bluuebunny/crossref_metadata_2025 huggingface dataset:
Some Notes on Flying Boats and Seaplanes
Authors: Lower J. H.
Published: August 2016

The terms “ Flying—boat ” and “ Seaplane ” convey to our minds two distinct types of marine aircraft, which have many points in common and yet many points not in common, and together they cover such a vast amount of subject matter,that it is only possible to deal with a limited number of aspects in this paper.
Airscrew Blade Stress due to Periodic Displacement
Authors: Knott G. M. W.
Published: August 2016

Airscrew blade stresses caused by periodic displacement of the airscrew shaft and the possibility of their elimination by elastic connection of motor and airscrew. are investigated.
Resistance-Wire Strain Gauges
Authors: Strong J. G.
Published: August 2016

It is odd to think that the resistance-wire strain gauge could have been put to use some 40 years ago, about the time of the first filament-wire lamp and the thermionic valve. The physical principles involved were already known. Kelvin had measured the resistance of wires in tension, there were galvanometers in plenty, and even crude valve amplifiers existed. It only really remained for someone to put two and two together. Instead we had to wait until the necessity of stressed-skin construction forced the hand of the engineer into seeking a more effective method of strain analysis than the old empirical ways.
The Structural Effects of Kinetic Heating in Supersonic Flight
Authors: Walker P. B.
Published: August 2016

The structural problems introduced by the kinetic heating of high speed aircraft require a radical extension of what has hitherto been regarded as the normal domain of structural theory. Aerodynamics, for example, cannot be regarded as a self-contained subject which merely provides basic data for the structural worker. Certain aspects of aerodynamic theory, particularly the mode of heat generation, have to be considered simultaneously with the structural problem. Thermodynamics and metallurgy are still more closely integrated with structural theory. The laws of heat transfer, and the variation of material properties with temperature, are both essential factors in the structural analysis.
Cold Weather Operation of Aircraft
Authors: Wilson G. W. , Bridgland E. P.
Published: August 2016

It is many years since aircraft were first A operated under extreme low temperature conditions, mainly by bush pilots pioneering the northern latitudes of Canada.The aircraft used were of the light and semi—medium type fitted with simple, low—powered engines. Consequently, crude methods could be adopted to keep them operating.

With the advent of high—powered boosted—engined aircraft, with their complexity and numerous complicated installations, together with other associated equipments, the difficulties became manifold and the earlier methods used were either impracticable or inadequate.

For this reason, some intensive testing and research has been done on the latest type of aircraft, engines and equipment, in an endeavour to solve the problems and, if not entirely successful, find what medium of success can be achieved with the least amount of subsidiary aid.
Reduction of Airline Costs
Authors: Crabtree Hedley S.
Published: August 2016

Sir William Hildred, C.B., O.B.E., Director-General of I.A.T.A., in his Annual Report, which he presented at the I.A.T.A. Conference in Paris in the middle of September 1954, pointed out that there was an urgent need for a drive for greater efficiency to obtain a balanced airline economy. He quoted some interesting I.C.A.O. figures. These covered all the world's scheduled operators, both the profit-making and the loss-making companies. In 1951, the world's airlines showed that total operating revenues were 6 per cent, higher than total costs. In 1952, this figure was down to 3·6 per cent, and in 1953, down to 1·1 per cent., which represented $27-million profit on a total business of $2,500-million. It should be noted that this $27-million profit is arrived at after the pay-out of direct taxation by the profit-making companies to the tune of $69-million.
The Second Barnwell Memorial Lecture: The Outlook on Airframe Fatigue
Authors: Tye Walter
Published: August 2016

My pleasure in accepting your invitation to lecture, which I treat as a great honour, has been somewhat overshadowed by doubt that I shall do justice to the occasion. This is but the second lecture to commemorate Captain Frank Barnwell. I am fully alive to the fact that the members of this Branch of the Society, many of whom were Captain Barnwell's personal friends, are very desirous of establishing, in these early lectures, a standard which is a worthy memorial.

Captain Barnwell was one of a small number—I suppose they can be counted on the fingers of two hands —who, by their courage and ability, made the barely flyable contraptions of 50 years ago into the aeroplanes we know today. The changes in aeronautical engineering have been so great that it is not easy to realise in 1955 the problems Barnwell and his colleagues faced in 1905, the year of the first Barnwell designs.
Australia in Empire Air Transport
Authors: Hudson Fysh W.
Published: August 2016

It is a great honour to have been asked by The Royal Aeronautical Society to give the foundation British Commonwealth and Empire Lecture, and I have accepted, having in mind the Australian pioneers of the air from whose past has sprung the beginning of our Australian part in the common effort of to-day.

I would like to congratulate the Society on founding this lecture, which it takes little prediction to forecast will grow into one of the most important annual aviation events in the Empire–as well as facilitating the assembling together in the Journal of information, opinion and suggestion from the four corners of the Empire. This, in itself, is only made possible by air travel, and as an illustration of what can be done, you should know that this is my third visit to this country from Australia in this year of 1945.
Method of Accident Investigation and Prevention Adopted by Air Transport Auxiliary
Authors: Wills P. A.
Published: August 2016

A large number of individuals took part in the development and application of the methods of accident investigation and prevention outlined in the following paper. Commodore G. d'Erlanger, C.B.E., O.C. Air Transport Auxiliary, took a major part in the general evolution of the procedure; Air Vice-Marshal Sir Lawrence A. Pattinson, C.B., D.S.O., M.C., D.F.C., with his great knowledge of R.A.F. procedure, was responsible for the production of the A.T.A. manual “Instructions for Reporting Flying Accidents, Forced Landings, Aircraft Defects and Casualties”; and starting from scratch, a very competent Secretariat, consisting of Flt/Capt. G. Merton, F/O D. G. Brinjes and F/O J. W. Gibbs, were responsible for the great amount of work involved in working the machine and in the eventual production of the data and information summarised herein. The Chief Medical Officer, A.T.A., Cmdr. A. Buchanan Barbour, is in general responsible for those paragraphs of this paper covering the field of aviation medicine.
Naval Aircraft and Carrier Equipment
Authors: Boddington L.
Published: August 2016

There are a number of essential differences between aircraft designed to operate from carriers and those designed to operate solely from land bases. Some of the features are detrimental to good structural weight and even to aerodynamic performance, and involve both the aircraft and carrier in special equipment.

Of these features the two most important are assisted take–off and deck landing. Assisted take–off includes catapulting, accelerating and rocket assistance; landing involves arresting and safety–barriers.

It is now the practice to refer to all methods of mechanically–assisted take–off as catapulting, to bring it into line with American terminology. Until recently, catapulting denoted a particular method of launching whereby the aircraft was supported entirely on a cradle with no part of the airframe in contact with the ship structure, and such equipment was installed in ships with no flight deck. Accelerating denoted that the aircraft was launched along the deck on its own undercarriage which gave it some degree of support. Accelerating was peculiar to ships with flight decks, i.e. carriers.
A Combination of the Quasi-Cylinder and Slender Body Theories
Authors: Warren C. H. E. , Fraenkel L. E.
Published: August 2016

The Quasi-Cylinder and slender body theories for the supersonic flow past bodies of revolution have been much used in recent years because, for reasonably simple body profiles, these theories permit a simple and rapid calculation of the first-order pressure distributions and aerodynamic forces. It is assumed in both theories that the body profile slope is small; in the quasi-cylinder theory it is also assumed that the body radius is nearly constant, whereas in the slender body theory it is assumed that the thickness ratio of the body (maximum diameter/length) is small.

In the present note these two theories are combined completely. From a strictly mathematical point of view nothing is gained by this combination, and, furthermore,application of the combined theory to a particular case is in general a little more laborious than application of either of the original theories.
Structural Safety
Authors: Pugsley A. G.
Published: August 2016

The present preoccupation of aircraft designers and users with fatigue problems, brought to a head by the Comet disasters, has rendered the notion of the finite life of an aeroplane a commonplace to the man in the street, and has made the assessment of probabilities of failure and the collection of statistics regarding loads and structural properties a matter of detailed concern for all designers. This was not always so. In 1939, when Fairthorne and I essayed a first paper on airworthiness statistics it received practically no attention and publication was delayed for years until after the 1939–45 War. Even in 1942, an exploratory “ Philosophy of Aeroplane Strength ” brought smiles to the faces of practical designers rather than the real interest that the “new slant,” as some said, of its probability approach raised in a few scientists.
Analogue Computing in Aeronautics
Authors: Diprose K. V.
Published: August 2016

I intend in this lecture to discuss tlie ways in which I think analogue computing can be of assistance to aeronautics in the future. I shall therefore be less concerned with how they are built, than with how they are used, and in fact, what circumstances justify using them at all. Up to a few years ago the only large computors were analogue ones, so the user had no choice, but when the automatic digital computor became established as a practical machine (and even before) there were many people to suggest that the analogue was obsolete. This view is now less widely held, even by makers and designers of digital machines, and reviews of aeronautical computing aids have usually found some place for the analogue computor, without establishing any general principles on which the choice has been made, except, perhaps, to suggest that the accuracy required is the criterion.

I shall start by describing three of the types of computor most commonly used in aeronautics, the “ response simulator,” the “ electrolytic tank” and the “network analyser” and use these to illustrate the particular properties of analogue computing.
The Bending Fatigue Strength of Aluminium Alloy MG5 Between 10 and 10 Million Cycles
Authors: Low A. C.
Published: August 2016

The work described was undertaken under a Ministry of Supply Contract to investigate the fatigue strength of certain materials where the expected endurance in use was less than the range of values usually examined in fatigue testing.

The material was supplied in the form of a 6 ft. x 3 ft. x 1/4 in. sheet of aluminium alloy MG5.

Tensile test pieces having a parallel length one inch wide by 4 1/2 in. long were taken in both directions from two diagonally opposite corners of the sheet. Later, similar longitudinal test pieces were taken from areas near the other two corners.

The plane bending fatigue test pieces were of the form shown in Fig. 1 and were all cut in the longitudinal direction. The waisted test portion was polished on the edges, the original sheet surface being retained on the faces. Steel plates were clamped to the ends of the test pieces by bolts passing through the holes in order to localise the strain in the test portion as much as possible.
Torsional Vibration Analysis of Systems Connected by Flexibly-Mounted Epicyclic Gearing
Authors: Manley R. G.
Published: August 2016

The author has described elsewhere (reference 1) the general principles of the dynamic stiffness method of analysing torsional vibration problems. Amongst the systems treated were those involving simple spur or helical gear-steps. The method can also be applied, however, to deal with epicyclic gearing, making proper allowance for the effect of flexibility in the gear-housing. The present paper outlines this extension.

A similar method may be used to allow for housing flexibility in normal spur gearing.
Buckling of Rectangular Plates under Bi–Axial Compression
Authors: Przemieniecki J. S.
Published: August 2016

The problem of the buckling under bi-axial compression is considered for flat rectangular isotropic plates with simple edge conditions and no lateral restraint. The buckling stress coefficient is plotted against the side ratio for various conditions of edge restraint and a known compression or tension on the sides of the plate. It is found that there is some reduction in the buckling stress if the sides of the plate are subjected to compressive stresses and, conversely, there is an increase for tensile stresses. Furthermore, for plates with large side ratios, there is a rapid decrease of the spanwise buckling stress as the chordwise compressive stress approaches its appropriate Euler instability value.
Meteorology and High Altitude Aviation
Authors: Dobson G. M. B. , Brewer A. W.
Published: August 2016

The regular operating heights of aircraft, both civil and military, are continually increasing until now regular flights within the stratosphere are planned. There is, therefore, much practical interest in the meteorological conditions to be found in the stratosphere and upper troposphere. For about half a century meteorologists have been sending up small balloons carrying recording instruments which measure the temperature and pressure at heights up to 60,000 ft. or more, while recently radio transmitters have been incorporated in the instruments which transmit the temperature and the pressure to the ground station. By following the path of the balloon either by sight or by radio direction-finding, the velocity and direction of the wind at the various heights can also be found. From measurements made in these ways meteorologists have for many years known the general distribution of temperature and winds up to great heights.
The Design of Compression Structures for Minimum Weight
Authors: Farrar D. J.
Published: August 2016

The primary structure of an aeroplane usually consists basically of a set of tubular beams. The main structural box of the wing or tailplane is a well-known example: a semi-monocoque fuselage is another. For any given loading condition of the aircraft the material in the tube is stressed mainly in tension, in shear, or in compression, depending on its location in the tube cross section.

The aim of the designer is to make the material fulfil these three functions in the most economical manner. In tension, he is limited only by the quality of material available. In shear, this is again substantially the case, although it is well known that very light shear webs over great depths do not develop as high an effective failing stress as do more sturdy webs. This property of dependence on theintensity of loadingis much more marked in the case of the compression structure, which is liable to instability in various ways.
Aircraft Defect Report Procedure
Authors: Greenwood A. H. C.
Published: August 2016

This review is an attempt to examine, very briefly, the existing methods by which the airframe, engine and accessory manufacturers are informed of the operational troubles which are experienced by the users of their equipment, and how these manufacturers thus come to possess the knowledge which alone can enable them to avoid the recurrence of similar faults in the future. The importance of this knowledge can hardly be over-emphasised, but it is suggested that, in the past, there has been an abundance of such information which has failed to reach the right people at the right time.

For the purpose of this review it is proposed to divide the troubles to which the aeroplane is heir, into three main categories:—

1

Aerodynamic or handling faults.

2

Structural or design failures.

3

The general unreliability of components which causes low serviceability and utilisation rates.
The Stressing of Deflected Propeller Blades
Authors: Hodson C. F.
Published: August 2016

This note is intended to cover the more interesting items of progress made since 1930 by the Fairey Aviation Company, Limited, in methods for ascertaining the relief centrifugal bending moments due to bending deflection in twisted propeller blades. Ref. 1 describes the only reliable method known to the writer in use at the commencement of this period. The first substantial change was made in 1932, when the time required to obtain a solution was reduced from over a week to about half a day without any considerable sacrifice in accuracy. Owing to independent research and the usual circulation of junior staff the 1932 method is now fairly widely known under various names, but this note would be incomplete without its inclusion as it forms the basis of subsequent methods. The convergence by this method is not very rapid as it only halves the error at each successive approximation. An alternative method reducing the error to about one-tenth at each step is also given.
The Determination of Vibration Modes
Authors: Harpur N. F.
Published: August 2016

At some stage in the design of every aeroplane it is necessary to estimate or to measure the resonance modes of vibration. This has not always been the case, but the problems of flutter, control reversal and dynamic loads have increased in importance as speeds have risen. Nowadays, it is an airworthiness requirement that these effects be considered and the aircraft made safe for all conditions of flight. A knowledge of the normal modes of vibration is essential for all accurate estimates of these aeroelastic effects.

Taking flutter as an example, the technique of flutter investigations consists of first determining which combinations of the various possible degrees of freedom are liable to excite dangerous oscillations. Typical degrees of freedom for a wing are bending and twist in each normal mode, aileron deflection and tab deflection; for a tailplane and elevator we might consider tailplane bending or twist, elevator deflection, tab deflection, fuselage bending and twist, and pitching of the whole aeroplane.
The Servicing of Aircraft: Choice of Principle and Procedure
Authors: Crawley Blick
Published: August 2016

This paper discusses a few simple ideas which may be supposed to form, consciously or unconsciously, a schematic basis for the servicing of given aircraft in given circumstances. It is not concerned with engineering technique but rather with the assumptions behind it.

The purpose of an aircraft's upkeep, by which is meant its servicing and maintenance in the widest sense, is to enable the machine to furnish the maximum output of flying work of the required kind and intensity. “Intensity” is used to mean an aircraft's rate of output of flying work in a calendar period.

For commercial aircraft the average intensity required is usually near the maximum that can be sustained at reasonable upkeep expense, because this tends to maximise net profit (or to minimise net loss if there is no profit) by lowering the overheads related to the capital cost of aircraft.
Mechanical Vibration and Aeroelasticity
Authors: Walker P. B.
Published: August 2016

In his article “The Expanding Domain of Aeroelasticity,” Professor Collar explains how, in the course of a few years, the subject of aeroelasticity has grown from a mere collection of problems of common interest to the aerodynamicist and the structural specialist to become a main branch of aeronautical engineering. Aeronautical engineers owe Professor Collar a debt of gratitude for defining in the clearest terms what aeroelasticity purports to be, and for removing the vagueness and uncertainty which so often permeates any new branch of science or engineering, especially when it is derived from long–established subjects, as aeroelasticity is from aerodynamics and theory of structures.

As is to be expected from one so distinguished in the aeroelastic field, Professor Collar writes especially from the standpoint of the aeroelastic specialist. Engineers with a different background, while accepting the broad principles which Professor Collar lays down, may see their applications and development in a different light.
Rockets and Assisted Take-Off
Authors: Cleaver A. V.
Published: August 2016

Under present conditions, the author of any paper on rocket power plant engineering must inevitably apologise for a certain reticence as regards technical details, which is imposed by security requirements. These arise from the important applications of rocket propulsion for guided weapons and other military purposes, and are less stringent in regard to its use as a means for providing take-off assistance. It is with the latter subject that this paper will be mainly concerned when practical applications are discussed.

Most of the fundamentals are common to all uses of the rocket motor and it is hoped that a general survey of these may be of some value, especially since the field of rocketry has been relatively neglected in the technical publications of this country.
Note on the Distortion Characteristics of Swept and Cranked Wings in Relation to Flutter and Other Aeroelastic Phenomena
Authors: Williams D.
Published: August 2016

The parts played by calculation, and by resonance tests on simplified scale models, in obtaining the normal modes of an aeroplane with wings of unorthodox plan forms are discussed on the basis that the normal modes are the best means of defining the elastic-inertia characteristics of an aircraft for the purpose of flutter investigations.

Methods of simplifying the model for ease and cheapness of construction are put forward.

The radical difference between the effects of shear-lag and of ordinary bending-shear flexibility is described, and an approximate method of allowing for the latter effect is indicated.
A Structural Test Frame with Automatic Loading
Authors: Page F. W. , King J. C.
Published: August 2016

The Design of test frames of all types owes a great deal to the pioneer work of the Structures Department, Royal Aircraft Establishment. This particular frame contains some novel features and has been subjected to some unusual overall calibration tests, particularly in relation to the entirely automatic and centralised control gear.

The choice of apparatus for testing large scale structural components may be influenced by many factors. In the present case, the choice of a test frame rather than other types of equipment was governed by the following considerations.

In an industrial establishment it is essential that test equipment should be put to maximum use. Unlike a central testing establishment such as the R.A.E., major strength tests are relatively infrequent and therefore the equipment should also be suitable for as much as possible of the development and research testing which cannot be undertaken on standard material testing machines.
Planning and Aircraft Development
Authors: Olaf Thornton F.
Published: August 2016

Much has been written about planning and progressing as applied to manufacture, but there is a noticeable lack of information on its application to the design work which must precede construction.

It is in order to help fill this gap that the present paper has been written.

The paper deals with planning applied to the development of prototype aircraft from the time of submitting a tender up to the first flight of the first prototype.

It discusses the methods of estimating the lapsed time up to first flight, the design man-weeks likely to be expended, methods of measuring design progress and the cost of design changes.
French Turbo–Propeller and Turbo–Reaction Engines
Authors: Destival P.
Published: August 2016

When, in the course of his visit to Paris in May 1948, Dr. Roxbee Cox invited me to lecture to the Royal Aeronautical Society on our work in the field of turbopropeller and turbo-reaction engines, I was torn between two sentiments; the great honour which was done to me, and the seeming temerity for a French engineer to discourse on aircraft turbines before some of the people who had been responsible for the W2 700, the Nene, Ghost, F2, Theseus, Mamba, and other engines. The first of these sentiments however carried the day, as it could hardly fail to do in view of Dr. Roxbee Cox's extreme kindness.

Therefore I ask for the indulgence of my audience in listening to this, the first account to be given of the modest work done since 1941 by a team of French technicians, who were specialists in steam and industrial gas turbines, who had foreseen the possible development of the latter for aircraft, and who, completely cut off from the engineering world during the Occupation, at first worked literally in complete isolation, unaware even of the existence of the British and German achievements.
The Development of the Goblin Engine
Authors: Moult E. S.
Published: August 2016

Work on the Goblin engine was started in 1941 when, at the invitation of the Ministry of Aircraft Production, the de Havilland Enterprise began to interest itself in jet propulsion. At this time de Havillands were much in ignorance of the work of Air Commodore Whittle, the Royal Aircraft Establishment and the Gloster Company in this field. The first step was to study what had already been done and in this connection the fullest co-operation was offered by all concerned. The author would like to express the appreciation of the organisation with which he is associated for the material help received in those early days by way of advice, data and drawings. As a result, it was possible to start fully abreast of what was being done in this country. The benefits of further experience and mutual assistance from the pioneers in jet propulsion were fostered by a process of frank discussion and exchange of information, finally to be cemented by the formation of the Gas Turbine Collaboration Committee.
Some Notes on Aircraft Overhaul and Maintenance
Authors: Jackson Clifford H.
Published: August 2016

Commercial aircraft, in common with all public transport, must be subjected to routine inspections and regularly overhauled in the interest of both safety and economy.

Aircraft maintenance and overhaul are not just the domestic concern of the organisation doing the work. There must be adherence to Standards approved by the Air Registration Board on behalf of the Ministry of Civil Aviation; and these Standards are the national interpretation of some of the directives issued by the International Civil Aviation Organisation as part of the international agreements regulating air safety. The regulations are neither rigid nor detailed, but they exist for the protection of air travellers against the remote chance of an operator failing to maintain airworthiness. In particular, they call for regular maintenance checks and, to procure annual reissue of the Certificate of Airworthiness, an annual overhaul or its equivalent.
High–Speed Flying
Authors: Derry John D.
Published: August 2016

The Title of this paper gives only the broadest indication of the line it is intended to take. Other papers with similar titles have been read by those connected with the design or aerodynamic side, but this paper is mainly concerned in conveying the pilot's own view of the problems of high-speed flying.

The paper is divided under the following main headings:—

1.

The obstacles to negotiate at high and low altitude.

2.

The approach to high–speed investigation and means of obtaining test results.

3.

Present and future requirements of research aircraft.

4.

Pilot safety measures.

5.

Some requirements of a pilot engaged in high speed research and development flying.

For the most part it is intended only to cover research and development flying. This necessarily entails some reference to combat, which is in itself a separate field.

The problems confronting a pilot who sets out to explore the behaviour of contemporary aircraft at high speed are considered first.
Power Plants for High–Speed Aircraft
Authors: Baxter A. D.
Published: August 2016

A few years ago when high–speed aircraft were mentioned, speeds of 300 to 400 m.p.h. came to mind. The advent of jet propulsion has made those figures 100 per cent, out of date and today speeds are discussed more and more in terms of Mach number; for example, high–speed subsonic aircraft fly at Mach numbers of 0.85 to 0.90, aircraft are flying in the transonic region and supersonic guided missiles are proposed for speeds anywhere between M=1.5 and 2.5, i.e. ground level speeds up to 2,000 m.p.h.

It is proposed to review very broadly the suitability of propulsion units for these transonic and supersonic applications. What is the difference between ordinary power plants and those for high speed? The answer might be contained in another question—why are supersonic aircraft different from conventional types? The aerodynamicist will give an involved explanation concerned with compressibility, drag rise, shock waves, and so on.
Prophecy and Achievement in Aeronautics
Authors: Garner Harry M.
Published: August 2016

The Fortieth Wilbur Wright Memorial Lecture, “ Prophecy and Achievement in Aeronautics,” was given by Sir Harry Garner, K.B.E., C.B., M.A., F.R.Ae.S., before the Royal Aeronautical Society on Thursday 29th May 1952 at the Institution of Civil Engineers, Great George Street, S.W.I. Mr. G. H. Dowty, F.R.Ae.S., President of the Society, presided over the meeting which comprised some 350 members and guests.

Medals and Prizes awarded by the Council for 1951-1952 were presented before the Lecture.
Research on Aerodynamic Noise From Jets and Associated Problems
Authors: Richards E. J.
Published: August 2016

After two years research work in the Universities of this country and elsewhere, there is need for a comprehensive review of the present position on the suppression of aerodynamic noise from jet engines. This report outlines the fundamental understanding of the problem that has been achieved, the basic experimental work done, and the noise suppression techniques which have been suggested.

A study is made of measured noise levels on advanced types of engines and an analysis is made of reductions required and so far achieved with the proposed noise suppression devices. While the basic principles underlying noise formation, both in subsonic and supersonic jet streams are beginning to be understood, the noise reductions so far achieved are still insufficient and warrant an extended programme of research.

The report includes helicopter noise analyses with pressure and pulse jets, and touches on the problem of structural fatigue in the vicinity of a jet stream.
The Flexural Centre or Centre of Shear
Authors: Duncan W. J.
Published: August 2016

This paper reviews work on the flexural centre of elastic cantilever beams and contains a number of hitherto unpublished results, including a formula giving the position of the flexural centre in terms of the Prandtl torsional stress function.

The appearance of the note by Jacobs has prompted the preparation of a review of this subject which is all the more desirable as several of the investigations made shortly before the 1939-45 War were never published and others, although published, seem to be in danger of being overlooked. The present paper contains a number of hitherto unpublished results. The question of nomenclature is worthy of mention since general agreement is lacking. Some of the names used are flexural centre, centre of flexure, elastic centrum and centre of shear but a complete search of the literature would probably lead to the discovery of yet other names. The terms “centre of shear” and “elastic centrum” seem vague and fail to indicate that the point referred to has any special relation to flexure. We shall here use the name “flexural centre” exclusively.
Airframe Fatigue
Authors: L. P. Coombes
Published: August 2016

The Journal in which Mr. W. Tye's Second Barnwell Lecture has been published (“ The Outlook on Airframe Fatigue,” May 1955 Journal) has now reached Australia. I felt that some comment was called for when I discovered that Mr. Tye had not mentioned the work done in Australia on the life of aircraft structures.

What I believe to be the facts are as follows. Australian concern regarding fatigue was awakened in January 1945, when a Stinson air liner VH-UYY crashed with the loss of ten lives. The analysis made by the C.S.I.R. Aeronautical Research Laboratory confirmed that it was caused by a fatigue failure in the welded tube of the primary wing structure.

Mr. H. A. Wills, in charge of structural and metallurgical research at the Laboratory, initiated a programme of fatigue tests on actual aircraft wings, designed to give factual answers to the problem of determining the safe life of aircraft structures. The basic idea that this could be done had been suggested in a paper by Bland and Sandorf0, and the Stinson accident provided the necessary urge.
Part 2 Some Features of Flight Testing on the Fairey F.D.2 Leading up to the Successful Attempt on the World Speed Record and Subsequent Flying
Authors: Twiss L. P.
Published: August 2016

The opening paragraph in my first Flight Test Report after the initial flight of the Fairey Delta 2 still rings very true today:—

“This aircraft shews every promise of being a very pleasant flying machine. Soon after take-off, I had confidence in the handling characteristics, and I should like to congratulate all the design and engineering personnel who made this possible.”

This great day was the 6th October 1954, at Boscombe Down, and was the start of an intensely interesting development programme—not without its setbacks and excitements—which was highlighted last March by the gaining of the World's Absolute Air Speed Record for Britain. The early flights followed the pattern of most prototype aircraft and, but for an unfortunate setback on the fourteenth flight, went very smoothly.
An Analysis of Flexural Systems under Arbitrary Distortion and End Loading
Authors: Midgley P. J.
Published: August 2016

The effects of end loading on an arbitrarily distorted flexing beam are investigated, with particular reference to bending moment distributions along the span of the beam, and the effects of lengthwise strains. Cross-spring and “ spider ” type flexural systems are treated in detail. Curves are presented which enable the stiffness and stressing of any flexural system to be calculated for any loading conditions, subject only to the restriction that deflections are small, so that the linearised beam equation may be applied.
Short Cut Method for Estimating Aircraft Direct Operating Costs
Authors: Hamshaw Thomas C. J.
Published: August 2016

While congratulating F. H. Robertson on his technical note in the January 1957 JOURNAL (page 52) on “short cut” methods of estimating aircraft direct operating costs, which certainly give a very rapid approximate answer, I am somewhat uncertain as to its practical value. In the analysis of possible projects, having established the general range of operating costs, which can usually be done by a combination of experience and inspection, interest lies primarily in the effect on cost of operation of such factors as change of type of power plant, fuel used, what complexity of structural designs is permissible from a cost aspect, how much is desirable from a weight saving aspect and so on. Unfortunately, Mr. Robertson's formulae do not allow such comparisons to be made primarily because of the assumptions made.
Solution of Aeroelastic Problems by Means of Influence Coefficients
Authors: Williams D.
Published: August 2016

It is shown that, on the basis of the data provided by two sets of influence coefficients for a wing (or other surface)–an “elastic” set giving deflections (and hence incidence angles) in terms of applied loads, and an aerodynamic set giving aerodynamic loads in terms of incidence angles (or other linear function of the displacements)–all “static” aeroelastic problems can easily and expeditiously be solved by the use of a digital computer. It is also suggested that the same method of approach may well be used for solving oscillatory aeroelastic problems such as flutter.
Thickness Parameters by Rapid Integration of Turbulent Boundary Layer Profiles
Authors: Garner H. C.
Published: August 2016

The turbulent boundary layer on an aerofoil is represented by simple distributions of velocity, so as to obtain approximate general formulae for the displacement and momentum thicknesses in terms of two ratios of local velocity to that at the edge of the boundary layer.

Optimum positions for the local velocity are calculated to be at 0·15 and 0·62 of the boundary layer thickness from the aerofoil surface. The accuracy of the formulae is closely examined. A rapid experimental and numerical procedure is given for estimating the displacement and momentum thicknesses within ± 2 per cent. A minimum of seven velocity measurements has been found satisfactory in practice.
Liquid Propellant Rocket Motors
Authors: Diplock B. R. , Lofts D. L. , Grimston R. A.
Published: August 2016

It has been said that a rocket motor is the simplest “ prime mover.” This is correct in theory, since fundamentally a rocket consists of a chamber containing a gas under pressure, having a nozzle at one end through which the gas expands, forming a propulsive jet. Since the pressure ratio of the rocket is always greater than the critical pressure ratio, the nozzle is invariably of the convergent-divergent or de Laval type in which the velocity is subsonic up to the throat, sonic at the throat and supersonic in the divergent portion.

It is a popular fallacy that a rocket or jet engine obtains a forward thrust by allowing the rearward jet of gas to push against the atmosphere in which it is operating. This is not correct and it can be proved that a rocket will operate successfully, and more efficiently, in a vacuum.
Tube of Least Weight for Given Torsional Stiffness
Authors: Howard H. B.
Published: August 2016

Consider a thin-walled tube fixed at one end and subject to torque of known distribution. The problem is to find how the thickness of the wall should vary along the length so that the weight is a minimum for a given angle of twist at the free end.

At distance x from the fixed end, let T be the applied torque, A the enclosed area of the tube, P its perimeter and y the wall thickness.
Reheat for Gas Turbines
Authors: Edwards J. L.
Published: August 2016

Some five years ago the author was privileged to deliver a Section Lecture to the Royal Aeronautical Society on the subject of reheat. The present paper attempts to summarise the problems which now arise and to give some idea of the progress which has been made in the intervening years.

In 1949, reheat was in its infancy in Great Britain. A certain amount of progress had been made in the United States but the information from that source was scanty and vague. Tests at the National Gas Turbine Establishment (N.G.T.E.) had given some engine data but this was in the nature of preliminary information only and was by no means complete. In fact the majority of the problems which now beset us were then completely unknown or were considered unimportant. The N.G.T.E. work was valuable, however, in that it demonstrated the practicability of reheat, although at the time the comments of many who saw this and other schemes in operation were somewhat sceptical and definitely unflattering.
Indicial Admittances for Linear Systems with Variable Coefficients
Authors: Duncan W. J.
Published: August 2016

The solution of a set of m ordinary linear differential equations of the nth order having variable coefficients can be provided by the use of a set of m2 indicial admittances and the solution is derived from that given by the use of impulsive admittances. The indicial admittances are easily derived from the impulsive admittances and vice versa.

An “indicial admittance” is a function representing the response of a system to an applied “input” in the form of a “unit step function” and the concept is due to Heaviside. When the indicial admittance is known, the response to an input which varies with time in an arbitrary manner can easily be found. Similarly, the response can easily be found when the “impulsive admittance” is known, where this is the response to a unit instantaneous impulsive input.
Experimental Study of the Effects of Jet Noise on an Aircraft Structure
Authors: Hetzel K. W.
Published: August 2016

Reports of noise effects on the rear fuselage structure of large British aircraft indicated that one might expect noise damage in this region on the Vickers Supermarine Type 544 aircraft. It will be seen from Fig. 1 that the jet efflux from each engine passes close to the fuselage side and under the tailplane. The fuselage structure proper is, however, protected from the heat and noise effects at the jet efflux by a fairing which is insulated at all attachments. This fairing, by virtue of its shape, is called the “ pen nib. ”
Integral Construction
Authors: Keen E. D.
Published: August 2016

There has been considerable activity of recent years, particularly in America, in the field of integral structures for aircraft.

The fundamental problem in aircraft structures is to make a relatively thin skin covering take applied compression, shear and bending loads. This has been achieved so far by the attachment of stiffeners, but this requires a large amount of riveting which in itself causes structural inefficiency and also spoils the smoothness of the skin, particularly when laminar flow is desired. Metal gluing shows great advantages over riveting in this respect but it is doubtful whether the bond strength will be great enough to attach very heavy stringers to very thick sheet. Where structural loadings become higher the required thickness of sheet and stringers may make the continued use of riveting difficult, if not impossible.
Some Measurements of Leading Edge Separation Bubbles on a 10 per cent Thick Symmetrical Aerofoil
Authors: Black J. , Hunt R. D.
Published: August 2016

Pressure Distribution and liquid-film tests on a 10 per cent, thick aerofoil revealed the presence of separation “bubbles” close to the leading edge. These bubbles are formed beneath the boundary layer which separates near the leading edge and re-attaches farther aft; their existence is usually indicated by localised constant-pressure regions in the pressure distributions. It is also believed that if a thin film of liquid (such as a suspension of lamp-black in paraffin) is spread on the surface, the scrubbing action of the air rotating in the bubble will tend to draw liquid forward into the bubble, and hence the location and extent of the bubble may be indicated approximately by the accumulation of the fluid.

Many boundary layer traverses of bubbles on N.A.C.A. aerofoils have been made, but it was felt that similar measurements of the bubbles on this particular aerofoil would provide useful data, since the separation characteristics of this section appeared to differ from those in the N.A.C.A. tests.
Results of Photoelastic Investigation of Stresses in a Tension Bar with Unfilled Hole
Authors: Jessop H. T. , Snell C. , Jones I.
Published: August 2016

Although this problem is one which has been investigated by many photoelasticians, there appears to be no record of any systematic exploration of the effect upon the stress distribution of the ratio of hole–diameter to width of bar.

In this investigation tests were made upon a standard sized bar with four different sizes of holes, and the stress distribution on the cross section of the bar through the hole centre was explored for the four cases.
The Jet Flap
Authors: Davidson I. M.
Published: August 2016

Throughout the animal kingdom powered flight is a surprisingly common attribute and whenever it occurs both the sustenation and the propulsion are provided by the same structural and aerodynamic mechanism. There is, in fact, but a single aerodynamic reaction which is divided, for convenience, into thrust and lift. In earlier times this convention was presumably not recognised, for the ornithopter appears to have formed for some centuries the principal technical basis of man's aspiration to heavier-than-air flight. Of the exceptions, Leonardo da Vinci's helicopter is now, of course, an accepted vehicle, but this lecture is concerned mainly with fixed-wing aircraft for which it is significant that success came only with the aeroplane, or, as Lachmann has recently put it, with the powered glider.
Some Thoughts on Aeronautical Research and Design
Authors: Morgan M. B.
Published: August 2016

“To know, can only wonder breede,

And not to know, is wonders seede.”

There is a peculiar magic in these lines of Sidney Godolphin, penned 300 years ago. I can think of no better introduction to a paper on aeronautical research and design.

Flying is rather a remarkable business, about which we are inclined to get a little blasé nowadays. Few things can tax the engineers' skill more than the design of a modern high performance aeroplane. In its way it represents supremacy in engineering achievement. Let us not take all this too much for granted; and let us remember those gifted designers—no longer with us— who laid the foundations of the art. Among these, the name of Roy Chadwick stands high.
Electronic Control Techniques in Aircraft Manufacture
Authors: Kermack G. S. , Ogden H.
Published: August 2016

This paper is concerned with a method of improving the utilisation of metal cutting machine tools and thus deals with that part of production covered by machining. It is particularly applicable to the Aircraft Industry, where the production of military aeroplanes must be as rapid as possible and the costs of civil aircraft in a competitive market must be kept to the minimum. As it is designed to be used in conjunction with small quantity manufacture it can be of great assistance in development work.

The limitation to the rate at which machining of any part can take place is generally dictated by the rate at which information can be transferred to a machine tool and converted into appropriate slide movements. In large scale manufacture where batch sizes are high, this transfer of information is normally effected by elaborate pre-set tooling arrangements and the cost and time required to prepare this information is acceptable only as the cost per part becomes very small.
Metals and their Heat Treatment
Authors: Williams S. G.
Published: August 2016

Mr. Williams remarked that the modern tendency in engineering is to endeavour to heat-treat the existing metals to enable them to withstand the stresses induced by modern design.

Many similar metals are used as in days gone by, but the modern steels are alloyed with other elements to enable them, with particular treatment, to give much higher strength results. For these alloy steels and also for the lighter alloys, special precautions have to be observed in their manufacture, whether they are destined for automobile or aeronautical work, although with aircraft work more precautions are necessary than in any other class of manufacture.