bluuebunny/crossref_metadata_2025 huggingface dataset:
The tip flow of a part span slotted flap
Authors: Willmer A. C. , Barrett R. V. , Coleman J. D.
Published: July 2016

The work to be described forms part of an experimental study into the overall influence that the end region of a flap has on the flow of a high lift wing system. Here, our attention will be restricted mainly, but not entirely, to the tip flow of the flap itself.

The study has been a collaborative venture over the past three years between British Aerospace-Civil Aircraft Division and the Aerospace Engineering Department of Bristol University, the latter funded by an SER.C research grant. BAe's major contribution was the undertaking of the main test programme, with University participation, using a large swept wing, high lift half model in the Filton low speed wind tunnel. The model was loaned by RAE for the study.
Strain Rate Changes During The Tensile Test
Authors: Penny R. K.
Published: July 2016

Rates of straining that are met in various engineering parts vary considerably from the very small values appropriate to creep to those amounts many orders of magnitude higher that are necessary during metal working processes. If laboratory testing is to follow the ideas of Taira on creep or McLellan on the effects of strain rate on the Ramberg-Osgood constituitive relationships it is necessary to enquire whether conventional testing procedures are adequate. Bodner and Rosen have shown that the phenomenon of discontinuing yielding is solely a function of a testing procedure which allows strain rate changes because of the interaction of specimen stiffness changes and the machine stiffness.
Recent Evolution in Problems and Methods in Aerodynamics
Authors: Germain P.
Published: July 2016

The Tenth Lanchester Memorial Lecture “Recent Evolution in Problems and Methods in Aerodynamics” was given before the Society on 11th May 1967 by Professor Paul Germain, Director General of ONERA. The Chair was taken by the President, Mr. M. B. Morgan, CB, MA, CEng, FRAeS.

Opening the proceedings the President said that they had had a memorable series of lectures in memory of that great man Lanchester and at many of them it had been a great pleasure to have with them his widow, and his brother Mr. George Lanchester and his wife. They were delighted to have them present that evening.

They were fortunate to have as their lecturer Professor Germain, a distinguished French Scientist. It was particularly appropriate that their lecturer should come from France when Franco-British aeronautical ties were already close. Professor Germain was well known to the aeronautical research fraternity. Born at St. Malo in 1920, after graduating in Paris he joined ONERA and later became Professor at, first, Poitiers, then Lille and Paris. Since 1962 he had been Director of ONERA. His theoretical work in the transonic and supersonic aerodynamics fields was well known and they also knew him well personally because he had paid numerous visits to research centres in this country.

Professor Germain was France’s National delegate to AGARD and Mr. Morgan knew from personal knowledge the intense interest Professor Germain had taken in that international organisation. He held an Honorary Doctorate from Louvain University, was a Correspondent of the Academy of Sciences, Paris, a Fellow of the American Institute of Aeronautics and Astronautics, a Foreign Honorary Member of the American Academy of Arts and Sciences and a member of the International Academy of Astronautics.
Buckling and Vibration of Triangular Flat Plates
Authors: Lockwood Taylor J.
Published: July 2016

Summary:—

Simple exact solutions have been tound for the modes of buckling or vibration of an equilateral triangular plate with supported edges. They may be classified as 1 (a)—modes symmetrical about all three medians, 1 (b)—modes symmetrical about one median, 2—modes anti-symmetrical about one median. Mode 2 obviously also covers the modes for a 60° right-angled triangle forming one half of the equilateral triangle. The frequency for each mode of type 2 duplicates that for a corresponding mode of type 1(b).
Technological Progress and the Airlines
Authors: Shaw R. R.
Published: July 2016

One of the few privileges the public lecturer has is to divide all mankind into two classes according to his prejudices, and this I intend to do: on the one hand those restless souls who constantly strive for innovation and change; on the other the great mass of humanity who resist and even resent any disturbance of the even tenor of their ways.

The first fish-like beast that crawled out of the primeval swamp on to land must have had something of this spirit of change and adventure. And from the dawn of history the rare men with these characteristics have provided the leadership and sparked the changes that have been at the heart of human progress.
Comments on “Transient Temperatures and Thermal Stresses in an Idealised Wing Structure“
Authors: Johns D. J.
Published: July 2016

In ref. 1 an analytical solution was given for the one-dimensional distribution of temperature in a web of an idealised, symmetric, multi-cell wing structure when symmetrically heated. It was assumed that the convective heat transfer coefficient, h, was constant, but the adiabatic wall temperature variation was assumed to be either an instantaneous or a linear function of time.

The purpose of the present paper is to indicate the application of an alternative, approximate method of heat flow analysis due to Biot and to show thereby how the usefulness of the results in ref. 1 can be extended by eliminating the assumption therein that the skin temperature was uniform at any given time. The notation of ref. 1 is used with additions as defined in the paper.
The Use of a Hot-Wire Anemometer in Turbulent Flow
Authors: Hoole B. J. , Calvert J. R.
Published: July 2016

The hot-wire anemometer is one of the few instruments which can be used to make velocity measurements in turbulent and unsteady flows. However, the probe supporting the wire inevitably interferes with the local flow and it has been found that the effect of this interference on the reading of the anemometer varies considerably as the orientation of the probe to the flow direction is changed (the wire itself being maintained in the same direction). This leads to errors in any measurements taken where the instantaneous local flow direction differs significantly at any time from the direction for which the anemometer was calibrated. Such errors are quite separate from, and in addition to, errors due to finite wire length, incidence of the wire to the local stream direction, etc.
The Study of a Single Degree of Freedom System with Time Dependent Parameters
Authors: Dasarathy B. V. , Srinivasan P.
Published: July 2016

The equations of motion of many mechanical systems reduce to ordinary differential equations with time dependent parameters. A single degree of freedom system, with the damping and restoring forces varying with time according to the law … m (t+k)nhas been studied using the WKBJ approximation. The general solution of the differential equation can be used to arrive at the response of such time dependent systems, subjected to excitations which are specified to be of either deterministic or stochastic nature.
Handling Criteria
Authors: O'hara F.
Published: July 2016

The nature of handling criteria and their uses in relation to the prediction of aircraft handling characteristics are discussed. A brief history is given of the development of ideas on handling, and a survey is made of criteria for modern aircraft, looking particularly at the physical factors affecting the pilot, as an indication of the basis of the criteria. The novel handling features arising with new aircraft species like slender wings and VTOL are considered. The scope of flight simulators and variable stability aircraft for systematic study of handling is discussed and the potentialities of theoretical study by means of servo analysis techniques considered. Finally, possible lines of development in relation to the assessment of aircraft handling characteristics are suggested.
A Thin Aerofoil of Small Camber in a Non-Uniform Flow
Authors: Nigam L. N.
Published: July 2016

The direct problem of aerodynamics (profile of the aerofoil is given—calculate the aerodynamic characteristics) has been studied for thin aerofoils with small camber. Given the undisturbed stream function

V, ω, α being the constant velocity, vorticity and angle of incidence respectively, the pressure distribution, lift coefficient and pitching moment have been calculated for a general profile.
On the Flow Past a Circular Jet Exhausting at Right Angles from a Flat Plate or Wing
Authors: Wooler P. T.
Published: July 2016

In recent years there has been considerable interest in the possibility of providing high speed aircraft with the capability of vertical or short take-off and landing (V/STOL). One method for achieving V/STOL is to use lifting engines or fans, the aerodynamic interference effects of which are not yet fully understood. Experimental work on this problem has been done by Jordinson, Otis, Vogler and research workers at the British Aircraft Cor-poration, but no satisfactory theoretical analysis is known. The object of this paper is to put forward a semi-empirical method for predicting the aerodynamic interference of an exhausting jet on a uniform mainstream flow past a wing.
Beryllium
Authors: Leadbeater C. J.
Published: July 2016

Beryllium is a metal possessing some attractive properties for aerospace applications, but its advantages are offset by the present inability to achieve acceptable isotropic ductility, by the high cost of the fabricated metal and by the special health precautions required for workshop treatments and handling.

Considerable research and development have been applied to the technology of beryllium during the past decade and comprehensive data are available in books and the proceedings of international conferences held in London, Gatlinburg, Philadelphia and Grenoble. Outstanding among the various problems discussed have been modes of deformation and fracture, the efficiency of various methods of purification and the influence of increased purification on the behaviour of the metal.
Wire Reinforced Metal Composites
Authors: Forsyth P. J. E.
Published: July 2016

The strength of a composite material will depend sensitively on that of the fibre chosen for reinforcement. Metallic and non-metallic whiskers can be very strong and other less strong, but more practical, fibres such as carbon, silica and boron are now available in experimental quantities. Some of the non-metallic whiskers, and the last three fibres mentioned, will no doubt eventually be made on a production scale.

The strongest drawn wires yet available have tensile strengths of more than 0.5 X 106 psi which is still only one-third of that of iron or sapphire whiskers, and compares with boron in filament form, although the specific strength of the steel wire would only be one-third of the latter. On the basis of specific strength drawn beryllium wire would be only slightly better than the steel, but would have about 6 times its elastic modulus (E) which is comparable to that of boron.
Production of Shear Profiles in a Wind Tunnel by Cylindrical Rods Placed Normal to the Stream
Authors: Cockrell D. J. , Lee B. E.
Published: July 2016

The production of required velocity profiles in a duct or wind tunnel is a necessary part of much research aimed at understanding fluid behaviour. Perhaps the most obvious application is the simulation of wind gradients for the study of wind effects on structures, but equally important is the study of diffuser and duct behaviour when subjected to a variety of known and convenient velocity profiles. Furthermore, the effects of the variation in turbulence characteristics within a range of identical velocity profiles produced by different methods are not clearly understood.
Post First World War
Authors: Fell L. F. R.
Published: July 2016

I returned to England in February 1919 to take over the duties of Assistant Director of Research and Development (Engines) under Brigadier-General Brooke-Popham, who was appointed Director of Research about the same date.

At that time it was anticipated (correctly) that there was no danger of another major war for at least ten years and the staffs of the Royal Air Force and the Air Ministry were cut down drastically to suit. The Engine Research and Development departments which had employed many hundreds during the war were reduced to about a dozen people. While this was being done the engine position as it existed was being examined. It soon became obvious that none of the engines which had been in production during the war were suitable for further development to meet the requirements of the 1920's.
Effects of an Initial Gap on the Flow in a Turbulent Wall Jet
Authors: Sridhar K. , Tu P. K. C.
Published: July 2016

The flow in a two-dimensional plane wall jet with different initial gaps between the nozzle exit and the leading edge of the wall was probed at various stations along the jet. The jet slot thickness and the velocity were kept constant. It was found that the region close to the leading edge of the wall behaved like a transforming region where the type of flow changed from a free jet to a wall jet. The length of this region, which depended directly on the gap size, was so short for small gaps that the gap effects were found to be negligible. In addition, it was found that the inner layer velocity distribution of a wall jet did not follow the classic one-seventh power law.
The Use of Wind Tunnels in the Study of Problems in Industrial Aerodynamics
Authors: Collar A. R.
Published: July 2016

I am going to restrict myself to consideration of those problems which arise from the natural wind, and I am going to begin—and perhaps also to continue—with what may be, to paraphrase one of our Chairman’s expressions, some offensively simple . considerations. I do this because, in our studies of industrial aerodynamics, we are increasingly applying the sophisticated techniques developed from years of aircraft aerodynamics; and there is always a danger that, unless we go back to fundamentals, we may invoke a theorem or technique from aircraft practice which is inappropriate for an industrial problem. First of all, therefore, I shall go back to square one.
Twenty Years of Guided Weapons
Authors: Smith T. L.
Published: July 2016

In a general survey of the Guided Weapon scene over the past twenty years, in the space available, it is not possible to be comprehensive, nor may it be desirable. It is necessary, however, in order to set the background, to go back to early work before the period under review.
Plowden and the Man in Industry
Authors: Davies S. D.
Published: July 2016

This article is intended to examine the Plowden Report as it affects the man in industry—is there a future for him, where will he go and what should he do? This is obviously a matter of vital importance to members of our Society and it is hoped that what follows will be constructive, although it is written in the atmosphere of an impending General Election with an apparent hiatus in any constructive thinking in Government circles on the matters which affect us most.

The appointment of the Plowden Committee was regarded by many people in the industry as an earnest of the Government's intention to end the waffling and indecision which has plagued us for many years.
The Application of Dynamic Programming to the Design of Invariant Auto-Stabilisers
Authors: Dyer P. , Noton A. R. M. , Rutherford D.
Published: July 2016

In the past decade considerable attention has been given to the possibility of using self-adaptive control systems to cope with the problem of providing stability augmentation to aircraft over extended flight envelopes. On the other hand, it has sometimes been considered that insufficient attention has been given to the design of autostabilisers with fixed parameters. The authors have applied recent developments In dynamic programming to the design of aircraft autostabilisers. The methods provide a highly systematic approach to the design of multi-loop systems which is especially useful for control of the lateral mode. Furthermore, the resulting optimum multiple feedback coefficients vary little throughout the flight envelope and the use of fixed parameters for the whole of the flight envelope appears to be possible. Aerodynamic data for two aircraft were used: a supersonic VTOL aircraft and a supersonic transport.
Body-Wing Interference at Supersonic Speeds
Authors: Phythian J. E.
Published: July 2016

A summary of available information on the problem of body-wing interference in supersonic flow has shown, inter alia, that a large number of theoretical methods are available for the prediction of interference characteristics. Many of these methods are chiefly concerned with the estimation of overall characteristics,i.e.normal force and pitching moment. Several methods are available to determine the pressure distribution for restricted types of configurations, but these often involve lengthy computation.

It is the aim of this paper (Part I) to summarise a simple yet reasonably accurate method of estimating the pressure distribution and hence (in Part II) the overall characteristics of as general a body-wing configuration as possible. The method which applies essentially to a cropped-delta wing symmetrically mounted on a cylindrical body, achieves reasonable accuracy without considerable computational effort; it is based on certain theoretical results together with empirical modifications. The results for pressure are generally valid up to an angle of incidence, α=6° —8° and in some cases for higher values of α. The overall normal force and centre of pressure position should hold up to α= 10°.
The Present Situation The State of Affairs in the Royal Air Force
Authors: Nance C. T.
Published: July 2016

Over the past ten years the RAF has cost the country an average of some £500 m per year. Of this sum about £200 m has been spent with the aircraft and electronic industries, of which about half has been for new aircraft and weapons, the remainder being needed for spares, modifications and ground equipment. A further £200 m is expended on service and civilian manpower, the majority of whom have been employed on the maintenance of technical equipments or are needed to provide direct support for personnel so employed. Thus we have a situation where something like £200 m a year—almost half of the total budget—is spent upon maintenance.

As the cost of modern weapons systems needed to achieve the necessary operational performance is increasing rapidly, the front line strength of the Royal Air Force will be weakened unless substantial savings in these maintenance costs can be made, and this in the face of increasing complexity of aircraft equipments.
The Safety and Reliability of Complex Systems
Authors: Lloyd E.
Published: July 2016

I Would like to describe an approach which is being made by the Air Registration Board to the Safety of complex systems such as those used in automatic landing, or in supersonic and other advanced aircraft, since I believe that these methods may have a further application in the assessment of aircraft reliability.

Airworthiness Requirements can be considered to be of two kinds. There are empirical requirements based on engineering interpretation of past experience, and there are those which stem from a selected level of safety and which involve consideration of probability of occurrences. This paper is concerned with the second kind since it is relevant to the consideration of reliability.
Lessons from Engine Experience
Authors: Bowling A. G.
Published: July 2016

First let us look at the history of our engines’ reliability. Fig. 1 shows the reliability in terms of unscheduled removals per 1000 hours and in-flight shut-downs for four Rolls-Royce civil engines since the time of their introduction into service.

It is significant that the general trend is similar and particularly, that after the initial years settling down period, the level of reliability defined in this way has stayed almost constant, despite considerable increases in overhaul life and, for the Dart, great increases in power output as later types of engine were produced.
Elasto-plastic Matrix Displacement Analysis of Three-dimensional Continua
Authors: Argyris J . H.
Published: July 2016

The author presented in his recent main lecture to the Society, “The Computer Shapes the Theory”, a number of novel developments in the matrix displacement method. Since the publication of the lecture and discussion will inevitably be delayed and cannot but illustrate the application of the new ideas on a series of examples, he has been repeatedly urged to summarise some of the more important theoretical contributions in the form of Technical Notes. The first deals with the elasto-plastic analysis, in the presence of strain hardening, of arbitrary three-dimensional configurations. The reader is assumed to be familiar with the corresponding elastic analysis given in refs. 2 and 3, where the medium is represented by a suitable assembly of tetrahedra under constant stress and strain. The corresponding two-dimensional case is investigated on the basis of triangles. Arbitrary anisotropic behaviour and large displacements were also included in refs. 2 and 3.
A Brief Note on the Effect of an Offset Thrust Line on the Longitudinal Static Stability of an Aeroplane
Authors: Tomlinson B. N.
Published: July 2016

If the thrust line of an aircraft does not pass through the centre of gravity, the offset will introduce a pitching moment whose variation with speed and incidence perturbations will affect the stability characteristics of the aeroplane. Both Duncan and Etkin discussed the influence of the propulsive system on longitudinal static stability, but Duncan's analysis for an offset thrust line is not correct and Etkin restricted consideration of thrust effects on static stability to angle-of-attack disturbances at constant speed. The following remarks have been written, therefore, to clarify the effect of an offset thrust line on an aeroplane's static stability. Consideration is first given to what is meant by static stability, and then the part played by the thrust term is examined.
Application of Time-Resolved Interferometer to Shock-Tube Performance Studies
Authors: Johannesen N. H. , Zienkiewicz H. K.
Published: July 2016

Rotating-Drum (or mirror) cameras have often been used in conjunction with schlieren apparatus to investigate the performance of shock tubes. In the conventional arrangement the working section is viewed through a slit parallel to the axis of the tube, which is also parallel to the drum axis. The photographic record obtained on a film attached to the drum represents the distance-time (x, t) diagram of the propagation of (density) disturbances in the working section. The quantitative information obtainable from such records is usually limited to the speed of propagation of such disturbances.
An Empirical Formula for Stagnation Point Velocity Gradient for Spheres and Circular Cylinders in Hypersonic Flow
Authors: Topham D. R.
Published: July 2016

When stagnation heat transfer rates are expressed in terms of free stream flow properties, the following combination of terms is found to occur: —

where ps pressure at the stagnation point

p∞free stream pressure

U∞free stream velocity

Dnose diameter

ßstagnation point velocity gradient.
Assessment of Thermal Fatigue Resistance of High Temperature Alloys
Authors: Barnes J. F. , Tilly C. P.
Published: July 2016

This note is concerned with the significance of a “hold period” on thermal fatigue endurances and on the use of a frequency exponent to correlate the results of mechanical fatigue tests at various temperatures.

In their note in the January 1965 Journal (pp. 53-55), Coles and Skinner quite rightly pointed out that residual stresses, set up as the result of plastic yielding in compression during an initial heating period, will undergo redistribution during a subsequent “hold period” at an elevated steady temperature. However, it is important to note that the redistributed stress pattern and the associated creep strains at the conclusion of the “hold period” will depend very much on the nature of the applied loading. For example, the compressive strain and the associated tensile stress set up in the rim of the disc will both fall in magnitude if the disc is not rotating and may reach infinitesimal values if the “hold period” is long enough.
Free Vibrations of a Circular Plate
Authors: Gajendar N.
Published: July 2016

The Free and damped vibrations of a circular plate with given initial conditions, which is either free or elastically restrained along its outer edge, are discussed using the method developed by Reid and some numerical results are also given.

The vibration of a circular plate has been studied considerably and most of the authors seem to be interested in determining the frequencies of vibration and the nodal patterns. A few investigators have studied the problem of determining the subsequent motion of a thin plate started with some given initial displacement or velocity. Sneddon has attempted this problem, taking into account an approximate boundary condition. Recently Reid has discussed this problem without taking recourse to any approximate boundary condition. He has developed a method of analysis to determine the displacement of a freely vibrating thin circular plate with the given initial conditions, using the norm of the eigen functions.
A Theoretical Calibration Curve for the Preston Tube on Smooth Boundaries for Larger Reynolds Numbers
Authors: Rajaratnam N.
Published: July 2016

Of the Several Methods available for the measurement of boundary shear, the simplest is perhaps the Preston tube. It is a total head tube resting on the boundary for which the difference between the dynamic pressure on the tube and the static pressure on the boundary is correlated with the boundary shear. It was evolved by Preston in 1954 mainly from similarity considerations and the existence of the wall law. In 1955, Hsu obtained Preston's original calibration curve theoretically for the one-seventh power law. In this note, a theoretical calibration curve is developed for the logarithmic law which describes the velocity distribution for larger Reynolds Numbers.
A Correlation of Leading Edge Transition and Heat Transfer on Swept Cylinders in Supersonic Flow
Authors: Topham D. R.
Published: July 2016

Summary:—

It is shown that stagnation line heating rates for laminar, transitional and turbulent boundary layers measured on swept cylinders at supersonic speeds, can be correlated in terms of a Reynolds number based on the spanwise momentum thickness at the stagnation line.

A critical Reynolds number for transition along the stagnation line is determined and experimental results show evidence of transition up to M= 10.
Generalised Single Component Insulation Requirement for the Hypersonic Glide
Authors: Baxter Bruce E. , Arthur Paul D.
Published: July 2016

Ablative cooling is a proven, reliable thermal protection method for entry vehicles with zero to moderate hypersonic lift/drag ratio. Unfortunately, this method becomes impractical for vehicles with lift/drag ratios greater than about 1-0, because of the severe weight penalties which accrue from long glide times and the large surface areas associated with high LID configurations. Moreover, to obtain high hypersonic LID it is necessary to minimise blunting of the nose and leading edges, a condition certainly present when ablation is used to protect the leading edges. This situation is commonly handled by the design of a high temperature radiation cooled structure of refractory metal with supplemental insulative protection in the stagnation region along the leading edges and in areas of local heating such as those resulting from shock impingement. This insulation may take the form of a high temperature foamed ceramic such as zirconia foam.
A Time of Transition
Authors: Rowe N. E.
Published: July 2016

This is a great occasion; I feel quite unworthy to do justice to this commemoration of a great man and a revolutionary event and to become one of the illustrious band who have so graced this occasion in the past. For the more one reads about the Wrights' achievements, the more one is impressed by them as men of stature—of great character, determination and intellectual strength with a most endearing modesty. They had too, such a sense of fun and there is a golden thread of family affection running all through the record. They were men of vocation just as their father, Bishop Milton Wright, and there is no doubt of the influence of the family ties on what they did. One senses how much home meant to them and how much they all turned to Katharine, the womanly stabilising element. A comment of Wilbur's in one of his letters to George Spratt commenting on a technical argument they had been having, is very revealing. "It is a characteristic of all our family to be able to see the weak points of anything", a vivid hint of most lively family discussions, and of course, this most rare combination of brothers must have been a fundamental element in all their work.
Aeronautical Research and Development in the Commonwealth
Authors: Woodward-Nutt A. E.
Published: July 2016

“Tadpole and Taper were great friends. Neither of them ever despaired of the Commonwealth.” Disraeli—“Coningsby”.

In looking through the list of British Commonwealth Lectures one finds that the great majority deal with the work or problems of a particular country. There are few which deal with the Commonwealth as a whole, the outstanding exception being the remarkable paper on Aviation and the Development of Remote Areas given by H.R.H. the Duke of Edinburgh in 1954.
The Prone Pilot Position
Authors: Cansdale Roger
Published: July 2016

When Man first dreamt of flying, he most probably envisaged himself soaring through the air with wings on his arms, and his legs trailing behind him like a bird's. This mental picture quite likely influenced a good deal of his early aeronautical thinking and it is a curious fact that even in comparatively recent years a number of the more bizarre aircraft have incorporated a prone pilot position as if the designers, having abandoned orthodox practice, had also reverted to what perhaps seemed a more natural position.
Efficiencies, Thermodynamics and the By-Pass Engine
Authors: Pearson H.
Published: July 2016

I Think Mr. Filleul's main point, (in the November Journal) somewhat hidden behind some obscure comments about Carnot engines and the like, is that in a by-pass engine with heat exchanger, the heat exchange process is making a definite alteration to the thermodynamic cycle efficiency of the whole engine and not just changing the propulsive efficiency. This may or may not be an important point, depending upon the point of view of the expositor of the subject. In fact, even without heat exchange and when the by-pass compressor and turbine have realistic efficiencies, the by-pass process itself does alter in an unfavourable direction the overall thermodynamic cycle efficiency. This is one reason why in a by-pass compressor with separate jets one does not wish to make for optimum performance the by-pass and jet velocities equal.
Tyre Design Considerations
Authors: Hughes A. J.
Published: July 2016

In the past ten years or so a number of changes have taken place in aircraft which have progressively reduced the potential tyre life and tend therefore to increase the operational cost. We now see that the latest aircraft have developed to such a stage that there is a certain hazard in stopping them on wet or slush covered runways. To ease this situation, further changes are recommended to the tyres, likely still further to reduce tyre life.
Heat Transfer to a Jet of Air Impinging Normally on to the Inside Surface of a Hot Smooth Tube
Authors: Mountain A. R. , Barnes J. F.
Published: July 2016

This investigation has been concerned with heat transfer between a jet and the inside surface of a circular cylinder whose axis was normal to the jet axis. Such a jet system could be used to direct cold air on to the inside surface of a sheet metal nozzle guide vane in a gas turbine engine. As will be seen later high rates of heat transfer can be obtained in the vicinity of the point of impingement, so that this method of cooling could be particularly valuable for reducing the temperature of a “hot spot.”
Eigenvalue Economisers in Vibration Problems
Authors: Irons B.
Published: July 2016

A Matrix Eigenvalue Calculation is rich in information content but expensive in computer time. This is why, in a typical vibration problem, there are many more elements than masses, or rather, many more elementary deflections than degrees of freedom for vibrations.
The Manufacture of Aerofoil-Section Blades for use in a Cascade
Authors: Clayton B. R.
Published: July 2016

A method is described by which blades of aerofoil section can be manufactured on a laboratory scale. Emphasis has been placed upon cheapness, rapid production, and the ability to obtain an accurate representation of the blade profile for a large aspect ratio of 3·5. In addition, for a series of experiments with a cascade in water, the blades were to be made from a material which did not require the use of a protective paint on the surfaces. To satisfy the above requirements a casting process was adopted, and the blades were made from a plastic resin material. Although the discussion presented is confined to the production of blades, the method can easily be extended to the manufacture of impeller hubs, fairings, nozzles, and so on.
Snap-Through Buckling of Thin Arched Ribs
Authors: Creighton A. J. , Tee R. S.
Published: July 2016

Structural failures have been experienced recently in some panels of relatively thin plating, dished to about twice the plating thickness, and failure has been attributed to snap-through buckling.

Snap-through buckling may be defined as the lateral instability of a dished panel when loaded on the convex side. (Such an effect js frequently observed in the lids of biscuit tins.)
From Ship-Accompanying Waves to Shock Waves of Supersonic Aeroplanes
Authors: Legendre Robert G.
Published: July 2016

When I was invited to deliver the Lanchester Memorial lecture, I wondered why the great honour of being the first Frenchman selected for the celebration of the deeds of a great engineer was conferred on me. However, I am well aware that the Council of the Royal Aeronautical Society cannot make a mistake and there is good reason to choose, after so greatly famed professors, an engineer of the French Navy to illustrate, using a slightly different point of view, the influence of Lanchester on the development of aeronautics. This way, I do not have to apologise for a possible inadequacy which then would not be my own responsibility. I have only to do my best, so as not to betray the confidence of the Society.

Answering so plainly this first question, I had to find out how to fulfil my task. Possibly, my contribution to the intrepretation of the vortex sheets starting from the thin leading edges of a delta wing is more in the Lanchester line of thought than it is an extension of Prandtl’s inferences.
Two-Dimensional Photoelasticity as a Method of Approximation to the Stresses in Three-Dimensional Problems with a Plane or Axis of Symmetry
Authors: Meyer M. L. , Oak A. N.
Published: July 2016

The fundamental advantage of two-dimensional photoelasticity is its great simplicity. Neither the frozen-stress three-dimensional method nor the photoelastic layer technique share this simplicity as yet. Whereas the frozen-stress and layer techniques are most suitable for final investigation into the strength of a finished design, the simple plane photoelasticity can be used as a tool by the designer at every stage of his design, as a specialised slide rule, so to say, that gives sometimes faster and frequently more accurate answers than complicated stress calculations. The consequences of given changes in the outlines of a component can often be studied more conveniently and cheaply by this method than by almost any other.
Structural Weight Estimations for Novel Configurations
Authors: Burt M. E.
Published: July 2016

The aims of structure weight estimation are discussed and a review is given of its development in this country during the past fifty years from the simplest of formulae to quite detailed methods. The limitations of formulae derived only from statistical analysis of actual aircraft structures are noted. For aircraft of novel configuration it is essential for the weight of the basic load-carrying structure to be estimated by methods which are based upon the actual design and stressing procedures. The principles of “optimum” or “minimum-weight” structural design are a valuable feature of such methods and are briefly described. Statistical analysis, however, is still important for estimating the substantial weight of the joints, cutouts, transparencies and other features which transform a theoretical optimum structure into a complete and practical one. The problems of several aeroplane and missile configurations of current interest are discussed, and also the extent to which detailed design work is necessary to provide reliable structure weight estimates for such projects.
Fluid Flow Through Screens of Low Solidity
Authors: Morgan P. G.
Published: July 2016

The general problem of the flow through screens has been widely studied, but certain difficulties have arisen in the comparison of screens of various solidities. A theoretical treatment and some experimental work on the flow through screens of low solidity are described below.
The State of the Art in Management Education Applicable to Aerospace Activities
Authors: Major E. R.
Published: July 2016

Management Education in the Air Corporations is based largely on the Air Transport Staff College, East Burnham. This was originally founded by BEA in 1960; BOAC had a similar establishment at Dormy House, Sunningdale, from March 1963. The two Corporations now share East Burnham on an alternate monthly basis. Up to 35 students can be accommodated.
The ‘Chu-tube’: a velocimeter for use in highly-sheared, three-dimensional steady flows
Authors: Chu J. K. , Rios-Chiquete E. , Sarohia S. , Bernstein L.
Published: July 2016

A velocimeter is described based upon the same principle as the five-hole Conrad tube yawmeter. However it uses a single tube, cut obliquely at 45°, that rotates about its own axis together with an outer closely-fitting concentric tube, cut normal to its axis, that can be slid forward over the mouth of the chamfered tube. The small measuring volume, about 1 mm3, and well-defined measuring point enable the probe to be used with some confidence in regions of high shear. Some typical results obtained with the probe in a highly-sheared, three-dimensional flow are given.
When Aeronautical Science was Young
Authors: Taylor Geoffrey
Published: July 2016

It is Always rather risky to ask old people to talk about what things were like when they were young. Having turned on the tap you may not see how to turn it off again. Fortunately there is a circumstance which keeps this trouble under control. Old people remember a lot of things when there is no call for them to do so but seldom when there is. That is the reason why I have written down most of what I can say for this lecture.

I cannot attempt to give a complete or an objective picture of aeronautical science when I started thinking about it. The best I can do is to describe a few of the things which happened to me in those days to try to convey some picture of our primitive ideas.
Aircraft Engine Developments During the Past Half Century
Authors: Nixon Frank
Published: July 2016

As was said of Richard Trevithick, “Practical men are too apt to leave facts unrecorded”, and this is particularly true of those involved in the development of Britain's aircraft engine industry.

The names of a few people come to mind immediately, but there are others whose contribution has played a crucial yet barely-recognised part in directing the overall trend. In addition there are many others who have filled lesser but vital roles as members of the teams led by the better-known pioneers.

Source-material on which to base an account of the work of Society members is scanty, since the great majority of published papers have preserved that strict anonymity which is indicative of British “team spirit”.
Reminiscences of 50 years in the Field of Aircraft Propulsion
Authors: Fedden Roy
Published: July 2016

Although the greater part of my working life has been concerned with aviation—and particularly with aircraft propulsion—I have never really regarded myself as a dyed-in-the-wool aeronautical pioneer. It has been my good fortune to collaborate with many whose names will long live in the history of aviation, and to have been able to play some part in the development of powerplant engineering over the past half century. I feel honoured, therefore, by being invited to contribute some personal anecdotes and views to the Centenary Issue of the Society's Journal.
Reflections on and Reminiscences of The Royal Air Force
Authors: Roberts Silyn
Published: July 2016

The Royal Air Force came into being towards the end of the 1914–18 War. In the time and space available it is impossible to write anything approaching a full history of it from its inception to the present day. I shall, therefore, only attempt to mention those events which have impressed themselves on my mind as landmarks in the history of the Service.

I shall also endeavour to outline briefly some of the achievements of some of our pilots between the Wars as they illustrate the development of aeroplane performance, followed by a few reminiscences and digressions in an attempt to illustrate the post-War trend.
A Discourse
Authors: Watson-Watt Robert
Published: July 2016

The celebration of an individual human birthday is an almost completely one-sided recapitulation of pleasant experiences in earlier years, together with a warmly optimistic forecast for coming years. This is wholly right and proper, although even here an occasional muted warning is of genuine value.

The celebration of a “technological birthday”, the review of the partial success, through one or more years of operation, of a man-sustained project, deserves notice of the same general type of review, promising further success, warning of potential difficulty, hoping for circumstances and facilities favourable to continued satisfaction, continuously qualified by mention of possible—indeed probable— change in the social climate, for good or ill.
Lipid structure does not modify incorporation of EPA and DHA into blood lipids in healthy adults: a randomised-controlled trial
Authors: West Annette L. , Burdge Graham C. , Calder Philip C.
Published: July 2016

Dietary supplementation is an effective means to improve EPA and DHA status. However, it is unclear whether lipid structure affects EPA+DHA bioavailability. We determined the effect of consuming different EPA and DHA lipid structures on their concentrations in blood during the postprandial period and during dietary supplementation compared with unmodified fish oil TAG (uTAG). In a postprandial cross-over study, healthy men (n9) consumed in random order test meals containing 1·1 g EPA+0·37 g DHA as either uTAG, re-esterified TAG, free fatty acids (FFA) or ethyl esters (EE). In a parallel design supplementation study, healthy men and women (n10/sex per supplement) consumed one supplement type for 12 weeks. Fatty acid composition was determined by GC. EPA incorporation over 6 h into TAG or phosphatidylcholine (PC) did not differ between lipid structures. EPA enrichment in NEFA was lower from EE than from uTAG (P=0·01). Plasma TAG, PC or NEFA DHA incorporation did not differ between lipid structures. Lipid structure did not affect TAG or NEFA EPA incorporation and PC or NEFA DHA incorporation following dietary supplementation. Plasma TAG peak DHA incorporation was greater (P=0·02) and time to peak shorter (P=0·02) from FFA than from uTAG in men. In both studies, the order of EPA and DHA incorporation was PC>TAG>NEFA. In conclusion, EPA and DHA lipid structure may not be an important consideration in dietary interventions.
Tools to Estimate the First Passage Time to a Convex Barrier
Authors: Hammarlid Ola
Published: July 2016

The first passage time of a random walk to a barrier (constant or concave) is of great importance in many areas, such as insurance, finance, and sequential analysis. Here, we consider a sum of independent, identically distributed random variables and the convex barrier cb(n/c), where c is a scale parameter and n is time. It is shown, using large-deviation techniques, that the limit distribution of the first passage time decays exponentially in c. Under a tilt of measure, which changes the drift, four properties are proved: the limit distribution of the overshoot is distributed as an overshoot over a linear barrier; the stopping time is asymptotically normally distributed when it is properly normalized; the overshoot and the asymptotic normal part are asymptotically independent; and the overshoot over a linear barrier is bounded by an exponentially distributed random variable. The determination of the function that multiplies the exponential part is guided by consideration of these properties.
Electronic Foreign-Exchange Markets and Passage Events of Independent Subordinators
Authors: Winkel Matthias
Published: July 2016

We set up a model for electronic foreign-exchange markets, suggesting subordinators to represent sellers' and buyers' offers. Its analysis naturally leads to the study of level passage events. The classical level passage event concerns the joint law of the time, height, and jump size observed when a real-valued stochastic process first exceeds a given level h. We provide an up-to-date treatment in the case when this process is a subordinator, and extend these results to a multivariate setting.
Asymptotic Probabilities of an Exceedance Over Renewal Thresholds with an Application to Risk Theory
Authors: Robert Christian Y.
Published: July 2016

Let (Y

n
, N

n
)
n≥1 be independent and identically distributed bivariate random variables such that the N

n
are positive with finite mean ν and the Y

n
have a common heavy-tailed distribution F. We consider the process (Z

n
)
n≥1 defined by Z

n
= Y

n
- Σ
n-1, where It is shown that the probability that the maximum M = max
n≥1
Z

n
exceeds x is approximately as x → ∞, where F' := 1 - F. Then we study the integrated tail of the maximum of a random walk with long-tailed increments and negative drift over the interval [0, σ], defined by some stopping time σ, in the case in which the randomly stopped sum is negative. Finally, an application to risk theory is considered.
Gillis' Random Walks on Graphs
Authors: Guillotin-Plantard Nadine
Published: July 2016

We consider a random walker on ad-regular graph. Starting from a fixed vertex, the first step is a unit step in any one of theddirections, with common probability 1/dfor each one. At any later step, the random walker moves in any one of the directions, with probabilityqfor a reversal of direction and probabilitypfor any other direction. This model was introduced and first studied by Gillis (1955), in the case when the graph is ad-dimensional square lattice. We prove that the Gillis random walk on ad-regular graph is recurrent if and only if the simple random walk on the graph is recurrent. The Green function of the Gillis random walk will be also given, in terms of that of the simple random walk.
Improving on bold play when the gambler is restricted
Authors: Schweinsberg Jason
Published: July 2016

Suppose that a gambler starts with a fortune in (0,1) and wishes to attain a fortune of 1 by making a sequence of bets. Assume that whenever the gambler stakes an amount s, the gambler's fortune increases by s with probability w and decreases by s with probability 1 − w, where w < ½. Dubins and Savage showed that the optimal strategy, which they called ‘bold play’, is always to bet min{f, 1 − f}, where f is the gambler's current fortune. Here we consider the problem in which the gambler may stake no more than ℓ at one time. We show that the bold strategy of always betting min{ℓ, f, 1 − f} is not optimal if ℓ is irrational, extending a result of Heath, Pruitt, and Sudderth.