. , Weiss K. R. 
Published: August 2016

Increasing interest has been shown recently in the measurement and interpretation of post-yield strains. Early investigators determined the nature and magnitude of such strains by observing the distortion of a grid of fine lines inscribed on the unstrained metal. A development of this method involved the use of a photographically deposited grid.In the present instance the initial requirement (August 1948) was for the measurement against time of strains of the order of 4 per cent. occurring as “ fast transients.”As the wire resistance strain gauge element was well established, it was natural to consider its extension to post-yield measurements, and it later became apparent that this had already been done by Swainger.
Experiments With Flat Planes (1866–1890)
Authors: Pritchard J. Laurence 
Published: August 2016

The pioneer rarely receives that meed of praise which is his due, until those days arrive when his pioneering has become a page or so of history. What meed of praise he may then receive is too often made savourless by critics unable to disassociate themselves from the knowledge of their own technical era. The halting speed of pioneering aerodynamic research cannot be judged by the supersonic speed of secret splittings of the atom.It was R. L. Stevenson who said that to travel hopefully is a better thing than to arrive. In aviation we have arrived at that streamline flow of technical jargon which deludes so many they have at last reached the boundary layer of aeronautical knowledge, so that they find experiments with plates always a little flat, although their curiosity may still be aroused by flying saucers.
Some Comments on High-Lift Testing in Wind Tunnels with Particular Reference to Jet-Blowing Models
Authors: A. Anscombe  , J. Williams  
Published: August 2016

SummaryThis paper considers some of the special problems of wind tunnel testing which arise in high-lift work. Discussion is confined to current experience in the R.A.E. and N.P.L. low-speed wind tunnels, and refers mainly to tests on blowing over flaps or jet-flaps. Comments are made on suitable size of model, methods of feeding compressed air into models without affecting balance readings, and general test technique. Methods of model construction are not specifically discussed.