bluuebunny/crossref_metadata_2025 huggingface dataset:
Astronautics and Guided flight section
Authors: Elliot H.
Published: July 2022

I shall discuss two examples of possible future deep space missions but first of all let me fill in a little of the scientific background in order to give you some idea of the kind of questions that we would aim to answer by undertaking these projects. It is now rather more than twelve years since the first spacecraft were placed in independent orbit round the sun. These were Lunik I and Pioneer IV which were the first satellites to make measurements in space outside the earth's gravitational field. In these twelve years as a result of the succession of space probes which has followed we have learned a great deal about the physics of interplanetary space where the situation is dominated by the solar wind and magnetic fields which it carries out from the lower corona. Let me remind you of the salient facts.
Technical aspects of the Schneider Trophy and the world speed record for seaplanes
Authors: Bazzocchi Ermanno
Published: July 2022

I was delighted and honoured to have been invited to give this lecture on the technical aspects of the Schneider Trophy and the world speed record attempts. Great Britain and Italy were the main contenders in the final and most exciting phase of the contest. As the Macchi aircraft were the most successful defenders of the Italian colours and, being myself the successor to Dr. Mario Castoldi, designer of the famous Macchi racers for the Schneider Trophy, I was very pleased to accept the kind invitation of the Society to give this lecture, especially in consideration of the fact that, as far as Macchi contribution is concerned, it was possible for me to collect first hand information directly from the people who actively collaborated with the racing effort.
American space station activities
Authors: Mathews Charles W.
Published: July 2022

The words “space station” mean many things to many people. In fact, a very wide range of craft have been studied under this name over the years. The range of such studies has included large rotating craft providing an artificial gravity environment and accommodating hundreds of people (the type envisaged by Arthur Clarke in his book, 2001: A Space Odyssey) and small two or three-man craft designed for mission durations of 30 days. The one thing that all these programmes have in common is that they emphasise the use of spacecraft for the conduct of meaningful and beneficial investigations using the vantage point or the environmental features of space. In addition, they have involved the presence of man as a means of providing more effective conduct of the assigned tasks. This approach differs somewhat from activities that are strongly aimed at specific and demanding mission accomplishments, missions which place great emphasis on reliable and safe operation of the flight hardware and the demonstration of new operational techniques. Nevertheless, past programmes such as Mercury, Gemini, and Apollo have included many of the basic space station ideas.
Hybrid computation in aeronautical engineering
Authors: Greene K. R.
Published: July 2022

Many engineering problems are unsuitable for either pure digital or pure analogue computation. An example is provided by the helicopter. Owing to the size of the problem, a digital solution takes too long, and far more equipment is required than is generally available on analogue computers. In addition, there is the difficulty of including important non-linear effects.

A hybrid computer is a combined digital and analogue computer and can be used to advantage in these circumstances. I shall mainly be concerned with the integration difficulties which arise when applying this form of computation to helicopter simulations. The concepts developed are not restricted to the helicopter problem and an integration technique will be explained which has wide application in the study of other engineering systems.
Air transport demand estimates for UK domestic and international routes Part 7—demand models
Authors: Ellison A. P.
Published: July 2022

Demand forecasting is a hazardous business, particularly in civil aviation. Any technique which can improve the accuracy of forecasts will aid the development of the industry, for demand fluctuations are a prime source of aviation's instability. If these fluctuations could be predicted accurately the consequences of wide demand fluctuations could be minimised, but this rarely happens. Many of the causes of the fluctuations are outside the control of the forecaster. Otherwise, ignorance of the relationship between cause and effect is the source of inaccurate predictions. An approach to forecasting, which is designed to overcome the latter, is the application of econometric models. Many of the econometric models in civil aviation are still primitive, yet, much has been expected of them.
Air transport demand estimates for UK domestic and international routes Part 2—estimates
Authors: Ellison A. P.
Published: July 2022

This section deals with the application of models developed in Part I to particular UK domestic and international routes. Most of the information used is in time series, a form of data which brings with it many problems. As well as the usual ones such as multicollinearity, serial correlation and simultaneity, the civil aviation market has its own characteristics which bring with it estimating problems. Special attention is paid to short- and long-run responses to income and price changes, to means of explaining secular trends in growth, and causes of fluctuations. When possible, generalisations concerning the size of parameters and the appropriateness of certain model forms will be made. The approach however is to treat routes and route groups as unique, with different passenger characteristics, development and histories. Such differences require different approaches and different models. Much of the discussion will be concerned with discussing the appropriateness of one or other model to routes of certain characteristics.
Development of a hypervelocity wind tunnel
Authors: Stalker R. J.
Published: July 2022

Wind tunnels are far older than powered flight. Including the aeroplane of the Wright Brothers, the introduction of new types of aircraft has almost invariably been preceded by extensive model investigation in wind tunnels. These investigations can be classified into two broad areas. One is development testing, in which models are tested and modified with the purpose of producing a specific aircraft configuration. The other covers the research and general experimentation which is necessary for the determination of the new rules governing entry into a new régime of flight. Thus, wind tunnels may conveniently be referred to either as “development” or as “research” wind tunnels, according to the type of work which is done in them.
V/Stol developments in Hawker Siddeley Aviation Limited
Authors: Brennan M. J.
Published: July 2022

At the beginning of manned flight, aircraft needed some length of ground run in order to take off and fly. The Wrights took under 60 ft, and with a wing loading of 1.47 lb/sq ft and a CL max of approximately 0.9 they achieved first manned flight.

Time went on, and man grew more familiar with the hazards of increased take-off length and take-off speed. His growing knowledge of aerodynamics allowed him to increase the CL max values on wings. These facts combined to allow him to use increased wing loadings to improve his flight efficiency in terms of payload, cruise speed and range. The following graphs show the growth of these characteristics.
The understanding and prediction of turbulent flow
Authors: Bradshaw P.
Published: July 2022

It was easy for me to choose a subject for this lecture. First, turbulence is an important part of engineering fluid dynamics which has not so far been treated in the Reynolds-Prandtl lectures; secondly, it is the most obvious link between the careers of our two heroes; and thirdly it is the only scientific subject on which I am even remotely qualified to lecture before such a distinguished audience. The first and second propositions are sufficiently demonstrated by the annual consumption of something of the order of 1010kg of kerosene to overcome the effects of Reynolds’ stresses in Prandtl’s boundary layers. Have any two human beings ever had such a spectacular memorial? (Yes, Lanchester and Prandtl, to whose induced drag we sacrifice another 1010kg of fuel each year.)
Industrial relations in the aviation industry
Authors: Atherton L. A.
Published: July 2022

The aviation industry, by definition of its products and their utilisation, is international. It may shortly become interplanetary. BOAC, by whom I am employed, operates its aircraft all over the world and employs staff in more than fifty countries. Our staff includes a very wide cross section of trades and professions, from aircraft cleaners to pilots, architects and lawyers, but with a few exotic exceptions, our industrial relations do not differ substantially from any other modern industry in the UK.
An independent view
Authors: Wood J. C.
Published: July 2022

Any assessment of industrial relations must start with consideration of the character of the industry in question. It would be, for example, impossible to understand the behaviour of the modern miner without some knowledge of the history of the coal industry. Aviation has only a brief history. It nevertheless has a flavour of its own.

Three distinctive features are of note. To the outsider it is clear that the aviation industry brings with it the sort of challenge which appeals to the enterprising and the romantic. It is therefore no surprise that the industry has more than its fair share of strong character. There exists an independence of outlook on both sides of the industry which is not always easy to control within the normal industrial relations framework.
Work study in aerospace
Authors: Heese Luke A.
Published: July 2022

A Large part of industrial engineering effort is devoted to “work study”. This term is put in quotes since the activity as practiced is more than just “measuring” the time associated with some particular work activity. In practice, the engineer also selects certain elements of an operation where possible to improve the method and procedure. In other words, “work study” really means a complete study and description of the operation. When referring to the “program” one must also consider a control system of daily, weekly or monthly reports whereby countable output can be related to time input.
A numerical experiment on two-dimensional turbulent separation
Authors: Sachdeva R. C.
Published: July 2022

The simplest practical type of flow involving separation is that past a smooth flat plate with uniform velocity U0 at inlet followed by a linear adverse velocity gradient dU/dx = Constant (Fig. 1). At first the boundary layer is laminar up to the transition point xL. The turbulent boundary layer then grows with uniform potential flow velocity U0 outside the boundary layer up to the point x1 From x1 downwards the boundary layer grows in the presence of an adverse pressure gradient and finally separates at the point xs.
Assessment of measures, legal and physical to fight hijacking
Authors: Tymms Frederick
Published: July 2022

The object of this paper is to assess the efficacy of various measures, legal and physical, for the prevention of hijacking. I limit myself to examining the inherent limit-ations of different measures; and I propose to elaborate certain proposals, already made, for closing the ring. First, it is desirable to see what conclusions can be drawn from past events.

Reports from the airlines on hijacking incidents, during a period of three years from July 1968 to August 1971, have been recorded by IATA. Summaries of these reports have been made available to us, by courtesy of the Director General, through Sir William Hildred. I base my analysis in Tables A to D (see Appendix) on these records, for they are the only source of information available on the course of events and the consequences of each incident.
Aircraft fault isolation based on pattern of cockpit indications: a human factors approach
Authors: Burrows A. A. , Miles W. L.
Published: July 2022

It is commonly recognised among operators of modern commercial aircraft that maintenance is a significant and costly part of their operation. In fact, it is estimated that 28% of all aircraft operating costs can be attributed to maintenance-related activities. A major portion of this activity can be classified as unscheduled, that is, maintenance other than regular servicing and periodic overhauls. Much of the cost of unscheduled maintenance derives from the actual man-hours and materials involved in isolating and replacing faulty components. However, additional consideration must be given to the fact that an aircraft which is detained beyond its scheduled departure time is neither producing revenue for the operating airline during that period, nor promoting goodwill among passengers inconvenienced by delays or cancellations.
Another Flying Dragon
Authors: Hart Clive
Published: July 2022

In my paper “Mediaeval Kites and Windsocks”, I attempted to throw some new light on the curious dragon-shaped objects shown flying on the ends of lines, or fixed to the tops of poles, in a number of mediaeval and Renaissance books of military technology. Until recently these have usually been interpreted as primitive aerostats whose lift is supplemented by wind-forces similar to those which raise a kite.

A further illustration of the flying dragon is reproduced here (Fig 1). As it does not belong to any of the general categories or groups into which the other illustrations fall, it is worth considering in detail. Its three-part tail and general outline indicate that it bears some relationship to the dragons depicted in Figs. 6 and 7 of my paper.
Non-linear vibration of rotating cantilever blades treated by the Ritz averaging process
Authors: Rao J. S. , Carnegie W.
Published: July 2022

The prediction of the forced vibration response of rotating cantilever blading is of considerable importance in the design of turbine and compressor blading where the rotational speeds are relatively high. Non-linearities in the blades arise from the effects of Coriolis accelerations due to the rotation of the blades mounted on the periphery of the disc.

Lo and Renbarger derived the differential equations of motion of a cantilever beam mounted on a rotating disc at a given stagger angle and show, for a linear case, that the frequencies of a bar vibrating transversely to a plane inclined at an angle to the plane of rotation can be found by a simple transformation of the frequencies of vibration perpendicular to the plane of rotation. Boyce, Di Prima and Handelman applied the Rayleigh-Ritz and Southwell methods to the case of a turbine blade vibrating perpendicular to the plane of rotation and determined the upper and lower bounds of the natural frequencies.
Concept and conduct of proof test of F-111 production aircraft
Authors: Buntin W. D.
Published: July 2022

F-111 aircraft are in service with both the Tactical Air Command and the Strategic Air Command in the USAF. The aircraft performs primarily in the fighter-bomber role for TAC and as a strategic bomber capable of high and low altitude penetration with SAC. Over 100 000 flight hours have been accumulated by the F-111 fleet including a limited amount of combat flying. The broad spectrum of service requirements for the F-111 include short field take-off and landing capability, all weather and deep interdiction, close air support with large payloads, high altitude high speed air defence, and world-wide deployment with minimum tanker support. Major technical advancements were necessary in meeting these requirements, including most notably a variable-sweep wing. The unswept high aspect ratio positions provide for maximum range and endurance and short take-off and landing distances. The wing in moderate sweep positions provides an efficient configuration for sustained high subsonic and high altitude supersonic flight. Supersonic flight at sea level at speeds in excess of the capability of any other aircraft plus supersonic speeds at altitude in excess of Mach 2.0 are achieved in a most highly swept low aspect ratio wing position.
Weighing pressures—a simple micromanometer
Authors: Head M. R.
Published: July 2022

Modern balances are rugged, sensitive and easy to read. A top-loading balance with a capacity of 1 kg and digital readout to 0.01 gm has been adapted for use as a micromanometer. A sketch of the arrangement is shown in Fig. 1. It will be seen that there is no modification to the balance itself, which can still be used for its normal laboratory function, and no calibration is required for pressure measurement provided the diameter of the fixed drum is known.
Some incompressible jet flow and reattachment effects in fluid control elements
Authors: Begg R. D. , Carter J. H. T. , MacLellan G. D. S.
Published: July 2022

The operating characteristics of certain types of fluidic element and fluid control valves are largely determined by the pattern of reattaching flow downstream of a nozzle or an orifice. In the simpler configurations, where a twodimensional (2-D) pattern can be assumed, the flow is similar to that studied by Bourque and Newman and by Sawyer, following on the earlier work of Dodds. These studies were concerned with the reattachment of a 2-D jet emerging from a parallel sided nozzle to an adjacent flat plate, and took into account the effect of turbulent entrainment on the lateral spread of the jet and of pressure difference across the jet on its curvature.
Axisymmetric hydroelastic sloshing in a circular cylindrical container
Authors: Bauer Helmut F. , Wang James T. S. , Chen P. Y.
Published: July 2022

The motion of liquid in the containers of a vehicle may have severe influence upon the stability of the vehicle. For this reason many authors have investigated the behaviour of liquid with a free surface due to various modes of excitation. In the earlier development of small vehicles, the frequencies of the elastic structures were relatively high compared to the propellant frequencies and the effect of their interaction could be neglected. With the increase of modern space vehicles this interaction of the propellant with the elastic structure is becoming a pronounced influence upon the design of the vehicle and its control system. This has some influence upon the stability and response behaviour of a large space vehicle, since the close grouping of propellant sloshing and structural frequencies around the control frequency of the vehicle creates continuous interaction during flight.
The Determination of Solar Heating
Authors: Benoy M. B.
Published: July 2022

A procedure has been developed by Moon for the determination of the total solar irradiance within the earth's atmosphere. The present note illustrates how transmission factors derived by Moon for the constituents of the atmosphere can be used with recent curves of spectral irradiance outside the earth's atmosphere to determine the solar heating at a point on or above the earth's surface at any given time. Special consideration is given to the variation in atmospheric water vapour content with altitude, season, and position on the globe since this is a parameter of some importance. The method described forms the basis of Engineering Sciences Data Item 69015.
A Comparison Between Some Approximate and Exact Solutions of the Laminar Boundary-Layer Equations
Authors: Stollery J. L.
Published: July 2022

There are many approximate methods for solving the laminar boundary-layer equations. They vary greatly in complexity and ingenuity but are similar in that most of them use the momentum integral equation together with data culled from Cohen and Reshotko's valuable catalogue of similarity solutions. Further details may be found, for example, in the book by Curle.

Perhaps one of the simplest approximate methods to use is that due to Luxton and Young. More recently Luxton has extended the method so that heat transfer rate distributions also can be obtained. He is careful to point out that, since his method depends on correlations obtained from similar solutions, it cannot be claimed a priori that the method gives an accurate result. Until recently there have been few “exact” calculations against which approximate methods may be tested. Indeed when Morduchow made his review of boundary-layer calculations in 1965 he quoted only two exact results for non-zero Mach number (by NPL) and cast doubt on one of those. Fitzhugh has now computed a number of solutions of the laminar boundary-layer equations using the finite-difference program of Sells. Further solutions have recently been obtained by F. Smith.
Experiments Towards a Circulation-Controlled Lifting Rotor
Authors: Dunham J.
Published: July 2022

The world's aircraft industries have devoted substantial effort in the past decade towards the realisation of aircraft which can take-off and land vertically. Such aircraft have many potential applications for both military and civil use. Two dominating operational factors have emerged: noise and downwash. In the author's opinion, jet lift and fan lift aircraft with their high disc loadings will prove too noisy for city-centre use and produce too violent a down-wash flow to operate from unprepared sites. These difficulties, added to the inherently higher power requirements of high disc loading, have swung attention more and more towards large lifting rotors, varying from large dual-purpose propellers to more conventional helicopter rotors.
Report on the Whittle System of Aircraft Propulsion (Theoretical Stage)—October 1935
Authors: Bramson M. L.
Published: July 2022

The purpose of this Report is to record the result of an independent step by step check of the theories, calculations and design proposals originated by Fit. Lt. Whittle, and having for their object the achievement of practical stratospheric transport. No investigation of the patent situation has been attempted.

The inventions and discoveries of Fit. Lt. Whittle have not yet reached the experimental stage, and so the material available for investigation is, necessarily, confined to a reasoned statement of the principles involved, coupled with justifying aerodynamic and thermodynamic calculations and design proposals.
On the Extension of the Kantorovich Method
Authors: Webber J. P. H.
Published: July 2022

In ref. 1, an extension of the Kantorovich variational method of minimising a functional is discussed. The extension is based on an iterative technique wherein functions derived from the solution of sets of simultaneous ordinary differential equations are used again in cyclic order to obtain an improved solution. It is conjectured that if the iterative procedure is continued indefinitely, the functional will be close to its correct value, and so also will the associated function. The method given in ref. 1 is a generalisation of the iterative technique for minimising a double integral given by the writer in ref. 4, although in this work the iterations are carried out in the first approximation of the Kantorovich method and convergence is obtained in the usual manner of Kantorovich. Like ref. 4, ref. 1 uses the classical torsion problem of a rectangular bar as an illustrative example. Each shows that accurate Prst approximation solutions can be obtained and ref. 1 goes on to show that, for this particular problem, the derived functions are unique and are not dependent on the initial choice for part of the function.
Experiments Towards a Circulation-Controlled Lifting Rotor. Part II. A Model Rotor
Authors: Dunham J.
Published: July 2022

Part I (ref. 1) explained the ideas underlying Cheeseman's circulation-controlled rotor proposals and described the wind tunnel experiments on circular sections equipped with circulation control slots. The present paper describes the model rotor built and tested at the National Gas Turbine Establishment. Its hovering performance is fully analysed using the sectional performance correlation of Part I.
The Pictures of The Three Favorite Aerial Travellers
Authors: Norton Kings
Published: July 2022

Early in May 1785, Mr. Vincent Lunardi, famous for the first balloon ascent in England on 15th September 1784, announced that he would ascend again, in his new balloon, on 13th May, this time accompanied by his friend Mr. George Biggin and a lady.

For the occasion a stipple engraving (Fig. 1) was published, entitled “V. Lunardi, Esq., Mrs. Sage, G. Biggin Esq.”, showing these individuals in the balloon’s car. On the engraving, the date of publication is given as 13th May, the date fixed for the ascent, Mr. Bovi is named as the publisher, F. Bartolozzi as the engraver and Rigaud as the artist who had painted the picture from which the engraving had been made.
Boundary-Layer Theory and the Flow in a Streamwise Corner
Authors: Zamir M.
Published: July 2022

The equations governing the flow in a boundary layer are a simplified form of the full Navier-Stokes equations; the simplification being based on the argument that within the boundary layer the velocity gradients normal to the solid surface are much larger than those parallel to the surface so long as the boundary-layer thickness is much smaller than (a) a representative streamwise length of the surface and (b) the principal radii of curvature of the surface.
Synthesis of an Aircraft Roll-Stabilisation System: An Application of Inverse Optimal Control Theory
Authors: Porter B. , Woodhead M. A.
Published: July 2022

During the past decade, the theory of optimal control associated with linear multivariable systems having state and output equations of the respective forms

and

has been applied extensively to the design of controllers for a variety of aerospace systems. Such applications of this theory have been mainly concerned with the design of controllers that generate optimal control vectors, ẑ, which minimise performance indices of the form.

where Q and R are positive-definite matrices.
Multivariate Search and Its Application to Aircraft Design Optimisation
Authors: Stepniewski W. Z. , Kalmbach C. F.
Published: July 2022

Long before the legendary Queen Dido cleverly maximised the area of future Carthage by choosing the optimum perimeter shape, man probably consciously or subconsciously tried to optimise his designs as well as his actions.

In a more modern time, the post Renaissance period witnessed development of the principles of optimisation on a rigorous mathematical basis, as exemplified in works of Newton, Leibniz, Euler and many others. Eventually, those optimisation ideas were even transplanted by Leibniz and his school to the field of general philosophy, providing an attractive target for the merciless satire of Voltaire in Candide.
Technical Development in Aviation
Authors: Rowe N. E.
Published: July 2022

It is a signal honour to be invited to give this particular lecture; for me personally, it is especially significant, since for a brief period, 12 months in 1937/38, I held at A&AEE, then based at Martlesham Heath, the equivalent of the post originally held by Tizard in 1916/17, when A&AEE was first formed. At an earlier period, 1926/29, I had been on the staff of A&AEE as a Technical Officer, one of the most enjoyable and fruitful periods of my career. Hence it gives me special pleasure to be here this evening, and a great sense of fulfilment.

Sir Henry Tizard was not only a great man, a great man of science, an inspired leader; he was also a great patriot. He spent himself in the service of the country he loved. His anxiety, always, was to see this country forge ahead, to realise her leadership in research and so stride ahead in industry.
The Slug, an Erstwhile Unit of Mass
Authors: Pankhurst R. C.
Published: July 2022

The general adoption of the International System of Units (SI) in engineering as well as in science makes this the time to relinquish the slug, an engineering unit of mass. Seldom has a convenient unit proved so contentious. This note sets out salient points in the controversy, and indicates basic issues which could scarcely have been appreciated universally at the time.

In essence the slug is the unit of mass that goes with the pound force or the pound weight, just as the poundal is the force unit that goes with the pound-mass. There has, however, been a great deal of argument as to whether it is a true derived unit or simply a fundamental unit in disguise, and about how to realise it in practice: in particular, if unit force is defined or established by reference to the gravitational force on the pound-mass, there arises immediately the question of the appropriate value to use for g, i.e. should it toe the local value, the value at a specified place, or some other agreed standard acceleration?
On the Rolling Up of a Trailing Vortex Sheet
Authors: Hancock G. J.
Published: July 2022

One of the best known results in finite wing theory, which is quoted in aerodynamic text books, states that the distance between two rolled up vortices behind a wing with an elliptic spanwise load distribution is sπ/2, where s is the wing semi-span. Within the framework of linear wing theory this result is correct. But it is of interest to enquire how this result is affected when the standard linear model becomes less valid, for example, at higher wing lift coefficients.

In this note, it is assumed that a continuous trailing vortex sheet rolls up into two discrete vortices. These two discrete vortices are assumed to have cores of finite radius; inside the cores the flow is taken to be solid body rotation, while the flow outside the cores is the standard irrotational vortex field. It is assumed that this rolling up process takes place far downstream of the finite wing which generates the trailing vorticity.
Calculation of Equilibrium Composition and Temperature of a Premixed Flame
Authors: Prasad K.
Published: July 2022

A Fast and efficient method has been developed to obtain the equilibrium composition of a flame at a given temperature, pressure and mixture strength. The Newton-Raphson iteration technique enables one to solve a set of simultaneous non-linear equations and in the present problem these are the equations relating the equilibrium partial pressures and equilibrium constants for the particular reaction and the conservation of atomic species in reactants and products. A trial solution is used to check the energy balance for the flame at the assumed temperature. The temperature is then suitably altered and the whole procedure is repeated till a reasonable agreement is obtained.
A Comparative Study of Aircraft Gust Analysis Procedures
Authors: Cox R. A.
Published: July 2022

The calculation of the response of an aircraft to atmospheric gust has two main purposes. These are, first, to make possible an assessment of the peculiarities of the response of a particular aircraft (e.g. the length of the discrete gust which produces maximum load), and secondly, to provide an estimate of the gust loads which the aircraft must be designed to withstand, in both the static and fatigue senses. (In this paper, however, the fatigue aspects are not considered.)
The Analysis of Cooling Towers by the Matrix Finite Element Method
Authors: Chan A. S. L. , Firmin A.
Published: July 2022

The analysis of axisymmetrical thin shells has always been an important part of the theory of structures, and recently the problem of the cooling tower has aroused considerable interest for practical engineering reasons. Various solutions have been obtained, using either the finite difference or the finite element methods, with varying degrees of success. Amongst the latter, elements such as the TRIB 3c from the ASKA library and the axisymmetrical elements from the SABOR programme, with either a straight or a curved meridian line, have given reasonable displacements. But, by the nature of these elements, the stress distributions are discontinuous across element boundaries. Other existing elements, e.g. the arbitrarily curved triangular shell element SHEBA developed by Professor Argyris's team at the ISD in Stuttgart, are also suitable for the purpose and yield an excellent estimation of the stresses.
Airworthiness and the Air Registration Board
Authors: Tye Walter
Published: July 2022

To be invited to give the British Commonwealth lecture was an honour which I was proud to accept. As one whose professional life has been concerned mainly with airworthiness of civil aircraft, the choice of the title of the lecture was simple.

But I found some difficulty in choosing a theme. The invitation to give this lecture coincided with the issue of the White Paper Civil Aviation Policy. This White Paper placed a large question-mark against the pattern of airworthiness control in future. It seemed to suggest considerable changes to the form in which the Air Registration Board had existed for 33 years, but what the future form would be was obscure.
The Orbital Transfer of TV Satellites by Ion Propulsion
Authors: Childs G. W. , Stott D.
Published: July 2022

Geostationary communications satellites relaying television pictures around the world have now become an accepted part of everyday life. The present type of system uses low power satellites in orbit transmitting to large earth receiving stations, the signal then being reformed and transmitted onward to the domestic television set through the existing network of ground transmission and repeater stations. It must be remembered that these existing satellites are primarily telephone links and that the ground receiving stations are operated by the national post office or telephone company who let circuits to the television companies. This system is viable where a network of repeater stations exists, but in very remote and mountainous areas the cost of providing enough repeater stations is prohibitive.
Space Technology “Spin-off” Benefits to Mankind
Authors: Wiltshire D. A.
Published: July 2022

With the continuing advances in aerospace technology, the “spin-off” benefits increase, too. Although man has now set foot upon the moon, sent unmanned probes to Mars and Venus and placed a series of satellites into earth orbit, we have only touched upon the fringe of celestial and interplanetary venture. Yet from these early and what will one day seem to be clumsy attempts, we have, as individuals, gained many assets which affect our daily lives.

It is indeed regrettable that the enumerable persons who denounce the space-programmes as “a waste of money” “an absolute waste of time”, “unfortunate in that the money could be used to improve the living standards of so many people”, etc., do not give a little more thought to the space programme as a whole, including the “spin-off” benefits.
Future challenges and opportunities in aerodynamics
Authors: Kumar A. , Hefner J. N
Published: July 2022

Investments in aeronautics research and technology have declined substantially over the last decade, in part due to the perception that technologies required in aircraft design are fairly mature and readily available. This perception is being driven by the fact that aircraft configurations, particularly the transport aircraft, have evolved only incrementally over the last several decades. If, however, one considers that the growth in air travel is expected to triple in the next 20 years, it becomes quickly obvious that the evolutionary development of technologies is not going to meet the increased demands for safety, environmental compatibility, capacity, and economic viability. Instead, breakthrough technologies will be required both in traditional disciplines of aerodynamics, propulsion, structures, materials, controls and avionics as well as in the multidisciplinary integration of these technologies into the design of future aerospace vehicles concepts. The paper discusses challenges and opportunities in the field of aerodynamics over the next decade. Future technology advancements in aerodynamics will hinge on our ability to understand, model and control complex, three-dimensional, unsteady viscous flow across the speed range. This understanding is critical for developing innovative flow and noise control technologies and advanced design tools that will revolutionise future aerospace vehicle systems and concepts. Specifically, the paper focuses on advanced vehicle concepts, flow and noise control technologies, and advanced design and analysis tools.
Propulsion airframe integration design, analysis and challenges going into the 21st century
Authors: Early K.
Published: July 2022

Propulsion airframe integration design and analysis has many challenges as we move into the 21st century. Along with the conventional challenges of integrating a propulsion system on an aircraft, new technologies and new business drivers dictate innovative approaches to the design process be developed and applied.

On the technical side, new innovations in jet noise suppression and new aircraft concepts such as the blended wing body (BWB) will give rise to many challenges in propulsion system performance, operability, and meeting system requirements such as thrust reverse capability. Aircraft engine and aircraft manufacturers must have the appropriate design and analysis tools in place which provide the ability to react quickly to inevitable design changes, driven by constantly changing requirements, during the product development cycle.

On the business side, the rapid globalisation of the business dictates that the latest electronic technology be utilised to enable speed in communication with global customers as well as revenue sharing partners. More than ever, cost and schedules dictate the use of analytical methods to minimise the amount of qualification testing. Design and analysis software must be flexible and capable of integrating CAD/CAM and CAE tools while maintaining configuration control of the product.

The following paper describes some of the new technical challenges facing the industry. Innovative methods of addressing those challenges are described.
Analysis of the stability modes of the non-rigid airship
Authors: Cook M. V. , Lipscombe J. M. , Goineau F.
Published: July 2022

This paper describes and compares various analyses leading to the development of approximate models for the linear stability modes of the non-rigid airship. The progress of the analyses was variously dependent on assumptions made from the detailed scrutiny of linear numerical models for three airships. For each airship studied, the linear models were obtained from non-linear simulation models by linearising about a number of chosen trim speeds representative of a typical speed envelope. The decoupled linear models comprised the longitudinal and lateral-directional state equations of the neutrally buoyant airship, for speeds from the hover to 30m/sec. Since the fidelity of the earliest airship models was not known, the principal purpose of this paper is to re-visit the original analysis using a later airship model of known excellent fidelity.

The longitudinal modes of the airship comprise the surge mode, the heave-pitch subsidence mode and the oscillatory pitch-incidence mode. The lateral-directional modes of the airship comprise the sideslip subsidence mode, the yaw subsidence mode and the oscillatory roll pendulum mode. Approximate models for these modes are derived and expressed in terms of concise aerodynamic stability derivatives. The mode characteristics are discussed, and the approximate models are compared with the actual airship modes over the typical airspeed envelope.
The upper troposhere/lower stratosphere ozone programme: contributing to research on aviation impact
Authors: Law K. S. , Penkett R. G.
Published: July 2022

This paper summarises our current understanding about the impact of aircraft emissions on the atmosphere and describes how the UK Natural Environment Research Council (NERC) Upper Troposphere/ Lower Stratosphere (UTLS) Ozone programme is contributing directly to research in this field. Understanding ozone change is a main focus of this research programme.

Ozone is a pollutant at the Earth's surface where it can lead to health problems, is a greenhouse gas and, in the stratosphere, it also shields the Earth from uv radiation. It is known that ozone has been severely depleted in the lower stratosphere (15-20km) over the poles due to increasing concentrations of man-made chlorine and bromine compounds (CFCs etc.). There has also been more limited ozone loss in the mid-latitude lower stratosphere but the reasons for this are less clear because ozone is governed by transport in and out of this region as well as chemistry.
Life extending control of aircraft: trade-off between flight performance and structural durability
Authors: Ray A. , Caplin J.
Published: July 2022

The goal of life extending control (LEC) is to enhance the service life of complex mechanical systems, such as aircraft, spacecraft, and energy conversion devices, without any significant loss of performance, and can be achieved by making a trade-off between dynamic performance and structural durability. This paper presents the concept and a design methodology for robust life extending control of aircraft structures that are typically subjected to cyclic mechanical stresses. The controller design procedure relies on the specifications of flight performance and allowable fatigue crack damage at critical points of aircraft structures that serve as indicators of the effective service life. As an example, an aeroelastic model of the aircraft wings has been formulated and is incorporated into a nonlinear rigid-body model of the flight-dynamics. The H∞-based structured singular value (μ) synthesis method has been used to design robust life extending controllers based on a linearised model of the aircraft and a (nonlinear) state-space model of fatigue crack growth. The results of simulation experiments show significant savings in fatigue life of the wings while retaining the dynamic performance of the aircraft.
Effect of aircraft surface smoothness requirements on cost
Authors: Kundu A. K. , Raghunathan S. , Cooper R. K.
Published: July 2022

Reduction of aircraft manufacturing cost benefits aircraft direct operating cost (DOC). The degree of stringency in specifying aircraft smoothness influences cost, i.e. the tighter the tolerance, the higher is the manufacturing cost. Discrete surface roughness arising from manufacturing tolerance at the wetted surface may be seen as an ‘aerodynamic’ defect. Features such as steps, gaps, waviness and fastener flushness (termed excrescence), seen as defects, contribute to aircraft parasitic drag.

The study is conducted on an isolated nacelle which is considered to be representative of an entire aircraft. Eleven key manufacturing features at the wetted surface of a generic long duct nacelle are identified, each associated with surface roughness. The influence of tolerance allocation at each of the key features is investigated to establish a relationship between aircraft aerodynamics and associated costs. The initial results offer considerable insight to a relatively complex problem in a multi-disciplinary environment.

Excrescence drag arising out of these ‘aerodynamic’ defects is assessed by using CFD and semi-empirical methods. Cost versus tolerance relationships are established through in-house methods using industrial data.

The aircraft unit price typically contributes from two to four times more than the fuel burn to aircraft direct operating costs. A trade-off study between manufacturing cost and aircraft drag indicates that, in general, there is scope for some relaxation of present-day tolerance allocation, to reduce aircraft acquisition cost, which would in turn reduce direct operating costs.
Technology development for high-speed civil transport
Authors: Wilhite A. W. , Shaw R. J.
Published: July 2022

The National Aeronautics and Space Administration sponsored a joint High-Speed Research Programme with United States airframe and propulsion companies to provide the critical high-risk technologies for a Mach 2·4, 300 passenger civil transport. Laboratory and medium-scale tests provided promising results in meeting both the environmental and economic goals for a future High-Speed Civil Transport. However, before the technologies were integrated at large and full scale, the programme was cancelled because of global economic concerns of the US transport industry.
Vortex formation and flow separation: the beauty and the beast in aerodynamics
Authors: Elsenaar A.
Published: July 2022

Ladies and gentlemen, it is an honour and a great pleasure to present this Lanchester Memorial Lecture. I thank the Royal Aeronautical Society and its Aerodynamic Committee for inviting me. In preparing this lecture I greatly enjoyed the added significance of presenting it in the historical context set by Lanchester. But the real pleasure is to be here among many good friends with whom I worked together for shorter or longer periods.

“A body that in its motion through a fluid does not give rise to a surface of discontinuity.” So Lanchester defined a ‘ streamline body’ in his standard work Aerodynamics. With ‘ discontinuity’ the boundary is meant between the outer flow and the dead water region formed by fluid that departs from the surface as illustrated nicely in Fig. 1 for the flow around a cylinder.
A generalisation of the Breguet range equation for multiple payload drops
Authors: Bardell N. S.
Published: July 2022

This paper has arisen from a more general investigation aimed at identifying appropriate manned aircraft that would make suitable stand-off cruise missile platforms. One primary measure of an aircraft's ability to fulfil such a role is found in its payload-range envelope for flight profiles involving one or more payload drop. To this end, a generalisation of the Breguet Range equation is developed initially for a radius-of-action scenario in which the entire payload is ejected at altitude at the designated drop point and the aircraft returns home. The more general problem is then addressed, namely that of establishing the payload-range envelope for an aircraft flying a predefined mission profile comprising a maximum of four consecutive legs each separated by a single payload release point. The ability to include a partial payload release at any drop point is built into the model to permit planners to investigate typical ‘what if?’ effects on the overall mission.

Six numerical examples are included, all based upon the Boeing C-17 as the parent aircraft. These examples describe in detail missions of increasing complexity in order to demonstrate the versatility and efficacy of the current method.

Attention is confined to turbojet-powered aircraft cruising in the stratosphere, although the analogous case of a turboprop-powered aircraft can be simulated simply by amending a single group of constants that appears in all the formulae. Neither air-to-air refuelling policies, nor complicating atmospheric effects such as headwinds, are considered in this paper.
The Design and Development of a Large Supersonic Free-Jet Test Cell
Authors: Ashwood P. F.
Published: July 2022

The NGTE Engine Test Facility has five test cells in current use and between them they can test aircraft powerplants over a wide range of operation at the precise conditions encountered in flight. Two basic testing techniques are employed—“connected testing”, in which air is piped directly to the engine compressor at the pressure and temperature conditions provided in flight by the intake, and “free-jet testing”.
Brief General Survey of the Edwards Inquiry Report into Civil Air Transport
Authors: Legg Keith
Published: July 2022

This brief survey endeavours to highlight the major points of the Edwards Report to provide background for the more detailed contributions and discussions to follow. It is perhaps worth repeating the terms of reference of the Committee:

“To enquire into the economic and financial situation and prospects of the British civil air transport industry and into the methods of regulating competition and of licensing currently employed; and to propose with due attention to other forms of transport in this country, what changes may be desirable to enable the industry to make its full contribution to the development of the economy and to the service and safety of the travelling public.“