bluuebunny/crossref_metadata_2025 huggingface dataset:
On the wrinkling of honeycomb sandwich columns with laminated cross-ply faces
Authors: Webber J. P. H. , Kyriakides S. , Lee C. T.
Published: July 2022

In the theoretical and experimental work on the buckling of sandwich panels with laminated faces reported in Refs. 1 and 2, panels which had certain coupling terms present in the constitutive equations for the faces were solved in an approximate manner. The previous theoretical solution for angle-ply lay-ups assumed that there were sufficient layers present to treat the faces as orthotropic, with the Bij coupling terms in the constitutive equations put equal to zero. Further simplifying assumptions were made when comparing theoretical and experimental results in Ref. 2 where tests were carried out on three different types of carbon fibre faces; orthotropic, balanced angle-ply and unbalanced cross-ply. It was only in the first case that an exact theoretical analysis was carried out, and the second case was again treated as an orthotropic panel neglecting coupling between direct and shear deformations and bending and twisting curvatures. The unbalanced cross-ply lay-up, which consisted of two fibre reinforced plastic orthotropic layers, one at 0° to the plate axis and one at 90°, gave rise to large B11 and B22 coupling terms which were taken into account approximately using “reduced stiffness” terms with the orthotropic equations. However, the disparity between theory and experiment was greatest in this case, particularly as far as wrinkling was concerned, where the experimental failure load was 78% higher than the theoretical wrinkling load. This type of cross-ply layup is important since it is used when making carbon fibre sandwich floor panels; it being chosen from the point of view of manufacturing convenience rather than from considerations of strength and stiffness. Furthermore, the bending stresses in the faces, which result from the normal loads, predominate in one direction so that one face is subjected to essentially a uniaxial compressive stress which might cause the faces to wrinkle. In order to study this problem in greater depth, it was decided to carry out further theoretical and experimental work on the simpler problem of the wrinkling of sandwich columns with carbon fibre cross-ply faces.
Design organisation — past, present and future
Authors: Conway H. G.
Published: July 2022

There can hardly have been a time in the history of Britain where a national consciousness of the importance of design to the future economic health of the nation can have been more needed. More investment, more wage restraint, a ‘fair day’s work’ and all the other matters about which we are exhorted would be of little avail if the products which we must sell to the world if we are to survive are not better, in the broadest sense of the word, and how can a product be made better if not by design?
Co-operation and Diversification
Authors: Strang William J.
Published: July 2022

This paper is intended to illustrate some of the new features of design management which are likely to be particularly important for the large, high technology organisations.

The two subjects that have been chosen for discussion are co-operation, both national and international; and diversification. The need to consider both of these subjects arises from the same cause; the general economic climate and the increasing complexity and cost of high technology projects. The complexity and more particularly cost mean that no one organisation or even country will tackle them alone—hence the need for co-operation.
Aspects of system procedure development for Concorde and future aircraft
Authors: Hobbs J. D.
Published: July 2022

The aim of this paper is to trace the evolution of the flight documentation of Concorde, with special emphasis on crew operating procedure, and to make some generalised predictions of the impact of recent technology on the methods of operating aircraft in the future.

The overall process of Concorde certification has been described elsewhere, the aspect with which we are concerned here being the approval of the aircraft’s operating procedures. The generation of these procedures is an involved process, one which started for Concorde in December 1967, with many possible difficulties foreseen in the aircraft operational sphere and neither of the prototypes having flown.
Uniformly loaded, simply supported, antisymmetrically laminated, cross- and angle-ply strips on a Winkler/Pasternak foundation
Authors: Turvey G. J.
Published: July 2022

During the course of the preceding decade, numerous solutions to laminated plate problems have appeared in the literature. This has been the direct result of the development of new materials, e.g. Carbon Fibre Reinforced Plastics (CFRP), for the aerospace industry, where lightness allied with stiffness are characteristics of paramount importance. However, it appears that few, if any, solutions have been published for the case of plates on elastic foundations, even though such solutions may be useful when analysing the face behaviour of certain types of foam-filled, sandwich panels. In attempting to provide such solutions and to establish the effect of the foundation on the plate response, the subsequent analysis was undertaken. As a first step towards this goal, it appeared sensible to consider the simple case of a plate strip, before considering the more complex case of a finite plate. Consequently the analysis and results presented herein are restricted to plate strips.
On the forward throw of the caustic associated with transonic acceleration of a supersonic transport
Authors: Onyeonwu Ronald O.
Published: July 2022

The use of the theory of geometrical acoustics in the calculation of focussed bangs has received wide attention over the past two decades. None of these calculations however had been formulated for an aircraft manoeuvring in an arbitrary manner in a real atmosphere. Further, in most cases the results have not been presented in such a manner as to be useful to practising engineers. Recent formulation now permits the prediction of the focussing ray precisely and directly without having to compute all the rays reaching the ground from the source.
Future trends in aero gas turbine design—Conventional engines
Authors: Denning R. M. , Miller S. C. , Wright G. H.
Published: July 2022

Three qualities come to mind as seeds for success in civil aircraft engine design over the next two decades—care, optimism and judgement; care to exploit and extend the technology of the high bypass ratio fan engine, optimism to continue to seek apparently unconventional concepts, and judgement to identify the opportunities when each should be applied.

This paper accepts this definition of the engine designer's choice and reviews a range of possible trends, some more likely than others. It is in two parts. The first, entitled ‘Conventional Engines', concentrates on the family of high bypass ratio single stage fan engines which has become established as the preferred design for application to aircraft cruising at high subsonic Mach numbers.
An appraisal of present and future large commercial hovercraft
Authors: Wheeler Raymond L.
Published: July 2022

It is only fifteen years since the hovercraft principle and early configurations were first described in Ref. 1. Since then, we have seen the development of a wide range of craft and many applications in both civil and military roles.

This paper gives a brief review of the performance capability of the Mountbatten Class SR.N4 amphibious hovercraft which are currently operating on the English Channel ‘short sea’ routes and indicates the improvements anticipated from a simple but substantial lengthening of the craft. A contract has now been signed with British Rail to lengthen both of their craft, and design and manufacture work is now in progress. The first craft returns to BHC in December 1976 and will be back in service in its modified form by December 1977.
Aeroelastic stability and control of an oblique wing
Authors: Jones R. T. , Nisbet J. W.
Published: July 2022

Aerodynamic properties of oblique wings have been studied intensively at NASA Ames Research Center and also by the Boeing Commercial Airplane Co. Figure 1 shows the design proposed by Boeing for a 200 passenger transport intended to fly in the transonic speed range; the design employs an oblique wing of high aspect ratio.

One feature of the oblique wing design that has not been fully documented is its aeroelastic stability. Since the oblique wing has one panel swept forward and the other swept back, it is perhaps natural to try to relate its behaviour to well known phenomena associated with conventional swept-forward or swept-back wings. This approach would lead one to expect aeroelastic divergence of the forward wing panel.
Non-active nutation damping for single-spin spacecraft of all mass distributions
Authors: Tonkin S. W.
Published: July 2022

The purpose of this paper is to describe a new component for spacecraft. The subject is not quite new in that the author presented a paper (Ref. 1) on the subject this year.

The original idea for the device came from thoughts about an extension beyond the terms of reference of a study contract. After a proposal had been made it became apparent that Cloutier of Hughes Aircraft had made a remotely similar proposal, but apart from its mention in some letters, no publication has been seen by the author.
Costs and decision making
Authors: Wimpenny J. C.
Published: July 2022

The preceding symposium papers have indicated the saleable developments on offer in the constituent parts of the civil transport system and their collective impact in aircraft project terms is covered in the paper by Brown and Lawson.

As the aircraft industry matures performance gains come less readily and costs have become a much greater determinant of progress. This paper therefore considers some of the fundamentals of cost reduction. This topic cannot be considered in isolation; cost reductions must be balanced against product effectiveness and there are major interactions between possible cost levels and sales volume. Thus, it is necessary to treat the subject in the broader framework of commercial viability. This paper attempts this task. It starts with the more direct cost questions, considers market interaction factors and concludes on a positive note by a critical review of the investment decisions needed, many of which are urgent and of critical importance to the future of the industry.
Advanced materials and their use in civil aircraft structures
Authors: Ham A. C. , Willshire A. J.
Published: July 2022

A comprehensive survey of advanced materials for civil aircraft structures from the research point of view would of course include new aluminium alloys, titanium alloys, steels, composites, transparency materials and adhesives. Such a survey is, however, out of the question within the scope of this part of the paper and attention will therefore be concentrated on fibre-reinforced composite materials, partly because as a primary structural material they are now widely recognised to offer much the greatest prospect for really substantial improvements in structural efficiency (weight saving of the order of 30%, for example Fig. 1.1 shows comparative specific properties of various structural materials) and for lower costs, and partly because to realise these improvements a wide and in many ways novel range of research problems throughout the whole spectrum of material development and characterisation, design, fabrication and testing needs to be solved. It will nevertheless be possible, even with this limitation, to do no more than to give a brief sketch of the present position in some of the main research areas, primarily from the UK point of view.
The analytical geometry of a simple skew-hinge mechanism
Authors: Burrows Francis M.
Published: July 2022

As one means of achieving the required movement of a flying control the simple skew-hinge mechanism appears attractive because it has a significant range of approximately linear operation and because all of its mechanical components can be accommodated easily within the sort of shallow depth available in some wings. The mechanism is kinematically similar to that of the well-known Z-crank and Fig. 1 shows one possible arrangement of it inside a wing. For this particular case an axial translation of the control push-pull rod AA causes rotation of the flying control H about its hinge axis BB and the mechanical connection between these driving and driven members consists of the skew-hinge itself, which is attached to the flying control H and which has an axis CC which intersects the axis BB at an angle α, together with the other components of the mechanism. These are the hinge driving-block F, the driving-link G, and the drive transmission-collar I.
A theoretical approach to the wedge shaped hot film probe performance
Authors: Aminzadeh M. , Modi V. J.
Published: July 2022

There are several well developed theories reported in literature for evaluating performance of a hot wire anemometer. On the other hand, although hot film probes play a rather useful role in the experimental liquid flow studies, no well developed theory systematically accounting for conduction and free convection losses is available, particularly, in the Reynolds number range of 2-350 (based on average flow rate and film width). This is indeed surprising since the fact that in this range of Rn viscous effects are of the same order as those due to inertia, was first recognised by Barker as early as in 1922. Thus it has been necessary to resort to careful calibration for each shape of the probe. The theory presented here represents a modest step towards minimising dependence on such tedious experimentation with reference to widely used wedged film probes.
Astronautics and Guided flight Section
Authors: Mathews Charles W.
Published: July 2022

During the first dozen years of space flight, from Sputnik to the initial Apollo lunar landing, the costs of space exploration and utilisation were not a major constraining factor. Indeed, the difficulty of initially penetrating beyond the earth's atmosphere and then the rapid extension of this capability to lunar distances (and beyond for unmanned spacecraft) dictated approaches that emphasised the highest performance, lightest weight, and the utmost in reliability that could be attained from the state-of-the-art available. As might be expected, conditions have changed. People are expecting a maturing relationship between the benefits achieved from space flights and the costs to attain them. Fortunately, approaches have been identified and the technology exists to greatly reduce the costs of space activities without degradation of safety or mission success. Of equal importance, we have identified many areas of actual or potential direct benefits from the ability to enter and operate in space which should be further developed. They include global communications, meteorology, earth surveys, materials processing, medicine, as well as the intellectual stimulation of scientific investigation and exploration, and others.
Effect of environmental forces on the attitude dynamics of gravity orientated satellites
Authors: Flanagan R. C. , Modi V. J.
Published: July 2022

For satellites that have part or all of their orbits extending into the earth's effective atmosphere, i.e. less than 500 miles, it is necessary to consider the contribution of the aerodynamic force in attitude dynamic studies. The importance of the aerodynamic torque is revealed by the fact that it is comparable to earth radiation at 500 miles, direct solar radiation at 400 miles, and depending on satellite geometry, can be as large as gravity gradient torque at 200-300 miles. Hence, in addition to solar and earth radiation torques, this paper includes the effect of the rarefied atmosphere on the response of gravity gradient satellites, thus covering the entire altitude range.
The calibration of a surface static tube
Authors: Sproston J. L. , Göksel Ö. T.
Published: July 2022

The usual method of determining the static pressure distribution about a model under test often relies on guessing the required positions of the static holes before the form of the distribution is known, and subsequently adding further holes to the model where particular interest may arise. This technique can clearly prove both tedious and expensive.

Therefore interest lies in the accuracy of representation of static pressure obtained from a static tube lying on the model surface.
Smoke observations of wakes of tandem cylinders at low Reynolds numbers
Authors: Zdravkovich M. M.
Published: July 2022

The appearance of the Kármán vortex street in the wake of bluff bodies has been well-known for sixty years. But the simple question of whether it appears also in the wakes of two cylinders in tandem at the same speed range, seems to have been unanswered as yet. The main reason for this is presumably the lack of practical interest. The only exception was in the early years of aviation in the era of biplanes. The use of streamlined or cylindrical struts was common and stimulated the investigations of Panell et al 1915, Wong & Yu 1917, Frazer & Simmons 1917, Biermann & Herrnstein 1933, and others.
The design of agricultural aircraft
Authors: Lockspeiser David
Published: July 2022

Aircraft have been used for survey and pest control for over 50 years, the business expanding from the early days of mostly converted military training aircraft to the present when agricultural aircraft are accepted as specialised aircraft designed for their specific jobs in their own right.
The Common Market and Australia's external aviation policy
Authors: Poulton Harold W.
Published: July 2022

On 13th November 1945, my distinguished countryman, Sir Hudson Fysh, KBE, DFC, delivered the first British Commonwealth and Empire Lecture inaugurated by the Royal Aeronautical Society. Significantly, in 1957 the title of this lecture series was changed to “The British Commonwealth Lecture”. Sir Hudson chose as his subject “Australia in Empire Air Transport”.

I feel deeply honoured to have this opportunity to contribute to the very considerable accumulation of knowledge which this series of lectures represents. My topic, despite the difference in title, is really a continuation of Sir Hudson's theme, with the advantage of an additional twenty-five years of hindsight.
Fighter testing—spin test or spin prevention test?
Authors: Rutan Burt
Published: July 2022

One of the severest operational limitations of a fighter is high angle of attack. I would like to discuss a philosophy of requirements on approach to testing and aircraft improvement. I will also summarise the results of the recent USAF, F-4E Stall/Near Stall Investigation.

For review, consider the classic approach used to testing at high angle of attack. All fighters are stall tested, i.e. a determination of handling qualities is made up to maximum usable lift. This, of course, also involves determination of natural stall warning, stall speeds and stall recovery techniques. Testing at angles of attack above maximum usable lift is generally delayed until a spin test programme is accomplished.
The operation of the Intelsat communications satellite system
Authors: Mellen Sydney L. W.
Published: July 2022

Since its creation in 1964, Intelsat has launched and positioned 10 satellites in synchronous orbit. The first of these was Intelsat-I, known as Early Bird, launched in April 1965; the most recent was Intelsat-IV (F-2), the first of a new series of Intelsat satellites. The IV (F-2) was launched in January 1971 and entered into service during March in the Atlantic Ocean area. The next Intelsat-IV satellite is scheduled to be launched later this month for positioning in the Atlantic Ocean area also. Subsequent Intelsat-IV launches are scheduled for 1972 and 1973.
On sonic boom avoidance
Authors: Batdorf S. B.
Published: July 2022

In a recent paper (Ref. 1) Dr. Hilton proposed the use of manoeuvres for creating zones of “no boom” which could be employed to protect cities situated along the flight path of a supersonic aircraft. The basic idea was to make use of the fact that curved flight causes a local focus of shock waves and that, in regions closer to the centre of curvature than this focus, shocks do not form.

In investigating this intriguing suggestion, the author found it advantageous to abandon the Huygens-type construction used by Hilton and employ in its place a technique which permits plotting the shock front directly. In applying this approach to manoeuvres of the type proposed for shock avoidance, regions of single, double and even triple shocks were found, but no shockless region. The method used and the results obtained are outlined briefly in the following sections.
The flexibility matrix for an “exact” torsion-bending finite element
Authors: Bolland G. B.
Published: July 2022

A finite element which allowed warping constraint effects in open tubes to be taken into account was developed in Ref. 3. Because of the assumption of linear variation of the warping constraint direct stresses along the length of the element its flexibility matrix was very simple, but approximate.

In this note the flexibility matrix for an “exact” element is derived which will give results which coincide exactly with those obtained from the theory given in Ref. 1. It is assumed that the applied torque and cross-sectional properties do not vary along the length of a given element, but variation from element to element is, of course, possible.
The use of model building in a production environment
Authors: Fleming D. , Laing R. M.
Published: July 2022

Rolls-Royce aero engines are used by 200 airlines, 300 corporate customers and 77 armed forces. To date 34 000 aeroplane engines have been built and, in the time that it has taken you to read this far, 10 aircraft propelled by Rolls-Royce engines have taken off.

The business is located in Scotland, England and Ireland and in England stretches from Bristol to North Yorkshire with the main head office at Derby.
Olympus in Concorde
Authors: Devriese J. , Young P. H.
Published: July 2022

Eight years ago, Dr. S. G. Hooker and M. Michel Garnier gave the 17th Louis Blériot Lecture on the same subject under the title “Power for Supersonic Flight”. Between then and now the airlines and the manufacturers have jointly evolved the new practices of health monitoring and modular maintenance, and have also made significant advances in both the basic safety of the design and the safety-monitoring of the functioning engine. More important still, the operators and manufacturers have become fully conscious of, and determined to respond constructively to, the growing public pressure to reduce pollution and technological nuisances of all kinds. Within the same eight years a complete new generation of civil engines, the large high bypass ratio turbofan, has been conceived, developed and has begun to operate in airline service. It incorporates many of the new concepts mentioned above, as well as reflecting the general progress in technology that has taken place in that time.
The Engine Scene
Authors: Hooker S. G.
Published: July 2022

The Fifty-Eighth Wilbur and Orville Wright Memorial Lecture was given by Dr. S. G. Hooker at the Royal Aeronautical Society on 4th December 1969. The chair was taken by the President of the Society, Air Commodore F. R. Banks. Following custom, the Society's honours and awards for the year were presented before the Lecture. These are listed, with their citations at the end of this lecture.

On 3rd December 1903, with the wind gusting up to 25 mph (11·2 m/s), Orville Wright staggered into the air in a flimsy aeroplane powered by a four-cylinder piston engine, and, with that event, the Wright Brothers had added a new dimension to man's ability to travel (Fig. 1).

Their success was not just a piece of luck, but the result of years of study and experimentation, coupled with great personal effort in the design and manufacture of their aircraft. Like all pioneers, they were faced with important gaps in the availability of suitable equipment, particularly an engine of sufficient power and light enough in weight, and a propeller of high enough efficiency. These they had to develop for themselves.
The Bursting Pressure of Metal Diaphragms in Square Section Shock Tubes
Authors: Edwards D. G.
Published: July 2022

In several recent papers the bursting pressures of shock tube diaphragms of various sizes and materials have been presented either as discrete values or curves of bursting pressure against thickness. The lack of a unifying dimensionless presentation, however, restricts the general applicability of such results and it is the object of this work to present a suitable dimensionless strength parameter, and to outline a procedure which enables predictions to be made of the bursting pressure of ductile metal diaphragms in square-section shock tubes of any cross-sectional size, without performing bursting tests.
The Impact of the Digital Computer on Engineering Sciences: Part 2
Authors: Argyris J. H.
Published: July 2022

The Space Division of the North American Rockwell Corporation has developed a comprehensive computer-based heat transfer and thermal analysis capability especially for design support of the Apollo command module. The heat transfer analysis primarily centres about the solution of the diffusion equation using finite difference approximations. Since most problems encountered are non-linear in nature this approach has proved highly effective in producing accurate results economically. Recent studies, however, indicate that heat transfer problems are most successfully analysed by the finite element method. On the other hand, the finite element method in this field of application was not yet established when North American initiated this work. Lack of time does not allow a deserved discussion of this topic.
Dagenham Days
Authors: Jarrett Philip
Published: July 2022

The year 1909 was certainly the Golden Age of aviation in Europe, but another year was to pass before practical flight became a reality in England. In this country in 1909 not only was the need felt for an efficient aeroplane, but a good flying ground was also lacking. The year saw three brave attempts to establish such a ground, those of Noel Pemberton Billing at Fambridge, the Aero Club at Shellbeach and the Aeronautical Society at Dagenham. Only at Shellbeach did any flights take place, and all of the grounds were to be abandoned as unsuitable by the end of the year because of their rough terrain. Of Fambridge and Shellbeach some history has been recorded, albeit not enough, but Dagenham has been sadly neglected, even in the Society's own histories. This paper is an attempt to rectify this omission.
ICAO—Its Origin and Development: A Personal View
Authors: Tymms Frederick
Published: July 2022

On the 1st November 1944 the delegates of 52 States met at Chicago at the invitation of the United States Government, and, on the 7th December, the Convention on International Civil Aviation (the Chicago Convention) was signed. It came into force on 4th April 1947. Today, there are 117 States parties to the Convention, albeit representing, in the main, the same territories.

To mark the achievement of 25 years of international co-operation through ICAO, I had personally hoped that it might be possible to get the President of the Council, Mr. Walter Binaghi, to give an up-to-date account of ICAO’s work. This not being possible, I have been asked to take his place, and I must make it clear that I cannot attempt to do the same thing. This is not a history of ICAO. I speak only from the point of view of my experience in the first 10 years. I hope to show the origin of some ideas and actions and trace certain changes in thinking and attitudes. I must apologise in advance if, in doing so, I seem to give undue attention to matters in which I have taken part and to ignore so much else that has been done. How much that is was impressively borne in on me, when I recently received the ICAO Bulletin for September 1969. For an authoritative and complete (though summarised) account of what ICAO is and what it has done, I commend this admirable review, and I wish to pay my tribute to those who have contributed so much to what there is recorded.
Thrust Measurement in Flight: The Requirements, Current Situation and Future Possibilities
Authors: Woodfield A. A.
Published: July 2022

Before considering the techniques used for in-flight thrust measurements, it is important to understand fully the basic reasons for such measurements.

For without this understanding it is difficult to assess the benefits to be gained from making accurate thrust measurements. Those readers who are actively involved in performance prediction and measurement on new aircraft will already be aware of many good reasons, but a brief review of the situation will help to set the scene.
Recent Progress in All-Weather Landing Techniques
Authors: McManus R. M. P.
Published: July 2022

It was quite a few years ago that BLEU showed the feasibility of automatic landing. In the intervening period, considerable development has taken place. Before we look at the recent developments, it is worthwhile reiterating the early findings of BLEU. They showed that an aircraft could be landed automatically using an extension of a standard autopilot plus radio altimeter and an autothrottle system. In the pitch plane the aircraft is controlled on the glide slope as usual, but continues to a low height (100ft-150 ft) (30-36 m); a short period of constant attitude flight follows to about 50 ft (15 m) when the autopilot switches to flare and the throttles are closed at a steady rate. The control for the flare comes from the radio altimeters and an exponential flight path is aimed for. The rate of descent is kept to one-fifth of the height. In the lateral plane the control is purely an extension of the usual localiser control. Originally it was intended to use leader cable, but this had added complications of installation, and as techniques developed the localiser was found to give adequate performance.
The Concorde Flight Test Programme
Authors: Burgess E. H.
Published: July 2022

The object of this talk is to give you a situation report on the Concorde flight test programme and to indicate the progress made to date.

Two aircraft have been engaged on the programme so far, the prototypes 001 and 002 (Fig. 1). The French base for Concorde flight test operations is at Toulouse and the British flight test base is at Fairford in Gloucestershire. The two prototypes will be joined in the flight test programme next year by the two pre-production aircraft, 01 and 02.

As is well-known, Concorde is a slender delta wing aircraft and it may be appropriate at this stage to state some of the considerations that led to the choice of this configuration. By virtue of a large root chord, the delta wing can overcome all the disadvantages of lack of structural stiffness and lack of wing volume associated with thin highly swept wings and yet remain aerodynamically thin.
French Marine Air Cushion Vehicles
Authors: Bertin J.
Published: July 2022

The first research carried out in France relating to air cushions was effected in 1957 by the Bertin Company. The phenomenon was first observed during thrust measurements on inward directed annular jet silencers (Fig. 1), in which the effects of air inlets were being studied. Thrust was measured by the weighing of a plate located in front of the nozzle; when the secondary air inlets were closed, the scheme was in fact the one of the peripheral jet air cushion and the thrust read on the dynamometer was found to be much greater than the theoretical jet thrust (Fig. 2).

It should be noted that this work was an extension of research carried out by SNECMA concerning striction, that is to say the control of the exit area of the engine nozzle by means of an inward directed peripheral fluid curtain the purpose of which was to increase the pressure inside the exhaust pipe which is the characteristic of annular jet air cushions (Fig. 3).
Relaxation Effects in Gas Dynamics
Authors: Becker Ernst
Published: July 2022

Classical gas dynamics is by definition the dynamics of gases that are in local thermodynamic equilibrium everywhere in the flow field so that their thermodynamic behaviour is completely specified by two independent variables of state, for example by pressurepand densityp. The fundamental assumption of local thermodynamic equilibrium is not valid in many flow situations of practical importance, and this fact has given rise to a revision and generalisation of classical gas dynamics. This generalisation is usually called “relaxation gas dynamics”. Ten years ago J. Ackeret mentioned this subject briefly at the end of the Daniel and Florence Guggenheim Memorial Lecture onThe Role of Entropy in the Aerospace Sciences.He gave that lecture at the 2nd International Congress of the Aeronautical Sciences in Zürich (12th September 1960) and he said on that occcasion: “Non-equilibrium states are of growing importance, for strictly speaking, exact (thermodynamic) equilibrium occurs only relatively seldom in gas dynamics. However, a rational theory of nonequilibrium states must necessarily be extremely complicated….
The Estimation of the Drag of Circular Cylinders at Subcritical Reynolds Numbers and Subsonic Speeds
Authors: Thomson K. D.
Published: July 2022

In an investigation, on the characteristics of the wake from slender cone-cylinders at large angles of attack, the strength and position of the vortices in the wake were determined for a large range of flow conditions. Two types of experiments were conducted, namely schlieren studies and wake traverses.

Schlieren photographs (such as Fig. 1) clearly reveal straight parallel vortex lines in the wake for subcritical values of the cross-flow Reynolds number component and for cross-flow components of the free stream Mach number up to at least 1·4. In ref. 1 numerous such schlieren photographs were analysed using the impulse flow analogy (refs. 2 and 3 for example). According to the analogy the progressive development of the wake along the body when viewed in cross-flow planes is similar to the growth with time of the flow behind a two-dimensional cylinder started impulsively from rest with the same cross-flow conditions.
Collision Avoidance Systems
Authors: Perry G. L.
Published: July 2022

The density of air traffic, particularly in the USA, is now X increasing at such a rate that the overloading of the Air Traffic Control system seems inevitable. Fig. 1 shows the expected increase in the size of the US civil air fleet and its operations over an eleven-year span, from 1966 to 1977.

Since January 1st 1968, there have been 58 mid-air collisions in the USA, including 19 this year. The majority of these were under positive Air Traffic Control in the vicinity of airports. Some form of airborne system to prevent collisions seems essential for the safe operation of aircraft in the 1970s.

A considerable amount of discussion and development has been carried out in the USA during the past 14 years, and some prototype equipments are now flying. The purpose of this paper is to describe the technique employed in these systems, and to suggest an original principle as a design basis for a collision avoidance system (CAS).
Protection of Work in Patents and Designs
Authors: Johnson W. E. P.
Published: July 2022

The title of this paper was not of my own choosing, although I could not resist the challenge which it presented. It illustrates immediately one danger of which industry must beware—that of under-rating the extent of protection which the laws of this country afford to inventors and innovators. The limitation to Patents and Designs implied by the title, will be exceeded and there are included in the following remarks, Copyright and Trade Marks, both of which can contribute to the protection of industrial innovations.
Structural Design and Thermal Control
Authors: Franklin I. V.
Published: July 2022

Space Technology, internationally, is now in its second decade and already in this comparatively short time new skills and disciplines have emerged and are still emerging. In other papers you will have read of new developments and improvements in electrical power supplies, ion propulsion systems, attitude control and telecommand and data handling. But in the midst of this brave new technical world there is the still small voice of the structures engineer who it is commonly thought only has to offer his 18 gauge sheet suitably bent, honeycomb panels, rivets, brackets, and a simple practical outlook. Perhaps due to the elementary and familiar nature of his materials, the structures engineer tends to be taken for granted when compared with his colleagues working in the more exotic technical fields. The usual procedure followed when a new satellite design is being undertaken and the part played by the structures engineer and analyst is described. Examples are given and views expressed on design philosophy and its implementation.
The Royal Air Force
Authors: Boyle Dermot
Published: July 2022

There is one point which I wish to make right away because I believe it to be true, important and appropriate to this lecture which is given in memory of a great aircraft designer. Raleigh, the author of the First Volume of The War in the Air wrote: “The man who makes a machine and the man who flies it are the heroes of the epic of flight”. This sentiment I fully support and I take no exception to the fact that the “maker” takes precedence over the “flier” since, apart from any other consideration, this represents a convenient sequence of events. Putting Raleigh's statement another way, I would say that such success as the Royal Air Force has had over the years has been dependent more on the British Aircraft Industry than on any other single factor except perhaps the existence of Trenchard who, incidentally, was himself wholly alive to the importance of a healthy aircraft industry if we were to have a healthy Air Force.
Shock-Wave Radiation from a Supersonic Ducted Rotor
Authors: Morfey C. L. , Fisher M. J.
Published: July 2022

Over the subsonic speed range, the pressure field attached to a ducted rotor decays rapidly with distance away from the rotor. This exponential decay, coupled with the low radiation efficiency of a subsonically rotating pressure pattern, is generally sufficient to bring the radiated sound power well below that produced by interaction of the rotor with disturbances in the flow. This is particularly true for multibladed rotors as used in aircraft-engine fans and compressors, and accounts for the importance of rotor-stator interaction as a source of noise at subsonic tip speeds.
A Note on Stratford's Method
Authors: Lister W. M.
Published: July 2022

In the theory of the incompressible laminar boundary layer, Stratford's method is widely regarded as one of the best practical methods for the prediction of separation. The method may also be used in conjunction with the Illingworth-Stewartson transformation (described below) for the prediction of the separation positions of certain compressible boundary-layer flows. For one such case, for which an “exact” solution has been computed, it has been suggested, in ref. 4, that the method, in its simplified form at any rate, is not quite as accurate as had been anticipated. It is the point of this note to show that the full Stratford method does in fact give an excellent prediction of the separation position for this flow.
Military Aircraft Market Research
Authors: Gulland Janet
Published: July 2022

The role of market research, as applied to the military side of the aircraft industry, is beset by various difficulties, but before discussing these it is essential to consider the reasons for which it should play an important part among the management tools of the industry. In other words, why market research? Too often the term is applied to desperate attempts to find a market of some sort for an aircraft built for the British Services, at a time when production for home consumption is coming to an end. Too often the answer has been “no good”, generally for one of two reasons. Either the aircraft, as initially conceived for the RAF or Royal Navy, has been too sophisticated and hence too expensive for foreign Air Forces, or else the British re-equipment cycle has been out of phase with the rest of the world. There is a widespread belief among people who should know better, that there is a mystique about selling military aircraft. It is true that it is not easy, but the basic conditions for a sale are similar to those for any product, i.e. that the product should meet the demands of the customer in terms of requirement and timescale.
CFD for aerodynamic turbulent flows: progress and problems
Authors: Launder B. E.
Published: July 2022

Current weaknesses in modelling the turbulent stresses arguably provide the main obstacle to relying on CFD predictions of complex aerodynamic flows. The paper reviews some recent strategies for obtaining more reliable models with especial focus on cubic non-linear eddy viscosity models and stress-transport schemes which comply with the two-component limit. Applications are shown for a broad range of test flows. Finally, important remaining weaknesses are considered.
NASA subsonic jet transport noise reduction research
Authors: Powell C. A. , Preisser J. S.
Published: July 2022

Although new jet transport aircraft in today’s fleet are considerably quieter than the first jet transports introduced about 40 years ago, airport community noise continues to be an important environmental issue. NASA’s Advanced Subsonic Transport (AST) Noise Reduction programme was begun in 1994 as a seven-year effort to develop technology to reduce jet transport noise 10dB relative to 1992 technology. This programme provides for reductions in engine source noise, improvements in nacelle acoustic treatments, reductions in the noise generated by the airframe, and improvements in the way aircraft are operated in the airport environs. These noise reduction efforts will terminate at the end of 2001 and it appears that the objective will be met. However, because of an anticipated 3-8% growth in passenger and cargo operations well into the 21st century and the slow introduction of the new noise reduction technology into the fleet, world aircraft noise impact will remain essentially constant until about 2020 to 2030 and thereafter begin to rise. Therefore, NASA has begun planning with the FAA, industry, universities and environmental interest groups in the USA for a new noise reduction initiative to provide technology for significant further reductions.
Modelling, simulation and flight test experience in the development of unstable robotic aircraft
Authors: Thomasson P. G.
Published: July 2022

The experiences and lessons learnt over the past twenty years developing a range of unstable unmanned aircraft are described along with the extensive use made of modelling and simulation in this development process. The scope for future developments is addressed and indicates even more on board intelligence is possible and desirable.
Tensile fracture of fibre reinforced metal laminates containing a circular hole
Authors: Govindan Potti P. K. , Nageswara Rao B. , Srivastava V. K.
Published: July 2022

Fibre reinforced metal laminates (FRMLs) are a new family of aerospace structural materials developed for fatigue critical applications. These materials are laminated sheets of thin and high strength metal layers, usually aluminium, and alternating plies of fibre reinforced polymer composite layers, viz, aramid/epoxy, carbon/epoxy, glass /epoxy, etc. Afaghi-Khatabi and Ye have considered the fracture data existing on various ARALL (aramid reinforced aluminium) laminates containing a circular hole for evaluation of notched tensile strength, using the effective crack growth model (ECGM), point stress criterion (PSC) of Whitney and Nuismer and damage zone criterion (DZC) of Eriksson and Aronsson. It is noted that ECGM overestimates, whereas PSC and DZC underestimate the notched tensile strength of FRMLs. This note highlights briefly the two different criteria of Whitney and Nuismer known as ‘point stress criterion (PSC)’ and ‘average stress criterion (ASC)’, and suggests a modification in the criteria for accurate evaluation of the notched tensile strength.
Improved estimation of lateral-directional derivatives of an augmented aircraft using filter error method
Authors: Singh J. , Raol J. R.
Published: July 2022

For an augmented aircraft, it is shown that filter error method leads to improved identifiability of aerodynamic parameters from measurements that are affected by the feedback from the flight controller. Simulated lateral-directional data of an advanced fighter aircraft, obtained from a nonlinear six-degree-of-freedom simulator, are used for the purpose of analysis. The aircraft stability and control derivatives are estimated using filter error method and compared to the estimates obtained from output error method to ascertain the degree of improvement achieved in the identified derivatives. Identification results with output error method show that feedback causes a discernible offset in the estimated values of the derivatives relative to the reference parameter values. The filter error method helps to reduce this offset and thereby yield estimates that match better with the reference parameter values.
Interaction of missile propulsion and aerodynamics
Authors: Buchanan C. R. , Gemmill A. J. T. , Martin P. G.
Published: July 2022

Some aspects of propulsion integration issues for ramjet powered missiles are outlined in this paper. The benefits of ramjet propulsion in the Mach 2-4 range over other types of airbreathing propulsion and rocket propulsion are well known. Compared with solid rocket motors, ramjet engines offer a much higher specific impulse and the capability of thrust management, enabling longer stand-off ranges and more flexible operation.

An overview of the ramjet engine cycle is given, highlighting engine/intake matching issues. This is followed by a performance comparison between a generic ramjet and a solid rocket powered missile (the air-to-air configuration is examined by way of example in this paper). As well as overall performance, intake integration and missile steering issues are considered.

A description of a wind tunnel test model, intake design and tunnel testing is given. The effects of design Mach number and side-wall removal have been investigated for twin ventral rectangular intake configurations. These tests were aimed at optimising performance at different flight conditions and improving tolerance to yawed flight. The impact of the alternative intake designs on missile performance is discussed.
The truth about global warming
Authors: Ewins P. D.
Published: July 2022

God said to Noah, “Make yourself an ark with ribs of cypress; cover it with reeds and coat it inside and out with pitch. The length shall be three hundred cubits, its breadth fifty cubits and its height thirty cubits. You shall make a roof, giving it a fall of one cubit when complete; and put a door in the side of the ark and build three decks. I intend to bring the waters of the flood over the earth to destroy every human being under heaven.“

Genesis Ch. 6

God and Noah were not only the earliest recorded partnership in the history of naval architecture but they were also the most successful. God prepared the requirement and outline specification; Noah responded with a fully engineered design and construction which was not only to survive the worst floods ever seen but was also completed on time. Of course, we know nothing about cost overruns, but I doubt that cost was uppermost in Noah's mind and labour - he used his sons - was in any case cheap!
Experimental investigation of axisymmetric bodies with negative pressure gradients
Authors: Nesteruk I.
Published: July 2022

Using an exact solution of the Euler equations, the pressure distributions over some axisymmetric bodies with a negative pressure gradient over the majority of the surface (from 99.7% to 88% of the total body length) have been calculated. The results of wind tunnel tests for these bodies are presented.