bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fuels for Aircraft Engines
Authors: Banks F. R. 
Published: August 2016

There has been a great advancement in recent years in the technique and production of suitable fuels for both aircraft and automobile engines and the author hopes that a few notes on the fuel problem with particular reference to aircraft work may be of help to those engaged on aero engine design and operation.In the author's opinion it is somewhat surprising that, with the information and data at present available on the subject of fuels, greater use is not made of this when considering the design and operation of an aero engine.
The Development and Characteristics of a Long-Range Flying Boat (The S-42)
Authors: Sikorsky Igob I. 
Published: August 2016

Almost a decade ago, with the rapid world-wide development of air transportation, came the demand for new types of aircraft. It became evident that a plane capable of operating from land or water was the logical step needed to open up larger areas for air transportation. The proximity of water compared with the remoteness of available landing fields to the centres of population was the deciding factor in amphibian development.While the advantages of the amphibian are obvious, the limitations and; difficulties of creating an efficient plane of this type are also evident. Compared to the seaplane or landplane, the amphibian must take care of the extra weight and parasitic resistance, as well as solve various other problems connected with combining the characteristics of the land and seaplane in one aeroplane.
The Spinning of Aeroplanes
Authors: Scott-Hall S. 
Published: August 2016

Apart from the subject of straight normal flight and all the problems of stability and performance concerned with it, more thought has been given to the spin than to any other form of motion of an aeroplane. The reasons for this are not far to seek. The spin is the evolution which, until the recent introduction of certain well known methods of lateral control and stabilisation, invariably followed the loss of control at speeds below the stall, and its occurrence near the ground has been responsible for the majority of fatal flying accidents.It is the only form of stable uncontrolled motion which is exhibited by an aeroplane other than that which it may possess in straight flight. This stability has in a number of cases proved extremely dangerous, if not fatal, as in prolonged spins on certain aeroplanes it has been found impossible to recover.
Modern Developments in the Helicopter
Authors: Liptrot R. N. 
Published: August 2016

The problem of the helicopter is one which has intrigued inventors for centuries, and which has perhaps attracted more attention and effort than any other phase of design of heavier-than-air craft.Even as far back as the fifteenth century we find Leonardo da Vinci devoting several years of his life to studying- bird and mechanical flight, and he has left many sketches showing- flying machines. Of particular interest to us is a design showing- an aircraft consisting of a sustaining screw driven about a vertical axis.The first helicopter actually to fly was a small model, little more than a toy, which was shown before the French Academie des Sciences in 1784 by Launay and Bienvenue, and since that time literally thousands of schemes have been proposed by inventors all over the world. The patent files of all countries are full of helicopter specifications, the greater part of them being based on faulty physical principles, and obviously impracticable.
Fuels and Modern Methods of Testing
Authors: Tett H. C. 
Published: August 2016

Petroleum as it occurs in Nature is a very complex mixture of hydrocarbons. Imagine a mixture of petrol, paraffin, gas oil, fuel oil and lubricating oil, together with a certain amount of water and other foreign matter, and you have an idea of crude petroleum as it is found in Nature.It is interesting to note that practically the sole use of petroleum for some time after the first well was drilled was as a burning oil. The object of the refiner was therefore to produce as large as possible a percentage of paraffin from his crude. The lighter fractions were regarded as a necessary evil, and it became a very difficult problem to dispose of them satisfactorily. It was, of course, necessary to keep the flash point of the paraffin high enough to avoid the danger of explosion of the lamps in which it was used. Petroleum inspectors were employed to ensure that the paraffin on sale was not “adulterated” with the then valueless light petroleum spirit. No market other than as a source for lighting gas was found for this light spirit until the advent of the motor car.
Wing Flaps and Other Devices as Aids to Landing
Authors: Alston R. P. 
Published: August 2016

It has long been recognised that landing and taking—off are the most hazardous periods of the average flight. In this respect an aeroplane is similar to a boat being launched or beached at high speed; the change from one medium of support to another is bound to involve possible damage especially if speeds are high.So far as risk of mechanical damage, due to uneven aerodrome surface (or swell in the case of a seaplane), is concerned, the speed of landing should be the minimum practicable. Very low landing speeds have a possible disadvantage in that one may not have sufficient aerodynamic control to compete with gusts, etc., but there are few aeroplanes of to-day which have landing speeds so low that this objection can be raised.The trend of design in recent years has been to increase aerodynamic efficiency by streamlining and to increase the wing loading.
The Aerodynamic Characteristics of Aircraft Skis and the Development of an Improved Design
Authors: Green J. J. , Klein G. J. 
Published: August 2016

Existing information on the aerodynamic characteristics of aircraft winter landing gear is very meagre and it was therefore desirable to test as many full size skis as possible in order to collect data concerning the various types of skis in actual use.It was known that the air resistance of existing types is quite high and the experiments were intended to explore the possibilities of producing an improved type of ski having considerably lower air resistance.The large pitching moments on present types of skis give rise to serious problems in trimming gear design, especially on high performance aircraft. The experiments aimed at producing a ski on which the pitching moments would be considerably reduced in order that the use of exterior trimming cables might be avoided.
The Importance of the Boundary Layer
Authors: Glauert H. 
Published: August 2016

When we consider the physical properties of the air, the most noticeable features are its low density and its compressibility, and a student new to the subject might be excused for doubting whether the air were not too light and yielding to support an aeroplane in flight. The air is indeed very compressible, but this property of the air becomes important only when the speed of motion becomes a fairly large fraction of the speed of sound, and in practice its influence is felt only in the behaviour of airscrews with high tip speeds.A more important property of the air is its viscosity or internal friction, and this property is of fundamental importance in flight, either by its direct frictional action or by its indirect action in determining the type of flow round a body. As an example of this indirect action we may consider the lift of a wing.
Research Work of the “DVL”
Authors: Hoff Wilh. 
Published: August 2016

In the later part of autumn last year, I was invited by your President, Colonel the Master of Sempill, to read a paper about the work of the “ Deutsche Versuchsanstalt fur Luftfahrt ”( i.e. “ German Aeronautical Research Institute ” ) . The Royal Aeronautical Society can look back to a long and successful development. Your Society has always aimed at the promoting of the technical work of your country and at the fostering of close scientific relations between air–minded countries. It is therefore a great honour for me to lecture before your Society.I regard co–operation in discussing areonautical matters between the various countries as very necessary. Representatives of aeronautical science have, during the past year, held international congresses at Stockholm, in the Hague and finally in Paris. Common problems were treated at these congresses by the representatives. New personal relations were formed during the meetings held there.
The effect of Aeration of the Oil on the Behaviour of an Engine Lubricating System Under High Altitude Conditions
Authors: Giffen E. , Mills H. R. 
Published: August 2016

The work described in this paper was done during the war, at the suggestion of the aircraft engine firms, as a result of difficulties with lubricating oil systems at high altitudes. Failure of oil pressure, seizure of bearings, or excessive loss of oil sometimes occurred and these defects were attributed to air in the lubricating oil, this air being greatly increased in volume at high altitudes because of reduced atmospheric pressure.The behaviour of air-oil mixtures therefore was studied to obtain fundamental information which could be applied to engine lubrication at high altitudes. The present paper deals with that part of the research which was done on a complete lubrication system under simulated altitude conditions.
The General theory of Cylindrical and Conical Tubes Under Torsion and Bending Loads
Authors: Hadji-Argyris J. , Dunne P. C. 
Published: August 2016

SummaryParts 1 to 5 of this paper (February, September and November 1947 issues of the JOURNAL) investigated the stresses and deformations of closed tubes in which the thicknesses were governed by the ts* and t* laws. In the present part, the analysis is extended to multi-cell tubes with openings, open tubes with or without St. Venant torsional stiffness, and to tubes formed by joining elements of different cross-sections. To illustrate the theory a numerical example of the stressing of a four-boom wing consisting of seven joined elements is fully worked out. Finally, an appendix gives practical methods of dealing with tubes which do not conform to the ts* and t* laws, and of finding approximate solutions for four-boom tubes with direct stress carrying covers.
Flutter of Propeller Blades
Authors: Inglesby J. V. 
Published: August 2016

SummaryAn analytical study of the flutter of stalled and unstalled propeller blades is recorded. The flutter of unstalled propeller blades investigated is unstable coupled flexural-torsional oscillation, while the flutter of stalled blades is assumed to be unstable torsional oscillation due to aerodynamical hysteresis, which is Studer's theory of stalled flutter.A method of estimating critical speeds, which is within the scope of Stress Office work, is proposed and examples given.The observed and calculated flutter speeds of propeller blades are tabulated.(All statements made and opinions expressed represent the author's own views.)
Eighth Louis Bleriot Lecture: Making Aeroplanes Independent of Runways
Authors: Hereil Georges 
Published: August 2016

As technical progress has improved the airborne performance of aircraft, so the difficulties associated with their take-off and landing have increased.The grass airfields which were still commonplace at the end of the Second World War have now developed into complex arrangements of concrete runways of up to three kilometres (two miles) long, taxiways, dispersal areas, and so on. The main disadvantages of these large airfields, both for military and for civil aviation, soon become obvious: —(i)The enormous expenditure in either case; for military aviation this expenditure has to be approved, but it is at the expense of the production of actual aircraft—like Ugolin who ate his children so that they would not be fatherless;for civil aviation, the high cost of airfield construction has hampered the development of aviation in the remote areas where it would be of particular use in raising the standard of living.(ii)The lack of flexibility of air forces operating from fixed bases, thus reducing their efficiency.(iii)The increase in vulnerability as destructive weapons become more highly perfected.
Effect of Variations in Weight or Normal Acceleration on the Ceiling of Jet-Propelled Aircraft
Authors: Sutcliffe P. L. 
Published: August 2016

The ability to manoeuvre at high altitude has become one of the main requirements in the design of modern military aircraft. Ability to manoeuvre enables the fighter pilot to execute tight turns during the attack on a bomber and the bomber pilot to perform evasive manoeuvres and so make the task of the fighter more difficult.Normally the main manoeuvre considered is the application of increased normal acceleration, or g, and if we assume that (a) there is sufficient pitching power available from the longitudinal control surface to increase the wing incidence to give the necessary increase in normal force, and (b) that the new wing incidence is below the stalling incidence of the wing, then the degree of manoeuvrability available is a function of thrust and drag alone. In the past the manoeuvrability required at a given altitude has been expressed in terms of the rate of climb available at that altitude and thus we have such definitions as “ the 1,000 ft./min. ceiling ” and so on.
The Influence of Body Forces on the Stability of a Reinforced Rectangular Plate
Authors: Amba Rao C. L. 
Published: August 2016

Reinforced rectangular plates find frequent application in the field of aeroplane structures, ship structures and allied fields. The stability of a structural element, if its critical load in compression is rather low, is normally influenced by its own weight. Usually the ratio of the body forces of the stiffened plate to the critical load is a considerable amount and the influence of the body forces of the plate and the ribs on the critical load of the stiffened plate is discussed here.In this note (following Timoshenko), the extensional deformation of the middle surface during buckling is neglected, which greatly simplifies the analysis. Although it leads to an under-estimation of the critical load (of the order of 10 per cent at most) it is not likely to influence the general conclusions. Strain energy method of analysis is used.
The Influence of Reynolds Number at High Mach Numbers
Authors: Ferri A. 
Published: August 2016

The experiments were carried out in the high speed wind tunnel at Guidonia on three brass spheres of 40, 60 and 80 mm. diameter, supported on rear spindles and on two steel cylinders of 15 and 30 mm. diameter respectively, which passed through the air jet.Both the total drag and pressure difference between the front stagnation point and a variable point at the rear were measured.The pressure distribution on similar models which could be rotated and which were provided with pressure holes was also determined.
The Stress Analysis of the Circular Conical Fuselage with Flexible Frames
Authors: J Goodey W. 
Published: August 2016

Summary:This paper is concerned with the problem of the skin–and–stringer–covered conical fuselage of circular cross section, having flexible frames and being subjected to an arbitrary distribution of loads applied in the planes of these frames or on the end cross sections. The skin thickness and stringer cross section may vary from bay to bay but are assumed to be constant in a bay, i.e. between any two consecutive frames. The stringers are assumed to be uniformly spaced round the circumference. The frames are assumed to be of uniform cross section (circumferentially) but their stiffnesses are arbitrary, as is also their spacing along the fuselage.This paper is a sequel to one previously published in the Journal, but the method of analysis is now by minimum strain energy instead of by deflections. Owing to the generality of the investigation it is impossible to present the solution—in terms of the known loads and stiffnesses—in any explicit form, and attention has therefore been concentrated on the technique of numerical computation. A scheme of tabulation has been evolved, and its use is illustrated by a fully–worked numerical example of a moderately complex type.
A Chart for Steady Circling Flight
Authors: Sponder E. 
Published: August 2016

For horizontal, or nearly horizontal, steady straight flight there exist some charts from which can be determined the speed at any altitude, the inclination of the flight path, and other quantities. This can be readily done, for instance, by a graphical comparison of the forces of drag and thrust, or by a corresponding representation of the powers, required and available. These charts, however, always involve the polar of the particular aeroplane, and are thus valid only for that aeroplane; they must therefore be replotted for each example. To avoid this and obtain a generally valid chart, the effect of the aerodynamic characteristics of the particular aeroplane must be eliminated; it is thus possible to prepare a chart even for the steady circling flight at any inclination of the flight path.The three equations for the description of the flight path may be derived on the simple assumption that the thrust acts almost along the direction of flight, i.e., that the angles of attack and of sideslip are negligibly small.
The Weight of Seaplane Floats
Authors: Rosenthal L. W. 
Published: August 2016

Although floatplanes were not popular during the war years, new types have made their appearance since, and presumably, for certain classes of work, more will be seen in the future. With this in mind, this paper is presented in the hope that it may help in assessing the float weights on any new designs that are contemplated. Some suggestions are included concerning geometry and design which, if adopted, may help to show a higher weight efficiency than existing practice.The paper is based upon an analysis of the weight and geometrical data relating to a large number of floats, although since the number built during recent years is small, a certain amount of data, which might possibly be considered old by some standards, has been incorporated. As will be seen by the curves, recent practice shows no radical departure from earlier years and the inclusion of the early data to establish design trends would appear to be warranted.
Coefficients of Friction
Authors: Pike E. C. 
Published: August 2016

SummaryA summary is presented of information collected on coefficients of friction (rolling and sliding) between rubber tyres and road or runway surfaces. Nearly all the data collected are from tests on automobile tyres and are limited to speeds of about 40 m.p.h. In some cases the primary object of the tests was to distinguish between good and bad roads, and not to determine absolute values of friction coefficients.The reasons for the importance of the information for aircraft design use are discussed and distinctions are made between coefficients measured in different ways.The results show the variation of sliding friction coefficient with various parameters at speeds up to 40 m.p.h. There is a set of American tests at speeds up to 110 m.p.h., and some estimates made by the Dunlop Rubber Company up to 120 m.p.h.It is concluded that for sliding friction coeficients differences in surface texture (as distinct from surface material) are significant, and that information can be given only in the form of limits within which the values can be expected to lie.Few results are available on the variation of rolling resistance coefficient, but it is felt that the approximate values quoted for different types of surface are sufficiently accurate.
A Note on the Time Required to make a Level Speed Measurement with a Turbine-Jet Aircraft
Authors: Lush K. J. 
Published: August 2016

SummaryIt was desired to confirm quantitatively pilots’ impressions that on turbine-jet aircraft in the region of 40,000 ft. the level speed stabilised very slowly.The time required to make a conventional level speed measurement has been examined, for a representative turbine-jet aircraft, over a wide range of air speed and height. The results are compared with those for a typical piston-engined aircraft and their implications discussed.It is concluded that the time required to make a conventional level speed measurement increases rapidly with height, in the absence of compressibility effects on drag, and is about five times as great at 40,000 ft. as at sea level. It is inconveniently large at high altitude and level speed measurements there will require very long runs, unless it is arranged that each run is started at an air speed near the steady level speed.This increase will be present in most level speed tests, especially those in the region of the best speed for range. In maximum level speed measurements, however, compressibility effects may be present and the air speed may then be expected to settle down quickly.The need for long runs at high altitude is not peculiar to jet aircraft, but has come into prominence concurrently with them.
The Human Factor in Aircraft Accidents
Authors: Newton J. A. 
Published: August 2016

Recently published statistics give the impression that an excessively high percentage of non-carrier aircraft accidents investigated during 1948 were primarily due to human error. Further, an examination of available data covering the past decade gives the same impression in respect of all aircraft accidents occurring during that period. The figures quoted convey in fact the unpalatable implication that, although in nearly a half century of aviation great strides have apparently been made in increasing the reliability of the aeroplane, very little has been accomplished in reducing the element of human error in aircraft accidents. Why is this?It has been claimed that the possibility of accidents in flying is inevitable by reason of the inherent conditions of flying which necessitate, besides reliance on the technical factor, considerable reliance upon the skill, judgment, memory, and physical and psychological conditions of the human being.
Indication, Measurement and Control of Ice Accretion
Authors: Lucking D. F. 
Published: August 2016

The rate of ice accretion on an aircraft depends upon meteorological factors and aircraft characteristics. There are on the one hand atmospheric pressure and temperature; water content; droplet size; electrostatic conditions. On the other hand, there is the collection efficiency made up of aircraft component design characteristics such as size; shape; material; surface finish. Finally, there are aircraft flight variables such as speed; attitude; skin temperature; vibratory state.Meteorologists are able to define potential icing intensity if they can forecast the ambient factors mentioned. The intensity may be defined as light, moderate, or severe, or by some such broad adjective, with reference to a hypothetical collector. Similarly, the air-worthiness authority, e.g. the Air Registration Board, must be satisfied that an aircraft can be operated safely in the appropriate meteorological conditions. Therefore the probable association of each meteorological factor with the others needs to be known.
A Review of Production Problems in Relation to Aircraft Design
Authors: Fielding C. E. 
Published: August 2016

My subject is too big to cover adequately in the time at my disposal and as I have been asked to emphasise the wartime experience in aircraft factories, I propose to confine myself to a few of the most interesting problems.Because of the urgent necessity to produce aircraft quickly in wartime the production engineer has a greater influence on design than normally, and many design problems are usually settled by a compromise between the requirement of the designer and the production engineer.The designer attempts to satisfy the aerodynamic requirements at the lowest possible weight and the production engineer has to consider the shop equipment and floor space available, the type and availability of labour and ensure that the aircraft can be built in a minimum of man–hours.