bluuebunny/crossref_metadata_2025 huggingface dataset:
Aerodynamics II
Authors: Sutcliffe P. L.
Published: July 2016

The flight plan of the supersonic transport demands efficient aerodynamics and propulsion over a wide range of speed and altitude. As an example, the typical trans-Atlantic flight shown in Fig. 1 demonstrates that apart from cruising efficiently at, say, M = 2·2 for 2.500 n.m. at altitudes from 50,000 ft. to 65,000 ft., the aircraft must also be efficient at subsonic speeds. This is particularly true on the portion of the flight after the normal stage length, i.e. the diversion and hold, since the fuel required here must be carried the whole way and the “ growth factor” on aircraft size is large.
Range Instrumentation Problems
Authors: Higgs H. J.
Published: July 2016

As this is a wide subject area with many specialised fields, a broad review from a systems viewpoint would appear to serve the purposes of this Symposium best. Also, such a review may help to show that the importance of range instrumentation in upper atmosphere research is rather more fundamental and widespread than generally appreciated.
The Certification of Civil Transport Rotorcraft with particular Reference to Multi-Engines
Authors: Le Sueur H. E.
Published: July 2016

For the past 150 years man's ingenuity has been exercised in producing machines to transport himself faster and faster until today he is talking of aircraft which can travel faster than the rotating speed of the earth at the equator, and such that any point on the earth's surface is within ten hours flight time from any other point. But such is the contrariness of the situation that these speeds involve the use of extensive runways away from the crowded city centres and, what with the crowded roads and trains, the journey from the airport to the city centre can be long, tedious and uncomfortable.

The helicopter enthusiast suggests that this problem can be overcome by using a machine that can take off vertically from the city centre and carry the passenger rapidly in comfort to the airport. He also suggests that for journeys up to 200 miles or more, the helicopter is the quickest form of transport from city centre to city centre.
A Method of Estimating the Permissible Fatigue Life of the Wing Structure of A Transport Aircraft
Authors: Raithby K. D.
Published: July 2016

For types of structure where safety standards cannot be preserved by reliance on inspection, a permissible “safe life” has to be determined by relating the loads experienced by the aircraft in service to the fatigue performance of the structure, with due allowance for scatter in fatigue strength and in the frequency with which loads are encountered. This paper gives a working method for estimating the “safe life”—at which the risk of fatigue failure is negligible—of the wing structure of a transport aircraft, where the flight loads giving rise to fatigue are overwhelmingly due to atmospheric turbulence but where allowance has also to be made for “ground-to-air” loads.
The Royal Aeronautical Society The First Fifty Years
Authors: Laurence Pritchard J.
Published: July 2016

The first paper read at the 1876 meeting was by D. S. Brown, his fifth paper to the Society, entitled “ The Advantages of employing power for aerial propulsion in an intermittent manner, and on the soaring of birds.”

Brown was silent on the advantages of intermittent application of power for flight, and was not much impressed by Sir George Cayley's ideas about birds soaring in upward currents of air reflected from cliffs, hills, and so on. But he spoke with obvious knowledge of the effects of increased size on a weight-strength ratio in the light of the cube/square law.

James Armour, whose paper, “ Wings for Men,” filled fifty pages of small type in the 1873 Annual Report, presented a further paper on the subject, read this time by Brearey in the absence of the author, entitled “ Air Compression under Wingplanes.” James Armour was a good engineer, and had to confess that though he argued on general principles about the supporting forces of an aeroplane in full flight, there were many unknown parameters.
VTOL and STOL: Simple Solutions to Some of the Operating Problems During Take-off and Landing
Authors: Fearon, J. R. C. , Norman, D. H.
Published: July 2016

The lightweight and compact separate jet lift engine has been with us long enough to have built up an acceptable level of confidence in its abilities, but there have been misgivings over the magnitude of some of the operational problems, in particular those of ground erosion and hot gas reingestion due to the high velocity jet.

The object of this paper is to present a Series of tests which has been made by Rolls-Royce to ascertain the nature of the problems and to put forward some simple solutions. It is not suggested that any of these solutions is unique but merely that they are adequate for our present needs.
Low Cycle Fatigue of an Aluminium-Copper Alloy B.S.L65C
Authors: Mackenzie C. T. , Benham P.P
Published: July 2016

A recent paper(1) gives details of an investigation on the low endurance fatigue behaviour of an aluminium-zinc-magnesium alloy (D.T.D. 683). It becomes apparent in subsequent discussion that information on another aluminium alloy to B.S. L65C would satisfy a wider practical interest than the former. Although the equipment used for the earlier work was engaged on another project, it was decided that the latter should be halted for a period to enable a brief programme on low endurance fatigue to be conducted on B.S. L65C material which had previously been kindly provided by the Aluminium Development Association.
Aircraft Safety and Missile Reliability
Authors: Wrigley H. B.
Published: July 2016

I feel that the title of this lecture needs clarification, because it would appear from it that aircraft reliability is necessary only in the interests of Flight Safety. Although safety is vital, the operational capability of the aircraft must also be considered because, as in a missile system, operational reliability is of paramount importance. An aircraft may be completely reliable from the Flight Safety aspect without necessarily having a reliable weapons system.

In the past few years, of course, much has been said about the need for reliability. Conventions have been held in this country and in other countries and it might be thought that the lesson has been so often and so well propounded that to discuss it again is hardly necessary. However, I hope to show that we still have some way to go before we even begin to approach the ideal.
Groups of Unknowns in Structural Analysis
Authors: Filho Fernando Venancio
Published: July 2016

Using the Argyris matrix formulation a concise and definite justification for the correctness of the use of groups of unknowns in the analysis of redundant structures is given. It is shown also that to consider groups of unknowns is equivalent to changing the basic system. These two intimately related concepts are applied to the force as well as to the displacement method.
New York Airways—1962
Authors: Cummings Robert L.
Published: July 2016

Possibly since the beginning of time, and certainly since early recorded history, man has been engaged in a struggle to fly straight up and to cover distances (including short distances) at an ever faster rate. Aircraft using the principle of the rotary wing are one result. There is evidence to support a theory that such machines may have existed, in one form or other, well before the birth of Christ. For hundreds of years, experimental work has gone forward persistently.
An Introduction to Hypersonic Ablation
Authors: Simpkins Peter G.
Published: July 2016

This paper is intended as an introduction to the theory of ablative processes in a hypersonic environment. The various types of ablation are discussed and the general heat transfer equation for an ablating body is given. The effects of radiation are introduced and the physical significance of the gasification ratio is explained. Throughout the paper the effects of a chemically reacting boundary layer are ignored.
Receptance Series for Systems Possessing “Rigid Body” Modes
Authors: Gladwell G. M. L. , Bishop R. E. D. , Johnson D. C.
Published: July 2016

Certain elastic systems may not only vibrate freely at proper (non-zero) natural frequencies, but may also move as rigid bodies. Such systems have “rigid body” modes which behave like principal modes corresponding to zero natural frequencies. These modes may be disregarded in the series representation of static distortions of such systems but must be taken into account in the representation of forced vibrations.

This note is concerned with the series representation of receptances of certain simple systems of this type, namely strings, bars, shafts and beams. These systems were discussed in reference 1, but there the rigid body modes were omitted. As the matter appears to raise some points of interest, a discussion of it seems to be called for. A similar analysis to that presented here may be applied to other unsupported, or partially supported systems, such as an unsupported plate.
Mixing of Exhaust and By-pass Flow in a By-pass Engine
Authors: Pearson H.
Published: July 2016

It is well known that the main purpose of the by-pass principle is to improve the propulsive efficiency of a simple jet engine by removing some of the energy left in the jet gases and using this to compress an extra quantity of air, known as the by-pass air, this air being ejected rearwards with the jet gases. In this way a greater mass of air is ejected rearwards at a lower jet velocity and thus a better propulsive efficiency is obtained. This is an extremely simplified view of the advantages of the by-pass engine, however, since an equivalent result of obtaining a lower jet velocity can be obtained by designing the jet engine for a lower combustion temperature. The by-pass principle is of advantage because it enables a higher propulsive efficiency to be obtained at the same time as employing a high combustion temperature and therefore a high basic cycle efficiency. If the component efficiencies of a gas turbine were 100 per cent, cycle efficiency would not depend upon combustion temperature at all, and there would thus be no advantage in principle in using the by-pass engine. In practice there would probably be some residual advantage left in that for a given thrust a lower engine weight could be obtained.
The Role of The United States Government and U.S. International Air Carriers in Commercial Air Transport Over The North Atlantic
Authors: Emery V. S.
Published: July 2016

Published statistics reveal an approximate six-fold increase since 1951 in commercial air transport activity over the North Atlantic. Scheduled passengers increased in number from 341,000 in 1951 to 1,919,000 in 1961; cargo increased from 7,700 tons to 53,000 tons; and mail carriage increased from 3,900 tons to 17,000 tons over the same period. For 1962 a further increase of 12 per cent in passenger traffic and 14 per cent in cargo is forecast. This rapid growth situation has not been accompanied by a corresponding increase in profits, however, as evidenced by a loss estimated in the millions in 1961 on the North Atlantic by the United States international air carriers alone, and an indeterminably greater amount by the foreign air carriers operating in this area. From the limited financial data available, it appears that, among all North Atlantic scheduled international air carriers, only Irish Airlines and Pan American experienced profitable operations for 1961.
Rates of Change of Eigenvalues, With Reference to Buckling and Vibration Problems
Authors: Wittrick W. H.
Published: July 2016

There are many problems in practice, particularly in the fields of buckling and vibration, where the required end result is a curve showing the relation between the eigenvalue and one or more of the basic parameters of the physical system. For example, the curve relating the buckling stress and side ratio of a rectangular plate, with some specified set of edge conditions, under uni-axial compression may be required. Or the problem may be the buckling of a rectangular plate of given proportions, under combined compression and shear, and the determination of the relation between the two types of load at buckling. Alternatively, the effect on the frequency of vibration of varying a concentrated mass, or the stiffness of an elastic constraint at a given point in an elastic system may be required.
A Note on the Undercarriage Aquaplaning of Aircraft Landing on Water-covered Runways
Authors: Gadd G. E.
Published: July 2016

When an aircraft lands on a runway on which there are extensive puddles, it appears that sometimes the water exerts a large upwards force on the wheels, so preventing them from making contact with the ground. The wheels are then said to “aquaplane”. In the aquaplaning condition the braking effectiveness of the wheels is reduced virtually to zero, and even at touch-down speeds insufficient to cause aquaplaning, when there is some contact between the wheels and the ground, water on the runway may cause appreciable reductions of runway friction forces. This note offers some tentative suggestions concerning the nature of the water flow when aquaplaning occurs, and is put forward as a basis for discussion of this important practical problem.
Configurations for High Supersonic Speeds Derived from Simple Shock-waves and Expansions
Authors: Flower J. W.
Published: July 2016

The Nonweiler method of designing delta wings (caret wings) to have plane shocks on the lower surface is extended to the design of upper surfaces. Cambered and shock-free surfaces are also deduced, and methods of design for complete configurations suggested.

An important point is that all surfaces are of single curvature.
Bristol Gas Turbines —The First Decade
Authors: Owner F. M.
Published: July 2016

The invitation to read this, the Ninth Barnwell Memorial Lecture, gives me the opportunity of acknowledging publicly the friendship and encouragement I used to receive from that great and kind gentleman. For several years before his death, he accorded me the privilege of a weekly meeting, and although I was in every way very junior, he invariably treated me as a friend as well as a colleague, thereby adding affection to the deep respect I felt for him.

I do not recall any details of our discussions of gas turbines, although I am certain we did review their possible advent on more than one occasion. Had he lived to see them, I am sure our efforts would have received his encouragement and support.
The Flow and Pressure Losses in Smooth Pipe Bends of Constant Cross Section
Authors: Ward Smith A. J.
Published: July 2016

Incompressible turbulent flow in smooth pipe bends of circular-arc curvature and constant cross section is discussed. The effects of bend angle, radius ratio, duct cross-sectional shape and Reynolds number are considered. Particular attention is paid to the influence of the tangents on the flow and losses in a bend. In addition consideration is given to the definition and measurement of the bend loss.

A correlation of experimental pressure loss data is made. It is shown that large variations in experimental results, which cannot be ascribed to the effects of geometrical parameters or Reynolds number, are accounted for by the effects of the downstream tangent and position at which the pressure measurements were made. The inadequacy of existing experimental information is an obstacle to the presentation of comprehensive data on the effect of geometrical parameters on bend losses.
The Effect of Mach Number, Incidence and Hole Position on the Static Pressure Measured by a Square Ended Probe
Authors: Hahn J. F.
Published: July 2016

Static probes, although widely used in supersonic tunnels and in flight, have not formed the basis for many reports on their design and behaviour at high Mach number.

It is known, however, that the flow over the nose of the probe causes pressure variations such that it is some distance along the probe before the static pressure is equal to free stream static pressure. The NPL, in a series of tests at M = 1.6 showed that the pressure measured at a point situated less than 10 calibres (probe diameters) downstream of the beginning of the parallel portion of the probe was dependent on the shape of the nose.
An Analytical Method for the Design of Two-Dimensional Contractions
Authors: Lau W. T. F.
Published: July 2016

An analytical method is presented for the design of two-dimensional contractions. In this method, the complex potential of the flow of an infinite row of equally spaced line sources normal to a uniform stream is obtained. By adjusting the strength of the sources, the streamlines of the main stream are used as boundaries of two-dimensional contractions of various contraction ratios. It is found that, in all cases, there is a region in the main stream between two neighbouring sources in which the speed of flow increases monotonically along streamlines. Contractions formed by any of the streamlines in this region would therefore have favourable pressure distribution along their boundaries except for very small adverse pressure gradient at the inlet and outlet which are due to the introduction of parallel sections.
The Speed of Sound and Mach Number Effects
Authors: Naylor V. D.
Published: July 2016

In a recent paper the suggestion is made that “it would be sensible when discussing the flow to use a Mach number based on the actual propagation velocity in the given circumstances.”

This directs attention to the deeper question of whether or not a Mach number however defined is a rational parameter in terms of which to express effects of flow.

In certain cases the quantity γp/ρ occurs quite naturally, regardless of any physical interpretation that can be given to it.
The Development of Blue Steel
Authors: Francis R. H.
Published: July 2016

Blue Steel is an air-surface missile carrying a thermonuclear warhead and intended to enable the V bombers to operate without going into areas in which they would be exposed to concentrated guided weapon attack. It has a canard configuration with small delta-shaped foreplanes for pitch control, a rear-mounted wing with inboard ailerons and a pair of fins of which the upper carries a yaw damper; the lower fin folds sideways to give sufficient ground clearance when the missile is installed on the aircraft (Fig. 1). Its exact performance cannot yet be stated but it is the largest of the British Missiles to get into Service.
Some Experiments with Vortex Breakdown
Authors: Lowson M. V.
Published: July 2016

Water tunnel flow visualisation experiments on a slender delta wing have revealed some new phenomena connected with vortex breakdown. Vortex breakdown hysteresis has been found, there being two steady flow states at some incidences, one with breakdown on the wing and one without. The formation of vortex breakdown has been studied and found to be a non-axisymmetric instability. It is suggested that pressure gradient plays a more general part in the phenomenon than has been thought hitherto.
The Rôle of the Test Pilot
Authors: Bedford A. W.
Published: July 2016

It is an honour, a privilege and a pleasure to deliver the Inaugural Lecture of the Test Pilots’ Group. It is encouraging to see such strong support for this function and on looking round it is only too apparent that there are many more able and deserving pilots present to deliver this lecture.

It is perhaps appropriate, first, to say a few words about the Group itself.

On the 28th November 1963 the Council unanimously approved the formation of a Test Pilots’ Group within the Society. The aim of the Group is The general advancement of aeronautical knowledge in the test flying field. It is hoped that through the Group the test pilot will be able to make a worthwhile contribution to the objects and purposes of the Society, at the same time advancing his own professional knowledge and standing.
Factors Affecting the Application of Low-Volume Sprays
Authors: Amsden R. C.
Published: July 2016

Aerial crop spraying necessitates the lowest feasible application rates to minimise costs. The low volumes now being used in the Tropics and in this country often require very high concentrations of active ingredient. Most agricultural sprays are formulated for use in 10-100 gallons per acre. When the same weight of chemical is applied in one gallon or less per acre any one of hitherto disregarded factors, such as surface tension, rate of evaporation, density, viscosity, dynamic catch, and so on, may unexpectedly reach a critical value. An understanding of the limits of these factors is essential for the diagnosis or prevention of faulty biological performance.
Trends in Land Tenure and Ownership
Authors: Dobb E. S.
Published: July 2016

In talking about trends in land tenure and ownership, I propose to confine myself, mainly, to agricultural land in England and Wales, as agriculture is by far the biggest single use to which our land is put. Let me say, at once, that there is a marked lack of co-ordinated statistics on many aspects of the subject and I have, therefore, thought it best to round-off the majority of the figures quoted. For the convenience of those who may wish to pursue the matter further, a list of the main sources of information has been included in the references.
The Use of Agricultural Aircraft in the Frozen Food and Canning Industry
Authors: Norman R. F.
Published: July 2016

The continuing increase in the standard of living has brought with it a marked trend towards the use of processed vegetables, especially those which are prepared and require little or no attention before serving. This has been particularly marked in frozen foods and more recently dried foods, including accelerated freeze dried products.

The customer demands products which are of a consistently high quality and the food industry is therefore concerned with the purchase of crops of a very high standard in order to produce consistent products for sale. This creates a demand for produce which is free from blemish, pest and disease effects. It also necessitates crops being harvested at the optimum time and any one crop should be as uniformly mature as is possible.
Forest Fire Control Aircraft in Canada
Authors: Fraser D. G.
Published: July 2016

The economic losses occasioned by forest fires in Canada are serious. Although the forest lands are largely under the jurisdiction of the provincial governments the forest resources are of national interest. For this reason the federal government, through the Department of Forestry, carries out a national programme of forestry research. The research in forest fire control encompasses the use of aircraft. This paper reviews the early developments in the use of aeroplanes in Canadian forestry operations. The more recent developments of direct fire suppression techniques, such as water dropping, are discussed in detail.
On the Performance of Lanchester’s “Aerial Tourbillion“
Authors: Parkinson C. V.
Published: July 2016

Wind tunnel measurements of the auto-rotation characteristics of Lanchester’s “aerial tourbillion” are presented in the form of tip speed plotted against wind speed. Three configurations were tested, a 10.94 inch diameter model with and without a cowling, and a 7.50 inch diameter model without a cowling. All showed a minimum wind speed for auto-rotation, dependent on friction at the shaft. At each wind speed above this value, there were two equilibrium rotational speeds, an unstable one, giving the required initial rpm for auto-rotation, and a higher stable one, the auto-rotation speed, which with increasing wind speed rapidly approached proportionality to the wind speed.

Fairly good agreement with an approximate blade element theory was demonstrated, the best agreement being obtained with the measurements on the model with cowling.
The Simplified Vibration Damper Problem and Its Solution
Authors: Morley A. W.
Published: July 2016

The linear vibrating system of two degrees of freedom, see Fig. 1, whose mathematical solution is well known (see for example ref. 1), is nevertheless on the verge of being too awkward for manipulation in the design office. It is of considerable interest as the basis of a vibration absorber and techniques continue to be developed for investigating the effects of changing the design constants on the properties of the system and the more complicated ones derived from it.
Additional Information on the Collapse of Pressure Loaded Spherical Shells
Authors: Klein Bertram
Published: July 2016

During the past ten years the author has been collecting test data on the collapse of pressure loaded spherical shells in order to establish good design curves. The presence of initial imperforations causes wide variance in strength values from one investigator to another. An effort is undertaken to attempt to analyse all available data on some rational basis. Certain diagrams have been presented in the past.
Some Problems Arising from the Use of Hydrogen-Fuelled Propulsion Systems
Authors: Maher L. E.
Published: July 2016

It is now generally recognised that liquid hydrogen offers a considerable increase in vehicle performance over the more conventional fuels, despite its relatively low density.

A design study on an upper stage, which uses a liquid hydrogen/ liquid oxygen chemical propulsion system, revealed a number of problem areas which extend beyond the current levels of experience and knowledge in rocket technology existing in the U.K. This study was made on the third stage of a communication satellite launching vehicle, and a number of the problems high-lighted during the course of the investigation, covering both the propulsion system and the structure, are described and discussed in terms of their importance and their effects on the launcher system. Solutions are suggested where possible—although, lacking practical confirmation, these must be tentative in the circumstances.

While no fundamental difficulties are anticipated in the development of a rocket engine using hydrogen, it is essential to accumulate some background of data and experience to ensure that early policy and designs are sound; the importance of beginning practical work as soon as possible is emphasised.
Sir Henry Tizard 1885-1959
Authors: Jones R. V.
Published: July 2016

Sir Henry Tizard’s work and–above all–his part in our survival in 1940–have been the subject of many memoirs since his death in 1959. The biography written by Ronald Clark at the invitation of Professor J. P. M. Tizard, Sir Henry’s eldest son, will shortly appear. This first Memorial Lecture of the Royal Aeronautical Society thus occurs when a full record of Tizard’s life is about to be made available, and there is therefore little point in the plain re-iteration of a condensed biography. Future Memorial Lecturers, as they inevitably grow more remote from personal contact with Tizard, may well choose to describe the advances of the future in those fields to which Tizard himself so notably contributed: science, defence, education and government. My purpose in this first Memorial Lecture is, therefore, to build a bridge between biography and those future fields in which Tizard’s example, although unlikely to be excelled, will be emulated and extended.
The Light Observation Helicopter Programme of the United States Army
Authors: Crawford Charles C.
Published: July 2016

The United States Army is now engaged in the selection of a Light Observation Helicopter (commonly referred to as the LOH) from three competing designs. It is estimated that large quantities will be procured to fulfil an operational requirement during the 1966-1975 time period. The paper describes the overall programme by examining the basic requirement and the development concept. In addition, a description of the actual hardware being developed is given and some economic considerations of the modernisation of the observation fleet are discussed.
Some Aerodynamic Aspects of Rear Mounted Engines
Authors: Moss G. M.
Published: July 2016

The advent of a new generation of turbojet powered transport aircraft with engines mounted on the rear fuselage has complicated the task of the aerodynamicist, particularly when an attempt is made to determine the individual contributions to the stability and aerodynamic loading of the aircraft. This paper gives some idea of the additional complexity which is directly attributable to the presence of these engine nacelles and their effects on manoeuvring tail loads. Where rational methods are available for determining these effects they are referred to or included.
Visual Aspects of Cockpit Management
Authors: Ormonroyd F.
Published: July 2016

This paper gives an account of some of the practical display problems met in day to day airline operation by BEA and the application of this experience to the improved displays specified for the Trident.
The Work of the Royal Aircraft Establishment
Authors: Nicholson L. F.
Published: July 2016

To write a paper on the work of the Royal Aircraft Establishment is a formidable task. To summarise the programme of work of the Establishment would either provide material for a series of lectures or, if compressed to a single lecture, would lead to a cursory and superficial treatment. I make no apologies, therefore, for not attempting any sort of complete survey. Within the scope of this lecture all I intend to do is to give a brief description of the RAE, what it is, what it does and how it is organised and then to consider a few items drawn from three of the RAE's research programmes, which have been selected to show some of the characteristics of the RAE and the kind of work which goes on there.

The first series of items to be presented fall in the field of the slender wing. The great potentiality of the slender wing for a wide range of applications was apparent from the time the concept was first considered. What I want to stress is the enormous range of detailed researches which are required before such a concept can be used in practical designs.
Helicopter Trials Over Sand and Sea
Authors: Hibbert W. A.
Published: July 2016

—The experience from several environmental trials on helicopters is reviewed to show how the life of main and tail rotor blades was reduced by erosion and how effective various modifications have been in protecting these blades. The compressors of the gas turbine power units were also affected by sand ingestion and intake filters were used on later trials to protect the engines. The engine erosion problem is discussed with reference to the position of the intake, the degree and type of filtration and the design of the compressor itself. The design features of the helicopter which affect its ability to operate in dust and salt-laden atmospheres are also considered, along with suggestions for further research and development.
The Dependence of Diffuser Performance upon Inlet Flow Conditions
Authors: Livesey J. L. , Turner J.T.
Published: July 2016

It was recently stated by Cockrell, Diamond and Jones(1) that attempts to correlate diffuser loss coefficients with the inlet boundary layer momentum thickness were generally unsatisfactory. In particular, it had proved impossible to align various results from diffuser tests which had been made with differing inlet flow conditions. The two methods of thickening the diffuser inlet boundary layer, using either

(a) a length of parallel pipe, or

(b) screen rings at inlet to the diffuser

led to a corresponding variation in diffuser performance.

The conclusion was drawn that “the manner by which an inlet boundary layer has been thickened is as significant in determining diffuser performance as is the thickness of the layer. No satisfactory inlet flow parameter is at present known”.
Integral Axi-Symmetric Nozzle Design
Authors: Cohen M. J.
Published: July 2016

This is an extension of the design method described in ref. 1 to the compressible flow in integral nozzles comprising both subsonic (contraction) and supersonic (effusor) parts. The nozzles are axially symmetric and will be considered as isentropic convertors of low speed high enthalpy inviscid gas to a high speed, relatively low enthalpy state, heat transfer effects being ignored. The key advantage of the method over existing hybrid design methods(2'3'4'5) is that no assumption is made as to conditions in the “sonic” throat region before expansion in the effusor, the design being integral from low speed inlet to high speed outlet. A slight disadvantage of the method is that of ref 1, namely that a nozzle of an ideally infinite extent has to be truncated both at inlet and outlet. However, for a given nozzle length this limitation can be biased towards the relatively insensitive low subsonic inlet to benefit correspondingly outlet conditions to the extent that it should be possible to make the maximum variation from the mean in the cross-sectional speed at outlet less than 0.01 per cent. The method is being applied to design integral hypersonic nozzle units for the projected small intermittent hypersonic facility in the Department of Aeronautics and Space Technology. This tunnel will have a nominal working-section diameter of 2 in and the flow will be accelerated from low speed (about 20 ft/sec) at inlet to Mach numbers of either 5, 6, or 7 at outlet to the working section using three alternative nozzles.
Aerodynamically Induced Vibration in Coolers
Authors: Mabey D. C.
Published: July 2016

Vortices shed from cooler tubes can excite standing pressure waves in coolers if the vortex shedding frequency coincides with the standing wave frequency(1, 2, 3, 4). If resonant conditions are encountered in a particular cooler the single vortex shedding frequency may be suppressed by fitting in-clined splitter plates into the coolers. These splitter plates also “detune” the coolers by raising the resonant frequencies.

Splitter plates of this type were used recently to eliminate severe noise and structural vibration in a new cooler for the 3 ft wind tunnel at the Royal Aircraft Establishment, Bedford.
Tetrahedron Elements with Linearly Varying Strain for the Matrix Displacement Method
Authors: Arcyris, J. H.
Published: July 2016

The author mentioned in his Main Lecture(1) the success achieved in the analysis of three-dimensional media, for small and large displacements, as well as anisotropic and non-elastic behaviour, by the introduction of tetrahedron elements of constant strain and stress(2), see also technical note 1 of this series(3). A cardinal point of the theory is the specification of natural strains, stresses and stiffness. At the same time attention was drawn to certain difficulties arising in the interpretation of the stresses at the nodal or other points, which are more severe than for constant strain triangles, the corresponding elements in the two-dimensional case. It was suggested in the lecture that a considerable improvement might be achieved by the specification of a linearly varying strain or stress state within the tetrahedron. The solution of this problem, limited to small displacements, is summarised in this fifth technical note and its application is to be demonstrated on an example in the printed lecture.
The Well-Balanced Structure
Authors: Pugsley Alfred
Published: July 2016

The Fifty-Fourth Wilbur and Orville Wright Memorial Lecture, “The Well-Balanced Structure”, was given by Sir Alfred Pugsley, OBE, DSc, FRS, HonFRAeS, on 9th December 1965 in the Lecture Theatre, 4 Hamilton Place, London W.I. The Chair was taken by Sir George Gardner, KBE, CB, HonDSc, HonFRAeS, President of the Society, who opened the meeting by expressing the sympathy of the Society to their colleagues in America on the death of Dr. Hugh L. Dryden on 2nd December; not only was he a distinguished man in his own country but he was a close friend of many in this country and an Honorary Fellow of the Society.

As has become the custom, the Society's main awards for the year were presented before the lecture. The presentations were made by the President and the citations were read by Mr. A. D. Baxter, MEng, FRAeS, President-Elect; the scrolls of three Honorary Fellowships and of two Honorary Companionships, and nine medals were presented. (The names of the new Honorary Fellows and Honorary Companions and the list of awards, with their citations, were published in the December 1965 Journal, pages LXXX and LXXXI.)

Introducing the Lecturer, the President said that the year of the Wright Brothers’ first flight had been the year of birth of a number of people who had made great contributions to the development of aeronautics; one of these was Sir Alfred Grenvile Pugsley. He obtained a first class honours degree in engineering of London University and then trained as a civil engineer and Student apprentice at the Royal Arsenal, Woolwich; there could be no doubt about his full qualifications as a “chartered engineer” according to the new standards. In 1925 he joined the design and research staff at Cardington working on the R101 and not only had he played his part in the design of various parts of the airship's structure, he had also taken part in the full speed trials of the airship. In 1931 Sir Alfred joined the scientific staff of the Royal Aircraft Establishment and worked on structural problems, particularly in the field of aeroelasticity. From 1941 to 1945 he was head of the Structures and Mechanical Engineering Department at Farnborough.

He was appointed Professor of Civil Engineering at the University of Bristol in 1945 and was Dean of the Faculty of Engineering from 1951-54, and Pro-Vice-Chancellor from 1961-64. Sir Alfred had acted successively on the Councils of the Royal Aeronautical Society, the Institution of Structural Engineers, the Institution of Civil Engineers and the Royal Society, and was President of the Institution of Structural Engineers in 1957-58. He was Chairman of the Aeronautical Research Council from 1952-57 and was a member of the Advisory Council for Scientific Policy from 1956-59. He was knighted in 1956 and was made an Honorary Fellow of the Society in 1963.
On the Aerodynamics of “Hangar” Type Engine Test Facilities
Authors: Wallis R. A. , Ruglen N.
Published: July 2016

The present aerodynamic study of “hangar” type engine test cells originated with a request for assistance following difficulties experienced in the commissioning of a Dart engine-test facility. The major improvements obtained resulted from a systematic programme aimed at understanding the basic problems involved. Extensive use was made of model techniques during this investigation.

Detailed flow studies in two other hangar type cells, in successful operation, disclosed certain vortex features which were common to all three cells. Hence in view of a dearth of information on the aerodynamics of such cells, it was decided to deal with the general design problem and to sup-port the study with selected results from the experimental work referred to previously.
An Investigation of Hovercraft Wavemaking
Authors: Hogben N.
Published: July 2016

The main purpose of the investigation has been to clarify the definition of hovercraft wavemaking resistance and to improve understanding of the physical mechanism. The most literal definition of wave resistance as the force which makes the waves is proposed and its practical and theoretical implications are considered. Various interim accounts of this work have already been written, but the time now seems appropriate to assemble and review the overall picture which is emerging.

The pattern of forces on a hovercraft over water is often difficult to analyse because of the complicated interaction between wavemaking, jet air momentum, cushion pressure, wetting and other effects. It is important, however, in making power predictions that the physical interpretation and corresponding scaling laws of the various forces should be understood. A significant feature of the present approach is that a positive and unambiguous basis for identifying the wavemaking force is offered and compared with theoretical predictions. This force, according to the definition proposed, is assured a proper compliance with the physical laws which govern the waves generated and the corresponding scaling and interference effects, which are predicted by theory.
The Momentum Equation—for a Static Hovercraft at Zero Incidence
Authors: Alexander A. J.
Published: July 2016

Simple theory for calculating the pressure beneath a hovercraft is well known, see for example ref. 1. Of the two results, and , the former is usually preferred on the grounds of simplicity since over a large range of jet thickness/height ratios the difference between the two results is negligible. For large values of t\h the latter equation is preferred since it tends to a possible limiting value, i.e., whereas in the former equation. This latter is a consequence of one of the basic assumptions, i.e. that and since in the limiting case h=0 there can be no jet, then However, neither equation can be regarded as valid for x > 1 since for this condition a constant jet thickness equal to the slot width t cannot be maintained. In practice what happens in this condition (x > 1) is that the rate of mass flow in the jet is reduced.
The Rates of Change of the Eigenvalues of a Lambda Matrix and their Use in Flutter Investigations
Authors: Woodcock D. L.
Published: July 2016

Consider a lambda matrix F(ƛ, δ). This may, for example, result from the equation of motion of a dynamical system, δ being a measure of the magnitude of some possible modification to the system or some other variable parameter. Let λ be an eigenvalue and p’ and q the corresponding left hand and right hand eigenvectors. Then

One wishes to determine the derivatives of ƛ with respect to δ. Expressions for the first two derivatives will be obtained on the assumptions that F is simply degenerate and that ƛ is not a repeated root.
Initial Flow in the Entrance of a Straight Circular Pipe
Authors: Gillis J. , Shimshoni M.
Published: July 2016

A solution of the problem of the initial flow in the entrance region of a pipe has been given by Atkinson and Goldstein. In this note the authors compute this solution in greater detail, and compare their results with those of Atkinson and Goldstein. The range of the validity of the solution is shown to be smaller than originally thought.

Atkinson and Goldstein considered the equations for the steady flow of an incompressible viscous fluid into a straight circular pipe of radius a. The flow is supposed to have axial symmetry, u being the velocity component parallel to the axis x, and v the radial velocity. The, distance from the axis is denoted by r.
A Career in the Aerospace Industry
Authors: Ewins P. D.
Published: July 2016

As I come to the end of five years’ training as an Aeronautical Engineer, several thoughts come to mind, both about my training up to the present time and the future of the aerospace industry in which I am about to serve.

During the past ten years, the aerospace industry has seen many changes, not only in the form of amalgamations and project cancellations, but also in the way it must face the future. More recently it has seen the publication of the Plowden Report with all its implications. Although for many the future paints a gloomy picture, at no time has the thought of leaving the world of aeronautics been farther from my mind than it is now.
Shear Stiffness of Sandwich Panels A Review of Test Methods
Authors: Grayley M. E.
Published: July 2016

For the analysis of sandwich panels it is necessary to know the shear and flexural properties of the sandwich. For some of the more common sandwich constructions theoretical solutions exist. However, in the majority of cases, it is necessary to determine these properties experimentally. This note, based on work done for the Royal Aeronautical Society's Structures Committee in which the major British aircraft companies interested in this subject were consulted, describes and evaluates the various test methods commonly in use. Particular reference to the accuracy of results obtained and to the relative economics of the test methods is made.
A Tapered TRIM 6 Element for the Matrix Displacement Method
Authors: Argyris J. H.
Published: July 2016

The success achieved in wing analysis and related problems through the introduction of triangular elements with six nodal points and a prescribed linearly varying strain or stress, naturally raised demands for a further sophistication in the idealisation process by triangularisation. In this context a practically important extension is concerned with the influence of taper in the thickness. We reproduce in what follows the theory for the special case of linear type. The paper may be considered as a generalisation of notes 2 and 3 of this series. However, the analysis is here based on the non-dimensional homogeneous triangular co-ordinates introduced in note 5, which simplify the argument considerably. A significant broadening of the applicability of the new element will be given in notes 9 and 10.
A note on Turbulent Skin Friction measured with a Preston Tube
Authors: Patel Rajni P.
Published: July 2016

In 1954, Preston introduced a new concept of skin friction measurement in turbulent flows by using a surface pitot tube. Since then considerable controversy has risen in the use of Preston tubes for skin friction measurements. However, Head and Rechenberg investigated Preston tubes extensively and confirmed the validity of the Preston tube method. Recently Rajaratnam has given a theoretical calibration curve for the Preston tube using logarithmic velocity distribution for the boundary layer velocity profile.
A Note on the Improved Displaced Frequency Method Applied to Dynamical Systems Having a Pair of Equal Frequencies
Authors: Simpson A.
Published: July 2016

In applying the numerical correction method to the case where two natural frequencies of the system under test are equal, it is necessary to ensure that the matrix

is diagonal in order to eliminate singularities. (In this equation δA is the displaced mass matrix; is the partitioned matrix containing the two modal columns appropriate to the equal frequencies and β is a transformation matrix (2 x 2), chosen to ensure that δαb is diagonal.)