bluuebunny/crossref_metadata_2025 huggingface dataset:
Biologically inspired visual sensing and flight Control
Authors: Barrows G. L. , Chahl J. S. , Srinivasan M. V.
Published: July 2022

There is increased interest in new classes of mini- and micro-UAVs with sizes ranging from one metre to ten centimetres. Many envisioned applications of such UAVs require them to be able to fly close to the ground in complex environments. The difficulties associated with flying in such environments coupled with the reduced payload capacity of such airframes means that new methods of sensing and control need to be considered. Good models for such methods are found in the world of flying insects. One particular visual cue used by insects is optic flow, which is the apparent visual motion seen by the insect as a result of its motion through the environment. This paper discusses several research efforts aimed at developing new sensing and control algorithms inspired by insect vision and flight behaviors. These efforts are part of DARPA's controlled biological and biomimetic systems (CBBS) programme. In these (and related) efforts, many elegant control stratagems have been discovered which suggest that simple reflexive schemes combined with the measurement of optic flow may be sufficient to provide many aspects of autonomous navigation in complex environments. Furthermore, these efforts are implementing these behaviors in real flying UAV platforms by using novel hardware and software to measure optic flow, and inserting optic flow measurements into a control loop using a combination of ‘best engineering approaches’ with inspiration taken from biology. This has resulted in fixed and rotary-wing mini-UAVs that are able to hold an altitude and perform terrain following.
Turbulent mixing layer from two non-parallel streams
Authors: Azim M. A. , Islam A. K. M. S.
Published: July 2022

An experimental investigation has been conducted on the mixing layers produced from the merging of two non-parallel streams. To study the effect of velocity ratio on its development, mixing layers were produced with velocity ratios 0·7, 0·8 and 0·9. The boundary layers were untripped and initially turbulent in all the cases. For each velocity ratio, measurements were made at six streamwise locations. It was found that for velocity ratios 0·7 and 0·8, mixing layers appear to attain self-similarity but failed for 0·9 within the measurement domain. The development distance of the mixing layer flow was increased with increasing velocity ratio and the splitter wake was found to play an important role in its development. The mixing layer growth was found to decrease with increasing velocity ratio though the spread of the layer was larger at the high speed side.
Progress in the development of a versatile pilot model for the evaluation of rotorcraft performance, control strategy and pilot workload
Authors: Bradley R. , Brindley G.
Published: July 2022

The evaluation of rotorcraft performance and handling qualities in piloted flight using a desk-top simulation is a desirable facility. The development of the SYCOS pilot model has brought this capability closer by simulating piloted flight along prescribed trajectories such as the Mission Task Elements of ADS-33. This development has overcome some of the limitations of the precise control of inverse simulation, by adopting a structure which includes a corrective component that adjusts the control strategy to counteract departures from the desired flight path. The development and implementation of SYCOS for a range of rotorcraft types and applications is shown to be well defined and straightforward. The capability and reliability of SYCOS is demonstrated through a number of recent applications in performance, control strategy and pilot workload studies. Some of the applications benefit from enhancements to the basic structure and these are described in context. The accumulation of experience with the SYCOS pilot indicates that it is a significant advance as a predictor of human control activity during helicopter manoeuvring flight.
Aerospace applications of luminescent paint
Authors: Kingsley-Rowe J. R. , Lock G. D. , Davies A. G.
Published: July 2022

A heat transfer measurement technique has been developed, which utilised a laser to heat a spot of the ‘standard’ luminescent paint on an insulated metal wind tunnel model. The convective heat transfer coefficient was determined from the experimental quasi steady-state surface temperature, and solutions obtained from radial and axial conduction in a numerical heat transfer model. The convective heat transfer coefficient variation over both a flat plate and a NACA 0012 aerofoil have been measured in transonic flow. Measurements obtained from the flat plate were seen to agree well with correlation data from the literature. Measurements on the NACA 0012 aerofoil indicated the point of transition from laminar to turbulent boundary layer as well as the location of shock boundary layer interaction. The luminescent paint provided simultaneous measurements of pressure and temperature (see Part 1). The distribution of pressure over the NACA 0012 aerofoil was shown to be in excellent agreement with conventional transducer data, although the luminescent paint data provided greater spatial resolution. The position of the shock determined from the heat transfer measurements was shown to be in excellent agreement with the pressure measurements.
Civil aviation and the environmental challenge
Authors: Green J. E.
Published: July 2022

In the coming century, the impact of air travel on the environment will become an increasingly powerful influence on aircraft design. Unless the impact per passenger kilometre can be reduced substantially relative to today’s levels, environmental factors will increasingly limit the expansion of air travel and the social benefit that it brings. This essay considers the three main impacts, noise, air pollution around airports and influence on climate change. Of the three, impact on climate change is taken to have the greatest long-term importance and is discussed at the greatest length. It is argued that, of the three main contributors to climate change from aircraft – CO2emissions, NOXemissions and the creation of persistent contrails – it is the last two which are the most promising targets. Ways of reducing the impacts of these two are discussed and it is noted that, in each case, the best environmental result is likely to entail some increase in CO2emissions. It follows that regulatory or economic measures to reduce impact on climate should be framed so as to do just that. Measures framed purely in terms of CO2emissions are likely to be counter-productive. Nevertheless, the design of aircraft to reduce fuel burn and hence CO2emission remains a key long-term objective; the essay considers the potential offered by new technology and new design concepts in this arena.
Passive mm-wave imaging from UAVs using aperture synthesis
Authors: Harvey A. R. , Appleby R.
Published: July 2022

Passive imaging using mm-waves offers very significant advantages in scientific and military surveillance. However, the relatively long wavelengths mean that for the resolutions that are typically sought, the input aperture of the imager needs to be quite large; typically in excess of one metre. Deployment of conventional dish antennae of these dimensions on small aircraft is highly problematic. The use of snapshot synthetic aperture interferometric radiometry (SAIR) offers an attractive route to integrating a two-dimensional antenna array into the structure of an aircraft so that the transverse effective dimensions of the antenna can be almost as large as the aircraft. We report here a study into the feasibility of deployment of a SAIR on unmanned airborne vehicles and the achievable performance parameters. Critical considerations are the achievement of acceptable sensitivity and angular resolution from a SAIR that does not require excessive complexity. It is shown that traditional approaches based on fully sampling the spatial frequencies in the scene are unable to simultaneously meet all of these criteria, but that a SAIR based on thinned sampling of the spatial frequencies shows promise.
Future air traffic management: strategy and control philosophy
Authors: Brooker P.
Published: July 2022

The aim is to explore the philosophy of air traffic management with different strategic visions of the future: to answer the key question: ‘Who is to prevent mid-air collisions and how are they to accomplish this?’ The best strategic vision may just be the one that has the best match with the consensus on the desired strategic direction. Nevertheless, it must satisfy the main safety, financial, human performance etc. constraints. To explore the question, a blend of concepts from a range of disciplines has been used. These include risk analysis, financial decision-making, ‘cognitive engineering’ research and simple cybernetics. ‘full delegation’ – with pilots being responsible for all the tasks related to separation assurance – appears to meet most of the constraints. Some important issues for safety analyses of full delegation are sketched. Research into the nature and rate of future conflicts in a full delegation environment, using models of error processes, is crucial.
Flight simulation – viability versus liability issues of accuracy, data and validation
Authors: Rolfe J. M. , Hampson B. P.
Published: July 2022

Flight simulation has become an indispensable tool for aviation training. Important decisions relating to the acquisition and certification of aircrew proficiency are made based on performance in simulated flight conditions. Such a high dependency on simulation can invite questions about the validity of the assumptions on which their employment is founded. If these should be shown to be in any way deficient, those who consider that they have suffered as a result may seek redress. The paper considers the possibility that such conditions could arise and require those involved in the design, manufacture, regulation and operation of flight simulators to justify their decisions. The paper suggests that the culture should be one which acknowledges that simulation has its limitations and, consequently, exercises a duty of care for those who undertake training and assessment in flight simulators.
Elastic buckling design curves for isotropic rectangular plates with continuity or elastic edge restraint against rotation
Authors: York C. B.
Published: July 2022

Elastic buckling design curves are presented for flat isotropic rectangular plates, which are either isolated or form part of a larger continuous plate structure. The design curves illustrate the effect of introducing combinations of elastic rptational restraints to the edges of simply supported isolated plates, which are subject to uniform in-plane compression or shear. Results for infinitely long and/or wide plates, with rectangular bays, are superimposed for comparison.
50 years of turbomachinery research at Pyestock — part 2: turbines
Authors: Dunham J.
Published: July 2022

The two parts of this paper summarise the turbomachinery research undertaken at Pyestock during the 50 years since the National Gas Turbine Establishment was formed in 1946. The theoretical and experimental activities are described, and their influence on UK military and civil aero engines is assessed. The way in which NGTE supported non-aeronautical gas turbines is also explained. Part 2 covers turbines.
Civil helicopter operations with British Airways
Authors: Parker M. A.
Published: July 2022

My experience qualifies me only to discuss maintenance aspects of our operation, and I feel very strongly that we in British Airways Helicopters have been forced into developing major design modifications in the past and that insufficient time and experience has been left over to devote to improving our maintenance philosophies and systems.

This was inevitable in the early days, but I now wish to make our position perfectly clear. We, in engineering, are predominantly in the maintenance business and our development and research time will become more and more biased towards maintenance problems.
The economics and noise of subsonic aircraft
Authors: Brown D. G. , Lawson K. S.
Published: July 2022

Noise and economics are major interlinking factors which are likely to have an impact on the whole future pattern of civil air transport development. In the past decade environmental pressures increased the need to design for low community noise levels; however, the fuel crisis and inflation have now shifted emphasis back towards fuel economy and lower operating costs.

The rate of growth achieved by air transport during the past three decades far exceeds that of any other transport system; this considerable rate of growth is clearly illustrated by, for example, the overall increase in total annual passenger movements at London's Heathrow airport, as shown in Fig. 1. It will be further noted that, despite the tendency for aircraft size to increase, the total annual aircraft movements at the same airport also show an overall growth pattern.
Handling qualities of aircraft with stabilty and control augmentation systems—a fundamental approach
Authors: Hodgkinson J. , LaManna W. J. , Heyde J. L.
Published: July 2022

Increasingly stringent operational demands on military aircraft, together with the widening flight envelopes made possible by advances in aerodynamic, structural and propulsion technology, have forced the complication of stability and control augmentation systems (S/CAS) upon the aircraft designer. The early SAS configurations were conceived as devices to enhance the natural response characteristics of the aircraft; later, CAS evolved as a way of making the desired response more independent of the basic aircraft characteristics. Many recent examples of S/CAS are very complex, with equations of twentieth or higher order commonly being used for linear handling qualities analysis. In view of the fact that aircraft of this complexity have been part of the handling qualities picture for ten years or more, it is surprising that no widely accepted criteria for these aircraft have evolved.
An attitude control system for a flexible satellite providing active damping of flexural motion
Authors: Gething J. M. , Gill K. F.
Published: July 2022

A great deal of interest has been shown in recent years in the problem of flexibility in spacecraft structures. Much published work has been devoted to analysing the dynamic interaction between deformation of flexible appendages and attitude control systems. A limited number of publications have sought to find ways of providing some form of active control of flexible motion. Where this has been attempted idealised systems consisting of flexible coupled pendulums or rotors have been considered.

The problem of flexibility may be tackled in three ways. Where the flexure can be shown to be secondary in nature, careful design of the attitude control system can ensure that interaction is kept to a minimum. To this end surveys of structural flexibility effect in spacecraft are invaluable to the design engineers. Where the flexural motion has a more dominant effect, as will follow from the inevitable increase in power requirements for communications, then a more direct approach will become necessary.
Design for safety
Authors: Tye W.
Published: July 2022

Since the advent of air transport half a century ago, safety has been a dominating influence in aeroplane design. It is by no means the only factor. The successful designer is one who uses his talents to arrive at the best balance between the competing demands of speed, reliability, comfort, and cost, while satisfying the demands of safety.

The fundamental reason why the aeroplane places high demands on the designer, perhaps to a greater degree than is the case with surface vehicles, is that the aeroplane proceeds on its way in defiance of gravity. It has to be light enough to fly, and it cannot stop for running repairs. Working within the limitations of available materials and fuels, it took mankind a long time to discover how to make an aeroplane light enough to fly at all. It is a near miracle that some 70 years later, today's aircraft carry large loads for long distances with remarkable safety.
Operations
Authors: Owens Charles
Published: July 2022

This paper deals with two operational aspects of civil aircraft design of major interest to Operators and Pilots,

(i)

Flight Control Systems and

(ii)

Information Requirements.

The first of these describes the problems encountered in our 10 years experience of autoflight, and the operational requirements arising from this, while the second describes the problems caused by the limitations in the availability and display of information to the pilot, and proposes improvements in three areas.
A new shape in the sky
Authors: Morgan Morieim
Published: July 2022

May I thank the Society for the immense compliment it has paid me tonight by the award of the Society's Gold Medal. Earlier this year I was prevailed upon by Council to prepare the Wright Brothers Lecture. This is an occupational hazard of the Director, RAE, and has led to a situation—unique in my experience—in which the Society has presented the Medal and then within a few minutes asked the recipient to stand up and earn it. I am not at all optimistic about the outcome—but will do my best.
Reply to comments by Dr. B.J. Jeffery
Authors: Grimson J. , Hay N.
Published: July 2022

In reply to Dr. Jeffery's discussion, we would point out that we did not use a single property of a wave to describe the waveform and to be used as a measure of the intensity of pulsation. The parameter s was the actual cut-off ratio imposed at the source by the pulsator, whereas the ratio A/h was obtained from the differential pressure records at the meter.
Mediator—a programme for a British advanced ATC system
Authors: Crew E. D.
Published: July 2022

The subject of my paper is the programme for a British advanced ATC system which is known by the code-name Mediator. The name has no particular significance. But before I tell you the history of its development—and this development is still far from complete—and before I go through the various problems which bedevil all such large scale and imaginative plans, I should tell you one or two things about the air traffic situation in the UK. This differs slightly from that in other countries, and needs to be understood from the outset.
Ground organisation of aerial crop spraying
Authors: Perrow Peter M. G.
Published: July 2022

Although the aeroplane itself is the king pin of aerial spraying, without the staff to sell the proposition and the ground personnel to organise and service it, the aeroplane could not operate efficiently and economically.

Aerial spraying is undoubtedly the most dramatic operation which contractors undertake on farms in the United Kingdom. It is the one about which the general public are most aware because in the first place they are affected more by this operation in areas near farms than by other contract operations; and second if there is any untoward incident with an aeroplane they hear about it on television and read about it in the newspapers. If a contractor has an accident with a sugar beet harvester or a combine it is hardly newsworthy.
Numerical results from the application of gradient iterative techniques to the finite element vibration and stability analysis of skew plates
Authors: Fried Isaac , Schmitt Karl-Hienz
Published: July 2022

The obtuse corner of the skew plate is a singular point with a stress singularity growing in intensity with an increase in the angle of skew. For regaining the full rate of convergence of the finite element method the mesh around the singular point should be properly refined or the leading singular terms included in the finite element scheme. In any event a large number of unknowns may be required. For obtaining an accuracy of 1% in the 10th Eigenvalue of a clamped square plate discretised with the 16-degrees-of-freedom elements used in the present calculations, about 300 variables are required. For computational convenience calculations were carried out here with a uniform mesh requiring even a larger number of unknowns.
Legal aspects of international co-operation on aircraft design and production
Authors: Jenkins W. B.
Published: July 2022

The subject of this discussion is not one which readily lends itself to division into separate compartments but, for the purpose of presenting our respective papers, Mr. White and I have agreed to divide the subject between us on the basis that he will deal with the legal aspects of international co-operation as between the participants in the project and third parties, while I propose to discuss some of the legal aspects arising out of the relationship between the companies engaged in such projects. As I have implied, such a division of the subject must of necessity be an arbitrary one, and it is evident that there will be many areas where the two sides overlap, so that they cannot in practice be treated in isolation, and Mr. White and I have felt free to include in our respective papers, matters arising from our own experiences which in some cases may be more appropriate to the other's half of the programme.
Co-operation between the parties to the project itself and third parties
Authors: White C. B.
Published: July 2022

Mr. Jenkins has described to you the matters between the collaborating parties. My task is to describe the problems between them and outsiders.

Because hardly any major European aerospace project lacks some form of collaboration, perhaps I may just make a few points from my own experience of this sort of business.

International collaboration has daunted many people, for rather the same reason that a lawyer like myself feels incapable of imagining how the process of a design office can ever achieve anything!

A lot of what occurs in the design office is summed up in the phrase “know-how”—I have often thought that there is no less a “know-how of collaboration”, particularly international collaboration.
Some experiments on the flow past a sphere
Authors: Calvert J. R.
Published: July 2022

There is little published work on the flow past a sphere. Some experiments were carried out in the 1930s (see Fage), and other measurements have been made more recently (Cometta and Kendall). Much of the work has been restricted to flow visualisation and to measurements of drag and surface pressure distribution. Very few measurements have been made in the near wake.

In the present paper, measurements of vortex shedding frequency, wake dimensions and static pressure up to three diameters downstream are reported. The experiments were carried out in the Aerodynamics Laboratory of the Cambridge University Engineering Department, under the supervision of Professor W. A. Mair.
Lifting body flight test
Authors: Gentry Jerauld R.
Published: July 2022

The concept of manoeuvrable re-entry vehicles capable of controlled re-entry from earth orbit to tangential landing is attractive to a number of military and civilian space missions. One of the several manoeuvrable re-entry techniques that has been proposed is the lifting body concept. Early studies on lifting body configurations indicated that unpowered horizontal landings would be feasible since subsonic lift/drag ratios of four or better were consistently obtained from model tests in wind tunnels. In 1962 the NASA Flight Research Center initiated a programme to investigate the capability of a pilot to control, manoeuvre, and land a lifting body vehicle. I would like to compare the philosophies and procedures used in the lifting body flight test programme at Edwards Air Force Base with those more commonly used in the flight testing of high performance aircraft. Also I would like to discuss limited results of the M2/F2 flight programme and give one pilot's opinion of the requirements for operational lifting bodies.
An airports system for United Kingdom air services
Authors: Masefield Peter
Published: July 2022

Forty years ago Flight Lieutenant John Nelson Boothman, AFC, RAF, won the Schneider Trophy outright for the Royal Aero Club of the United Kingdom, flying a Vickers-Supermarine S-6B (S.I595) on Sunday 13th September 1931. “The better the day the better the deed.”

To some, that win at 340.8 mph over a 270 mile course seemed the end of an era and the climax of the careers of both Reginald Mitchell, and of Henry Royce, the designers of the S-6B and of its 2300 bhp Rolls-Royce “R” engine.

In the event, as history has unfolded, the winning of the Schneider Trophy was but the opening page of a more significant story—the evolution of Mitchell's Spitfire, of Camm's Hurricane and of their Rolls-Royce Merlin engines. Those later Schneider Contests—from 1927 to 1931—led directly to the winning of the Battle of Britain in 1940—and to our presence here in a free world tonight.
Optimal paths for minimising landing transition distance for jet-lift VTOL aircraft
Authors: Huntley E.
Published: July 2022

The question to be considered is the following—starting with the aircraft flying at the minimum conventional flying speed at a given height above the ground, how should the controls be operated and the flight path chosen, in order to bring the aircraft to rest on the ground in an optimum fashion? Optimum fashion can mean different things at different times but, in this context it usually means the simultaneous loss of speed and height in such a way that obstacles are surmounted but the total transi tion distance, time, or fuel used are minimised. The problem is one which may be solved mathematically by variational methods following Hacker or Brüning, but the approach in this study is a simpler one and is based on an intuitive search for near-optimum solutions by means of physical arguments.
A simple analytical solution to an unsteady compressible homentropic flow problem with a zero spatial pressure gradient
Authors: Woods W. A.
Published: July 2022

Numerical solutions to unsteady flow problems have been developed, and often it is not possible to carry out a direct check on their accuracy. However, such a check was given in Ref. 3 using an analytical solution for zero spatial velocity gradient. The object of the present note is to present a different simple analytical solution which can be used as a special case for checking the accuracy of a numerical solution. Also, the solution is of interest itself as it corresponds to certain gas dynamic problems.
Industrial relations in civil air transport
Authors: Thomas Tudor
Published: July 2022

Under the Civil Aviation Act there is a responsibility on the Airways Corporations to establish machinery for the determination of terms and conditions of employment and consultation with the staff they employ. There is, equally, a responsibility upon the Boards of the Corporations to recognise those unions who are appropriate to the grades of staff they employ.

The machinery, which was created in 1949, was based on the concept of Whitleyism but its application had to be rather wider than was the case in other industries because:

(i) Civil aviation was in its infancy at the time

(ii) The formidable task of bringing together a wide variety of skills

(iii) The problems of adjusting to the varying practices and philosophies of unions catering for a wide variety of occupational groups.
Spectral gust alleviation factors for pitching aircraft
Authors: Huntley E. , Littlewood P. G.
Published: July 2022

This paper represents a second stage in a continuing theoretical study of aircraft longitudinal responses to random turbulence based on stationary random process theory. In previous papers the spectral gust alleviation factor for eg normal acceleration, was studied in detail. In the first, the aircraft was assumed to be rigid, responding only in heave, and the effects of unsteady aerodynamics were K, systematically considered. Wherever possible, comparisons were made with previously published work. For the published version the report was revised and expanded to include some results for the pitching aircraft but this analysis was not complete. This paper is concerned with a more complete analysis of the longitudinal responses of a rigid aircraft, free to heave and pitch, flying through random turbulence. The turbulence is assumed to have a power spectral density function described by the Dryden model.
A new method for the evaluation of slotted wind tunnel interference parameters applicable to subsonic oscillatory tests
Authors: Streather R. A.
Published: July 2022

Until a few years ago it was the practice to neglect lift interference on oscillatory model tests in high-speed subsonic wind tunnels, whatever the working section configuration. However, in 1960 Bratt and Wight discovered a large interference effect on the pitch damping derivative of an M-wing measured in the slotted working section of the 25 in x 20 in tunnel at the National Physical Laboratory. In 1964 Wight reviewed a number of oscillatory tests and showed that in many cases there were significant interference effects on both stiffness and damping derivatives when measured in slotted working sections.
Pitcher and the Multiplane; an addendum to the paper published in the May issue of The Aeronautical Journal
Authors: Jarrett Philip
Published: July 2022

Following the publication of my paper “Pilcher and the Multiplane” in the May issue of the Aeronautical Journal, I have had cause to reperuse the various accounts dealing with the operation of the “gust damping” device used by Chanute on his quadruplane and probably adopted by Pilcher for the multiplane.

Referring back to the original patents, which I had read thoroughly during the preparation of the paper, I realised that I had omitted to mention Chanute’s proposal of the deliberate operation of this system as a positive means of control.
The third London airport—the process of decision
Authors: Keith-Lucas D.
Published: July 2022

The Report of the Commission on the Third London Airport tells the story of an interesting exercise in airport location. It includes what is possibly the most extensive cost benefit analysis ever undertaken for a civil project and it tells of an experiment in decision taking in a democratic society. At the time of writing this paper the report has been published for a little over three months but the Government has not yet announced its decision. After publication of the report there was an immediate popular outcry against the recommendation of an inland site and it now looks likely that the Government will not accept the recommendation.
The operational angle
Authors: Newham D. F.
Published: July 2022

The purpose of this paper is to outline the “operational angle” of the hijacking problem and of the measures which might be taken to combat it.

Before considering what can be done on the aircraft itself to prevent or deter the hijacker from achieving his or her objective, I think it important to first review the likely circumstances of a hijack incident. By this I hope to ensure that my conclusions are seen against an essentially practical background.
The pressure-jet helicopter propulsion system
Authors: Nichols J. B.
Published: July 2022

The helicopter rotor probably represents one of the most difficult of all power-transmission problems in the fact that high power is required at relatively low rotational speeds. High power at low speed defines high torque, and high torque in a mechanical transmission requires large, heavy gears. In addition, since every action has an equal and opposite reaction, the shaft torques must be reacted, and this requires a tail rotor system for the shaft helicopter.

A jet-propulsion system offers certain distinct advantages in comparison with a shaft-drive system for powering a helicopter rotor. It delivers a driving torque to the rotor in the form of a tangential force at the tip of the rotor rather than by twisting a shaft at the centre of the rotor.
Predicting Design Costs
Authors: Leech D.J. , Earthrowl D. L.
Published: July 2022

An investigation of design procedures in high technology engineering organisations is being undertaken by the Divi-sion of Industrial Systems Engineering at University College of Swansea. To ensure comparable levels of en-gineering sophistication the study has been confined mainly to the aircraft component industry.

Initial work in this study has revealed some interesting facts about the prediction of design and development costs. Detailed information about design and development expenditures, estimated and actual, has been collected from one company and less precise data indicating similar trends has been gathered from three other companies.
Concorde navigation system
Authors: Hill H.
Published: July 2022

Nothing in the Concorde could be more conventional in this day and age than its navigational equipment installation. Triple inertial systems, dual VOR/DME, dual ILS and even dual ADF are fitted to the basic aircraft. About the only thing we do not have is a navigator.

This is really where the story starts, about 12 years or more ago, with a three man crew which did not include a navigator. His absence was only loosely related to being supersonic. Admittedly, the flight deck of any faster aircraft is very likely to get cramped, particularly in its width, and space for crew members costs money but it is economic pressures which apply to all aircraft which have gradually displaced the specialist crew member. The skill of the equipment designer has made this possible by providing simple controls capable of being operated by the pilot without distracting him from his main task. The specialist radio operator has gone and we are how entering an era in which the navigator will also disappear.
The aeroplane as a threat to the environment
Authors: Lloyd P.
Published: July 2022

Aeroplanes are often noisy, and sometimes smelly. Some of them also produce smoke. The purpose of this paper is to attempt an assessment of these and other forms of environmental pollution, also to consider the engineering and administrative measures which are being taken to control them. But before embarking on the subject one must try to put the matter in perspective. As I see it, the threat to the environment does not just come from aeroplanes, transport systems, factories or advancing technology. It comes from man.
Scar tissue and aircraft propulsion development
Authors: Simpson E. C.
Published: July 2022

Involvement with the development of an aircraft engine can create deep mental scars. There seems to be an almost infinite variety of ways to encourage failure when considered in detail, and at the same time, there is no rule that will ensure success, except “Don't make any mistakes!”, a rather absurd bit of guidance. There is a small number of basic resources necessary for success, but only proper application of these resources can permit success. The basic resources are money, manpower, facilities, and knowledge. This paper provides, on the basis of one man's scar tissue, some guidance in creating an environment to encourage success. This introduction defines the general size and importance of the problem and the resources applied to the paper. The problems of organisation are outlined, followed by a definition of the game rules. The problems line people must overcome are discussed, followed by what to expect and where to inspect for problems. The paper ends with a suggested approach to the technical portion of the problem.
Pressure airships: a review
Authors: Hecks Karl
Published: July 2022

Given the situation that there is at present something of a resurgence of interest in airships as practical vehicles, and that most people in aeronautics today are not very familiar with lighter-than-air flight, particularly in its technical aspects, it seems worth setting down a brief survey of the special characteristics of airships, as a contribution to the general understanding.

The present article was written with this aim in mind. It refers mainly to non-rigid or pressure airships, reflecting the fact that in most applications these appear to be simpler and cheaper than rigid airships, even for very high volume. However, much of the text applies equally well to rigid ships, and it must be accepted that adopting the “rigid” approach can give a useful extra measure of design flexibility (e.g. for internal cargo stowage).
SI Units applied to aircraft performance calculations
Authors: Wingham P. J.
Published: July 2022

The advent of SI units makes it necessary to revise many standard constants and numerical values which are familiar to a generation of aeronautical engineers whose education and practical experience have been solely with the British system of units.

Most affected by these changes are not so much those who spend all their time carrying out (computer-aided) calculations, but those who direct such work and whose personal calculations are limited to the backs of envelopes. The task, for the latter, of assessing and communicating data presented in unfamiliar units is very daunting, and the possibility, for them, of ever being able to think in the new units may seem remote.
Applications of shock expansion theory to the flow over non-conical delta wings
Authors: Squire L. C.
Published: July 2022

Shock expansion theory was first used by Epstein to calculate the characteristics of aerofoils with sharp leading edges and attached shock waves. In this case the aerofoil characteristics were found by assuming that the flow downstream of the leading edge shock was the same as in a Prandtl-Meyer expansion with all reflected waves neglected. In 1955 Eggers and Savin considered the extension of the method to three-dimensional hypersonic flows, with particular reference to bodies of revolution at incidence. Eggers and Savin point out that the most important factor influencing the method is the accuracy of the basic conical solution at the apex, since inaccuracies at the apex are reflected strongly in the pressures downstream. For this reason most applications of the method have been restricted to inclined bodies of revolution with pointed noses, since solutions for yawed cones can be used to start the solutions. Recently it has been shown that thin-shock-layer theory as originally developed by Messiter can give accurate solutions for the shock shapes and pressure distributions on the lower surfaces of conical bodies with a wide variety of cross-section shapes and for a wide range of hypersonic flight conditions.
Formula one air racing
Authors: Hardy R. J.
Published: July 2022

If air racing history is reviewed, it will be seen that the peak was reached when British light aircraft manufacturing was supreme. In 1927 alone, there were no fewer than 81 records set. The resurgence of interest following the Second World War declined until 1963 when only three records were set. Since then, air racing has progressed in one form or another to recent times when the Trans-Atlantic air race produced many new records. Unfortunately, this type of air race does little for the sporting aircraft enthusiast, and since the last Schneider Trophy Race, 40 years ago, there has not been a major international air race where aircraft have been pitted against each other to determine which flew the fastest.
A linearised theory of parachute opening dynamics
Authors: Heinrich H. G.
Published: July 2022

The inflation of a parachute encompasses problems of aerodynamics, dynamics, and elasticity. The most noticeable effects of the interaction of the events are the opening force and the filling time. Attempts to analyse the opening process and to predict the opening force date back to 1927. Since then a considerable number of methods have been published. Some of them are primarily analytical, others more empirical, and several deal with isolated problems. The earliest and most analytically oriented studies are by Scheube and O'Hara.
Engine Development in an Operators' Market
Authors: Edwards J. L.
Published: July 2022

The modern aero engine is one of the most sophisticated machines currently produced by man. Its design, manufacture and repair necessitate the use of the latest knowledge and techniques, and development in one form or another continues throughout its service life.

Despite this high technical content, the fundamental requirement of the industry is to run on a sound economic basis. Often, however, this objective is lost in the equally demanding requirements of flight safety, or meeting over optimistic dates and of keeping up with competition in a multiplicity of other ways.

Much has been written about the initial development of engines up to type approval. This paper proposes to go beyond that and to describe some of the problems which arise during manufacture and operation, to emphasise the frustration and fury of an operator who has to unload 100 passengers and find them hotel accommodation—at his expense—in some outlandish part of the world because of a leaking oil pipe, and to highlight the need for repair techniques which are economical and simple.
The Management Organisation of the
Martel Project
Authors: Franks P. R.
Published: July 2022

Although this paper forms part of a symposium dealing with management techniques used in guided weapon development, it is concerned with the organisation of management rather than with the techniques used. Techniques used on different guided weapon systems may well be the same in principle, although differing in detail. Martel differs from the other weapon systems considered in this symposium, however, in that it is a project in which the development was carried out by organisations in two different countries working in collaboration. The lessons which may be drawn from Martel, which cannot be drawn from other guided weapon projects, are concerned with international collaboration, and not with the detailed techniques used to manage the project. It seems, therefore, that it is desirable to concentrate on the management arrangements associated with this project and not on the detailed techniques used. It is an inevitable consequence of this concentration on international organisation that this paper is concerned mainly with the Government agencies and the main contractors.
Management of the UK Polaris Project
Authors: Dossor F.
Published: July 2022

MY paper concerns the Management of the UK Polaris Project. Only Admiral Sir Hugh MacKenzie, leader of the UK Polaris Team, with his complete knowledge of the story, could do justice to this subject. However, as a member of the Polaris Management Team from January 1963 to December 1968 I was in a position to know most of the story.

Before describing the management organisation, it is necessary to outline the job to be done. Major features of the UK Polaris Programme were:—

(a) The design and building in the UK of four 8000 ton nuclear propelled submarines, craft twice as big as the Valiant class.

(b) The procurement from the USA of Polaris A3 weapon systems for the submarines.

(c) The design and manufacture in the UK of nuclear war-heads for the missiles.
The Helicopter—Today and Tomorrow
Authors: Sikorsky S. I.
Published: July 2022

In the first 30 years of its existence, the helicopter has grown four times in speed and 75 times in gross weight. A comparable period in fixed-wing operation showed a speed growth of eight and 40 times in gross weight. The US aerospace industry (total 1.3 million persons) is currently employing 48 000 (3%) of its total force to build helicopters. However, this 3% is delivering over half of the manned aircraft being procured. US military inventory of helicopters has grown from 7317 helicopters in fiscal 1966 to 12 486 in fiscal 1969, thus comprising 35% of US manned aircraft. Military pilot training has already swung in favour of helicopters in the US, with 6000 fixed wing pilots trained annually compared with 7500 helicopter pilots annually. A similar trend is expected to take place in Europe and Asia.

The helicopter is beginning to stabilise in several fairly clear families or classes.
Laminar Boundary Layers Behind Strong Moving Shock Waves
Authors: Ackroyd J. A. D.
Published: July 2022

The problem considered in the present note is that of the laminar boundary layer created by the motion of a strong shock wave. Such shock-induced boundary layers occur in shock tube flows behind the primary moving shock wave. For structural reasons, shock tubes frequently do not have very large diameters, so that such boundary layers often adversely affect the quality and duration of the test gas flow. The latter problem is studied, for example, in ref. 1 and to attempt such a problem a fairly detailed knowledge of the behaviour of shock-induced boundary layers is required. Such basic boundary-layer studies have been described in refs. 3-8 and the situation which occurs when the shock wave is strong is investigated here. The boundary-layer equations are expanded in a series form which involves a small parameter. This small parameter is shown to be the ratio of the gas densities fore and aft of a strong shock wave.
High Lift-Drag Ratio Double Wedges of Given Volume which Support Two-Dimensional Supersonic Flow Fields
Authors: Bartlett R. S.
Published: July 2022

Several authors have considered the lifting characteristics of various simple shapes at hypersonic speeds. Non-weiler has dealt with shapes derived from wedge flows, and Townend has considered a class of two-dimensional shapes with concave undersurfaces. Cole and Aroesty and Pike have both considered two-dimensional shapes which are perturbations of simple wedge flow. They show that slightly higher values of the lift-to-drag ratio than that of the wedge are obtainable. Cole and Aroesty apply hypersonic small disturbance theory, under the constraint of constant lift, and suggest that the optimum shape is a “multi-wedge”. They show further that the optimum of a more restricted class of shapes having undersurfaces made of two plane surfaces, has a slightly concave surface. Pike has applied a more accurate (second-order) perturbation theory to a class of shapes which consist of small deviations from a wedge. He finds that the optimum undersurface consists of two plane surfaces, and confirms Cole and Aroesty's result that it must be slightly concave, except perhaps at low Mach numbers below the hypersonic range. It must be remembered that these results depend upon the assumed constraint of constant lift.
Non-Linear Vibrations of Rotating Cantilever Beams
Authors: Rao J. S. , Carnegie W.
Published: July 2022

The problem of flexural vibration of a rotating cantilever blade is non-linear when the vibration takes place in a plane other than perpendicular to the plane of rotation. The non-linearity arises from the effects of Coriolis accelerations due to the rotation of the blade mounted on the periphery of a disc. Lo and Renbarger neglected the non-linear terms in their investigation and arrived at a simple relation for the frequency of vibration in terms of the stationary frequency of the beam, the rotating speed and the orientation of the plane of vibration. Lo in his analysis simplified the non-linear problem by assuming the blade to be rigid everywhere excepting at the root and presented the solution in a phase plane. Isakson and Eisley have considered a similar model to determine the natural frequencies in coupled bending and torsion of twisted rotating cantilever blades.
Major A. R. Low, RAF, MA, FRAeS 1878-1969
Authors: Edmonston Low R. C.
Published: July 2022

It is undoubtedly true to say that with the death of Archibald Reith Low on the 21st January 1969, there departed from the scene the last of the early pioneers of British aviation.

Born in Aberdeen on 31st December 1878, he was brought up with four brothers and three .sisters at the Manse at Fountainbridge, Edinburgh, where his father was Minister of the Church of Scotland. His mother was Jane Stuart Reith, aunt of the present Lord Reith, who was thereby his first cousin.