bluuebunny/crossref_metadata_2025_split huggingface dataset:
Note on the Application of Busemann's Formula to a Simple Two-Dimensional Curved Aerofoil Section
Authors: Dunsby J. A. 
Published: August 2016

The theoretical aerodynamic properties of supersonic aerofoils of polygonal section are well known. This note describes the results obtained by applying supersonic aerofoil theory to a simple curved aerofoil of arbitrary maximum thickness position, the leading and trailing edges of which are pointed.The results for a symmetrical curved section are compared with the theoretical properties of a symmetrical double-wedge section.
Unsymmetrical Bending and Bending Combined with Axial Loading of a Beam of Rectangular Cross Section into the Plastic Range
Authors: Barrett Anthony J. 
Published: August 2016

SummaryThis note considers two cases of bending beyond the limit of proportionality which have not received a great measure of attention in the past. These are Case(i). A beam subjected to a pure bending moment acting in a plane other than one of symmetry. Case(ii). A beam subjected to a bending moment and an axial load.A mathematical form is used for the stress–strain curve in order that the results shall be applicable to a large number of materials and to avoid the tedious arithmetical summations which would be necessary if actual stress-strain curves were used. All the results are presented in terms of form factors since this notation is convenient for design purposes and is consistent with current British practice. Although the method adopted in the analysis is applicable to a number of different types of beam cross section, only rectangular cross sections are considered in detail at the present time.Curves are presented showing the variation of the form factor with respect to the angle of the plane of loading, for Case(i), and with respect to the ratio of bending moment to axial load for Case(ii). These curves are based upon a standardised form of the stress–strain curve which may be taken as representative of a range of aircraft materials. Consideration is given to the automatic satisfaction of present military proof loading requirements when these form factors are used for the estimation of maximum permissible bending moments and axial loads under ultimate loading conditions.The recommendations of F. P. Cozzone, for dealing with these two problems are examined and comparison is made between the theoretical work of this note and a limited number of test results available for Case(i).
The Normal Functions of Beam Vibration in Series Solutions of Static Problems
Authors: Bishop R. E. D. 
Published: August 2016

The normal functions of beam vibration may be used in series to solve statical problems of beam flexure and the recent appearance of tables of these functions has rendered this method practicable. An outline is given of the procedure.The simple equation of free flexural vibration of beams is1where v is the displacement, EI the flexural rigidity andAp the mass per unit length. The separation of variables and the application of appropriate boundary conditions at the ends x = 0 and x = l, gives the following normal functions ϕ(x).
The Use of Radar to Measure the True Air Speed of an Aircraft
Authors: Warner J. , Heffernan K. J. 
Published: August 2016

There is at present no thoroughly satisfactory method of measuring accurately the true air speed of an aircraft, particularly at high speeds.Ground radar can accurately follow a high-speed aircraft but, without the development described here, can only measure the speed of the aircraft relative to the ground. The method developed by the authors makes immediate allowance for wind speed and is capable of giving the true air speed of an aircraft to within one per cent. There is no apparent reason why the method should not be applicable even at very high speeds and there is no limit in aircraft altitude at which the measurement may be made.
Turbo-Prop Performance Analysis and Flight Planning
Authors: Baxter J. R. 
Published: August 2016

When Viscount 720 aircraft were delivered to Trans-Australia Airlines it became clear that increased attention would have to be given to performance analysis and the preparation of flight planning data.Previous operational experience had been restricted to piston-engined aircraft which, for flight planning purposes, could be regarded as cruising at a certain air speed and burning fuel at a certain rate. Temperature effects were negligible because it was the accepted practice to restore power on hot days by slightly increasing boost settings. Altitude effects, although not truly negligible, were certainly small and could be covered by using flight planning figures from the conservative side of the range. With the Viscount, however, the specific range at cruising altitude was found to be almost twice its sea level value and a 10°C. rise in temperature was capable of reducing true air speed by 20 knots.
Measurement of Gust Loads in Aircraft
Authors: Taylor J. 
Published: August 2016

Fatigue of aircraft parts due to small but numerous vibrations has been known about for some time, but in 1944–5 cases of structural fatigue were found which were thought to have been caused by loads greater, but less frequent, than the usual vibration loads. Such loads could be ground loads due to taxi-ing, take-off and landing or they could be air loads caused by gusts and manœuvres.A general study of the fatigue properties of typical structures was made in the laboratory and it became apparent that the loads likely to do the most damage were those occurring about a million times in the life of the aircraft.
Part 1 Design and Construction
Authors: Lickley R. L. 
Published: August 2016

The development of manned supersonic aircraft in this country suffered a setback at the end of the 1939-45 War, when it was decided that the use of manned aircraft would be too dangerous; however, more realistic views soon prevailed and, as a result, the ordering of such manned aircraft was considered in 1947 by the Ministry of Supply and in our submissions to M.o.S. in 1949, we described the aircraft as having as its primary function “Research Flying at Transonic and Supersonic speeds up to M =1·5.”The background which led up to this submission is of interest, as it shows a logical line of development within the Company.
Problems of Short-Haul Air Transport
Authors: Brooks Peter W. 
Published: August 2016

The first part of this paper discusses some fundamentals of Air Transport and shows how these affect the organisation of airline operators. Against this background, Part II examines some of the particular problems of the short haul operator—the side of the Industry with which the author has been associated in British European Airways.Commercial Air Transport has existed for more than thirty years. It has made important progress, but has still a long way to go to fulfil its destiny. Although progress in developing the vehicle since the first aeroplane flew in 1903 has been highly spectacular, Air Transport itself has made a slow start. This is shown by Fig. 1 which compares the increases in passenger traffic that occurred in the first thirty years of British rail and air transport.
Transient Temperature Distributions and Thermal Stresses in Fuselage Shells with Bulkheads or Frames
Authors: Przemieniecki J. S. 
Published: August 2016

SummaryThe temperature distribution and thermal stresses are calculated in a configuration consisting of a cylindrical fuselage shell with bulkheads or frames. It is shown that at supersonic speeds thermal stresses are set up in a conventional fuselage structure as a result of the bulkhead restraint against circumferential expansion of the fuselage skin. The thermal stresses due to restraint by fuselage frames are usually less severe. The relative merits of various combinations of materials for the skin and the bulkhead diaphragm are discussed. Furthermore, the possibility of the use of light alloy bulkheads to alleviate thermal stresses is investigated. Diagrams are given for calculating maximum thermal stresses and stress-time variation for various rates of heat input in the fuselage skin due to aerodynamic heating.
On Obtaining the Shear Stress-Strain Relationship from a Hollow Specimen in Torsion
Authors: Ellington J. P. 
Published: August 2016

A method is given whereby the shear stress-strain relationship of a material can be obtained from observations made during a torsion test on a hollow circular specimen. An examination is then made of the corrections necessary when using thin-walled specimens, and some advantageous definitions of the mean diameter of a tube are suggested.The use of torsion tests to obtain shear stress-strain relationships is now well established and takes one of two forms. A thin circular tube can be used, it being assumed that the stress distribution is uniform across the wall thickness, or a solid circular bar can be used, the results being analysed by a method ascribed to Nadai. Swift has shown that these two methods give comparable results for moderate strains.
Stress Analysis of Circular Frames in a Non-tapering Fuselage
Authors: Dallison K. J. 
Published: August 2016

SummaryThe problem of the stress analysis of circular fuselage frames has been investigated by a number of authors; the analyses are, necessarily, rather mathematical in nature although in some cases the final results have been presented in extremely practical form. The present paper offers, in non-mathematical language, a short account of the fundamentals of the problem and a brief guide to the more important published literature. It also develops an approximate method for the analysis of frames using Lagrange's method for minimising a function of several inter-dependent variables. This method is shown to be particularly suitable for the analysis of frames with large cut-outs, about which little has previously been published. In addition, the underlying parameters which determine the stress distribution are deduced from the theory, and the deductions are compared with previously published work. In general, agreement is good. The paper is written throughout with a view to being of practical use in the actual stressing of frames. Numerical examples and explanations of mathematical methods are included in Appendices.
Synthetic Aids to Flying Training
Authors: Makinson W. , Hellings G. M. 
Published: August 2016

The piloted aircraft provides the supreme example of the highly complex machine performing a precise function in which the control loop is still completed through a human operator. Although both physically and mentally his task has been greatly assisted by the introduction of automatic pilots, auto-stabilisers, power controls, flight directors and the like, he still possesses the ultimate advantage over the machine of being able to use judgment in the face of arbitrarily changing circumstances. Thus, until it is possible in advance to define the required tasks exactly, and to measure the subsequent performance of the system in precise and unambiguous terms, the pilot will be saved from the encroachment of automation.The performance of the human operator is described by the aptness and speed of his reaction to the pertinent stimuli, in effect his transfer function as an integral element of the overall control loop.
The Use of Normal Modes in Problems of Forced Vibration and Impact
Authors: Jones R. P. N. 
Published: August 2016

SummaryA simple exposition, using d'Alembert's principle and methods of virtual work, is given of the properties and applications of the normal modes of vibration of a linear elastic system. The use of the normal modes in problems of free and forced vibration and dynamic loading is discussed with the aid of simple examples, and it is shown that by these methods dynamical problems for any linear system may be solved without the use of the fundamental equations of motion, provided the natural frequencies and modes of the system are known. In most problems the solutions converge rapidly, so that only the first few modes of vibration need be considered, and in these cases the solution may be modified to give further improvement in convergence. Unsatisfactory convergence may be obtained, however, in problems where there is an exciting force of very high frequency, or an impact of short duration. An approximate allowance may be made for damping, provided this is small.
Note on an Improved Short-Cut Method Jor Estimating Aircraft Direct Operating Costs
Authors: Robertson Frank 
Published: August 2016

In the early stages of preliminary design, it is essential to have a method for the comparison of aircraft on an operating cost basis. The standard S.B.A.C. method is too lengthy and, in any case, demands a greater amount of data than is usually available in the early design stages.The formula presented in this note is an extension to the ones presented by the author in the January 1955 and November 1956 Journals and is more accurate in that it provides for variation in aircraft first cost, type of power plant, speed and range.It is submitted that the formula gives a reasonable first estimate, suitable for early design comparisons, and that the few parameters required are normally available at the earliest stage of the design.
Effects of Inlet Boundary Layer on Pressure Recovery, Energy Conversion and Losses in Conical Diffusers
Authors: Winternitz F. A. L. , Ramsay W. J. 
Published: August 2016

SummaryA study has been made of the effect of inlet conditions on the performance of conical diffusers with 4:1 area ratio and 5 and 10 degrees total angle of expansion. The conditions at entry were varied by using different approach lengths of diffuser inlet diameter, and by means of projecting annular screens of woven wire cloth. With this new technique it was possible to vary the velocity distribution substantially within moderate settling lengths, and to produce velocity profiles with inflections. The suitability of the annular screen method of boundary layer generation for diffuser investigations was confirmed from the comparison with the approach length results.Energy and pressure coefficients, as well as diffuser energy efficiency and the conversion efficiency, were found to depend on the diffuser angle β and the momentum thickness ratio at inlet θ/D0. The latter emerged as one of the chief parameters controlling diffuser performance. Variation in the inlet shape parameter H of the order of 20 per cent did not significantly affect the pressure recovery or the losses in the diffuser. For moderately thick boundary layers, θ/D0 X β<0·1, the diffuser angle could be eliminated as a parameter by plotting the pressure coefficient against θ/D0 X β. The Reynolds number based on diffuser inlet diameter was, for essentially incompressible flow, 2·5 X 105 in all tests.
Optimum Conditions for the Operation of Airline Aircraft
Authors: Stephenson J. M. 
Published: August 2016

In A. H. Stratford's interesting note in the August Journal, he assumes that an airline is presented with an aircraft of given performance, and must decide what is the best range for it to fly. Surely the practical case is the exact opposite: that an operator wishes to carry passengers or freight between two given points, and must choose between perhaps three or four available types of aircraft. Moreover, it is up to the operator to tell the manufacturers which feature he wants improved (e.g. fuel consumption, take-off distance, and so on), when he is ready to order replacements.Secondly, Mr. Stratford wishes to replace the usual concept of direct operating cost per payload ton mile by that of per cent, profit, as a measure of the efficiency of operation over a certain route. While this may be a more realistic approach to the problem of a private airline company, operating over a single route, its merit is not so obvious for the large national or subsidised airlines, which are often required to fly unprofitable routes.
Aviation and the Development of Remote Areas
Authors:   H.R.H. The Duke of Edinburgh, K.G., K.T.
Published: August 2016

It is a very great honour indeed to find myself addressing the Royal Aeronautical Society. If, as I am often told, “a little learning is a dangerous thing” then you are in for a very dangerous address. For much as I would like to say that I know nothing about aviation it would not be altogether true. My knowledge is of the picked-up rather than the learned variety. During the war I was either at the receiving end of enemy aviation or under a friendly and comforting umbrella, which counts as passive experience. I started flying as a passenger in about 1935, and in common with many others 1 have put up with all the frustrations and delays of airline travel, particularly getting to and from the airfields—this I put down to semi–active experience! The active part of my experience began two short years ago when I started to learn to fly.From this you will gather that any views I express this evening must be treated with caution if nothing else.
The Aerodynamic and Aeroelastic Characteristics of the Crescent Wing
Authors: Lee G. H. 
Published: August 2016

It would be possible to write a paper conforming, literally, to the above title in very few words by simply describing the behaviour of the crescent wing in various circumstances. Such treatment, however, would avoid what is really the prime question of all, namely, why is the crescent wing used? What is the attraction of this layout? The answer to that question is performance. One essential characteristic of the crescent wing is thus its performance characteristic.Therefore, in this paper, the matter will be introduced from a performance angle and an attempt will be made to show, in general terms, why there should be a performance gain from the crescent layout. Having established the case, the aerodynamic and aeroelastic characteristics will be considered in some detail so that, with these properties explained, the way will be clear to consider a performance comparison in greater detail and thus gain a fuller appreciation of the situation.
Flow Studies of the Leading Edge Stall on a Swept-Back Wing at High Incidence
Authors: Black Joseph 
Published: August 2016

SummaryThe flow separation on a swept-back wing with 44 degrees leading edge sweep at 18 degrees incidence has been investigated by means of detailed pressure distribution measurements over the leading edge, boundary layer flow determination with liquid film technique, and yawmeter traverses. A wool-tuft grid was also used, and a spin detector was developed to search for regions of vorticity. These tests established that the flow separates on the leading edge; over the inboard sections it re-attaches behind a “ short” separation bubble, while outboard it only re-attaches near the trailing edge, thus forming a “ long ” separation bubble, or else fails to attach. The separated flow in what has been commonly called the tip stall does in fact take the form of a “ ram's horn “ vortex with the origin, or “ tip,” located at the junction of the two bubbles on the leading edge. The vortex lies outwards across the wing surface at approximately 20 to 25 degrees to the line-of-flight before curving aft to be shed into the wake, where it extends almost from mid semi-span to the wing tip. This vortex induces considerable changes in flow direction, both on and over the wing, and also in the wake. Thus in the wake a maximum downwash of 23 degrees is induced aft of the mid semi-span, and there is an upwash of 17 degrees at the outer edge of the vortex, almost aft of the tip. A good correlation between yawmeter results and the boundary layer flow direction indications from the liquid film technique was obtained.
A New Concept in the Design of Jet Engine Mufflers and Test Cells
Authors: Richards E. J. , Evans D. J. 
Published: August 2016

SummaryA new concept is put forward which should help materially in the design of engine test cells and ground mufflers. It is suggested that a relatively small spreader can be added behind a jet nozzle which changes, the shape of the jet from circular to a long annular slot. The frequency rise which may be obtained in this way is used to reduce low frequency noise, possibly at the expense of more easily attenuated high frequency noise. As a modest example, tests are described on one particular version which gives an attenuation in the most important low frequency range of nearly 20 decibels. It is shown that the back pressure on the engine is negligible even with a cooling flow equal to the engine mass flow. Other applications are discussed and tested, while suggestions for full scale installations are made.
A Tension Field Calculator
Authors: Noble K. G. F. 
Published: August 2016

The calculator is a device in slide rule form for assisting in the design and stressing of flat rectangular panels in shear.In the Incomplete Tension Field theory, the ratio q/qb becomes an important factor, whereq applied shear stress (lb./in.2)qb shear stress at which panel first buckles (lb./in.2).This ratio is normally evaluated by use of the formulaqb = KE(t/b)2where E Young's modulus (lb./in.2)t thickness of panel (in.)a length of longer side of panel (in.)b length of shorter side of panel (in.)and K depends on the value of b/a and the edge conditions, and is normally obtained from R.Ae.S. Data Sheet 02.03.01.This method becomes laborious when dealing with large numbers of panels.By the use of the Calculator, q/qb may be found quickly, with no unnecessary paper work.
A Simple Method of Constructing Duct Models for the Electrolytic Tank
Authors: Norbury J. F. , Platt A. 
Published: August 2016

A problem which occurs frequently is that of choosing a suitable shape for a duct, such as a wind tunnel contraction or an air intake. Basically similar problems, involving potential flow fields, occur in other branches of engineering, particularly in electrical engineering, and the electrolytic tank is now established as a tool which may usefully be employed in their investigation. The use of the simple shallow tank is limited to those fields which can be treated as two-dimensional or axisymmetric, but many problems fall within these categories.In forming a duct model for the electrolytic tank the walls of the duct are represented by insulating surfaces, and electrodes are positioned to represent two suitable velocity potential surfaces up- and down-stream of the duct. To represent a sector of an axi-symmetric duct the base of the tank must be inclined at 3°-5° to the horizontal and the water line on the tank base then represents the axis of symmetry.
Some Problems in Aerodynamics and Their Solution by Electrical Analogy
Authors: Küchemann D. , Redshaw S. C. 
Published: August 2016

Some purely aerodynamical phenomena, which might profitably be investigated by means of electrical analogue computors, are described. No attempt has been made to furnish a complete catalogue of problems but rather to present current issues, the solution of which would aid the development of practical aerodynamics.Consideration has only been given to those questions which can be solved more suitably by an analogue computor rather than by a digital machine, although the feasibility of partially solving certain of them by the use of an analogue computor, and completing the work with a digital machine, is mentioned.In scope, the survey includes two and three dimensional aerofoils as well as interference and a number of special problems.The relative merits of the various forms of analogue computors are not extensively discussed.