bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concussion in Hockey: Compliance with Return to Play Advice and Follow-up Status
Authors: Ackery Alun , Provvidenza Christine , Tutor Charles H. 
Published: August 2016

Objectives:To determine the compliance rate among hockey players with concussion or other head injuries who were advised by a physician about return to play. To assess compliance of hockey players with return to play advice and to assess the incidence of long-term post-concussion symptoms.Methods:A retrospective chart review, telephone questionnaire and follow-up analysis of income, level of education and professional aspirations. The study examined 40 hockey players with concussion or other head injury treated at a neurosurgical ambulatory clinic, who had initial visits between 1995 and 2003, and had been seen at least two years prior to completing the questionnaire.Results:There was a 58% (23 of 40) participation rate in the study. Fifteen (65%) of the 23 participants were advised to never return to play, and 5 (33%) were non-compliant and returned to play. Four (80%) of the five non-compliant players continued to suffer from post concussion symptoms. Overall, 15 (65%) of the 23 players participating in the study continued to suffer post concussion symptoms at least two years after the clinic visit.Conclusions:Five (33%) of 15 hockey players advised to never return to play were non-compliant and returned to play, and four continued to suffer from post concussion symptoms two or more years later. After repeated concussions, 65% of hockey players had long-term sequelae that prevented return to play and produced long-term post-concussion symptoms.
The Use of Glass Cloth/Resin Moulded Components in the Laboratory
Authors: Irving F. G. , Saunders R. A. 
Published: August 2016

The purpose of this note is to call attention to the convenience of glass cloth/polyester resin laminates as a means of constructing certain parts of experimental apparatus, such as small ducts or nozzles.The advantages of the material are that it is strong, light in weight, easily worked in that heat and pressure are not required, and a high degree of accuracy and surface finish are easily achieved. For the purposes considered here, convenience in fabrication is the main consideration, since it is easier to shape the outside of a suitable male mould rather than the inside of a small duct.
Wind Tunnel Balance Design— The Simultaneous Measurement of Forces and Moments
Authors: Saunders C. G. 
Published: August 2016

An electro-mechanical method of simultaneous component separation is suggested as an alternative to mechanical systems. Based on the commonly used weighbeam, employing a motor driven leadscrew, poise weight, selsyn repeater circuit and counter, component separation is proposed by means of the selsyn differential circuit.The use of the selsyn motor as a direct or differential telemeter mechanism is well known, and as such, has many industrial applications. Such use, applied to the aerodynamic balance, offers the advantage of avoiding many of the difficulties associated with design and in particular, the construction of a mechanically independent and simultaneous measuring instrument.
Foaming and Aeration of Oils in Aviation Powerplant
Authors: Tourret R. 
Published: August 2016

The presence of foam or unduly aerated oil in the lubricating-oil systems of aircraft power plant can be very troublesome—more so in reciprocating engines than in gas turbines, since the rates of circulation are greater and the viscosity grade of the oil is higher. Consequently in this paper, which surveys present knowledge about oil foaming, reciprocating engines are the main consideration.In the conventional aircraft “dry-sump” oil system, a simplified diagram of which is shown in Fig. 1, oil is pumped from a supply tank to the bearings, and so on, by a so-called “pressure” pump. This oil then drains down into the sump and is picked up by “scavenge” pumps which return it to the supply tank. There are usually at least two scavenge pumps so that the oil is cleared away irrespective of the attitude of the aircraft.
Measurement of Noise on the Ground from Aircraft in Flight
Authors: Fleming N. 
Published: August 2016

In cases of noise nuisance, measurement of the noise has several uses. It helps in deciding the degree of noise reduction which is desirable; it may serve to identify the most important source or sources of the noise where this is in doubt; and it is of assistance in devising methods for reduction of the noise. For the first purpose a single figure to characterise the noise would be preferable, but for the others some form of noise analysis is needed.To the sufferer from the noise the most important characteristic is the annoyance it causes, or its nuisance value. This may be assessed very differently by different individuals, and consequently it is not very amenable to measurement.
Minimising Zero-Drift in Electrical Strain Gauge Bridges
Authors: Urwin C. R. , Swainger K. H. 
Published: August 2016

Summary“Potential” leads are used to put strain gauge switches and leads in series with high resistance ratio arms in a modified Wheat-stone Bridge. Thus the effects of switch contact resistance change and temperature-resistance change in leads can be minimised to any desired values. The high resistance ratio arms allow coarse resistance changes at the measuring bridge to measure the small resistance change at the gauge due to strain.High potentials are applied to the bridge to minimise the effects of thermal e.m.f.Active gauges and the temperature compensating gauges are in circuit for only a few seconds while the measurement is made.
The Development of an Early Helicopter
Authors: Aldridge P. J. 
Published: August 2016

It is only in very recent years that the helicopter has begun to find a place in the pattern of Aviation. Although its development has not been so intensive nor so widespread as that of the more conventional fixed wing aircraft it has remained a positive and progressive force running on a parallel course.The idea of the screw, as a method of propulsion or lifting, is not new, yet at the beginning of the 20th century its use was still restricted to propelling ships. It is therefore not surprising to find that the development of an early helicopter was carried on in a shipyard.
The Development of the Spill Flow Burner and its Control System for Gas Turbine Engines
Authors: Carey F. H. 
Published: August 2016

Since the advent of the aircraft gas turbine engine, various ways have been employed for feeding the fuel into the combustion chambers in the most advantageous manner. Perhaps the most commonly employed method has been the use of swirl atomising nozzles, and in this group is the spill type which has been used successfully for many years in industrial oil burning furnace equipment.Arising from the general review of burner nozzles made for the aircraft gas turbine engine in its early days, spill burners were used experimentally on the W2/700 engine. Among the problems encountered was that of achieving suitable flow matching characteristics between the several burners of a set and also, that of arranging a satisfactory control system. The knowledge gained by this early work has been made available and has proved helpful to those who chose to carry on with this particular type of fuel nozzle.
Recent Fog Investigations
Authors: Petterssen Sverre 
Published: August 2016

Fog is the result of a condensation process near the earth's surface when the air is cooled below its dew-point temperature by one or more of the processes which will be discussed in the second part of this paper.The classical experiments of Wilson (I) showed that some types of particles, now called nuclei of condensation, must be present in the air if condensation is to occur with a reasonable degree of supersaturation.
A Theoretical Investigation of Plastic Torsion in an I-Beam
Authors: Christopherson D. G. 
Published: August 2016

The distribution of stress in an I-beam in torsion is investigated by a method of successive approximation, and the regions of initial yielding are determined for several values of the angle of twist. Formulas are given for elaborating the methods of Southwell and of Shortley and Weller in order to facilitate this determination.The value of the stress-concentration factor in the fillets is found to agree well with results obtained by soap-film tests, and regions of plastic flow approximate closely those observed by MacGregor and Hrones by the use of the etching method.
Study of Airscrews for High Speed Aeroplanes
Authors: Lazzarino Lucio 
Published: August 2016

RésuméIt is demonstrated how, with increase in speed, the diameter of optimum efficiency and the maximum possible value of efficiency of an airscrew diminish. The efficiency of a system of two counter-revolving airscrews with different angular velocities is then determined, and the variation of efficiency with variation in the relation between the angular velocities of the two airscrews.With increase in the height and speed of flight, airscrew performance inevitably falls off, frequently in a marked degree; this being mainly due to the decrease in aerodynamic efficiency of the blade sections at high Mach numbers.The object of the present article is to analyse the influence exerted upon the performance of an airscrew by the various parameters that determine it, wit-h special reference to those connected with the speed and height of flight.A similar study has also been made of systems constituted of two counter-rotating airscrews, with a view to comparing them with isolated airscrews designed to absorb the same power under identical conditions.By the methods here described, an approximate numerical evaluation of the performance can be made, utilising the experimental results which are already to hand.
The Stabilisation of a Thin Sheet by a Continuous Supporting Medium
Authors: Gough G. S. , Elam C. F. , Tipper G. H. , De Bruyne N. A. 
Published: August 2016

The structural problems of metal aircraft design largely centre round the difficulty of making efficient compression members. This difficulty is accentuated when loads are small in relation to the size of the structure. For example, the diameter of an aeroplane fuselage cannot usually be less than the height of a man, which results in such small forces at the surface of the shell that the lightest practicable beam is quite disproportionate to its strength.As a measure of load in relation to size, it is convenient to use a quantity that we suggest may be called the “ structure loading.” This quantity, due to H. Wagner (8), is simply the square root of the applied load divided by a characteristic dimension (such as the length) of the member.
Some Modern Methods of Research in the Problems of Flight
Authors: Lewis George W. 
Published: August 2016

As a guest of the Royal Aeronautical Society, I wish first to express my sincere appreciation of the opportunity to join those others who have appeared before you in years past to present the Wilbur Wright Memorial Lectures. To those of us who are primarily concerned with the scientific aspects of aviation this continuing series of lectures, now nearly as old as the art of human flight itself, is the finest tribute that could be offered in honour of the accomplishments of the Wright brothers. It is on this account that I feel most sincerely the honour and privilege that has been granted me through your invitation to present the Twenty-seventh Wilbur Wright Memorial Lecture.The title—“ Some Modern Methods of Research in the Problems of Flight ”— is, I confess, somewhat ambiguous. At the time it was selected, some months ago, several investigations then in progress gave promise of results sufficientlyinteresting to be included.
Experimental Research in the Guidonia Supersonic Wind Tunnel
Authors: Ferri Antonio 
Published: August 2016

Our first phase of activity, at the Guidonia supersonic wind tunnel, was devoted to studying and designing the necessary apparatus for carrying out systematic research. (See Captain Gasperi's paper, read before the Lilienthal Congress in 1937-) This apparatus consisted principally of:—(1)A series of transformer jets, to create the requisite speeds in the test chamber;(2)A balance, to determine the forces exercised by aerodynamic phenomena upon the objects under test;(3)The striometric and interferometric apparatus.The initial study was long and laborious; since we lacked the great help furnished by previous research, which is nearly always forthcoming in similar studies, we had to proceed by means of successive experiments until the apparatus took its final shape. Eventually we evolved a series of jets, a balance and an optical installation which we hope are permanent. These, however, being still under construction, have not yet been tested.
The Fundamentals of Boundary Layer Theory, with Some Applications to Aircraft
Authors: Leaderman H. 
Published: August 2016

The recently issued Report of the Aeronautical Research Committee draws attention to the fact that much work, apparently of academic interest only, is now of direct practical utility. In particular, the theories of the boundary layer and of turbulence, though admittedly very incomplete and uncertain and lacking a secure scientific foundation, have been developed to the stage in which they can be applied to explain and predict the behaviour of aircraft, and to show how aircraft may be improved. The physical structure of the boundary layer will be described, and the methods by which the problems have been attacked mathematically to get useful results and to check the theories.In conclusion, the theory of the boundary layer will be applied to the calculation of the drag of an airship or aeroplane fuselage under full-scale conditions, and to an explanation of the behaviour and performance of different types of aerofoils.
The Domain of the Helicopter
Authors: Hafner Raoul 
Published: August 2016

The Seventh Louis Bleriot Lecture was given in Paris on 10th March 1954, by Mr. Raoul Hafner, F.R.Ae.S., under the auspices of the Association Française des Ingenieurs et Tèchniciens de L'Aèronautique (A.F.I.T.A.)The Lecture was attended by the President, Sir William S. Farren, C.B., M.B.E., F.R.S., F.R.Ae.S., and several members of Council of the Royal Aeronautical Society, by the Secretary, Dr. A. M. Ballantyne, T.D., A.F.R.Ae.S., members of the Society and of the British Aircraft Industry, and by a large and distinguished French audience.Monsieur Jules Jarry, President of A.F.I.T.A., presided at the meeting and welcomed the guests before introducing Sir William Farren, President of the Society.
Empirical Formulae for the Determination of Stress Curves
Authors: Nicholls A. C. 
Published: August 2016

In the analytical presentation of curves the main requirements perhaps are those of accuracy and simplicity and the problem confronting the engineer is the efficient combination of the two. A further important consideration is that of the range over which the empirical formula (or formulae in some cases) is to be effective, for clearly the greater this range is, the more useful will be the formula.It is obviously desirable that any equation that is chosen should be as close a fit as possible to the practical curve. It must not be sensitive to small parametric differences and it should be possible to determine these parameters with a fair degree of precision.
The Use of Light Alloys in Aircraft Construction
Authors: Le Coeuvre R. 
Published: August 2016

Light alloys now play a most important part in aircraft construction. It is probable that they will keep their present superiority over other materials which have been in use, because manufacturers are continually adapting light alloys to the need of the day.Light alloys have, however, formidable rivals. There are many arguments for the use of wood, and we must recognise that in certain aspects (such as resistance to vibration and ease of working) the use of wood has definite advantages, particularly in the case of plywood.
Critical Speeds of Monoplanes
Authors: Hanson J. 
Published: August 2016

The fact that attention must be given to stiffness as well as strength in aeroplane design is now generally recognised. The provision of adequate strength alone is not sufficient to ensure that an aeroplane is immune from such troubles as flutter, loss of lateral control due to twisting of the wing and wing divergence. This is illustrated by the case of the Puss Moth. As shown in R. and M. 1645 this machine was examined in detail by the Aeronautical Research Committee and found to be completely satisfactory as far as the existing official airworthiness requirements were concerned, and yet it experienced failures which were attributed to flutter, an instability involving the stiffness of the wings and tail.In the earlier stages of the investigations into these stiffness problems it appeared to many practical people that the work. was of academic interest only. As a matter of fact it was of subsidiary importance while operational speeds of aeroplanes were relatively low, but the higher speeds of the modern aeroplane make such problems of direct practical interest.
The Autogyro Rotor as a Sail
Authors: Moore-Brabazon J. T. C. 
Published: August 2016

The idea of navigating a certain type of sailing boat of mine by an autogyro instead of an ordinary sail has long been a desire of mine, in that I always have considered sailors to be very out of date as to rigs.In conversation with J. Weir this question arose, whereupon he said that he had within his organisation of the Autogyro Company an engineer named O. Reder who had the same desire. We, therefore, got in touch and although the time was very short got out a rig and installed it upon a very small onedesign class, well-known in the Solent, namely, the Redwing. These boats are about one ton, and the rules governing their racing are that the hulls are standard and that any rig can be used, but that the sail area must not exceed 200 sq. ft.
Fuels for Aircraft Engines
Authors: Bass E. L. 
Published: August 2016

It is unnecessary to enlarge on the importance of the fuels used in aviation in a paper before this Society. Not only is fuel quality the most important individual factor to be considered in the economics of civil aviation, but engine development, aircraft design and performance depend upon it.An apology is offered, in view of the title of the paper, that as it is barely possible in the confines of a single paper to deal adequately with the volatile fuels (known as petrols and gasolines) used in the normal carburettor or homogeneous charge engines, other types of fuels have necessarily been omitted.
Winter Landing Gear
Authors: Ferrier A. 
Published: August 2016

Snow falls in a great variety of forms, depending on a large number of conditions affecting the crystallisation of the moisture in the atmosphere. The forms may even vary from place to place or from time to time in one storm.The character of snow as a medium for transportation depends not only on the form of its constituent crystals, but on the nature of the ground on which they fall, the depth of the total covering, the previous history of the underlying layers, and of course on the history of the last fall and the atmospheric temperature of the moment. Considering the characteristics for the purpose of aircraft operation, it is sufficient to make the broad classifications shown in Table I (page 504).
The Refuelling of Aircraft in Fligh
Authors: Larrard J. H. B. 
Published: August 2016

The establishment of contact between aircraft in flight for the purpose of refuelling, has until recently been regarded as a somewhat hazardous procedure employed mainly during attempts to create endurance records.It would appear, however, that if such contact between aircraft could be established safely and as a routine operation, considerable advantages could be obtained by the employment of such a scheme.From the point of view of commercial aviation, not only would it make possible long distance non-stop flights over regular air routes, but it would enable a large increase in pay load to be carried, since the bulk of the aircraft's consumable load, i.e., fuel, would not be taken on board until the aircraft had left the ground and climbed to a reasonable height.
Liquid-Cooled Engines-Design and Application to High-Speed and Other Aircraft
Authors: Graham Forsyth A. 
Published: August 2016

The liquid-cooled engine is generally associated with high speed aircraft, and as I have had some experience in connection with the development of racing engines, when I received the honour of an invitation to read a paper for the Royal Aeronautical Society, I chose this title because it gave me a chance to further the cause of the liquid-cooled engine and to interest you in possible developments of engines suitable for high speed and other types of aircraft.In attempting to forecast possible developments, I am taking a grave risk, as anything connected with aeronautical engineering is doubtful owing to the rapid changes which take place in a short time, and I can only indicate where I think improvements can take place, based on present progress, and can only hope that my remarks will invite criticism and discussion.During the paper the “ hardy annual ” ‘ frontal area ’ will be raised; a slide will be shown of a liquid-cooled engine superimposed over an air-cooled radialof the same b.h.p.
The General Theory of Cylindrical and Conical Tubes Under Torsion and Bending Loads
Authors: Hadji-Argyris J. , Dunne P. C. 
Published: August 2016

This paper presents a rational method of stressing single or many cell tubes particularly of the type encountered in wing structures. The theory has been developed for conical or cylindrical tubes of arbitrary cross-section the shape of which is maintained by a closely spaced system of diaphragms rigid in their own planes and parallel to the root section. Within the limits of the assumptions the theory is exact for right cylindrical tubes, and is applicable with adequate accuracy to cylindrical or conical tubes in which the inclination of any generator to the normal to the root plane does not exceed 10°.The analysis given unifies the theories of bending and torsion and shows that the commonly used method of separating the bending and torsion loads by means of a shear centre is in general incorrect.The formulae have been developed in such forms that attention is concentrated on the necessary corrections to the stresses as indicated by the ordinary engineers' theory. These correction terms include all effects of shear lag, diffusion, and end effects hitherto taken into account only in some very special cases.Particularly important for practical applications is the structure consisting of a number of direct stress carrying members (booms) connected by walls effective only in shear. The simplest structure of the latter type is the four-boom tube with or without nose and trailing cells, and in this case explicit formulae are given which are immediately applicable to practical calculations. Formulae are also given for the more complex case of a six-boom tube in which the two extra booms are introduced to represent more accurately the direct stress carrying capacity of the top and bottom panels between the two spars.
An Automatic Variable Pitch Airscrew
Authors: Townend H. C. H. 
Published: August 2016

Some wind tunnel experiments have been made on a variable pitch airscrew which shall change its pitch automatically as V/nD changes. The change in pitch is operated by the resultant effect of centrifugal and aerodynamic forces.Reduction in air density, e.g., due to increase in height, causes an increase in pitch.In the event of engine failure the blades assume the position of minimum drag.A tentative design for a model screw, together with tests thereon, are described, and it appears that if the friction in the bearings about which the change in pitch occurs can be made reasonably small, it should be possible to construct a satisfactory full-scale screw.