bluuebunny/crossref_metadata_2025 huggingface dataset:
The Organisation of Air Routes for Night Flying
Authors: Benkendorff Rudolf
Published: August 2016

The operation of scheduled night flying presents two tasks to aviation:—

(1) The technical task of taking off from and landing on an aerodrome.

(2) The operation of the flight from one aerodrome to the other.

The first task presents no completely new problem, as sufficient experience was gained during the war. All that was necessary was to provide facilities which guaranteed regular traffic.

The second task was purely one of navigation. It had to be solved in accordance with the strict demands of maximum safety and maximum regularity of the service. The only means of navigation then available, the compass, was not sufficient for these requirements, and at night it was not possible to count on keeping on the course by observing objects on the ground.
Some Problems Connected with High-Speed Compression-Ignition Engine Development
Authors: Dicksee C. B.
Published: August 2016

In this paper the author does not propose to deal with any particular form or type of engine or fuel-injection system, but to discuss some of the problems which are encountered when engaged on the development of a high-speed compression-ignition engine.

The main problems to be solved consist in devising suitable means for utilising to the fullest possible extent the oxygen available within the cylinder and for avoiding the production of smoke and noise and, in so far as it is connected with combustion conditions, smell.
The Equilibrium of Loaded Impeller Blades with Special Reference to the Strength of Thin Metal Airscrews
Authors: Ralli Pandia Antonio
Published: August 2016

The co-ordinate system used is shown in Fig. i.

The axis coincides with the axis of rotation and the plane is chosen parallel to the plane of rotation.

The plane serves as a longitudinal datum plane for the airscrew blade, and is perpendicular to the planes of the cross-sections of the blade. The axis OX is drawn in the direction of the radius from root to tip.
The Metalclad Airship
Authors: Fritsche Carl B.
Published: August 2016

An invitation to address the Royal Aeronautical Society, the first Society of its kind ever founded, is indeed a signal honour and not without misgivings to a humble visitor who, in the land of Elizabethan English, finds himself embarrassed for words adequate to express his appreciation. The scientific contribution of the Society to the advancement of aeronautics and the meritorious achievements of its members are well known in the United States.

A sort of unselfish and patient willingness, which encourages men to depart from beaten paths and invade unknown realms to bring forth something new and beneficial to society, is indispensable to any new enterprise, and most characteristic of those who are pioneers in airship development. Certainly none so far have garnered any substantial profits.
Modern Aerodynamical Research in Germany
Authors: MacColl J. W.
Published: August 2016

This paper aims at giving the most important results of modern German research upon the motion of incompressible fluids. Before dealing with the latest developments, I have thought it advisable to give a short account of the older researches upon which the present work is based. It is hoped that this résumé will give a fairly complete survey of the methods that have led to the present insight into the hydrodynamical mechanism.
Air Photography Surveys
Authors: Durward J.
Published: August 2016

Air Photography and its serious application to map-making may be traced to the Great War. It was at this period that grave consideration had to be given to Air Photography as a method of producing maps.

In all the theatres of war, which included France, Palestine, Salonica, and Mesopotamia (or Iraq as this country is now known), extensive operations were carried out in Air Photography, and the photographs used for the amplification of existing maps, and in many cases to the compilation of new maps.
Some Notes on the Design of Aeroplane Control Surfaces and Control Systems
Authors: Dowsett Walter F.
Published: August 2016

The control of an aeroplane is effected through the medium of three distinct sets of control surfaces known as the elevators, ailerons, and rudder, these surfaces being so disposed with reference to the centre of gravity of the machine as to be capable of producing rotation about three mutually perpendicular axes passing through this point, and called the lateral, longitudinal, and normal axes respectively. Thus, the elevators cause a rotation about the lateral axis of the machine, the resulting motion being known as pitching, the ailerons a rotation about the longitudinal axis, producing rolling, and the rudder rotation about the normal axis, producing yawing.
Recent Developments in High Speed Research
Authors: Beavan J. A. , Holder D. W.
Published: August 2016

Much work has been done on compressible flow since the contribution of the Aerodynamics Division to research in this field was last described to the Society by the late C. N. H. Lock in 1937. At that time he was able to review many of the data which were available from other sources, whereas today such a task would be impossible in a paper of this length. We shall confine ourselves here, therefore, to a description of some of the experimental work that has been done during the past few years in the high-speed laboratory of the Division, and to an account of the lines along which it is intended to continue the work in the future.
Factors of Safety—Or of Habit?
Authors: Tye W.
Published: August 2016

Our engineering habits form slowly, and once formed are slow to change. This is perhaps less true in aeronautics than in other branches of engineering. Nevertheless some aeronautical customs are deeply rooted, so much so that it is easy to confuse the superstructure of habit with the basic foundations. In this article I have reviewed some of the customary methods of specifying strength conditions and have tried to disentangle the underlying principles. Current changes in these methods emphasise the need of a proper appreciation of the principles, and a study of these principles suggests even more radical changes of methods in future.
The Interference between the Body and Wings of Aircraft
Authors: Parkin J. H. , Klein G. J.
Published: August 2016

Tests on certain aircraft having disclosed discrepancies between the characteristics estimated from the figures for the individual components and those observed for the complete model, the present investigation was undertaken to determine the nature and magnitude of the effects of interference between the body and wings of aircraft and to ascertain the factors influencing the interference.

The models were made up of standard 3in. x 18in. duralumin aerofoils and fuselages of wood.

The aerofoils employed in the investigation were:–

(a)

R.A.F.-15–a thin section.

(b)

U.S.A.-27–a section of medium thickness.

(c)

Gottingen-387–a thick section.

The fuselages used were:–

a.

Fuselage A–of streamline form.

b.

Fuselage B–of cabin form.

c.

Fuselage C–of usual open cockpit form.

A number of typical monoplane and biplane combinations Of wings and fuselages were tested, and in some cases the effect of fairing between wings and fuselage was studied.

The results of the investigation indicate that the interference effects are dependent on the shape of the fuselage, the aerofoil section and the relative position of the fuselage and aerofoil. The better the aerodynamic form of the fuselage, and the thicker the aerofoil section, the greater are the interference effects and the more marked the influence of the relative vertical position of the wings and body on the interference.

Interference between wings and body tends, in general, to lower the critical angle and increase the drag of the combination as compared with the individual components. It may increase or decrease the lift.

From an aerodynamic standpoint, the best position for the wing is at the top of the fuselage, and the worst that at the bottom.

Fillets and fairing may improve a combination having poor characteristics, but have little effect if the arrangement already possesses good characteristics.

An explanation of the cause of the observed interference effects is advanced.
Astronomical Navigation without Mathematics
Authors: Mieville A. L.
Published: August 2016

Multitudes of young- men are starting to study navigation. As a rule it is only after many months of painful work that they come to see what it is all about –many of them never get to that point at all.

In none of the books on navigation have I been able to find a simple picture, defining each step in the reasoning that enables us to navigate by the stars. Hence this effort. As set out here the principles can be grasped by anyone.
The Production of Large Forgings in Aluminium Alloys
Authors: Smith C. , Crowther J.
Published: August 2016

Today there is growing interest on the part of aeronautical engineers in forgings of large size, for three main reasons. Certain types of forgings will naturally need to be bigger as the aircraft itself becomes bigger; more composite structures are being replaced by single components made as forgings; and there is an increasing use of complex units machined directly from blocks of metal which are too big in at least one dimension to be made as extrusions or rolled plate. It is with these larger forgings that we are mainly concerned. Their production presents many serious problems. It is reasonable to hope that some of these will be overcome as experience grows and techniques are improved but others seem to be inherent in the materials used and must be appreciated at the design stage of the component if fully satisfactory service is to be obtained.
Boundary Layer Control
Authors: Lachmann G. V.
Published: August 2016

It has almost become a tradition in recent years to begin a paper on boundary layer by paying a tribute to the great Prandtl and his famous paper in which he introduced the conception of boundary layer into Fluid Dynamics.

The year 1954 is, however, not only memorable to mark the passing of fifty years since Prandtl's classical demonstration of the effect of boundary layer suction on the flow pattern around a cylinder; it is also memorable because in 1954 most convincing demonstrations of practical applications of boundary layer control for aircraft have taken place. I am referring, in particular, to the demonstrations with the Attinello flap in the United States which mark the introduction of one form of boundary layer control as an engineering and practical reality.
Development of Large Intermittent Wind Tunnels
Authors: Lukasiewicz J.
Published: August 2016

Two types of intermittent wind tunnel drives, the pressure storage drive(with atmospheric exhaust) and the vacuum storage drive (with atmospheric inlet), are examined and found to match well the tunnel pressure ratio-mass flow characteristics over a wide Mach number range (0 to 4). The design of components of intermittent wind tunnel installations, their operation and instrumentation are then considered in some detail. In order to increase the output of intermittent wind tunnels to a level comparable to that of continuously running tunnels, it is proposed to drive the models during each tunnel run through a range of incidence. This technique is at present under development in the National Aeronautical Establishment's High Speed Aerodynamics Laboratory and results so far obtained are discussed. Two tunnels are considered as examples of large intermittent installations: a 4 ft. square pressure-driven tunnel and a 6 ft. square vacuum-driven tunnel. The former is found to be a more compact and economical installation. Relative merits of continuous and intermittent installations are discussed.
Navigational Systems and Instrument Aids
Authors: Adams D. E. , Uttley A. M.
Published: August 2016

To the aircraft designer and contractor, those of us responsible for equipment may appear as arch-perpetrators of complex, bulky and weighty “ gadgets,” impossible to install and the source of all unsightly excrescences on the aircraft's skin.

Any aircraft, from its inception should be designed for some specific role, and its usefulness may well depend upon the availability or simultaneous development of equipment.
Cooling and Governing Problems on a Water-Cooled Auxiliary Generating Plant
Authors: Winn R. B.
Published: August 2016

The A.G.P. is required to produce 20 kw. A.C. and 3 kw. D.C. continuous normal full load, at 3,750 r.p.m. The load is required for operating the electrical services on a large aircraft and must be maintained both when it is stationary and when it is in flight up to an altitude of 11,000 feet.

The A.G.P. must run cool in the standard English summer atmosphere (23°C. at ground level) and draw the necessary air from ports cut in one side of the aircraft. These ports must be formed from a 1ft. diameter hole divided on its diameter. The cooling air is to be drawn in through the forward semi-circular hole and, after passing through the installation, expelled through the rear semi-circular hole.
Industrial Wind Tunnels
Authors: Ellis D. L.
Published: August 2016

The paper discusses the application of wind tunnels to aircraft design and consideration is given to the potentialities and limitations of types designed specifically for industrial use. Arguments affecting the choice of type, size and speed are stated and a detailed description is given of a particular tunnel which has very steady and even flow with a reasonable turbulence level. This description covers the aerodynamic and engineering design, the electrical driving arrangements and the six-component automatic balance.

A description is also given of a new type of high speed tunnel which has recently been put into operation. This is of the simple straight-through type and is driven by a jet engine acting as an ejector pump; the exhaust heat is used to control humidity and prevent condensation in the working section. This tunnel reaches a Mach No. of 0.9 when empty, and over 0.85 with a model in place. The Reynolds No. is 1.6 x 106 for a three-dimensional half model and 5 x 106 for two-dimensional wings.
The Expanding Domain of Aeroelasticity
Authors: Collar A. R.
Published: August 2016

By means of a broad survey of the developments in aeroelastic science during the past ten years and of comparable developments in associated fields, in so far as they involve elastic deformation, the present paper attempts to show how the individual subjects concerned are developing strong interconnections. At one time the subjects were for the most part regarded as discrete entities; now they are developing into component parts of an integrated whole —the dynamics of a deformable aeroplane.

It is suggested that in the future it may be necessary to discontinue the present methods of treatment of the component subjects as separate, and to adopt a standard method of attack on the problem treated as a unified whole, especially when adequate computational aids become available. A modified approach, involving an arrangement of the subjects in a frequency spectrum, is also discussed. Some speculations on the elastic provisions which may be necessary in the future are included.
Some Problems Associated with Stress Concentration
Authors: Cox H. L.
Published: August 2016

The theory of stress concentration is such a fascinating study that the whole of this lecture could be most happily devoted to discussion of the stress distribution round all sorts of special boundaries. At the same time the most detailed knowledge of elastic stress distribution is of little value unless we can be sure how the stresses computed will be reflected in the actual strength of the part. For that reason this paper is divided into three sections: the first deals with certain moderately simple cases of stress and load concentration and shows how the stress analysis is confirmed by static and fatigue tests: the second describes some investigations of special two–dimensional boundaries and indicates, some fairly general theoretical conclusions which can be drawn: in the third I shall try to review the possible reasons why, in practice, the best found conclusions are not always borne out.
Notes on the Opening Behaviour and the Opening Forces of Parachutes
Authors: O'Hara F.
Published: August 2016

An approximate theory of parachute opening is suggested. A formula is derived for the critical opening speed (the highest speed at which the canopy develops fully) which indicates variation of the critical speed with fabric porosity, rigging line length and so forth, of the order observed in wind tunnel tests. Assuming a simple form for the air flow about the parachute, a formula is obtained also for the rate of opening of a canopy. This enables an analysis to be made of the motion of a store-parachute system during canopy development. The theory confirms the possibility of a large increase with altitude, found experimentally, in the maximum parachute force on the store.
Performance Calculation for Jet-Propelled Aircraft
Authors: Page R. K.
Published: August 2016

An analytical method is developed for calculating the speed and climb performance of jet-propelled aircraft, given the drag and thrust data. A method is also given for dealing with the effects of compressibility and the results in a typical example are included to illustrate the form of curves obtained.

In the past, when dealing with aircraft driven by reciprocating i-c engines and propellers it has not been possible, even on the assumption of the available power being independent of forward speed, to evolve an analytical method of calculating the complete level speed and rate-of-climb performance of the aircraft, because the level speed equation is a cubic, for which there is no general solution, while even a constant speed propeller causes the thrust horse power in the region of the best climbing speed to vary with forward speed in some manner that cannot be expressed as a simple function.
Some Aspects of the Relationship between Airworthiness and Safety
Authors: North J. D.
Published: August 2016

The purpose of this paper is to attempt to examine the relations between airworthiness and safety.

It seems to me that the problem of safety in aviation is fundamentally a problem of human behaviour. The human controlled aeroplane is mechanically extended man. To quote Sherrington

“The cerebrum … . comes, … to be the organism par excellence for the readjustment and the perfecting of the nervous reactions of the animal as a whole, so as to improve and extend them. These adjustments … . in higher animals form the most potent internal condition for enabling the species to maintain and increase its dominance over the environment in which it is immersed.”

If we exclude the effect of the counter strategies of competition an accident is a measure of the incompleteness of this dominance.
Boundary Layers and Skin Friction in High-Speed Flow
Authors: Young A. D.
Published: August 2016

In this paper an attempt is made to review present knowledge of the subject of boundary layers at high speeds, without delving too deeply into the theory, and to draw attention to the results of practical interest. The introductory remarks describe broadly the special features of boundary layers in compressible flow, namely the existence of both thermal and velocity layers and their interdependence, the sensitivity of the external flow to the layers, and their inter-action with shock waves. The results of importance arising from the theory of the laminar boundary layer and of its stability to small disturbances are then discussed, followed by a summary of the present inadequate state of knowledge of turbulent boundary layer characteristics. It is noted that progress in the latter must await the production of more experimental data. The paper concludes with a discussion of scale effects and the allied problem of boundary layer—shock wave inter-action.
Fuel Systems for Turbine-Engined Aircraft
Authors: Walker J. E.
Published: August 2016

The 855th Lecture to be given before the Royal Aeronautical Society, “ Fuel Systems for Turbine-Engined Aircraft ” by Mr. J. E. Walker, A.F.R.Ae.S., was read under the auspices of the Luton Branch of the Society on the 24th April 1952 at Luton.
Power Steering for Aircraft
Authors: Hancock K. G. , Person P.
Published: August 2016

The 846th Lecture to be given before the Royal Aeronautical Society was read under the auspices of the Brough Branch by Mr. K. G. Hancock, B.Sc, A.F.R.Ae.S., and Mr. P. Person, M.A., A.F.R.Ae.S., on “ Power Steering for Aircraft,” on the 21st February 1952, at the Electricity Showrooms, Hull.
Aeroplane Tail Loads for Longitudinal Manoeuvres
Authors: Smith G. W. , Rea J. B.
Published: August 2016

This paper deals with the application of the Transfer Function-Fourier (T.F.F.) Method to the calculation of longitudinal manoeuvring tail loads for aeroplanes.

It has been found that the tail loads computed by this method agree very well with those computed by the standard method outlined in Ref. 1. The main advantages of the T.F.F. method are the time saving and the convenience in handling an arbitrary elevator input. Having once calculated the transfer function between elevator input and tail angle of attack output, it may be used repeatedly to compute the longitudinal manoeuvring tail loads for various arbitrary elevator inputs. This is done by simply expressing the input as a Fourier series and multiplying each term in the series by the value of the transfer function for the corresponding frequency. Then the resulting output series is summed at enough points to obtain a plot of the transient output. This process can be done in approximately one hour of engineering time for each arbitrary elevator input, exclusive of machine calculating time. The machine (usually I.B.M.) calculating time is about half an hour per input. On the other hand, experience has shown that the engineering time required per input by the standard method is approximately forty hours for the first input, and approximately five hours for each additional input.

It is concluded that the calculation of longitudinal manoeuvring tail loads by the T.F.F. method is accurate, dependable, especially adaptable to machine methods, and can conveniently handle arbitrary inputs.
Reduction of Flight Test Data From Linear Accelerometers
Authors: Mokrzycki Andrew
Published: August 2016

The problems discussed in this note refer to the simplest case of the use of linear accelerometers, in which the flight path is in the vertical plane of symmetry of the aeroplane, and the acceleration normal to the path is to be determined.

Generally two facts are neglected:–

(i)

That the accelerometer senses along an arbitrary body axis ZB (Fig. 1), instead of along the wind axis Z (normal to the path).

(ii)

That the accelerometer is not placed exactly at the e.g. of the aeroplane but at some point A, having co-ordinates xA and zA in the body axes.
The Development of “Probe and Drogue” Refuelling
Authors: Macgregor P. S.
Published: August 2016

There have been many proposed, but few practical, methods of refuelling in flight since the first early experiments in 1923, and until some three years ago the only tried and accepted method was the “ looped hose ” system developed since 1934 by Flight Refuelling Limited, and still in use (with British equipment) by the United States Air Force.

This system consisted, briefly, in carrying a hose unit with a capacity of some 230 ft. of hose in the tanker aircraft, and a hauling line and windlass in the receiver aircraft. Operators were employed for both tanker and receiver aircraft.

To make contact between the aircraft, the receiver operator first trailed his hauling line, with a “ sinker ” weight on the end of it, so that the line curved downwards. The tanker aircraft then flew alongside and a projectile, attached to a “contact line,” was fired from a line–throwing gun, so as to pass the contact line under the hauling line.
Some Aspects of Three-Dimensional Cavity Flow
Authors: Taylor-Russell A. J.
Published: August 2016

Some experiments concerned with the wake flows of a number of flat plates of low aspect ratio (Fail, Owen and Eyre) have suggested that for large angles of inclination to the undisturbed stream the wake includes a region of recirculation. The present observations include a detailed study of this region, with particular reference to the wake produced by an equilateral triangular plate, and an attempt is made to explain why the recirculatory flow is found only at angles of incidence greater than 35°. The data includes some wind tunnel measurements of force coefficients, static pressure and mean velocity, and observations of the wake flow made in a smoke tunnel and in a water tunnel.
Comments on Some Recent Calculations Relating to the Laminar Boundary Layer with Discontinuously Distributed Suction
Authors: Coleman W. S.
Published: August 2016

In References (1), (2), Dr. Lachmann develops a method for calculating the growth of the laminar boundary layer over an aerofoil surface with spanwise suction slots placed at intervals along the chord. For this form of control, the laminar flow develops normally from the downstream edge of a slot until it attains the critical Reynolds number (expressed in terms of either the displacement or momentum thickness) at which transition is imminent. The layer then encounters another slot which so thins and stabilises the part not removed by suction, that it is able to continue downstream in the laminar state.

A new feature of the above investigation is the establishment of a second critical Reynolds number which provides an initial condition on the downstream side of a slot. Essentially it defines the minimum value of the displacement or momentum thickness for which, in relation to the local surface roughness, there is no danger of transition due to this form of disturbance.
An Experimental Study of a Symmetrical Aerofoil with a Rear Suction Slot and a Retractable Flap
Authors: Heughan D. M.
Published: August 2016

Experiments were made on an aerofoil of 25 per cent, thickness with a suction slot at the rear and a flap that could be withdrawn into the slot. The main object of the work was to investigate the effect of withdrawing the flap when all the air in the boundary layer was sucked into the slot. In particular, as a test of the type of anti-gust device proposed by Thwaites, it was required to observe the change of lift that occurred during withdrawal of the flap and a subsequent change of incidence (with the flap still withdrawn).

The flow was investigated by the use of smoke and tufts, by pressure plotting on the surface of the aerofoil, and by measurements of total and static pressures in the wake. The effects of varying incidence, flap position, and suction velocity were investigated.

It was found that the provision of a flap downstream of the enclosing streamline, so that the rear stagnation point was not in the free fluid, was all important in relation to the behaviour of an aerofoil which had a suction slot at its rounded rear.

With the flap extended beyond the enclosing streamline and with the ratio of suction-slot velocity to free stream velocity higher than the theoretical value, a stable flow was obtained within the theoretical incidence range. A favourable pressure gradient was observed in the slot entry and no measureable wake existed downstream of the flap. Smoke filaments, emitted from a tube projecting from the slot slightly beyond the enclosing streamline, travelled far downstream with apparently little diffusion.

When the flap was placed so that its trailing edge was inside the enclosing streamline, i.e. so that there was in theory a stagnation point in the free fluid, an instability of a three-dimensional character occurred, with a wide wake and a large drag coefficient. The lift curves were unusual and it was found that movement of the flap caused a large change of lift coefficient. There was no evidence that the lift could be maintained constant, independent of incidence, when the flap was withdrawn into the slot.
Fatigue Life of Wing Components for Civil Aircraft
Authors: Williams Keri
Published: August 2016

In the past attempts have been made to correlate the estimated load variations which the component will experience during a stipulated lifetime (in hours) with estimations of the fatigue strength (in cycles of loading) for typical structural components, such as wing spar boom joints, riveted joints, and so on. The trend of thinking so far has been that one shoulddesignfor a certain fatigue life. In this paper it is shown that, even with the most careful attention given to the detail design of aluminium alloy components, it is not possible to attain what has been regarded hitherto as the minimum acceptable fatigue strength for typical structures,i.e.2 x 106cycles of 1g±7½ per cent. ultimate strength of the structure, based on present British Civil Airworthiness Requirements (Reserve Factor 1.0). There is no implied criticism of the criterion which is an ideal one, and if structures attained the criterion then the fatigue life would be adequate.
The Bending of Some Common Beam Sections into the Plastic Range
Authors: Barrett Anthony J.
Published: August 2016

There is already in existence a fair volume of work on the subject of bending beyond the limit of proportionality, most of which requires the use of actual material stress-strain curves. This note aims to examine the problem in a more general way by using an accurate mathematical form for the stress-strain curve, strain and bending moments being expressed as functions of the ratios of various properties of the material.

The value of maximum permissible fibre stress is considered in relation to current requirements for military aircraft stressing and a guide is presented for the maximum permissible bending moment in some of the more familiar beam cross sections bending about an axis of symmetry.
The Application of Air Survey to the Economic Development of a Country
Authors: Weatherhead T. D.
Published: August 2016

The purpose of this paper is to attempt a broad review of some of the factors that influence the economic development of a country and to illustrate in general terms the importance and the application of airborne survey techniques, as a means of collecting the information on which any sound development must be based.

The industrial and agricultural revolution that is now taking place on a world-wide scale demands a completely new approach to the problem of economic development. When economic development was slow and confined to small areas it was sufficient perhaps to base that development on limited information. Today, however, the pace is quickening every year, but the speed with which we are obtaining the information, on which such development must be based, is lagging behind.

Why is the present position different from any other epoch in world history? The main cause is the industrial revolution, which has produced rapid means of communication, by air and by radio. The Twentieth Century now lives literally as neighbour to the Stone Age.
A Method of Valve Timing Design for Two-Stroke Cycle Engines
Authors: Williams T. , Pullman W. A.
Published: August 2016

A method is described for determining the inlet and exhaust valve area requirements of a two-stroke cycle engine. It is shown that the valve timings are interdependent and that the final choice is a compromise with a number of other factors.
Developing Aviation Fuels and Lubricants
Authors: Davies C. B.
Published: August 2016

The purpose of this paper is to illustrate the research and development work necessary to improve existing products and to anticipate demands for new products facilitating the advance in efficiency and performance of aircraft. The experience of Thornton Aero Engine Research Laboratory, in which the author has worked since it came into operation in 1941, has been drawn on almost entirely.
The Noise from Aircraft Travelling with Velocities Greater than that of Sound
Authors: Walters A. G.
Published: August 2016

There has been much discussion of late on the nature of the noise from aircraft travelling with velocities greater than that of sound. It is possible that these phenomena can largely be explained in terms of the Doppler effect. For a source of sound travelling with a velocity greater than that of sound relative to the observer, the Doppler effect takes a very interesting form. It is discussed mathematically in Ref. 1.
Wing Section Design for Swept-Back Wings at Transonic Speeds
Authors: Haines A. B.
Published: August 2016

It is well known that the performance at high subsonic and transonic speeds of a swept-back wing-body combination in which the wing is untwisted and has the same section at all stations along the span and in which the body is not specially shaped to allow for the presence of the wing, falls far short of what would be predicted for the corresponding infinite sheared wing. For example, with a sweep of 45° and a thickness/chord ratio of 6 per cent it has been found experimentally that a rapid shock-induced increase in drag occurs above a Mach number of about 0·95 and a peak value of CD is obtained at Mach numbers slightly in excess of 1·0, whereas it can be estimated that for the corresponding infinite sheared wing, sonic speed in a direction perpendicular to the isobars (the lines joining points where the pressure is equal) would not be obtained until a Mach number of 1·18 was reached. The poorer performance of the finite swept-back wing results principally from the fact that the pressure distributions for sections near the root and tip are distorted in shape from what would be obtained on an infinite sheared wing and, as a result, the isobars tend to lose some or all of their sweep. With a moderate aspect ratio such as 3, such effects extend over most of the span at high subsonic speeds.
Finite Fourier Transform Analysis of the Flexure of a Non-Uniform Beam
Authors: Jones E. E.
Published: August 2016

The object of this paper is to present an analytical method of investigating the flexure of a non-uniform beam under transverse loading. A method due to Strandhagen for a uniform beam is extended to the case of a non-uniform beam, the deflection appearing in the form of a Fourier series, the coefficients of which are functions of the loading, the end-conditions, and parameters which define the non-uniform flexural rigidity of the beam.
The Resistance to Air Flow of Wire Gauzes
Authors: Annand W. J. D.
Published: August 2016

Wire gauzes are used in air duct systems and wind tunnels for many purposes. Methods of estimating the pressure loss through a gauze currently available are often found in practice to be unsatisfactory. In this paper data obtained by several experimenters are correlated. It is shown that the effect of Reynolds number on pressure drop is similar for a large range of gauze porosities. An empirical method of estimation of the pressure drop is given which can be used with confidence for gauzes of porosity (defined as the proportion of area not blocked by the wires) from 0·27 to 1·00, and over a range of Reynolds number, based on approach velocity and wire diameter, from 20 to 600.
The Potential and Field of Flow (Induced Velocity) of a Plane Vortex
Authors: Taylor J. Lockwood
Published: August 2016

Vortices are not usually treated by potential theory, but the latter is so well known and of such general application that there seem to be advantages in doing so.

Consider first the potential function

i.e. distance from O.
Sir George Cayley, Bart.|The Father of British Aeronautics
Authors: Pritchard J. Laurence
Published: August 2016

The True Balance of a man's worth cannot be struck by a knowledge, however full, of only one of his activities.

I do not propose to confine myself to Cayley's aeronautical activities in this paper, for that would be to do much less than justice to a man whose interests, when known and understood, can only add to the stature of a great Yorkshireman and a great Englishman, one, to quote William Cobbett, “of the resident native gentry, attached to the soil, known to every farmer and labourer from their childhood, frequently mixing with them in those pursuits where all artificial distinctions are lost, practising hospitality without ceremony, from habit and not on calculation.”

Sir Walter Raleigh, in his introduction to the History of the War in the Air (1914-1918), referred to Cayley as one who “amused his leisure with science.” Raleigh was not aware and, indeed, very few who know something of Cayley's aeronautical work are aware, of how active was the interest Cayley took in scientific and engineering matters during his long life. I hope in this paper to add something to Cayley's stature, great as it is, in this respect.
Minimum Weight Design of Thin–walled Cells in Torsion
Authors: Cadambe V. , S. Krishnan
Published: August 2016

The minimum weight approach to structural design was introduced by F. R. Shanley with reference to narrow and wide columns and shells subjected to bending, and was later dealt with more comprehensively in a book by the same author. This was further extended to structures like tapered round thin-walled columns and frames. In this paper expressions giving optimum sectional dimensions for long thin walled cells of circular, semi–circular, rectangular and triangular shapes and uniform wall thickness have been derived. The design criteria used to obtain the minimum necessary conditions are (1) failure by local buckling and (2) a limit on the twisting deformation of the cells. Working curves from which the optimum sectional dimensions can be read for given torque and limiting twist have been plotted. And finally, a method of approach to the problem of combined bending and torsion has also been indicated.
Generalised Stress-Strain Data for Aluminium Alloys and certain other Materials
Authors: Barrett Anthony J. , Michael Maureen E.
Published: August 2016

In many engineering problems it is necessary, from time to time, to deduce from only a few characteristic values data which would ideally be obtained from a complete stress-strain curve. For instance many handbooks, used in design offices and published by materials manufacturers and others, contain values of Young's modulus and minimum guaranteed, or typical, values of various proof stresses for materials. From these, estimates of strain, tangent modulus or ratio of stress to tangent modulus appropriate to known stress values may be required, or various processes involving integration of the stress-strain curve may have to be carried out. Even when a complete stress-strain curve is available from a special test, the differentiation and integration of it, which may have to be repeated several times, are timeconsuming processes. Also, in analytical work involving the use of materials beyond the limit of proportionality, it is desirable to have available a generalised mathematical form of the stress-strain curve in order that the results obtained may be applied to a wide range of actual materials simply by the substitution of appropriate coefficients. These and many other applications will be familiar to the reader.
Methods of Reducing the Transonic Drag of Swept - Back Wings at Zero Lift
Authors: Küchemann D.
Published: August 2016

The purpose of this paper is to review briefly some means of reducing the normal-pressure drag at transonic speeds of wings and wing-body combinations without lift. By transonic speeds is meant here not only the range of main stream Mach numbers around unity but, more generally, that speed range where a transonic type of flow around the body may exist. Thick non-lifting bodies as are considered here cause a displacement flow and it may be recalled that at least three different types of flow are involved: a subsonic, a transonic, and a supersonic type of flow, all of which are here assumed to have one attachment line along the leading edge and one separation line along the trailing edge. This excludes types of flow where separations occur elsewhere, such as shock-induced separations along some line within the wing chord.
The Structural Aspects of Jet Noise
Authors: Wolfe M. O. W.
Published: August 2016

The increase in jet engine thrust has been accompanied by an increase in the noise generated by the jet stream to such an extent that the associated noise pressures are now capable of exciting vibrations in an aircraft structure which are potentially dangerous from the fatigue aspect. Several examples of fatigue damage of this kind have appeared already on aircraft in this country and in the United States.

The noise generated by a gaseous jet arises principally from disturbances caused by high velocity gradients at the jet boundary. Classical theoretical work on noise generated in this way has been done by Professor Lighthill. He introduced the concept of an “acoustic quadropole” as the elementary sound generator, and showed mathematically that the total acoustical power radiated by a jet varies directly as the eighth power of the jet exit velocity and the second power of the jet exit diameter.
An Electronic Instrument for the Accurate Measurement of the Frequency of Structural Oscillations
Authors: Hicks W. D. T.
Published: August 2016

An instrument is described which measures the time duration of a specified number of complete cycles of an oscillation over the frequency range OT cycles per second to 500 cycles per second. The accuracy of the reading is dependent on the frequency measured and the number of cycles taken; but, in most cases, an accuracy better than 01 per cent is obtainable. The construction of the instrument is described and circuit diagrams given.
A Method for Calculating the Exhaust Port Area for Two-Stroke Cycle Engines
Authors: Benson R. S.
Published: August 2016

The design of the exhaust ports of a two-stroke cycle engine is mainly based on the area required to reduce the cylinder pressure at the end of the expansion stroke to scavenge air pressure in the minimum practicable time. The flow through the exhaust ports is both sonic and subsonic; in the former case the flow is independent of the exhaust pipe conditions but not in the latter case. In the first stage of the design, however, the exhaust pipe conditions may be assumed to be constant when calculating the port area, subsequent calculations of the pressure drop allowing for the pipe size may then be made by the methods suggested by Wallace, Cole, or Benson. In the following Note formulae are developed for estimating the port area neglecting the exhaust pipe size.
Materials for Aircraft Structures Subjected to Kinetic Heating
Authors: Murphy A. J.
Published: August 2016

The requirements of aeronautical engineers have been one of the greatest stimulants of metallurgical research and development during the present generation. Materials for the piston engine and the airframe had shared about equally the attention of the research metallurgist from the early twenties to about 1945. Then the gas turbine appropriated the major effort in metallurgical research because it was clear that progress with this propulsive unit was inescapably dependent upon the production of metals and alloys capable of giving reliable service at ever increasing temperatures. Here it was a question of evolving new materials having characteristics for which no appreciable demand existed before the advent of the gas turbine. The past five years have seen the airframe come back into the picture metallurgically, because of the new concern with fatigue and because supersonic speeds are bringing with them service temperatures for the airframe higher than anything arising while speeds of flight were comfortably subsonic.
Normalised Orthogonal Deflexion Functions Jor Beams
Authors: Duncan W. J.
Published: August 2016

A Set of normalised orthogonal polynomial functions suitable for problems concerning doubly built-in uniform beams was given in R. & M. 228l. The nth function of the set was expressed linearly in terms of three Legendre polynomials as follows:—

where
Temperature Control of Blow-Down, Supersonic Tunnels
Authors: Thomson T. A.
Published: August 2016

The blow-down type of intermittent, supersonic tunnel is attractive because of its simplicity and because relatively high Reynolds numbers can be obtained for a given size of test section. An adverse characteristic, however, is the fall of stagnation temperature during runs, which can affect experiments in several ways. The Reynolds number varies and the absolute velocity is not constant, even if the Mach number and pressure are; heat-transfer cannot be studied under controlled conditions and the experimental errors arising from the effect of heat-transfer on the boundary layer vary in time. These effects can become significant in quantitative experiments if the tunnel is large and the variation of temperature very rapid; the expense required to eliminate them might then be justified.
The Theory of the Autogyro
Authors: Glauert H.
Published: August 2016

It is now over a year since the Society had the pleasure of listening to Senor de la Cierva’s paper on the development of his new type of aircraft. In view of that paper it is unnecessary for me to enter into any detailed historical account, but I would like to recall to your minds just these few facts. The object which Senor de la Cierva had in view was to design some form of aircraft which would avoid loss of control on stalling and would at the same time facilitate the process of landing.
The Provision of Aerodrome Obstruction Data for Rational Code Civil Air Transport Operations
Authors: Petts F. C.
Published: August 2016

The introduction of rational performance requirements governing the operation of civil transport aircraft has given rise to a need for accurate and detailed information on obstructions in the vicinity of aerodromes. This paper states the origin and nature of the requirement and describes a survey technique, a particular application of terrestrial photogrammetry, which was used to meet it.

In the United Kingdom and in other member countries of the International Civil Aviation Organisation considerable progress has been made towards the rationalisation of performance requirements governing the operation of civil transport aircraft.
Some Aspects of Modern Naval Aircraft Design
Authors: Hollis Williams D. L.
Published: August 2016

It is almost four years since a series of papers on Naval Aviation was presented to the Royal Aeronautical Society in the full day session held on 7th May 1947. The first paper in that series, “Technical Problems of the Design of Naval Aircraft,” read by W. S. Farren, stated the fundamental problems clearly.

During the intervening years, the general trends in aerodynamic and power plant development have been reflected in the design of carrier-borne aircraft and are beginning to stabilise into a recognisable pattern. Thus, turbo jet and turbo-propeller engines are now accepted for Service use, there has been general aerodynamic improvement including the suppression of drag arising from the carriage of stores, and it is normal to find that prototypes are mounted on a nose-wheel type undercarriage.
Recent Advances in the Knowledge of Transonic Air Flow
Authors: Warren C. H. E.
Published: August 2016

The most powerful theoretical tool in the solution of the aerodynamic problems of aircraft is the theory of small perturbations, which states that if a wing is thin (or a body slender), and if the incidence is small, then in inviscid flow the fluid velocity at any point can be treated as a small perturbation from the stream velocity. The backbone of our knowledge of the aerodynamics of aircraft is provided by this theory, to which the effects of thick wings and large incidences, and the effect of viscosity, introducing as it does the concept of boundary layers, can be added as additional or correction effects. It is known that at subsonic and again at supersonic speeds, the theory of small perturbations is a linear theory; that is, the assumptions implicit in it lead to a linear partial differential equation for the velocity potential, with linear boundary conditions.