bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electric Propulsion Development
Authors: Openshaw P. R. 
Published: June 2018

Parts I and II of this series of papers have dealt with the development of ion thrusters for use in an orbit transfer manoeuvre, and of various types of micro thruster for position and attitude control. The present paper deals with the actual satellite electric propulsion system and configuration needed for expansion manoeuvres. The control problems both during the expansion phase and subsequently in the required orbit are discussed. Short analyses for two specific cases (ELDO launcher and Black Arrow) are presented in which payloads and missions are defined.Burt has shown that all the orbital elements of a spacecraft can be changed by means of a small continuous thrust. He gave particular attention to the problem of expanding from a low orbit to a synchronous one, and the change of orbit inclination and orbit eccentricity was also considered. Such a type of manoeuvre is eminently suitable to electric propulsion because the high exhaust velocities possible lead to a small propellant mass; this mass saving is achieved at the expense of the time taken for the manoeuvre.
Two and Three-Dimensional Flow using Finite Elements
Authors: Argyris J. H. , Mareczek G. , Scharpf D. W. 
Published: June 2018

The method of finite elements is in certain cases advantageous when dealing with flow problems in a finite domain. This is particularly so when attempting to include subcritical compressibility effects.In the present note we first consider the two-dimensional flow using TRIC and TRIM-like triangular elements in conjunction with the concept of the stream function, which is assigned to the nodal points of the elements. The application of the stream function allows a direct and exact satisfaction of the boundary conditions. Strictly the elements in question could also be used in conjunction with the potential function but the observance of the boundary conditions is then cumbersome.
A Review of Engineering Developments in Helicopter Design
Authors: Speechley J. 
Published: June 2018

One of the most interesting aspects of the aeronautical endeavours of Henson and Stringfellow was their awareness of the impact of the aeroplane as part of an overall transport system. It is all too easy in the field of aeronautical engineering to become mesmerised by the engineering intricacies of what one is doing and so fail to see the vehicle as part of this overall system concept.In many respects we have, I think, been able to avoid this inward thinking in the helicopter since its vertical flight capability has become intimately bound up with considerations of its operational duties.
The Next Generation of French Helicopters
Authors: Legrand L. F. 
Published: June 2018

It is a great honour for me to present this lecture as a tribute to the memory of La Cierva.In my opinion, La Cierva was more than a pioneer who designed practical rotor-craft: he was, above all, the engineer who tried to understand how these machines worked and what is more remarkable, he sometimes succeeded! I am afraid that this attitude of mind has been somewhat forgotten since La Cierva, but the manufacturers willing to survive should now follow his example.I have been asked to present the next generation of French helicopters but it would be more appropriate to speak of the next generation of Anglo-French helicopters. For, as you know, the models of the near future are being developed and produced under the terms of a co-operation agreement concluded between our two Governments. Other lecturers, with better qualifications, have already emphasised the “pros” and “cons” of these international programmes.
Man-Powered Flight—A New Approach to an Old Dream
Authors: Richmond S. 
Published: June 2018

There is an old saying in the aircraft industry that you can make a brick fly, if you give it enough power. How true this is I would not care to say, but it is certainly true that the worries of the designer are lessened if he knows that he can always give the throttle a little extra push, if all else fails.This is not to say that the design of a conventional, high powered, aircraft is a simple, hit or miss affair, that would be ridiculous, but it does serve to show the special difficulties faced by the builders of a man-propelled aircraft who have less power available to them than is used by a small electric fire.
Requirements for Future Civil Aircraft
Authors: Brown D. G. 
Published: June 2018

Requirements fall into two categories: —(i) the demands of the market leading to a capacity requirement, which, dependent on the technical solutions, leads to a market requirement in terms of the number of aircraft.(ii) the technical requirements in terms of the vehicle characteristics required to provide the most competitive aircraft to achieve maximum market penetration.An appreciation of future civil requirements is presented as seen through the eyes of a project engineer rather than a market research economist. The title of the symposium suggests a focusing of attention on two main fields of air transport, namely, the successors to the supersonic long-range aircraft and the large subsonic short-range aircraft. It is, however, the intention to broaden the survey to cover the major areas of activity in civil aviation, since in many ways there may be inter-relations between the developments in different fields.
Synthesis of Aircraft Modal Control Systems having Real or Complex Eigenvalues
Authors: Crossley T. R. , Porter B. 
Published: June 2018

The theory of modal control is concerned with the design of control loops for systems with governing equations which can be adequately approximated by linear vector-matrix equations of the formwhere x is the system state vector, y is the control vector, A is the matrix of the uncontrolled system, and B is the control matrix.
The Advantages of Three-Shaft Turbofan Engines for Civil Transport Operation
Authors: Armstrong J. P. , Jones A. T. 
Published: June 2018

The engine parameters which most obviously must improve to contribute to the continued lowering of aircraft Direct Operating Costs are those of prices, weight, volume and fuel consumption. These affect the base-line performance characteristics of the aircraft and in any formula for estimating Direct Operating Costs they will appear in the general cost of flying a load of passengers or freight from A to B.Engines also unfortunately generate other costs in their own right. These include:Maintenance labour while mounted on the aircraft.Repair and overhaul shop labour (including time to remove and re-install the engine).Replacement parts cost.Spare engine holding.Spare parts holding.Overhaul shop overheads.
Thrust Vector Control by Secondary Gas Injection in Two-Dimensional Nozzles
Authors: Neilson John H. , Gilchrist Alastair , Lee Chee K. 
Published: June 2018

When side force is produced by the injection of a secondary gas into the supersonic region of an axi-symmetric nozzle, the body shape of the obstruction caused by the secondary flow induces a cone-shaped separation region upstream of the port. From the apex of the cone a conical shock front is developed. Part of the total side force produced is due to the excess static pressure acting on the nozzle wall in(a) the separated region, and in(b) the wall area lying between the separated region and the trace of the shock on the nozzle wall.In such a field the static pressure is not uniform downstream of the shock but varies from point to point on the nozzle wall areas in question. This aspect of axi-symmetric flow makes attempts to correlate theoretical and experimental work difficult. It was considered that basic information about the important parameters, which influence side force, could best be obtained in experiments with two-dimensional nozzles. Here the circular secondary port is replaced by a rectangular port, the separation zone is wedge-shaped, the shock has a plane front, and in theory, the static pressure is uniform between the port and the point at which the boundary layer separates.
Flow Separation and Stall Characteristics of Plane, Constant-Section Wings in Subcritical Flow
Authors: Chappell P. D. 
Published: June 2018

SummaryThis paper discusses the various aspects of flow separation on wings and aerofoils at subcritical Mach numbers. It is shown that in general the onset of non-linearities in the aerodynamic characteristics, for plane constant-section wings, can be related to the initiation of regions of flow separation somewhere on the wing and often near the wing tip.Empirical correlations are produced, tor plane wings of constant symmetrical section, enabling estimates to be made of the lift coefficient for onset of separation at either the leading or trailing edge of the wing.A correlation of stall types on aerofoils, due to Gault, is extended in application to the estimation of initial stall and separation types for plane wings of constant symmetrical section. Suggestions for extending the application of this correlation to the estimation of section stall type for cambered, twisted and non-constant section wings are made.
Functional Requirements for Research/Work Submersibles
Authors: Flemming N. C. 
Published: June 2018

SummaryA submersible is defined as a neutrally buoyant submarine which relies largely on the buoyancy of the hull rather than gas or liquid filled floats at ambient water pressure. 29 different kinds of submersible have been built in USA and 15 in other countries. One has been built in England. Half of these do not go below 2000 ft and one third do not go below 1000 ft. The minimum safe weight for a vehicle is 5 tons at 1000 ft and 10 tons at 20 000 ft. A useful research or light work vehicle must be twice the minimum weight, and a heavy work vehicle in the 30-100 ton range.High utilisation factor can only be obtained with special handling and support equipment, underwater navigation aids, high manoeuvrability, and a reserve of speed, life support, payload, and endurance. Principle applications of submersibles are in scientific research, geological mapping, prospecting, the oil industry, dredging, pipe-laying, and search and salvage.
Calculation of the Response of a Fighter Aircraft to Turbulent Air and a Comparison with Flight Measurements
Authors: Mitchell C. G. B. 
Published: June 2018

Summary:—The response of a P1a fighter aircraft to vertical and lateral harmonic gusts is calculated, and the predicted spectra for response accelerations at many points on the structure compared with previous flight measurements in continuous turbulence. The frequency range for the comparison is 0.45 c/s to 30 c/s and the response includes the short period pitching and the dutch roll rigid–body modes as well as oscillations in five symmetric and four anti–symmetric flexible modes. Structural flexibility is represented by measured vibration modes and aerodynamic forces are calculated by an oscillatory lifting surface theory.
Clamped Skew Plate under Uniform Normal Loading
Authors: Kennedy J. B. 
Published: June 2018

In their paper in the February 1967 Journal, Iyengar and Srinivasan have presented a solution to the problem of uniformly loaded clamped skew plates by employing characteristic functions for the modes of vibration of clamped-clamped beams. They compared their theoretical results with those obtained by Morley and Kennedy.The writer has recently extended the 3-parameter solution by assuming a deflection function in the form:
The Ratio of the Wall Shear Stresses in Concentric Annuli
Authors: Quarmby Alan 
Published: June 2018

SummaryExperimental results are presented of the measurement of the ratio of the wall shear stresses at the inner and outer surfaces of concentric annuli. Five radius ratios were investigated with Reynolds numbers in the range 2000-89 000 with air. The Reynolds number is defined as where ū is the bulk velocity.It is concluded that the ratio of the shear stresses is very different from the corresponding laminar flow value and is a function of both radius ratio and Reynolds number.
Guided Weapon Simulators
Authors: Cartmell I. N. , Williams R. W. 
Published: June 2018

The authors were requested to present short papers giving opposing views on the subject of Guided Weapon Simulators. Much of this subject is now a matter of fact and the authors found themselves in agreement on far too many points regarding the present situation to follow the requested approach, and instead have adopted the method of writing a joint paper briefly reviewing the past history of simulation and setting out the present state of the art as they see it, leaving the discussion of probable future trends to encourage controversy. It has still been difficult to be controversial, but if some of the statements made stimulate discussion then a useful purpose will have been served. It may turn out that what the authors have found difficult to produce between themselves has been created only too readily between themselves and their audience.It is not possible to discuss simulators without bringing in the concept of modelling, indeed an apt title for this paper could have been “From Simulation to Modelling”. The model technique has been defined as “a procedure in which a representation of a system is developed in some more convenient medium and checked to show that its behaviour agrees with that of the original system for a wide variety of conditions”.
The Atmospheric Environment and Aircraft—Now and the Future
Authors: O'Hara F. , Burnham J. 
Published: June 2018

SummaryA survey is made of the effects on aircraft of the main atmospheric factors and of the way they are dealt with, in design and operation, at the present time. Possible developments in the pattern of the relationships of aircraft to the atmospheric environment are discussed, in the light of expected advances like operational VTOL, and orbital-type flight, reliable weather forecasting, and effective turbulence avoidance and gust alleviation systems. These developments should all be conducive to safer and more comfortable flight. Marked further benefits would accrue from weather control in the vicinity of airfields, of which there are some prospects, improvement in en-route operation through weather control appears less probable, and the prospects of smoothing turbulence ahead of the aircraft are speculated on.
Thoughts on Flight Instrument Presentations
Authors: Gill T. E. 
Published: June 2018

One of the difficulties in giving a talk on flight instrument displays is that everyone in aviation seems to be an expert on this particular subject—or at least everyone has such fairly violently held prejudices that new ideas tend to be automatically opposed and are certainly viewed with suspicion. I am no exception although, of course, I consider my prejudices to be calmly reasoned opinions. Accordingly, being nominated by my Commanding Officer to address this test pilots’ group I swam into the literature on the subject— and there are fathoms of it—to find that most of my “new” ideas have been put forward before and, not only that, have often been rejected on pretty good grounds.In fact, insofar as instrument displays are concerned, history is anything but bunk and, quoting C. G. Grey of Aeroplane fame, “history is the greatest plagiarist and repeats itself to such an extent that if you knew all history one would never make a mistake in life because one would know all the mistakes that had been made”. And as you know, the difference between plagiarism and research is that if one steals ideas from more than one person, it is research.I hope to show that many of the latest ideas on displays have been previously tried but not pursued until later technological developments made their use necessary and possible. I also hope to put forward some of my ideas on this subject.
The Influence of Aerospace on Future Transport Systems
Authors: Legg Keith 
Published: June 2018

“We are concerned, not with nature alone, but with the total relation between man and the world around him. Its object is not just man's welfare, but the dignity of man's spirit.”Lyndon B. JohnsonI am most conscious of the honour of being invited to give the Sixth Handley Page Memorial Lecture, particularly in view of the renown of the previous speakers. Since these lectures are jointly sponsored by the Royal Aeronautical Society and the Cranfield Society, I am especially delighted at being the first ex-student of Cranfield who has been invited to present this paper.
The Buckling of Shallow Corrugated Webs in Shear
Authors: Rothwell A. 
Published: June 2018

SummaryThe results of a series of shear buckling tests on shallow, flat-sided, corrugated webs are presented, and a comparison made with a theoretical analysis in which the web is assumed to buckle either as an orthotropic plate or in a local mode. An expression is derived for the efficiency of a corrugated web in shear, and used to compare the four shapes of cross-section tested.
Helicopter Armament for Land Operations
Authors: Kennedy Brigadier C. D. S. 
Published: June 2018

Now that the British Services are becoming drawn inexorably into the business of helicopter armament, the attitudes of individuals are widely diverse; some are appalled; some are eager; others mutter evasively “Can't we leave this sort of thing to the professionals?” Number me among the enthusiasts.My aim this afternoon is simply to air the current problems relevant to helicopter armament in support of British Army operations—in the hope that members of this Society will later come up with clever ideas to solve them.
Possibilities of Compound Rotorcraft—Status 1968
Authors: Carlson Richard M. 
Published: June 2018

SummaryThe paper considers the possibilities of a single type of VTOL vehicle—the compound rotorcraft—in the context of 1968 technology. Past and current compound programmes are reviewed in establishing technical status and include the XV-1, Fairey Rotodyne, Kamov KA-22, US Army Aviation Material Laboratories experimental compounds and the AH-56A (AAFSS).Qualitative characteristics of compound rotorcraft such as airframe vibration, gust response, landing and take-off characteristics, and safety are discussed and compared with both fixed- and pure rotary-wing aircraft.Characteristics such as cruise speed, vehicle lift/drag ratio, empty weight fraction, and maintenance are examined quantitatively for a 30-passenger compound rotorcraft, and appropriate limitations of these characteristics are discussed. Sensitivity of direct operating costs to changes in these characteristics is considered.The compound method of VTOL flight appears to offer great promise in both military and commercial fields, particularly as it can be applied to the inter-urban mass transport problem and to Army logistics and ground attack functions.
Health Facilitation
Authors: Bergin K. 
Published: June 2018

The organisations involved in health facilitation are 3
international ones, 1 national one and 1 local
one.The three international ones are:(a) The World Health Organisation, an offshoot of the
United Nations and before that the League of
Nations. This body has headquarters at Geneva and
disseminates on a daily basis, world-wide
information on epidemic diseases, thus keeping
countries fully informed of the current disease
position in other countries.(b) The International Civil Aviation Organisation,
which is a consortium of Government Agencies which
draws up statutory regulations for the international
control of air travel including, among others,
personnel and medical problems. Its objective is to
implement the Chicago Convention which, in turn, was
the successor to the Paris Convention. It is
obviously desirable that recommended practices of
medical standards for pilots should be uniform
throughout the world. Sir Frederick Tymms was at one
time the UK representative.(c) The International Air Transport Association, a
voluntary organisation of air operators which
endeavours to regulate conditions among commercially
competing airlines. The medical committee, like
other committees, makes an annual report to the
Executive. Sir Wjlliam Hildred was its distinguished
chairman for many years.
The Design and Construction of Two-Seater
Hovercraft
Authors: English Anthony J. 
Published: June 2018

It is not generally realised that the ground effect
principle on which the air cushion vehicle is based
was first expounded by a Scandinavian scientist some
hundred years before Sir George Cayley grasped the
basic principles of flight and two hundred and fifty
years before the hovercraft went into commercial
service. The basic principle of the air cushion
vehicle is extremely simple, but, as in many
branches of engineering, simplicity of principle and
ease of achievement do not go hand in hand!How does a hovercraft hover? Let us take a vehicle with
a weight of 1000 lb (454 kg) and a flat undersurface
of 100 sq ft (9m2) in area. If we
increase the air pressure under the machine by 10
lb/sq ft (478 N/m2), the total reaction
pushing upward from the undersurface of the machine
will be 10 x 100 = 1 000 lb (454 kg). This, being
equal to the weight of the machine, will cause it to
leave the ground.
Some Thoughts about the Future of European Aeronautics
Authors: Davies Handel 
Published: June 2018

The twenty-first Louis Blériot Lecture was given in Paris on 5th April 1968 under the auspices of L’Association Françaises des Ingénieurs et Techniciens de L'Aéronautique et L'Espace. The lecture “Some Thoughts about the Future of European Aeronautics” by Handel Davies, CB, MSc, CEng, FRAeS, FAIAA, was read on his behalf in French by General Lecamus, FRAeS. The Lecture was attended by the President, Mr. M. B. Morgan, CB, MA, FRAeS, the Secretary of the Society, Dr. A. M. Ballantyne, OBE, TD, PhD, by several members of Council and a large and distinguished French audience.The Chair was taken by Monsieur Robert Blum, President of AFITAE. Following the lecture a dinner was given by AFITAE.
An Experimental and Theoretical Investigation of Simply-Supported Thin Plates Subjected to Lateral Load and Uniaxial Compression
Authors: Sharman P. W. , Humpherson J. 
Published: June 2018

In the design of compression structures, the effect of lateral loading is usually ignored. This assumption has been justified where the structure has represented the wing skin of a conventional aircraft, in which the compressive end load due to bending is high, but the lateral load due to aerodynamic pressure is comparatively low.However, in some cases the approximation is too crude, such as where the effect of the aerodynamic pressure is added to by pressurised fuel tanks together with the possibility of the accelerated weight of fuel. Such situations arise in supersonic transport aircraft where a considerable weight of fuel is carried in the wing and aerodynamic heating causes high compressive stresses in the skin.
A Proof of the Biot-Savart Law
Authors: Newman B. G. 
Published: June 2018

The Biot-Savart law gives the velocity associated with an elemental portion of line vortex, or the magnetic field associated with an elemental portion of line current. The following proof may appeal to students who approach fluid mechanics or electromagnetic-field theory from the engineering viewpoint. It will be stated in terms of fluid mechanics.Consider a very small length δs of line vortex of circulation strength Γ. At P(x) the velocity δV associated with this portion depends on
Γ δs and x.