bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Methods of Calculation for the Determination of a Special Form of Instability of the Elastic Equilibrium of a Cantilever Wing
Authors: Viola Tullio 
Published: August 2016

SummaryThe superposition of the flexural instability of the plane form of a cantilever wing in its own plane, over that of the torsional elastic equilibrium, gives rise to a special phenomenon of mixed instability which has been translated analytically by Prof. C. Minelli into the problem of determining the first positive characteristic value of a certain system of two ordinary, linear and homogeneous equations, in two unknown functions, with given limiting conditions. The methods of calculation, both analytical and numerical, for the solution of this problem are described. The results confirm the intuitive inferences according to which, other conditions being equal, the backward displacement of the elastic axis worsens conditions by lowering the critical speed.
Some Experiences and Lessons Learned in Spinning Aeroplanes
Authors: Taylor James B. 
Published: August 2016

The author's experience in flying dates from before the war and includes a good many years as a naval test pilot, over 5,000 hours of actual flying time in the air in some 360 different types of aeroplanes, ranging from purely experimental to large modern passenger transports and the latest single-seater fighters, and the interest created by some of his experiences has prompted him to attempt some consideration of the complex problem of spinning.The phrase “tail spin” was probably adopted by reason of the fact that when an aeroplane is in this manoeuvre, it appears, from the ground, as though the nose were pointed straight down and the tail was describing a circle, whereas a spin is a complicated manoeuvre and the nose is actually travelling in a helical flight path, the radius of this helix being relatively small.
Aircraft Performance Estimation
Authors: Vernon C. O. 
Published: August 2016

Almost the first thing anyone thinks of, when confronted with a type of aeroplane which he has not seen before, is its performance. He thinks, “ What will she do?” This paper is an attempt to set out the methods by which the performance is estimated for a new design.The subject has considerable scope, and only a certain portion of it will be covered here: Level speed and climb, range (at constant r.p.m.) and the take-off run.Before anything can be done at all, something must be known about lift and drag, and something about airscrews. These will therefore be considered first.
The Trend of Development in Military Aircraft
Authors: Petter E. W. 
Published: August 2016

The subject which I have chosen for my lecture this evening must be one of profound interest to all engaged in the design of aircraft to meet military requirements.This country, with its great Empire sprawling over some three-quarters of the habitable globe and in many parts sparsely inhabited, must form an object of envy to nations cooped up within narrow confines with teeming and everincreasing populations. We therefore cannot shut our eyes to the possibility of attacks being made upon us which we shall have no alternative but to defend ourselves against, if we are going to exist and hold the Empire which our forefathers have bequeathed to us.The next consideration which we do not require professional training in military or naval tactics to appreciate, is that the predominant and indeed possibly almost solitary duty will fall upon the aviation arm of our military forces to resist attack and carry on a war.
Surging in Helical Valve Springs
Authors: Dick J. 
Published: August 2016

The high-speed internal combustion engine presents many problems arising from dynamic effects. Amongst these is the phenomenon known as “ surging ” in the helical springs used for the operation of the valves.If a helical spring is held at both ends, any disturbance in the spring passes up and down as a wave, being reflected at each end in turn. This to and fro movement continues until it is damped out by friction and air resistance. With most springs the speed of propagation of the disturbance is considerable and only a confused flutter of the coils is apparent to an observer. A disturbance of this type is caused by any movement of the end of the spring. The more abrupt the movement of the end, the more pronounced will the disturbance be. An instance of the type of movement producing a pronounced surge is that due to impact between the tappet and the valve when the valve commences to open.
“ Wapiti ” Steel Wings
Authors: Martin Brian 
Published: August 2016

With the present-day normal type of wing the spars are the principal members, and I propose to start by tracing very briefly the evolution of the spars which are used in the Wapiti wings to-day.The personnel of the Steel Wing Company have been designing and making spars ever since 1912. I shall start from the time when we first began to use what might be described as the box type of spar, which was composed of four strip steel sections.The first spar that we made of the box type had channel webs with flat flanges, which had only shallow corrugations, and the rivetted joint was flat. This spar was not very efficient in steel, so we deepened the corrugations and curved the rivetted joint, and this gave a better result.
Testing Aeroplane Controls
Authors: Stevens H. L. 
Published: August 2016

Before beginning this lecture I have first of all to thank the Air Ministry for permission to give it and to explain that any opinions expressed are my own and do not necessarily reflect the opinion of the Air Ministry.Secondly I must express my appreciation of the honour conferred on me by the Society in asking me to deliver a lecture before them; though I wish they had chosen a less difficult subject.As regards the title of this lecture it sounds very circumscribed, but you can't test anything without having a fair idea of what its complete function is or without some standard of reference; and in trying to discuss these parts of the problem I am afraid you will find that I have been, if anything, too. general.
The Origin and Development of Heavy—Oil Aero Engines
Authors: Pye D. R. 
Published: August 2016

In this first lecture upon the origin and development of the heavy oil aero engine to be delivered under the Akroyd—Stuart foundation, it is appropriate to devote some space to the early history of oil engines generally, for it is certain that the aero engine of the future will claim a direct descent from some terrestrial parent. The early history moreover, of the heavy oil engine is of quite exceolional interest, both technical and personal.Herbert Akroyd—Stuart was born in 1864.His father, Charles Stuart, owned a small engineering works at Fenny Stratford, and it was here that the son gained his training as an engineer. Between 1885 and 1890 he took out several patents for the improvement of oil engines, which appear to have been the outcome of his experience with a “ Spiel ” petroleum engine used for power generation at his father's works.
Certificates of Airworthiness
Authors: Howard H. B. 
Published: August 2016

The object of the present paper is to place before the Society certain general considerations regarding the effect of airworthiness regulations on the design of civil aircraft.I should like first to thank the Air Ministry Authorities for permitting me to read this paper, and to explain that any opinions expressed are entirely my own.The Air Navigation Regulations, which set up organised Government control of civil aviation in this country, came into effect on the 1st May, 1919, so that the influence of Government supervision has been present during the whole period of post-war development of civil aviation.
Aircraft Vibration
Authors: Constant H. 
Published: August 2016

In the early stages of development of every form of transport, the pioneers have cheerfully undergone great extremes of discomfort and unpleasantness. As the sense of novelty and adventure began to lose its early appeal a slow but insistent demand for greater comfort arose. To-day, there is a growing tendency to take aeronautics as a matter of course, and an increasing demand for those standards of comfort which have become the rule in the older methods of transport.The two factors that most seriously prejudice one's comfort in aerial transport are probably noise and vibration. The problem of aircraft noise was laid before you last session by Dr. Davies.The engineer has seldom a good word to say for vibration. In all his schemes it comes to cross him like an ill-tempered fairy godmother. In the days when men designed by eye and worked in tenths of an inch instead of in thousandths, vibration was more of a nuisance than a serious problem. To-day, when factors of safety are being pared to the bone, when weight is regarded with a jealous eye and members are being stressed right up to the limits of their capacity—to-day, vibration is rapidly becoming a definite limiting factor in design, and the problem of vibration in all its varied forms, one of the most pressing that the engineer has to face.
Present Thoughts on the use of Powered Flying Controls in Aircraft
Authors: Lyons D. J. 
Published: August 2016

It has long been the practice in engineering to use direct manual operation of the controlling parts of a machine, so long as it was within the strength of the operator, and so long as design of the operating gear was relatively simple. In innumerable applications, however, the increased demands for power by the controls, and the need for greater accuracy, have necessitated the development of servo mechanisms to drive them; that is, we have to sever, partially or completely, the direct mechanical link from operator to control, and use the inserted backlash, elasticity, and so forth, to meter power from an external power source.In the flying control field we have come at this time to the transition stage, in that we have realised that, for a large number of applications, direct manual operation is impractical, and we are feeling our way towards suitable forms of servo controls for our various needs.
Some Unusual Aspects of Turbulence
Authors: Bethwaite F. D. 
Published: August 2016

The first idea about unsteady motion in the atmosphere seems to have been the vague notion of “ Air Pockets”—areas or gaps, wherein the air just does not generate lift, and an aeroplane falls in consequence. It is astonishing how widely this view is still held.Those engaged in aviation soon learned that unsteady flight was due to turbulence and two sorts, friction and orographical, were quickly recognised. Friction turbulence, which affects only the lower layers of the atmosphere, can best be observed by watching a soaring sea-bird in a breeze. The friction of the water surface creates a velocity gradient or variation of windspeed with altitude, and the bird will probably be diving down-wind, and climbing into wind, with no effort— from the bird's point of view a fair approach to perpetual motion. However, the air is really a mass of tiny eddies where friction is at work and close observation of the bird's wings and feathers will show them to be constantly in motion as they yield to each puff.
A Survey of the Technical Problems of the Design of Naval Aircraft
Authors: Farren W. S. 
Published: August 2016

In a necessarily brief introduction it is best to choose a few topics which seem to me to be of first–class importance, and to leave it to the discussion to bring up others.I wish it had been possible to include one other aspect of Naval aircraft in these introductory papers– the aircraft carrier. Many of the technical aspects of carriers may be more appropriate as a subject for the Institute of Naval Architects, but I feel that our discussion will be incomplete unless ship designers contribute.
Flight Control
Authors: Draper C. S. 
Published: August 2016

Summary:Flight before the Wright brothers demonstrated their powered man–carrying flying machine was based on the philosophy of vehicles with high inherent stability combined with pilots whose only duty was to steer. This combination resulted in low controllability and poor manoeuvrability, with a strong response to the disturbances of rough air. The Wright brothers broke with the high–inherent–stability concept and combined inherently unstable aircraft with three–axis control operation by human pilots to achieve stable flight systems with good controllability and good manoeuvrability. This change from inherently stable to inherently unstable aircraft was the basic contribution made by the Wright brothers to start the age of flight.In this paper, a picture of the state of flight control before the Wright brothers is built up from references to the literature. A similar picture is drawn for flight control developments after the Wright brothers, and the effect of their efforts on the progress of events is discussed. Plots with time as the independent variable and non–dimensional ordinates are used to illustrate the overall pattern of past developments in flight control and to indicate the course of future progress.
Air Safety from the Pilot's Point of View
Authors: James J. W. G. 
Published: August 2016

Before I present my written paper I would like to refer to two aspects of my subject which have been omitted from the paper, icing and static discharge.I have no records of icing being a direct cause of accidents but it is important to appreciate the effect that it has on a pilot when flying an aircraft which picks up a lot of ice which he knows he cannot get rid of when he wishes. I look forward to the time when there will be installed on aircraft a de-icing system which will enable a pilot to get rid of ice at the right time.
Operational Research into Air Traffic Control
Authors: Bell G. E. 
Published: August 2016

With the return of British civil aviation to normal operating conditions after the war it was found that several problems which had previously given little cause for concern had become acute. More especially, the increase in the volume of traffic, particularly under instrument flying conditions, together with certain indirect consequences of the greater sizes and weights of aircraft, had brought about greatly increased congestion around major airports, and there was, therefore, an urgent requirement for an effective system of close air traffic control to ensure the safety and rapid movement of the traffic.The Ministry of Civil Aviation immediately gave much attention to this problem of air traffic control, but at once found itself in serious difficulties on account of lack of sufficiently precise knowledge of the traffic and the traffic pattern. The then Controller of Technical and. Operational Services, Sir Conrad Collier, realised that the obtaining of the necessary data concerning air traffic control and other matters of technical interest was essentially a matter of operational research, and in 1947 a small operational research section was established which began work in the autumn of that year.
Useful Load Ratio with Jet and Airscrew Propulsion of Aircraft
Authors: Lundberg K. O. 
Published: August 2016

SummaryIn a search for a rational basis for a transport-economical comparison of jet and airscrew propulsion of aircraft, a method has been developed which is generally applicable for evaluating any kind of propulsion of aircraft, as well as the efficiency of any principle or type of aeroplane design. The method is based on the assumption that the ratio between the useful load and the gross weight (or empty weight)—when related to the speed —is representative for the overall efficiency of the aircraft, including the power plant, from a transport point of view. General equations have been deduced for this useful load ratio as functions of, in addition to the speed and altitude, all major design parameters, as wing loading, power loading (or thrust loading for jet aeroplanes), specific engine weight, specific fuel consumption, parasite drag coefficient, effective aspect ratio, and two structural weight coefficients. This has been possible by the deduction of a formula for the gross weight, which appears to be usable even for general analysis of other aircraft performances, whenever the useful load has to be considered.The method presented has been applied in this paper particularly for a comparison between jet-propelled aeroplanes and piston engine-airscrew aeroplanes. This has revealed that pure jet propulsion seems to be superior to the conventional system at speeds as low as 200 to 300 m.p.h., depending upon the duration in hours of flight and the detailed assumptions made.Lack of accurate data for the gas turbineairscrew combination has prevented the writer from making a closer investigation of this system, but a preliminary study of the same kind seems to indicate that the turbineairscrew aeroplane—although for most purposes definitely superior to the piston engine aeroplane—is inferior to the pure jet aeroplane for durations up to about two hours of flight. If, however, all the mechanical complications involved in retaining the airscrew are taken into consideration, it appears doubtful whether the turbine-airscrew system will be any more than an intermediate step in aeronautical development. At the best, it might remain only for extremely long ranges, or transport of cargo at comparatively low speeds.The conclusions drawn are based on the present stage of development of jet engines, but naturally it will take at least some three to six years before the jet aeroplanes contemplated are built and put into service.
The Theory of Limit Design Applied to Magnesium Alloy and Aluminium Alloy Structures
Authors: Panlilio Filadelfo 
Published: August 2016

This paper is a study of the questions: (1) Are the simplified equations and design procedure in Limit Design that have been developed for application to structural steel construction, applicable without modification to light metal structures? (2) How do the properties of these metals which are different from those of steel affect the application of the theory? Do they offer any advantages? Any disadvantages? (3) What changes in traditional design procedure are warranted? What changes are imperative?No claim is made to a complete solution of the design problem, since each particular structure involves a thousand and one details. Only the broad fundamental philosophy is discussed here. The discussion and conclusions are supplemented with a report of a number of experiments on a few extrusions of some of the more important alloys of magnesium and of aluminium.
Some Aspects of Noise From Supersonic Aircraft
Authors: Lilley G. M. , Westley R. , Yates A. H. , Busing J. R. 
Published: August 2016

SummaryThe noise problem associated with an aircraft flying at supersonic speeds is shown to depend primarily on the shock wave pattern formed by the aircraft. The noise intensity received by a ground observer from a supersonic aircraft flying at high as well as low altitudes, is shown to be high, although it is of a transient nature.A study of the shock wave patterns around an aircraft in accelerated and retarded flight is shown to lead to an explanation of the one or more booms, of short duration, heard by ground observers after an aircraft has dived at supersonic speeds.The shock wave patterns associated with an aircraft flying in accelerated or retarded flight at transonic speeds are shown in certain cases to be very different from the corresponding patterns observed in steady flight. The significance of these results, with reference to problems of flight at supersonic speeds is briefly discussed.
Lifing of Aircraft Equipment
Authors: Stevens H. L. 
Published: August 2016

Reading the paper by Tye and Cundall in the June issue of the journal, I was started on a train of thought on the same lines.I agree with the paper but feel that the argument has not been taken far enough. The main conclusion is:–So long as a random failure is no more expensive and troublesome than a controlled replacement, it is always cheaper to wait until an item fails before replacing it. This is quite independent of the law of failure with time.
Some Problems in the Development of Air Transport in West Africa
Authors: Walker Hubert 
Published: August 2016

West Africa, particularly British West Africa, has been one of the last areas to be opened up to Air Transport and because of physical and financial difficulties, progress has been slower than in most other parts of the Empire.As West Africa, even today, is not very well known in other parts of the Empire, it will be useful to give a brief description of the territory and the early history of aviation there before dealing with the special problems encountered in the development of air transport. While the particular territories dealt with in this lecture are the four British West African Colonies and Protectorates of the Gambia, Sierra Leone, the Gold Coast and Nigeria, it will be necessary, from time to time, to make passing reference to the adjacent French territories and even to the Anglo–Egyptian Sudan. The four British territories, unlike those in East Africa, are not contiguous but each is surrounded on the land side by the intervening French territories of Senegal, Guinea, Ivory Coast, Dahomey, Volta, Niger, Chad and the Cameroons.
Modern Wind Tunnel Balance
Authors: Leavy L. E. , Saunders C. G. 
Published: August 2016

Because of the limited nature of its application the wind tunnel balance has never been the subject of steady development along well defined lines such as are discernible in the development of most other mechanisms of comparable size and complexity.The diversity of types and forms of balance which have been constructed in the past, reflect the wide range of tunnel sizes, financial resources, and personal preferences which are characteristic of some laboratory equipment.The design and construction of a balance suitable for use in a medium–to–large industrial wind tunnel is a relatively costly undertaking, and the problem of providing such equipment is made more difficult by the paucity of published information, of a sufficiently detailed nature to be of assistance in making a decision on either a suitable specification for this class of machine, or the practical means by which a specification can best be met.As part of the modernisation of the Blackburn and General Aircraft Aerodynamics Laboratory at Brough, a new six–component balance was installed, some few years ago, in a 7 ft. x 5 ft. wind tunnel having a maximum speed of 300 ft./sec. A detailed description of this balance is given.
Two-Dimensional Bow Shock Wave Detachment Distances
Authors: Bryant R. A. A. 
Published: August 2016

In the recent paper by Warren a summary was made of current data on two-dimensional bow shock wave detachment distances. It was shown that the experimental results of Griffith and Alperin, as well as the detachment distances computed by Vincenti and Wagoner, could be collapsed into a single curve by using Spreiter's Transonic Similarity Parameter. This has been confirmed by the present authors who have found that the experimental results for wedges obtained by Bryson also correlate favourably with the curve given by Warren (Fig. 3 of Ref. 4).The results of the foregoing workers have been for steady flow conditions. However, it has been noted by Lilleyet aliathat a steady shock wave pattern can be established in free flight only after steady motion has been maintained for a considerable (infinite) time. In general, the locus of detached bow shock waves depends on the time history of the motion whenever a body is accelerated from subsonic speed.