bluuebunny/crossref_metadata_2025 huggingface dataset:
Shock Waves in Compressible Flow
Authors: Davies D.M.
Published: November 2014

THE earlier classical treatises on aerodynamics concerned themselves with the properties of incompressible fluids. The theory developed on this basis gave an excellent theoretical background to the aeronautical engineer and made possible a scientific approach to the problems of aircraft flight. With the steady increase of aircraft speed, however, it soon became evident that the theory would have to be extended to take compressibility into account. One important result, brought out by Glauert's analysis, was the modification of the flow pattern with increasing Mach number. A more striking divergence of compressible from incompressible flow, first encountered at near sonic speeds, is the occurrence of shock waves. A shock wave, in the specialized aeronautical sense, is a pressure impulse travelling through the flow causing a sudden transition from supersonic to subsonic speeds (normal to the wave front) with an attendant increase in pressure and temperature. A brief statement of this sort, however, is of little or no value in giving an idea of the physical nature of the phenomenon. A considerable amount of attention is now focused on the repercussions of shock waves on aeroplane design. It is far easier to understand these design trends if one has a good grasp of the fundamentals underlying the problem. This article sets out to give a brief survey of these fundamentals. It is not easy also to give a complete physical picture of a shock wave but at least a discussion of their formation, propagation, etc. goes a long way towards clarifying one's ideas.
Design and Production Technique
Authors: Schroeder A.J.
Published: November 2014

PRESSING technique comprises the methods of working in which material is formed between upper and lower dies.
The Evolution of Energy in Jet and Rocket Propulsion
Authors: Bielkowicz P.
Published: November 2014

A GENERAL outline of the processes occurring in the working fluid of a rocket engine has been summarized previously, but the total picture is still far from complete, a number of important phenomena not having been taken into account. Their full analysis would be, however, beyond the scope of this paper, and may be left to specialists more qualified than the author to give an account of combustion processes.
Aero‐Engine Injection Carburettors
Authors: Reid R.A.S.
Published: November 2014

THE following article is an attempt to provide those unfamiliar with the subject with a review of the working principles and the reasons for the use of so‐called ‘injection’ carburettor equipment, which has in recent years come to replace the conventional suction carburettor on reciprocating aero engines. As an introduction to the arguments, to be developed later, it is necessary to state a few simple definitions of the basic requirements for any form of carburettor for use on these engines.
The de Havilland Hornet Wing Spar
Authors: Harper R.H.T.
Published: November 2014

IN the following article an outline is given of the design reasons which led up to the type of construction adopted for the Hornet wing spars; together with a description of part of the test programme which was carried out during the development stages.
Adiabatic Flow in Pipes
Authors: Lukasiewicz J.
Published: November 2014

THE graphical methods of one‐dimensional gas dynamics are reviewed and developed to obtain a complete representation of adiabatic flow of perfect gases in ducts of constant cross‐section. The dimensionless charts, from which the variation of the state of the gas along the duct axis can be determined, are analysed and the methods of their construction given. The form of the charts depends only on the value of the ratio of specific heats.
Joints in Flat Panels Subjected to Shear and Combined Shear and Tension
Authors: David F.W. , Solvey J.
Published: November 2014

THIS paper deals with semi shear‐resistant panels (incomplete tension fields) subjected to pure shear—as well as combined shear and tension loads. It establishes the stresses in the midplane of the sheet and the loads acting on panel joints.
Variation of Engine Power with Height as Determined in Flight by indirect Methods
Authors: Hislop G.S.
Published: November 2014

THE variation of full throttle engine brake horsepower with altitude at constant rotational speed is a matter of great importance to aircraft designers and those concerned with the measurement of aircraft performance. For the former its main importance probably lies in the design of aeroplanes intended for high altitude use where accurate knowledge of the engine power available is of paramount importance in the evolution of a successful aircraft. In the measurement of aircraft performance it is necessary to reduce the observed results at non‐standard atmospheric conditions to those obtaining under the chosen standard conditions, and for this it is essential that the variation of engine power with altitude is well established.
The Treatment of Continuous Beams by the Moment Distribution Method
Authors: Nicholls D.A.C.
Published: November 2014

THE method which is to be outlined is not a new way of approaching continuous beam problems, it was first introduced in America by Professor Hardy Cross, and appears to be little known in this country. It is felt that the method is much easier to handle than the normal approach to such problems by the Theorem of Three Moments. Engineers dealing with structural design will find it particularly useful, as a very good approximation to the bending moments at the supports can be obtained during the early stages of the work. The method will be helpful to the engineering student, in removing any doubts he may have in determining the directions of bending moments at the supports.
Rolling Performance of Aircraft
Authors: Roberts H.
Published: November 2014

FORMULAE and curves arc given for the derivatives lρ and lξ for three types of wing; elliptic, straight tapered and trapezoidal, based on a modified form of the Schrenk distribution of lift. Comparison with experimental curves for the derivatives shows that the method gives good agreement and enables reasonably accurate estimation of the rolling performance of an aircraft to be made.
The Servicing of Hydraulic Equipment
Authors: Conway H.G.
Published: November 2014

THESE notes have been prepared because it is a fact that there is no publication available to the ordinary aeroplane mechanic which gives him the essential information which will guide him in the overhaul and maintenance of hydraulic equipment. There are only one or two books which even touch on the subject other than the official (and very excellent) R.A.F. publication, A.P. 1803.
Torsion of Thin Walled Multi‐Cell Boxes
Authors: Rice G.E.H.
Published: November 2014

THIS article is concerned with the type of multi‐cell box found in wings, fins and tail planes, etc. It does not include the effect of axial constraint applied to the box root inducing differential bending of the box spars, or the type of box whose individual cells have vastly different rates of change of cross sectional properties, i.e. a twin cell box with one cell remaining constant in area and the other tapering sharply—this type would require special analysis, in which the loads imposed on the internal ribs, due to their finite stiffness, would need investigating.
The Stress‐Strain Characteristics of a Magnesium Alloy Beam
Authors: Johnson A.E. , Herbert D.C.
Published: November 2014

THE work described in this paper was undertaken to investigate the behaviour of a magnesium alloy beam clastically and plastically deformed by a uniform bending moment at room temperature. The object of the work was to obtain relations between stresses and strains in the beam, to afford a basis for design, in cases where it is required to submit magnesium alloy structures to bending stresses exceeding the elastic limit.
Power Boosting of Jet Engines by Reheat
Authors: Baxter A.D. , Kell C.
Published: November 2014

IT is well known that aircraft designers and operators are never satisfied for very long with the power available from the engines installed in their aeroplanes. They arc always demanding overload power or some form of boosting for special conditions such as take‐off on elevated or tropical airfields or for interceptor aircraft during climbs. In the case of turbo‐jet engines, one way of achieving this is by ‘reheating’ or, perhaps less ambiguously, ‘after‐burning’. There have been many references to this form of boosting which would lead one to assume that it is a very recent idea; in fact, a Meteor aircraft was flying with an experimental reheat power boosting system as long ago as 1944. While the system suffered from a number of troubles, it is of more than historical interest and some account of its performance may be useful in assessing the potential value of reheat.
Full‐Scale Research on a Flying Wing
Authors: Murray C.V.
Published: November 2014

SIX years ago Sir W. G. Armstrong Whitworth Aircraft Ltd. began to take a serious interest in the design and development of tailless aircraft and today two types arc undergoing research flight testing.
Aircraft Structural Weight and Design Efficiency
Authors: Grinsted F.
Published: November 2014

THE importance of achieving a low structural weight is illustrated by simple estimates of the large decreases in aircraft gross weight and size made possible by conscientious weight saving in structural design. A brief review is then made of the many variables in aircraft design which affect the weight of the structure. The review is made chiefly to emphasize the close interplay in project work between the structural and aerodynamic effects of changes of layout. Finally some remarks are made about comparative structural design efficiency. It is concluded that good weight prediction formulae are at present the best means by which the structural design efficiencies of different aircraft may be readily compared.
A Note on the Principle of Uniqueness
Authors: Roberts H.
Published: November 2014

THE stress analysis of perfect frameworks, in either two or three dimensions, is possible by a large number of standard methods. The case of structures which under a prescribed loading system have some of the members unloaded deserves a little consideration, since it is often possible to use the principle of superposition to break down a given external loading into loads each of which give only a limited number of stressed members. When this is possible, the technique of stress analysis can be radically simplified by consideration of the principle of uniqueness as stated below.
A Problem of Nose‐Wheel Undercarriage Reactions
Authors: Orloff G.
Published: November 2014

WHEN the brakes are suddenly applied on an aircraft rolling on the ground, the forces set up form a pitching couple which will impart an angular velocity to the aircraft about its centre of gravity.
A Rapid Method of Estimating the Severity of Icing
Authors: Schaetzel S.S.
Published: November 2014

A method of three dimensional plotting is adopted, where the ROC at any station on the wing is plotted vertically on a base representing the maximum icing conditions (FIG. 5). This allows a rapid estimate of the ROC at any icing condition. Also, by plotting the isothermal lines on the base and on the surface representing the ROC (FIG. 10), an immediate estimate of the maximum rate of heat supply at a given temperature is possible. (Since the amount of heat lost by convection is constant along an isothermal line.) By plotting those maxima against the ambient temperature, the most severe icing condition may be established. It is then sufficient to consider only the above condition in the design of the de‐icing system, all other combinations of the icing parameters producing a less critical heat requirement. It has also been found that the relation between the drop size (d) and the ROC (at any given speed between 150 and 350 f.p.s.) is almost linear for drop sizes between 10 and 40 microns. (cf. FIG. 6, REF. 3.) A general relation, of the form: ROC=Am(d‐D) is then established between the rate of catch, the liquid water content and the drop size. By using graphs giving the variation of the coefficients ‘A’ and ‘D’ with speed and position along the wing, it is possible to have a complete estimate of the severity of icing in a small fraction of time formerly required to complete the calculations.
Airworthiness Requirements and Fatigue of Helicopters
Authors: Shapiro J.
Published: November 2014

PROFESSOR PUGSLEY was the first to have popularized the term ‘philosophy’ in connexion with airworthiness. Generally, unless structures are completely safe they are regarded as unsafe. A flying machine, however, can at best be only approximately safe. Hence the need for an a priori definition of safety. Not only is it necessary to make a statistically definable sacrifice of safety to obtain a machine which will fly at all, let alone lift an economical payload, but this sacrifice must be spread in a certain manner to give acceptable returns.
Rotary Derivatives in Yaw
Authors: Falkner V.M.
Published: November 2014

Calculations have been carried out on two elliptic wings, with ratios of major to minor axis 2·5 and 5 to 1 respectively, in order to demonstrate the use of vortex lattice theory in calculating lr and nr by lifting plane theory for wings of arbitrary plan form. Special tables of downwash, required in order to allow for the curvature of the wake, are included, and the origin of the formulae by which these are derived in a form applicable to linear theory is fully described. For the first wing, the calculated results for lr and nr and for local aerodynamic centre, load coefficients, and local lift coefficients are given for the Glauert‐Wieselsberger lifting line solution as well as for lifting plane solutions with three, six and nine control points respectively. The main work on the second wing is concerned with a six‐point lifting plane solution. The results show that there is not a serious difference between lifting line and lifting plane theory, excepting that the former does not give reliable values for the local a.c. For straight wings the six‐point lifting plane solution gives excellent accuracy. The method is applicable to wings of arbitrary plan, but the field of sweptback wings is unexplored and it should not be assumed without check that the relation of accuracy to number of control points is always the same. A further investigation is also required on the formula for nr when sweepback is present. The calculated value of lr for the 5 to 1 elliptic wing is in close agreement with the measured value for this wing obtained by Wieselsberger on a whirling arm. The report is concerned mainly with the calculation of spanwise load grading and local aerodynamic centre, and extension to detailed pressure distribution may require the use of more variables.
The Experimental Approach to Aircraft Structural Research
Authors: Walker P.B.
Published: November 2014

Research in aircraft structures is constantly bringing forward new problems of a fundamental character. Many of these respond to systematic experiment, and the paper presents the experimental approach in terms of recent work done in Great Britain and particularly at the Royal Aircraft Establishment. One aspect of research considered is the testing of small specimens made of xylonite. Another is the strength testing of actual aircraft, which opens up several fields of research activity for discussion. Design studies of new testing equipment for large aircraft and for pressure cabins are also described. Consideration is given to the measurement of external forces in flight and the design of measuring instruments, including a description of the new counting accelerometer recently developed by the R.A.E. Finally, structural fatigue is discussed as being one of the most difficult subjects with which the structural specialist has yet had to deal.
Atmospheric Wet Bulb Temperature
Authors: Williams J.A.C.
Published: November 2014

AIRCRAFT performance is dependent upon a number of independent variables such as air density. Any variation in one of these variables, if not allowed for in performance correction, causes discrepancies in corrected performance figures.
Forced Vibration of a Rotating Elastic Body
Authors: Johnson D.C.
Published: November 2014

In a previous paper the writer has shown how equations for the free vibration of a rotating body may be obtained; in the present paper the inclusion of forcing terms in the equations is allowed for, and the effect of damping forces within the body and also in the medium in which the body rotates is considered.
Solutions of Problems on the Slightly Curved Beam
Authors: Ratzersdorfer J.
Published: November 2014

A slender beam with slight geometrical curvature is divided in bays with different cross‐sections subjected to uniformly distributed and concentrated transverse loads. Combined with the conditions which hold at the first and last point of the beam, the bending moments at tbe ends of the bays will be determined by three moment equations, or, when uniformly distributed transverse loads are operative, graphically by use of polar co‐ordinates. Knowing these moments a polar diagram can be completed for each bay. Further, a convenient method is shown for the solution of deflexions of the beam. An additional remark deals also with the beam under tension. Finally numerical examples give an illustration of the procedure.
A New Electronic Analogue Computer
Authors: Lloyd Thomas E.
Published: November 2014

THE increasing necessity for large‐scale calculation in the design of aircraft has, in recent years, emphasized the lack of adequate computational facilities and transferred attention from the problem of formulation to that of solution. Thus, unless a reliable simple theory is available, the designer is forced to base his design on approximate formulae which do not always reflect current trends in a fast developing science. The more elaborate theory is therefore usually applied as a check to the final design, and much valuable time is wasted while such computations are carried out, even if they do not indicate the need for major structural modifications.
The Elementary Theory of Aero‐Elasticity
Authors: Broadbent E.G.
Published: November 2014

IN Part I wc saw how structural flexibility could introduce aerodynamic forces which might eventually lead to instability, or to the complete nullification of a desired aerodynamic effect. The phenomenon of flutter presents another problem in stability, but in this case an oscillatory instability is threatened. It must be realized at the outset that flutter is no mere resonance phenomenon such as the bad vibrations a motor‐car may exhibit at a particular engine speed. Flutter is a vibration in which energy is extracted from the airstrcam to help build up the amplitude, and a catastrophic failure can easily occur within a second of the start of the flutter.
The Calculation of Reheat and Expansion Efficiency
Authors: Ryley Denis J.
Published: November 2014

For any convergent nozzle passing a compressible fluid and discharging against a pressure below the expanding power of the nozzle, there is a unique pressure and temperature distribution both of which depend upon the overall resistances to flow and the reheating effect incurred. By measurement of a single function of state along the flow path it is theoretically possible to calculate the reheat and expansion efficiency. The following analysis for one‐dimensional irrotational flow is an attempt to predict on a basis of theory the probable difficulties which would arise in practice and the accuracy to be expected. It is found that the pressure distribution is insensitive to reheat, but that the temperature distribution provides a fair indication.
Anglo‐American Conference on Combustion
Authors: Spalding D.B.
Published: November 2014

AS was announced in the June 1955 issue of Aircraft Engineering, this conference was held in Boston, Massachusetts in June, and again in London in October.
Measurement of the Aerodynamic Forces on Oscillating Aerofoils
Authors: Molyneux W.G.
Published: November 2014

AT the present time it is a general practice to make extensive investigations of the flutter and oscillatory stability characteristics of all prototype aircraft at an early stage in the design. So far as theoretical investigations of these characteristics are concerned there is often considerable uncertainty as to the values of the aerodynamic coefficients to be used, for there is evidence that measured and theoretical coefficients may differ considerably. Measured values of the coefficients are therefore required both for direct use in calculations and as a check on the theoretical coefficients, and also to provide a guide in the development of more precise theories. Unfortunately the wide variations in wing plan forms and the rapid increase in flight speeds which have occurred in recent years have meant that experimental work in this particular field has not kept pace with development and the designer is faced with the problem of ensuring the safety and operational efficiency of his aircraft using theoretical coefficients whose values may be unreliable.
The Electronic Digital Computer in Aircraft Structural Analysis
Authors: Hunt P.M.
Published: November 2014

This paper develops general purpose programmes for an electronic digital computer for use when the Argyris Matrix Method of Structural Analysis is employed. Programmes for both the force and displacement methods are given and they apply for arbitrarily large structures. The procedure to be followed in the particular case of the structural analysis of a delta wing is outlined and the advantages of using magnetic tape storage are considered.
Turbine Disks for Jet Propulsion Units
Authors: Johnson A.E.
Published: November 2014

THREE methods of elastic stress computation are described in the following section.
Plastic Pressure Cabins
Authors: Walker P.B.
Published: November 2014

IN the February 1956 issue of AIRCRAFT ENGINEERING the Editor put forward the suggestion that the pressure cabins of civil aircraft might with advantage be made of reinforced plastics instead of aluminium alloy. He had in mind recent difficulties encountered in pressure cabin design, especially those arising from metal fatigue, or revealed as a result of fatigue investigations. Plastic materials, maintains the editor, may well lend themselves to pressure cabin construction and provide a means of overcoming many of the current difficulties of design.
Selection of Aluminium Alloys by Fatigue Properties
Authors: Ward R.G.
Published: November 2014

WHEN selecting alloys for use in structures whose life would be limited by fatigue, the choice is greatly aided by consideration of fatigue tests on simple test‐pieces in which the effects due to stress‐raisers, fretting, temperature, etc., are dealt with under idealized conditions.
Tensor Analysis of Finite Rotations
Authors: Bateman E.H.
Published: November 2014

The orientation of a rigid body is described by a position‐tensor, composed of three unit vector axes fixed in the body; rotation is effected by tensor transformations in which a rotational operator is a Cartesian matrix, formed from the co‐ordinates of the pivot axis and components of the angle of rotation; rotational sequences are represented by matrix products. Three practical applications are discussed: sequences of aircraft manoeuvres, which include composite rotations of roll and pitch, or roll, pitch and yaw, applied simultaneously; the variation of sweep, incidence and dihedral of a wing moving on any axis fixed in the aircraft; the direction of the pivot axis and the angle of rotation in the motion of a retractable undercarriage between two specified positions.
Some Developments and Applications of Brittle Lacquers
Authors: Linge J.R.
Published: November 2014

The calibration of brittle lacquer is an important part of the technique. The photograph, FIG. 10, gives some idea of the essentials of a cam operated cantilever beam bending rig with a steel beam in position, partially deflected; the equipment shown is in certain respects similar to an American apparatus the subject of U.S. Patent No. 2,310,845. FIG. 11 shows the typical formation of a crack pattern in an early type of cantilever calibration beam the dimensions of which are given in FIG. 12. The cracks observed may be grouped into two classes, the first incomplete cracks at A, distance L1 from the root, and the first complete crack at C, distance L2 from the root of the beam. Consistent results have been obtained using the mean position at B, corresponding to ×=1/2(L1 + L2) in. to compute the strain sensitivities of lacquers. The distance A to C, equivalent to (L1−L2.) in. is invariably quite constant for a given type of lacquer, and thickness of coaling, a typical relationship between dimension (L1−L2) in. and the thickness of a lacquer is illustrated by FIG. 13.
Some Notes on Pressure‐Cabin Design
Authors: Walker P.B.
Published: November 2014

IN Los Angeles in June 1955 the writer read a paper on fatigue of pressure cabins to the Anglo‐American Conference, and a British version of this paper was published in Aircraft Engineering for January 1956. The paper gave the first published account of fatigue tank testing for complete aircraft, and discussed some of the main design issues such as fuselage frames and passenger windows. Since that time much practical experience has been obtained; and it has been suggested that some of the earlier ideas and principles could usefully be extended and brought up to date.
The Solution of ‘Ill‐Conditioned’ Linear Simultaneous Equations
Authors: Head J.W. , Oulton G.M.
Published: November 2014

When linear simultaneous equations are ‘ill‐conditioned’, small variations in the (usually measured) quantities on the right‐hand sides of the equations are associated with large variations in the values of some of the unknowns. The basic reason for this is that the matrix of the coefficients has at least one small latent root. Associated with each small latent root λr is a quantity Ur, a linear combination of the quantities on the right‐hand sides of the original equations, and the uncertainty associated with the ‘ill‐condition’ is essentially uncertainty as to the values of the quantities Ur; the original equations can be replaced by another set of equations which is not ill‐conditioned but involves the Ur. General methods are used, but applied to two specific cases; in one of these there are two equal small latent roots of the matrix of coefficients and the necessary adjustments for this case are explained. Two alternative methods for determining the small latent roots of a matrix are discussed.
Structural Flexibility and Undercarriage Impact Loads
Authors: Alexander H.R.
Published: November 2014

The calculation of undercarriage landing reactions and dynamic stresses is discussed, and the merging of the two calculations under certain circumstances is proposed. ? formulation of the combined problem is outlined, and numerical examination of a simple case shows that in some cases the reaction forces are appreciably reduced by the adoption of the combined approach. Finally, a criterion is derived which could be used in the early stages of undercarriage design to predict the elicci of aircraft flexibility.
Discontinuity Stresses in Stiffened Cylindrical Shells
Authors: Johns D.J.
Published: November 2014

THIN cylindrical shells stiffened at intervals along their length by internal frames or bulkheads are often used in fuselage design. When such shells are pressurized or heated, expansion of the shell results and, unless the subsequent deformations of shell and stiffeners are equal, discontinuity stresses are induced in the region of the shell‐stiffener joint making all the deformations compatible.
Magnesium and Aircraft Engineering
Authors: Kennedy A.J. , Sollars A.R.
Published: November 2014

MAGNESIUM, because of its low density, has obvious possibilities as an aircraft structural material. The useful magnesium alloys have densities in the range 1·76 to 1·83, compared with the aluminium alloys range of about 2·5 to 2·8. The melting point of magnesium is 650 deg. C., almost identical with that of aluminium (660 deg. C.), so that generally the alloys of each of these base elements have applications in much the same temperature band.
Pressure Cabin Analysis
Authors: Houghton D.S. , Chan A.S.L.
Published: November 2014

An extension is made to the theory on which most aircraft pressure cabins are designed. In the existing theory the effect of the curvature of the deformed cylinder is neglected. This paper examines the manner in which this effect influences the stress distribution.
The Avoidance of Ground Resonance
Authors: Price H.L.
Published: November 2014

An examination is made of the way in which the ground resonance properties of a helicopter depend on the fuselage damping, blade damping, drag hinge offset, inter‐blade spring stiffness, blade mass and angular velocity of the rotor as specified by the parameters λƒ, λβ, Λ1, Λ2, Λ3 and Ω respectively. A direct method of drawing stability boundaries in the (Ω, λβ) plane is developed, and the geometry of these boundaries as the remaining parameters vary is studied theoretically at length. Arising out of the geometry, the validity of Coleman's criterion for stability is examined, and it is shown that the requirement that the product λƒ,λβ should have a certain minimum value is not itself sufficient to ensure stability for all Ω. The condition can be made sufficient by a proper and unique choice of the individual values of ?f and ??, and these values are found in terms of Λ1, Λ2, and Λ3. All other cases of stability require a larger value of the product λƒ, λβ. An alternative criterion for stability is developed which gives the minimum value of λƒ capable of ensuring stability for all Ω. This, and the preceding criterion, are mathematically exact, and follow from Coleman's equations of motion as applied to the case of a helicopter on isotropic supports. A brief account is also given of the case of a rotor having inter‐blade friction damping as against the viscous damping previously assumed.
The Library Shelf
Authors: A.D.Y.  , B.S.O.  , W.L.M.  , H.B.H.  , W.A.M.
Published: November 2014

The title of this volume is one that should bring an eager sparkle to the eyes of your aerodynamic friends. Both turbulence and heat transfer are topics of major practical importance, and for engineering purposes they share a common basis of empiricisms, regarded with justifiable suspicion by fundamental research workers, but on which useful working formulae have been developed. Meanwhile, the said research workers have pursued thoroughgoing scientific investigations into the phenomenon of turbulence and although as yet no important practical applications appear to have resulted from their work they have built up a body of knowledge which has its own intrinsic value and which will undoubtedly have important applications in the future. Good books on these topics are very rare, hence the interest which this title will arouse in aerodynamic circles. An optimist will expect the book to provide him with a complete and ordered survey of both the fundamental and applied lines of development, with appropriate critical comments, and he will expect to find the answers to many of the current problems with which he may be concerned. His expectations will not be entirely fulfilled, the arrangement is not as well ordered as it might be and the writing was largely completed in 1956, so that more recent developments and problems are not dealt with. Such defects are however inevitable in a collection of articles of this kind dealing with a rapidly developing group of subjects, and there is much of value in the book.
The Library Shelf
Authors: B.S.O.  , A.R.C.  , A.D.Y.
Published: November 2014

Vol. XVII, No. 2, or this scries begins with the 1958 William M. Murray Lecture on ‘Mechanics applied to Creep Testing’ by N. J. Hoff. The lecture surveys the factors making the analysis of structures under creep conditions more difficult than under conditions where linear clastic laws are obeyed. Empirical creep laws are reviewed and the dangers of extrapolation pointed out. For complex states of stress a law is recommended based on the assumptions that principal axes of stress and strain coincide and that principal stress and strain components are in the same ratio. It is shown that slight inaccuracies in the measurement of stress, fluctuations in stress and temperature, and changes in specimen geometry, may all contribute appreciably to the scatter of test results, in addition to the effects of lattice defects and intcrcrystalline bonds. The stress distribution in redundant structures will be different under creep and clastic conditions; an analogue method for analysing the former condition, using variational principles is outlined. The problem of determining stress distribution when the condition is intermediate between fully clastic and one of steady creep, is even more difficult. Some simple examples are discussed. The final section of the paper deals with instability in the creep tensile test, and with creep buckling.
Design of Wind Tunnel Contractions
Authors: Jordinson R.
Published: November 2014

A method is given for the design of a two‐dimensional wind tunnel contraction for incompressible inviscid flow. The contraction is considered to join parallel channels of different width and is of finite length. The contraction boundary consists of two curved portions fairing smoothly into the channel walls at the upstream and downstream ends and a straight portion in between joining the other ends of Ihc curved portions. The shape of the boundary is determined by specifying: (i) constant velocities along the curved portions and (ii) the angle of inclination of the straight portion to the tunnel axis. The solution to the problem is obtained by working in the hodograph plane. For this purpose the contraction is considered to be made up of two distinct parts, upstream and downstream, and the solution is worked out for each separately. Results are given in tabular form for differing values of the above parameters (i) and (ii). It is hoped that the results will be found useful in the design of most low‐speed tunnels and particularly those with large contraction ratios. The results given here have been used in the design of a smoke tunnel (contraction ratio 15 to 1), a model of which has been built and tested with satisfactory results.
Boundary Layer Control for Low Drag A Review of the Present Situation and an Assessment of the Potentialities of Laminarization Techniques
Authors: Lachmann G.V.
Published: November 2014

Since the end of the Second World War, many spectacular advances have been made in aeronautics, thanks chiefly to the development of more powerful and economical jet engines. As to the parasitic drag of manned aircraft, progress has been confined to reducing unfavourable compressibility effects (area rule, Whitcombe bodies); methods to suppress separation have been developed but no new methods to reduce the drag resulting from turbulent boundary layers developing over the exposed surfaces have as yet found practical application.
Aerodynamic Design Problems of Jet Lift V.T.O.L Aircraft
Authors: Fletcher J.
Published: November 2014

The stability and control systems adopted by the Bell Aircraft Corporation and for the Short S.C.1 are discussed with reference to efficiency, and the importance of low loss nozzle systems is emphasized. The form of auto‐stabilization and its application to the aircraft control system are to sonic extent governed by the operating requirements of the V.T.O.L. aircraft. Lift engine intake problems and the interaction effects of the airflow passing through the lift engines on the airframe as a whole are considered at length, along with ground effects and novel model testing techniques. The author concludes that much model and full‐scale research is still needed to investigate further the many problems which remain and which can critically affect the feasibility of projects for operational use.
Part Three—Missiles and Rockets A Survey of British Policy and Design Trends in the Guided Rocket Field
Authors: Pardoe G.K.C.
Published: November 2014

TO the guided weapon industry in Britain, a trend in the last few years has regrettably been very apparent—fewer and foreign. Of contemporary weapons we can justifiably be proud of our national products so far as the design and performance is concerned, although certain of them have taken a depressingly long time to reach fully operational service. The quality of UK weapons is certainly on a healthy upward trend; however, the national armoury has undergone a considerable change over the last decade or so, since the first generation was conceived due to the influence of international arming.
Northampton College Shock Tube and Shock Tunnel
Authors: Scibor‐Rylski A. , Barry B.
Published: November 2014

THE development of a shock tube by the Department of Aerodynamics and Space Technology commenced in September, 1961, and was completed towards the end of 1962. The shock tube and the shock tunnel will fulfil two functions. They will serve primarily as teaching facilities, with post graduate courses in view and will also be used as an advanced tool for staff research.
The Development and Testing of Elastomeric Materials for Fluid Sealing Applications
Authors: Blow C.M.
Published: November 2014

A Discussion Involving the Significance of Laboratory Test Methods and a Description of the Properties of Some of the Latest Polymers Including Rubbers Suitable for Use with Skydrol 500A Hydraulic Fluid. The significance of laboratory test methods now commonly applied to elastomeric materials is discussed in relation to service performance. Hardness, elastic recovery properties, heat resistance and liquid absorption are among the most important and experimental results are given to illustrate the effect of the various factors involved. Attention is drawn to the general properties of some of the newer polymers now becoming available. The development of rubbers for use with the fire‐resistant phosphate ester hydraulic fluid Skydrol 500A presented a problem because it is heavily absorbed by the usual oil‐resistant rubbers. First butyl rubber and subsequently ethylene/propylene copolymers were found suitable but the production of satisfactory materials for seals took time. Reference is made to other subjects of importance in the use of rubber for seals, such as the difference in the coefficient of thermal expansion of rubbers and metals, and the methods of reducing surface friction.
The Scientific Investigation of Aircraft Accidents
Authors: Walker P.B.
Published: November 2014

Aircraft investigation is here treated as a problem in detection, calling for observation and deduction, and sometimes for scientific experiments to test tentative explanations. After consideration of preliminaries, such as the discovery and retrieval of the wreckage and its reconstruction as a jig‐saw puzzle, most of the principal methods for ascertaining the cause of an accident are described under separate heads. It is shown how the different lines of investigation may proceed more or less simultaneously, and may substantiate each other. They include the analysis of fractures and the study of scratches, marks and indentations. Disruption of mechanical and electrical components is considered and also the evidence of eye‐witnesses. Consideration is also given to methods that can be used even when no wreckage is available. The treatment is essentially practical as it proceeds from one specific example to another, with several illustrations taken from actual cases. The paper concludes with a few remarks on modern trends, which do not appear likely to upset any of the basic principles here described.
Origin, Basic Design Philosophy and Evolution
Authors: Edgerton K.
Published: November 2014

Background to the Design Development of the Hawker Siddeley 748 leading to the Series 2 aircraft, with an Outline of its Principal Features. TO build and produce an aircraft which is cheaper than its competitors, has higher performance and sufficient market appeal to enable it to sell in large quantities, was the aim stated in the directive which heralded A. V. Roe's re‐entry into the field of civil aviation. For many years the Company (now the Avro Whitworth Division of Hawker Siddeley Aviation) had concentrated on military types of aeroplanes, but when the Sandys White Paper on Defence appeared in 1957, with its forecast of no more manned military aircraft, the Avro design team began to examine the possibility of building a civil transport.
Some Aspects of Aeronautical Research in the United Kingdom
Authors: Collar A.R.
Published: November 2014

THE paper selects for brief discussion a very few of the successful aeronautical researches conducted in the United Kingdom in recent years. The selection includes illustrations of the work of government establishments, of industry, and of universities. Moreover, the choice made is intended to exemplify the principal fields of activity of the Aeronautical Research Council, as represented by its standing committees and group of special committees: aerodynamics, mechanics, propulsion, and special topics. The paper concludes with a plea for continued research on as large a scale as possible.
A Look at Aircraft Fire Precautions and Protection
Authors: Madgwick T.
Published: November 2014

THE need for serious attention to fire precautions is becoming increasingly important in satisfying the demand for improved overall flight safety. The need arises from a number of considerations, of which the following are typical:
Factors in Fastener Reliability
Authors: Hall G.N. , Breward Oliver
Published: November 2014

A WIDE range of reliable threaded fasteners have been developed to meet the increasingly exacting demands of the aerospace industry.
The Aerodynamic Design Philosophy of the Handley Page Jetstream
Authors: Lee G.H.
Published: November 2014

THE relation between aerodynamics and the design of an aircraft and its power plant is unique in engineering; it is only in aircraft design that good aerodynamics is a prerequisite for success. Of course the structure must be good (though this is true of ships or bridges) and so must the motor (but this also applies to motor cars and railway engines) and the electrics must be efficient (and so must they be for a television set); and so on through many other technologies. But the start, and the heart, of the design is aerodynamics, the one feature that distinguishes aeroplanes from all other forms of transport. At the present time Handley Page Limited is engaged in the production of a new turboprop business cum feeder‐liner aeroplane the H.P. 137 Jetstream, which made its first flight on August 18.
Structural Design
Authors: Obee K.R.
Published: November 2014

ALTHOUGH the first certification or the Jetstream is to be to B.C.A.R. Section K and F.A.R. Part 23, it has always been intended that full airline standards will be maintained and ultimately certification to Section D, and Part 25 will be obtained. From the point of view of static strength these standards differ little and will have a minor effect only on the structural design. The spirit of the full airline requirements, however, is aimed at long life and fail safe philosophies, and this has been foremost in the thought behind Jetstream's structure. The design crack‐ free life is 40,000 flights (30,000 hours) with the additional aim of a fail safe primary structure. The long crack‐free life will be obtained by restricting the working and fluctuating stresses to values decided for each component by its own spectrum of load cycles. Fail safe primary structure is achieved by the duplication of members, alternative load paths, ‘catchers’, or by effective crack stoppers.
Manufacture of the Radome for the Prototype Concorde Aircraft
Authors: Meades G.F. , Young R.F.
Published: November 2014

IN mid 1963 the Guided Weapons Division of the British Aircraft Corporation was charged with the problem of producing a nose radome for the Concorde supersonic transport.
Fifty Years of Landing Gear Development
Authors: Barfield N.A.
Published: November 2014

SINCE the original British patent for telescopic oleo‐pneumatic shock absorbers for aircraft landing gear was drawn up in 1915 by Vickers engineer T. S. Duncan — with his invention of the positive recoil damping principle — Weybridge has been in the forefront of landing gear development on all types of aircraft for over half a century. Today, as a member company of British Aircraft Corporation, the Weybridge resources in this field are unique to a prime aircraft manufacturer. The landing gear units for the VC10 and B.A.C. One‐Eleven airliner families and the supporting design, production and testing facilities at Weybridge are among the most advanced in the world.
The Production of Air Cushion Vehicles
Authors: Gilberthorpe E.F.
Published: November 2014

WHEN Sir Eric Mensforth — now, appropriately, President of the Institution of Production Engineers — presented the 1964 Lord Sempill Paper of ‘Background to the Production of Helicopters and Hovercraft’ in April of that year, he remarked on the hovercraft being still in its infancy and on the ‘state of constant and exciting advance’. Sir Eric, at that time, was able to refer to the in‐service achievements of the 27 ton SR.N2 and the 37 ton SR.N3, the beginning of manufacture of the 7 ton SR.N5, and the projected 160 ton SR.N4 — all in the five short years since the advent of the original 4 ton SR.N1 research vehicle in 1959.
Aircraft Electrical Ice Protection Systems
Authors: Foster R.A.
Published: November 2014

THERMAL protection from the effects of ice built up can be achieved by means of anti‐icing or de icing. Most aircraft structures are de‐iced since this consumes considerably less power, but in some cases it is essential that the surface be anti‐iced, (e.g. engine intakes, where ice ingestion to the engine is unacceptable and any formation of ice must therefore be prevented).
Materials and Manufacturing Techniques
Authors: Newman M.A.
Published: November 2014

THE simplest definitive description of the electro‐thermal de‐icing system postulated by Dunlop is the encapsulation of selected resistors within thermally conductive, but electrically non‐conductive, materials.
The Optimization of Vehicle Propulsion
Authors: Mouritzen Gunnar
Published: November 2014

THE effect of the propulsive efficiency is analysed for all speed regions and methods for obtaining optimum propulsive efficiency for any speed and environmental conditions are investigated for different type vehicles. Also, the importance of the propulsive efficiency is compared to other factors such as weight of power plant, specific fuel consumption, specific power ratio, specific thrust ratio, etc. Finally, on the basis of considering all power plant factors, it is shown how to achieve optimum propulsion for any vehicle at required operating conditions.
The B.A.C. One‐Eleven Family
Authors: Barfield Norman
Published: November 2014

In a modern commercial airliner programme the ability to produce a technically good product at the right time is not enough. Efficient programme management, in all its facets, is absolutely essential to ensure a proper return on the big investments required and the smooth and progressive deployment of financial, plant and manpower resources through each programme to the next.
Flight simulator as a design tool
Authors: ACKLAM D.J.
Published: November 2014

TO MANY PEOPLE in the aeronautical world a flight simulator is a training device ranging in complexity from the old Link Trainer to the latest fully representative airline simulator, in which aircrew can practice operating procedures and emergencies at a fraction of the cost of airborne training, and without risk.