bluuebunny/crossref_metadata_2025 huggingface dataset:
Elastic Theory in Sheet‐Forming Problems
Authors: Shanley F.R.
Published: February 2008

THE main object of this paper is to help bridge the gap that exists between the scientific knowledge of materials and the practical application of that knowledge to the production technique of sheet‐metal forming. During the past year the Production Research Group of Lockheed's engineering department has given special attention to this important problem and has worked closely with the production departments in an effort to put sheet‐metal forming on a scientific basis. The following discussion is based largely on the work of the Production Research Group, as reported in various references and in papers yet to be published. Mr. William Schroeder and Mr. G. A. Brewer of this group have been particularly helpful to the author in the preparation and editing of the technical material. Because of the scope of the present paper, detailed discussion and analysis of new developments cannot be undertaken; however, such information will be made available as soon as possible in the form of individual papers by those directly responsible for the work.
Strain‐Gauge Technique in Design
Authors: Strang C.R.
Published: February 2008

STRAIN‐GAUGE technique might, at first glance, seem so highly technical a subject as to occasion some surprise at interest in it at a time when production problems seem to require all of our attention. Actually, of course, the greatest possible aid to increased ease in production is to start with the original design and simplify the structure itself, resulting naturally in a simplification of the entire production problem right from the outset. Better understanding of the problems involved already has allowed considerable progress in the matter of reducing the complexity of aircraft structures. So far, every effort has been made to limit the application of the techniques about to be discussed to those problems for which solutions are needed most urgently, always with the idea in mind of reducing the factors of ignorance involved to the point that we are permitted to simplify the structures which may be in question. The very words “strain gauge” infer a primary concern with theory, due largely to their past limitation to laboratory work. They are, however, here discussed as a work‐a‐day aid to the structural designer, substantiating past decisions and supplying information for better future decisions. In general, these methods, in a halting sort of way, provide a seventh sense that permits the designer to see and understand the inner workings of a structure under load.
A System of Works Control
Authors: Tiranti D.
Published: February 2008

A SYSTEM as applied to a general factory would come under the broad heading of Works Organization. It could be embodied to embrace every activity of the company from a canteen to the welding of a part.
Woods Used in Russian Aeroplanes
Authors: Theiner J.
Published: February 2008

COMPOSITE wooden construction has long been the rule in Russia for a great variety of aircraft types: fabric and/or plywood skins on a metal and/or wooden framework are to be found in airframe components side by side with all‐steel or light‐alloy components. Some aircraft types are even of all‐wood construction.
The LAGG‐3 Russian Fighter
Authors: Hulten Nils
Published: February 2008

THE machine is described from Finnish sources as satisfactory in horizontal flight, but with poor acceleration and there is a tendency to go into a spin in sharp turns. Attempts have been made to improve the flying qualities by reducing the armament; the wings have also been fitted with fixed slots to improve the landing qualities while, in the latest models, automatic slots have been tried. Visibility is good forward and on either side, but insufficient to the rear. The type appears to possess better combat qualities than the earlier MIG‐3 fighter.
The Powdered Metal Process for Moulding Parts
Authors: Wilkin Perry Harry
Published: February 2008

MORE progress in the art of powder metallurgy is said to have been madcin the last year in the United States than in the preceding ten years. The new developments and great expansion of production by this method are direct consequences of the demand for the fastest possible output of the largest possible volume of equipment for war. This objective is attained in part by taking advantage of the speed with which duplicate parts of machines can be pressed from powdered metals.
The Strength of Glued Joints
Authors: de Bruyne N.A.
Published: February 2008

WITHIN the last year or so we have learned to glue metals together with a strength which brings this method of joining materials into competition with riveting, at least in the thin gauges used in the aircraft and motor industries. Apart from this new extension of gluing to the metal working trades synthetic adhesives have already revolutionized the woodworking industries. This revolution is due to the superior quality of the resulting products and the increased rate of output made possible by the intrinsic high speed of setting of synthetic adhesives aided by such novel methods as high frequency heating, infra‐red heating and the like. In aircraft in particular the “weather‐resistance” of synthetic adhesives has largely removed the disadvantages of wood construction, due to the use of casein glues, so much in evidence in the first winter of this war. It may be said therefore that gluing has been raised from the status of a useful but humble convenience of daily life to a process of engineering significance. But before engineers can use gluing in the fabrication of structures they must be provided with data sufficient to enable thorn to compute the strength of the joints, and we at Aero Research Ltd. have therefore endeavoured to find a simple relation between the strength of a lap joint and its geometry. Such a simple relation is found in “the joint factor” which is defined3 as the square root of the thickness of the sheet divided by the length of the overlap.
Engine‐Airscrew Vibration
Authors: Morris J.
Published: February 2008

IT is usual when presenting a paper of this nature to start off with an ex cathedra pronouncement that the results of recent research and past experience now make it possible, for critical speeds to be calculated in advance with a degree of accuracy sufficient for practical purposes. I make no such assertion. What I have done is to formulate an analytical solution of the problem of coupled engine crankshaft torsional and airscrew blade flexural vibrations in which the assumptions made, in order to render the problem soluble, are not unreasonable. I fully realize that anyone disposed to be critical will find much to criticize. But I think I can say that my work has elucidated much that was hitherto obscure and that my results may enable designers to ensure better provision against possible trouble. The data and conditions of the problem are by no means precise, and no exact solution seems possible or likely to be forthcoming, either from practical experiment or from theoretical treatment.
The Use of Drills as Precision Tools
Authors: Moore H.
Published: February 2008

A TWIST drill should not always be regarded as something fit only, for producing holes of approximate accuracy. With close attention to the rules govering this kind of tool it is possible to turn out work with finished holes which are straight, smooth and to size: three most essential conditions. In many cases, it is true, the work demands the use of a reamer, but it is equally true that reamers are frequently used because the possibilities . of drills have not been fully explored. A brief description of some of this exploratory work can refer only to the smaller sizes of drills; generally understood to mean all those below a quarter of an inch. Drills above this size are usually handled in a manner quite different from the others.
General Circular Ring Analysis
Authors: Beskin Leon
Published: February 2008

THE purpose of the present report is to present tables and to summarize formulas which are required for the analysis of circular rings, under forces in the plane of the ring or out of the plane. Usually, rings which are redundant structures are calculated by considering strain due to bending only. It is shown that for the stress distribution in a circular ring under given loads, the solution introducing strains due to shearing and axial loads is the same as the solution conventionally used.
The Geometry of a Structural Joint
Authors: Allen C.F.
Published: February 2008

THE author makes no claims of originality in the following article. It is written with the idea of assisting students when doing the preliminary layouts of a structural joint with compound angles.
The Graphical Representation of Hydraulic Systems
Authors: Hodgson M.
Published: February 2008

WHEN a new branch of technology emerges as an offshoot of existing practice, its results are first described in the language of the parent subject, but later, as it grows in importance, a specialized jargon becomes current. Often, as part of this vocabulary, conventional diagrams are evolved to impart information in a concise and convenient manner. The application of hydraulic actuation to aircraft mechanisms is no exception to this rule.
Strains and Stresses in Cellulose‐Nitrate Films
Authors: Gourlay J.S.
Published: February 2008

THE phenomenon of curling of systems comprising colloids such as cellulose nitrate, deposited on non‐rigid substrates such as paper or fabric, has been known for nearly a century. There is, however, no indication in the literature of any attempt to correlate this behaviour with, for example, the phenomenon of the bending of plates. The present investigation presents certain analogies, which enable us to interpret much of the behaviour of these colloid systems on substrates.
Composite‐Engined Aircraft as a Basic Conception
Authors: Gordon H.S. , Johnston R.B.
Published: February 2008

BY way of introduction we shall explain that we have used the rather unwieldy term “composite‐engined aeroplane” to define the type of aircraft with which we at Ryan are working. This is one having two power plants of different kinds, which are, in the FR‐1, Fireball, a nine‐cylinder Wright Cyclone engine of 1,820 cubic inches piston displacement and a General Electric 1–16 turbo‐jet engine of 1,600 pounds static thrust.
Oxygen Injection as a Means of Increasing Aero‐Engine Performance
Authors: Hawthorne E.P.
Published: February 2008

ON aircraft operating in the rarefied atmosphere at high altitude, the idea of supplementing the air consumed by the engine with extra oxygen would seem to be a logical and desirable development, because the power output of a reciprocating engine is a direct function of the oxygen content of the air charge, provided that all the oxygen is burnt in the cylinder. However, the normal and most satisfactory line of development has been to fit the aircraft with engines of increased capacity or supercharge, so that the oxygen content of the air charge is increased simply by increasing the total mass of air consumed by the engine.
A New Jointing Compound
Authors: Squires A.T.B.P.
Published: February 2008

A NEW metal to metal jointing compound, possessing many salient features, has been developed in the Rolls‐Royce Laboratories as a result of considerable trouble which was experienced with well‐known types of joint washers or gaskets, and proprietary liquid jointing compounds, when these materials were applied to the joints of Merlin and Griffon engines in attempts to overcome oil leakage.
Synchroscopes for Multi‐Engined Aircraft
Authors: Hunt V.C.
Published: February 2008

TO overcome the discomfort, nerve strain and fatigue to both passengers and crew on multi‐engined aircraft resulting from the noise and vibrations of engines running at slightly varying speeds, the need of an accurate, easily read indication of such variations is readily apparent. A direct comparison of r.p.m. indicators is ineffective because the permissible tolerance on each indicator might result in a total difference of the order of 50 r.p.m. even though the speed of the engines under comparison is the same. The development of the 3‐phase electric tachometer indicators overcame this difficulty by comparing the relative frequencies of two or more tachometer generators (not the voltages), before this has been translated into an indicated r.p.m., by means of a small synchronous motor operating a magnetic drag unit; the desired result is obtained even though the possibility of permissible errors in a yet serviceable indicator has not been obviated. These two frequencies arc used to operate what is, in reality, a beat‐frequency indicator with a pointer rotating in proportion to the difference in speed. As the difference in speed of the two engines results in a difference in the frequencies developed by the two tachometer generators, so the pointer of the synchroscope will rotate either clockwise or anti‐clockwise according to which engine is running faster. When both engines are running at the same speed the frequencies will be alike and the pointer will remain stationary. Any difference in voltage output of the two generators will not affect this final indication, but will have some bearing on the speed difference at which the pointer begins to rotate where this rate of rotation is directly proportionate to the difference in engine speed. However, as a large variation between engine speeds will not cause any pointer rotation at all, but merely be shown as a flickering of the pointer, this is of no material importance.
Air‐Cleaning intakes for Aero‐Engines
Authors: Bigg F.J.
Published: February 2008

SAND is very harmful to engines. During recent tests conducted by me in the North African Deserts, as much as half a pound of sand has been collected in ten minutes in each air intake of a Mosquito aircraft taxying, alone, downwind on a desert airfield. Had the Mosquito been following another aircraft, or had its air intake been situated lower, the quantity of sand would have been much larger. Under such conditions the importance of having efficient air cleaning intakes fitted to every aircraft engine is obvious. Sandy conditions are not confined to desert airfields, some airfields in this country and on the Continent are as bad.
The Effect of Stabilizing and Stress Relief Heat Treatment on Welded 18‐8 Stainless Steel
Authors: Hubbell Wilson G.
Published: February 2008

AS a result of the rather conflicting information available concerning the effect of stabilizing and stress relief heat treatment upon welded 18‐8 stainless steel, the Ryan Aeronautical Company Laboratory has recently concluded a series of investigations on this subject. These tests were designed to determine the particular benefits, if any, which might be imparted by these processes to 18‐8 type 321 and type 347 stainless steels for use on exhaust manifolds. Benefits which would be reflected in greater serviceability of the aircraft exhaust manifolds manufactured from this steel were of prime importance to this inquiry.
The Explicit Determination of Orifice Parameters in Shock Absorbers
Authors: Dirac G.A.
Published: February 2008

THE differential equations governing the behaviour of even the simplest type of oleopneumatic shock absorber have to be integrated by an approximate step‐by‐step method. Such methods have been given by several writers. The orifices enter into these equations in the form of a parameter. To determine the orifices a value of this parameter is guessed and the equations are solved by the empirical method. If the solution obtained is not satisfactory, further values are guessed until a suitable value is obtained.
Freight Loading Facilities on Transport Aircraft
Authors: Allward M.F.
Published: February 2008

ONE of the many features that need careful consideration during the initial design stages of a modern cargo carrying aircraft is the adequate provision of suitable loading facilities. A commercial aircraft is only producing revenue when it is in the air carrying cargo and it is therefore essential that the greatest number of flying hours possible be achieved. Speed is one of the main factors in reducing costs to an airline operator, because it enables him to spread his fixed operating costs over a greater number of miles per hour. The efficiency of a freighter in the air, however, can be nullified by its ‘performance’ on the ground, for a 30 m.p.h. increase in cruising speed, for example, might well be outweighed by delays in loading and unloading the aircraft at its stopping places.
Developing the Epitrochoid Curve in Gear Teeth Below the Base Circle
Authors: Pepper H.C.
Published: February 2008

IN text books on gears and gear teeth the form of the tooth below the base circle is usually dismissed with a few words of advice on the evils of undercutting, and while formulae for calculating the form of the involute curve abound, no one worries about the epitrochoid which is the form of the curve below the base circle. This may be because the involute is a self‐respecting curve that never varies except in size while the epitrochoid varies as the distance below the base circle and the ratio of the rolling circles vary. Of course in the case of generated gears, provided that the root diameter gives sufficient clearance the cutter will sweep out its own correct path, but with gears ground with formed wheels the question of the form below the base circle does arise, especially with small pump gears of about nine to sixteen teeth. The easiest way to examine the form of the root is by projection and here comes the problem of drawing the correct form.
Conics as Applied to Mathematical Lofting
Authors: Morrison R.L.
Published: February 2008

THE rapid progress made in aircraft design during the past few years is demanding a more modern way of obtaining the lines of an aircraft than the older methods of lofting as borrowed from the shipbuilding industry. With the current demand for reduced drag a more exact method of defining the lines than was possible by eye, as formerly practised, becomes imperative. If it be shown that the lines of an aircraft can be determined mathematically, a tool becomes available to the designer with which he can define his shapes to whatever degree of accuracy he wishes to work. Furthermore, the designer will have more complete control of the lines than in the past, when he had to rely on lines lifted from the loft floor. Finally, if mathematical analysis of aircraft shapes is feasible then it is possible to define any given point on the envelope with exactitude and if the shape be curved he can give the curvature in all the planes and the slope of tangents in all planes. This becomes useful in determining clearance points, etc.
A High‐Output Reciprocating Engine Design
Authors: Castellini A.
Published: February 2008

IN the development of the reciprocating aero‐engine it is not often possible to announce a marked step forward in the constant endeavour to improve the important factors of b.h.p./weight ratio and economy, but it is believed that the design of the Lindum 6,500–4,500 and 4,000 h.p. aero‐engine which is described here represents an advance of a nature which has not been achieved for many years.
The Vibration of Propeller Blades
Authors: Dirac G.A.
Published: February 2008

THE study of the vibration of a straight elastic bar is a very old one. The vibrations may be classified as lateral (or transverse) torsional and longitudinal. The first two are the more important ones and also the more difficult. We shall consider the lateral and torsional vibrations of a bar clamped at one end and free at the other, which may rotate like the blades of an airscrew. Both cases, rotation or none, are important problems of civil engineering, marine and aeronautical engineering and the theory of elasticity.
Designing a Modern Electrical Installation
Authors: Brookesmith F.
Published: February 2008

SOME time before the war was over an opportunity was given me to join the Airspeed design stall, who were then in the early stages of producing the prototype Ambassador. I welcomed this chance of taking a hand in the development of a modern civil transport and I was glad to be able to put behind me the various limitations in military design.
Notes on Martin Manufacturing Methods
Authors: Perry H.W.
Published: February 2008

This article contains short accounts of some of the means adopted by Glenn L. Martin to build their first post‐war air liner, the 2–0–2, without the prior building of a prototype. Although this commendable effort to hasten into service a replacement for the Dakota eventually resulted in the production of an excellent air liner, we understand that it is an experiment that is not likely to be repeated. As was almost invariably the case during the war when a prototype was dispensed with, the delay in ironing out the teething troubles (which always seemed to be more than usual in such cases) and modifying the machines on the line was greater than that between the prototype and production.—EDITOR.
Factors Affecting the Design of an Air Conditioning and Pressurizing System
Authors: Brice P.E.R.
Published: February 2008

IN designing for passenger comfort in modern commercial aircraft, many laboratory tests and research investigations have shown that the fundamental requirement for human comfort is physiological, and can be summed up by saying that the optimum conditions for comfort are those existing when the body can maintain complete thermal equilibrium, with only minor adjustments in the heat regulating mechanism of the body. Heat is produced in the human body by the process known as metabolism, in which food is oxidized, or absorbed, by the cells in the body. The body temperature is the result of the automatic balancing of this heat production—which is more than the amount needed to keep the body warm—and the heat loss from the body. Heat is lost by radiation, convection, and evaporation. The radiation loss is dependent upon the skin, or clothing, temperature, and also the temperature of any surrounding surfaces. The convective heat loss is a function of air velocity over the body and a positive temperature differential between the skin, or clothing temperature, and that of the surrounding atmosphere. The evaporative loss is a function of temperature, velocity, and humidity, and takes place when the partial pressure of the water vapour in the surrounding air is less than the pressure of the moisture on the skin, or in the lungs.
Weight Estimation of Metal Wings
Authors: Gates G.K.
Published: February 2008

THE need for accuracy in estimating the component weights of project designs cannot be over‐emphasized, forming, as they do, an important part of the stressing and performance calculations. Of the items controlled by the airframe manufacturer, the wing is not only the heaviest (often representing as much as 50 per cent of the structural weight), but is also the most difficult to predict. In order to arrive at a suitable figure, numerous formulae have been used in the past, these falling into two broad categories:
The Silencing of Test Houses for Turbo‐Jet Engines
Authors: de Rosen A.
Published: February 2008

THE problem of silencing test houses for turbo‐jet engines is, acoustically, analogous to that for test beds for piston engines1 and 2 but is more complicated owing to the working conditions of turbo‐jet engines.
Aircraft Engineering Reference Sheet
Authors: Tonkin T.
Published: February 2008

Type: Composite construction, strut braced, high wing mono‐plane.
A High‐Power Two‐Cycle Sleeve‐Valve Engine for Aircraft
Authors: Hiett G.F. , Robson J.V.B.
Published: February 2008

The first part of this section deals in general with considerations of engine design, and the latter part with the effects of engine operating conditions.
Fire Resistant Finishes for Aircraft
Authors: Jones J.A. , Niswander R.V.
Published: February 2008

THE occurrence of isolated fires in commercial, passenger carrying aircraft has focused considerable attention upon the fire risks involved in the use of combustible materials, the arrangement of functional equipment and accessories, and the effectiveness of fire‐proof finishes and coatings. In addition to other studies concerning the elimination of fire hazard through careful survey of the electrical system and other functional systems, studies have been made concerning the improvement of the ignition resistance of materials and the subsequent propagation of fire. Serious fires have developed as a result of propagation by materials which were not responsible for the original ignition of fire. An intensive effort has been made to reduce this fire hazard by the development and application of protective coatings and finishes to vulnerable and combustible materials. This work led to the obvious need for, and development of, a testing apparatus by which a realistic comparison could be made of combustible materials under conditions simulating those of an actual fire.
Materials for Aircraft Structures
Authors: de Bruyne N.A.
Published: February 2008

In this article the author discusses the suitability of existing materials for aircraft structures and shows that a hypothetical material derived by expanding an aluminium alloy would greatly simplify the structure of fuselages
Piston Velocities and Piston Work
Authors: Glass J.S. , Kestin J.
Published: February 2008

WHEN evaluating engine efficiencies, mean effective pressures or the work done by the piston in internal combustion engines or compressors, it is generally assumed that the state of the working fluid is uniform throughout its mass. From this it follows that the expression for work where P denotes pressure and V, volume, holds. Now, it is known that, strictly speaking, this expression applies only in the limiting case of zero piston velocity, when the motion of the piston, and the thermodynamic process in the cylinder are said to be quasi‐static. The question, therefore, poses itself as to how far such an assumption is justified, when applied to a modern high‐speed reciprocating engine, say, an aircraft or motorcar engine, when piston velocities of the order of 40 ft./sec. are encountered.
The Dynamic Balancing of Turbines and Impellers
Authors: Tomlinson J.W.
Published: February 2008

DYNAMIC balancing has become an important function in the production and repair of gas turbines used in aircraft. It is now general practice to dynamic balance every turbine wheel and impeller assembly before fitting to the engine. Maintenance engineers, while having a background in the theory of vibrations caused by unbalance, must now know the practical side of dynamic balancing, since it is almost impossible to carry out a major overhaul without checking the balance of the rotating assemblies.
The Effect of Grain Direction on Mechanical Properties of Light Alloy Extrusions
Authors: McElhinney D.M.
Published: February 2008

IT has been generally accepted for some time that the mechanical properties of light alloys varied with the direction of grain, but even in the design of aircraft structures only a slight allowance has been made for this variation. The importance of this grain direction on the strength of light alloys was first realized as a result of the abnormally low test strength of one lug made from a 6½″ dia. DTD.683 extruded bar.
Notes on the Development of the Bristol 171 Helicopter
Authors: Stokes F.W.
Published: February 2008

THE Bristol Aeroplane Company entered the field of helicopter production when a design office was inaugurated at the wartime dispersal factory at Banwell, Somerset, in July 1944. The first Bristol helicopter flew in July 1947.
The Use of Auxiliary Rockets in High‐Speed Aircraft
Authors: Plaskowski Zb.
Published: February 2008

ALTHOUGH a new epoch in high‐speed flight opened with the introduction of the jet propulsion engine, new problems were presented by the thrust characteristics and high fuel‐consumption of the gas turbine.
The V‐g Recorder Gust Investigation
Authors: Usher C.V.G.
Published: February 2008

A notable feature of the collaboration between this country and the U.S.A. since they became allies in World War II has been the exchange of ideas and the pooling of equipment, and one such item of equipment which has come our way is the V‐g (velocity and g) recorder, an instrument originally devised by the National Advisory Committee for Aero‐nautics in America and sent to us during the war, which we improved and have used ever since to assist in our operational research.
Pneumatics for Ancillary Power in Aircraft
Authors: Haerle H.R.
Published: February 2008

THE development of aircraft penumatic equipment has progressed so satisfactorily in recent years that actuation of vital services by means of compressed air is becoming increasingly popular. In this brief review of developments to date an attempt will be made to show how the air which has been made available as a result of compressor improvements is utilized and by way of introduction it may be of interest to recall some of the bold experiments which were made in earlier years.
Flow of a Compressible Gas with Friction
Authors: Naylor V.D.
Published: February 2008

IT is usual in theory to treat questions on gas‐flow, as if the flow takes place isentropically, i.e. is subject to the law. This is equivalent to assuming the gas is frictionless or non‐viscous: it also implies that the gas is non‐conducting, for in writing down the equations of motion of a particle we must assume there is no transfer of heat to a neighbouring particle if the changes involved are to be even adiabatic. By ‘adiabatic’ we mean there is no heat transfer between the particle considered and neighbouring particles: by ‘isentropic’ we mean there is no change of entropy, so that an isentropic change implies while an adiabatic change does not.
Letters to the Editor
Authors: Thompson L.N.
Published: February 2008

To the Editor, DEAR SIR, In a letter, which has just come to my notice, published in your October 1951 issue, Mr A. V. Cleaver advocates the use of sub‐orbital refuelling techniques as a means of rendering interplanetary flight an economic proposition, and suggests that the importance of this factor was underestimated in the above paper which was reprinted in your August issue.
Limited Production of a Light Amphibian
Authors: Hay Stevens James
Published: February 2008

THE Piaggio Company has long been known for the design of unconventional aeroplanes; unconventional, that is, in the sense that they have broken with the general practice of the day. Their first post‐war type, the P‐136 five‐seater twin‐engined amphibian flying‐boat, is no exception. The prototype was generally considered to be one of the most interesting aeroplanes exhibited at the 1949 Salon de l'Acronautique. A second prototype was completed for demonstration purposes and, although civil sales were limited to a single example bought by King Farouk, the Italian Air Force adopted the P‐136 as a seaplane trainer and a first series of fifteen was recently completed for them at the company's main aircraft works at Finale Ligure. Piaggio &.C., although well‐known as an aircraft and aero‐engine constructor, is primarily an industrial firm making many different products, including railway coaches and the familiar Vespa light motor cycle.
High Temperature Propellent Reactions
Authors: Osborne F.E.
Published: February 2008

AT temperatures below some 2,000°K. the significant end‐products of technically important reactions involving propellents of molecular forms compounded of C, H, O and N atoms are of the following familiar types:
Electric arc Welding of Magnesium Alloys
Authors: Khrenoff K.K. , Gapchenko M.N. , Sakhatzky G.P.
Published: February 2008

The authors describe tests on the carbon are welding of corrosion‐resisting magnesium alloy. Recommended pract ice covers the use of fluxes, welding procedures and welding conditions, and preparation and positioning of components. Mechanical and metallographic tests and general inspection lead to the conclusion that all types of joints can be carried out, giving good appearance and sound welds, but somewhat lower mechanical properties. Subsequent heat treatment improves uniformity, but not mechanical strength.
High Temperature Thermodynamic Processes
Authors: Osborne F.E.
Published: February 2008

AT temperatures commonly attained in the reaction of liquid propellents at operative pressures in rocket combustion chambers, the significant gaseous end products can be shown to consist at chemical equilibrium of some or all of the following types: H2O, CO2, N2, CO, H2, O2, OH, NO, H, O, N and (rarely) C‐gaseous. The concentrations of these constituents are dependent, for a given propellent combination, upon the temperature (and to a less extent the pressure) conditions under which the reaction proceeds to equilibrium. Thus at temperatures below 2,500°K., the products H2O, CO2, N2 alone are of significance for the case of oxygen balance, whilst to these are added O2 for the oxygen excess case, and CO and H2 for oxygen deficit. The other products are formed by dissociation of these, and their concentrations increase sharply as the temperature rises above some 2,700°K.
Dynamic Reactions in Hop Dampers for Bogie Undercarriages
Authors: Nightingale J.
Published: February 2008

THE function of hop damper units as fitted to modern multi‐wheel bogie undercarriages is to dissipate the kinetic energy of the bogie, wheels and brakes due to their rotation about the bogie attachment pin. This rotation of the bogie may be caused by impulsive application of the wheel brakes, and the purpose of the hop damper is to reduce the angular velocity of the bogie, so that when it comes up against itsstops, the angular velocity is substantially zero, thereby reducing the mechanical shock which may be felt in the undercarriage as a whole.
The New Saab Wind‐Tunnel
Authors: Wänström Frid
Published: February 2008

THE need for an ‘industrial’ wind‐tunnel at Saab for tests in conjunction with test flying and project work has been felt for a long time and at the beginning of 1950 this need became acute. It then became necessary to project a serviceable transonic industrial wind‐tunnel which could be built in the shortest possible time and at reasonable cost.
The Library Shelf
Authors: A.R.C.  , R.M.
Published: February 2008

The contributions which Prandtl has made to the science of fluid dynamics are so numerous and so important that any work from his pen on this subject must be keenly anticipated. Moreover, Prandtl has a gift for clear exposition and for simplicity of illustrations which stems from his deep understanding of the subject. It is a pleasure to record that, in the main, this book has fulfilled all that the reviewer anticipated from it. It is true that it bears a number of similarities to his earlier works, and inevitably there are certain repetitions. At the same time, the subject in all aspects is brought very fully up to date, particularly in the matter of references.
One‐Dimensional High‐Speed Flows
Authors: Kestin J. , Zaremba S.K.
Published: February 2008

The paper discusses the types of singular points occurring in the first‐order ordinary differential equation which describes compressible viscous flow in a channel or stream tube of varying cross‐sectional area. The treatment is one‐dimensional, viscosity being allowed for by assuming a tangential stress acting on the circumference. The resulting patterns of the integral curves arc examined. It is shown that for convergent‐divergent channels whose profile has no point of inflexion, the singular point is a saddle point, as is the case in frictionlcss flow. However, the sonic section or the section of highest or lowest Mach number do not coincide with the throat but arc situated downstream of it in the divergent portion. The slopes of the integral curves which pass through the sonic section arc evaluated. When the convergent‐divergent channel has a point of inflexion in its profile there may be two singular points, the first being a saddle point and the second cither a spiral point or a nodal point. It is shown that spiral points are more likely to occur than nodal points and that, when they occur, there is no radical change in the Mach number variation along the channel due to friction. On the other hand, the existence of a nodal point admits the possibility of a continuous transition from supersonic to subsonic How in which the Mach number at exit may vary within certain limits, the Mach number in the second sonic section remaining always equal to unity. In all types of flow there arc portions of the channel over which the influence of friction outweighs that of area change.
Tension Pads for Structural Testing at Convair
Authors: Vollmecke A.R.
Published: February 2008

IN order to simulate flight and landing stresses on the ground, a measurable load with a given distribution must be transmitted to an aircraft structure by some mechanical means. Some thirty years ago, when the Consolidated Vultee Aircraft Corporation was organized, this was commonly accomplished by piling sandbags on the structure or by clamping yokes over ribs and frames for loading. Another method, later used, involved the direct attachment of spokes and clips to the structure.
Pressure Ratios for Aero‐Engines
Authors: Stephenson J.M.
Published: February 2008

IT is usually supposed that the designer of a gas turbine engine has considerable freedom in choosing the pressures, temperatures and other features. Indeed this apparent flexibility has been claimed as an inherent advantage of the gas turbine, which enables it to be tailor‐made for any prescribed duty.
Rotor Blade Motion in a Vertical Sharp‐edged Gust
Authors: Payne P.R.
Published: February 2008

Part I—Constant Chord Blades 1. Summary Rotor/fuselage clearance is the most fundamental design consideration when laying out a new project, and it is essential to estimate this accurately at a very early stage. When centrifugal force droop stops are fitted to a rotor, the design criterion is usually the effect of a sharp‐edged down gust impinging on the rotor when it is not generating thrust; for example, whilst running‐up on the deck of an aircraft carrier. In this paper the dynamics of blade flapping motion are developed and a method for rapidly obtaining maximum gust deflexion is presented in the form of a Data Sheet (FIG. 5). This enables the maximum deflexion in a gust to be determined with no calculation. The solution obtained is exact; hitherto the only attempts to calculate gust deflexion known to the writer have developed an approximate equation of motion for the blade, and offered the Particular Integral as a sufficiently accurate solution. It is shown in Part II of this paper that this can be very misleading, and undcr‐estimates the true deflexion. In preliminary project design, the blade inertia is, of course, unknown. It is shown that this is a function of the coning angle and CL, basic only, probably the two most fundamental design parameters.
Rotor Blade Motion in a Vertical Sharp‐edged Gust
Authors: Payne P.R.
Published: February 2008

In Part 1 it is shown that the equation for blade equilibrium about the flapping pin is
Fundamental Principles and Methods of Thermo‐Elasticity
Authors: Hemp W.S.
Published: February 2008

THE notation is that used by Love, The Mathematical Theory of Elasticity.
The Library Shelf
Authors: J.R.P.  , C.F.B.
Published: February 2008

Despite—or perhaps because of—the tremendous effort which has been concentrated during and since the War on the development of the multistage axial flow compressor there has hitherto been a dearth of unrestricted information on this vitally important aspect of propulsion engineering. Most gas turbine textbooks devote a more or less brief chapter to this subject, and one finds scattered information in all manner of publications, but it has needed the enterprise of Messrs Springer to bring out the first really detailed textbook by one of the leading German authorities.
A Production Application of Structural Adhesive Bonding
Authors: Holback G.E. , Burridge S.C.
Published: February 2008

AIRCRAFT structural engineers have long been intrigued by the possibility of eliminating the thousands of assembly operations involved in a typical airframe structure—one composed of many formed pieces joined by rivets and bolts—and of replacing these multiple operations with a double, or even a single, automatic operation employing simply temperature and pressure.
The Library Shelf
Authors: R.H.W.  , K.G.W.
Published: February 2008

This I.A.T.A. Symposium held during the I.A.T.A. Technical Conferences at Puerto Rico in April 1953 had as its object the free exchange of views and experience primarily between helicopter manufacturers and civil aircraft operators. The helicopter has been in operation for about ten years. The types available have, however, been in the main small, single‐engined military aircraft, but technical developments now promise fairly large, multi‐engined helicopters suitable for public transport operation. At this juncture, therefore, a conference of this nature is particularly valuable. Of course, definitive conclusions could not be reached, but the results of such a gathering of the most knowledgeable people concerned with helicopter design and operation cannot fail to be of the greatest interest.
Aluminized Coatings
Authors: Thomson A.G.
Published: February 2008

SINCE 1949 the British Iron and Steel Research Association have been studying the properties of hot‐dip aluminized coatings. This work has led to the development of a simplified process for coating steel or cast iron with aluminium which appears to offer interesting possibilities for the protection of aircraft components.
Research on Creep and Fracture at High Temperatures
Authors: Thomson A.G.
Published: February 2008

IN 1946, a short conference on creep in metals was held at the initiative of the National Physical Laboratory. The aircraft gas turbine was then relatively new. It had been developed during the war as a small fighter engine with outstanding power/weight ratio and short life. Since then it has been applied successfully to commercial aircraft and to ship propulsion and its use in power generation is being actively explored. These applications require in general larger engines, longer lives (up to 100,000 hours in many cases), and high thermal efficiency.
High Offset Flapping Pin Rotor Analysis
Authors: Payne P.R.
Published: February 2008

The theory of rotor dynamics given in Ref. 1 is extended to include the effects of coupling between feathering and flapping (δ3 angle) and flapping hinge offset. Both introduce considerable modification to the classic equations, and instead of simple explicit equations for flapping amplitudes, coning angle, collective pitch and inflow angles, five simultaneous equations have now to be solved. Data sheets have been constructed which enable this to be done quickly and accurately for any design of linearly tapered and twisted blade. It is suggested that the intelligent use of such data sheets is of great assistance in a design office, not only because of the very considerable time savings achieved, but also because they eliminate the most fruitful sources of error in numerical calculation. It is shown that a high offset rotor enables much higher speeds to be achieved with a conventional helicopter—an effect which has already been fairly well publicized. A penalty is paid for this in the form of hub pitching moments which have to be balanced out externally; either by the use of two rotors, offset C.G., aerodynamic surfaces, or inclination of the mechanical axis. These effects will be considered in detail in a further article. Finally, equations are developed for a convenient method of calculating blade elemental angle of attack which is claimed to be superior to classic methods for design office purposes.
An Analysis of Thrust Estimation
Authors: Cushing W.R.
Published: February 2008

WITH the coming of high speed flight it becomes increasingly necessary to define clearly what is meant by the thrust of a propulsive unit, or if an arbitrary definition is made, a clear idea of the full implications of such a definition is necessary. The latter case is the present day state of affairs, and to cover the inadequacies of our definition of thrust, corrections are necessary under certain conditions. These corrections are usually accepted as an additional burden by the aerodynamicist under the varied titles of ‘spillage drag’, ‘incremental scoop drag’, ‘additive drag’ and ‘pre‐entry drag’ (these terms, while being in the same category, do not in fact all refer to the same thing). These concepts and their relative importance are discussed below.
Augmenting Helicopter Take‐off Power by Ram‐jets
Authors: DeVault R.T.
Published: February 2008

The problem of supplying additional power to a helicopter rotor for take‐off or hovering under overload, hot‐day or altitude conditions is discussed briefly, and the boost system requirements are defined qualitatively. The Mirquardt Aircraft Co. is in process of developing a novel ram‐jet engine to meet these requirements under the sponsorship of the United States Air Force. The progress to date is reviewed, and the eventual application of this engine is discussed.
Corrosion Protection for Aircraft Wheels
Authors: Thomson A.G.
Published: February 2008

SOME four or five years ago, the Wright Air Development Centre, Wright‐Patterson Air Force Base, Ohio, began to receive an increasing number of complaints of corrosion of wheel bearings on both operational aircraft and aeroplanes which had been inactive for extended periods. Many instances of wheel bearing corrosion were also reported by the U.S. Navy, mostly on stored aircraft. The greases in question were those meeting Specification AN‐G‐15.
The Brooklyn Conference on High Speed Aeronautics
Authors: Horton W.H.
Published: February 2008

TODAY aviation is a most influential factor in our lives and Brooklyn a most influential factor in aviation. This was clear to all who attended the very successful conference on High Speed Aeronautics organized as a feature of the Centennial year by the Department of Aeronautical Engineering and Applied Mechanics of the Institute. Over 600 research workers and technicians assembled at the Engineering Societies Building, New York, to hear and to discuss papers by scientists and engineers from America, England, France, Germany, Italy and Sweden.
High Temperature Power Plant Materials
Authors: Levy Alan
Published: February 2008

THE use of metals at temperatures in excess of 1,200 deg. F. and up to temperatures in the vicinity of their melting points is a challenging and fascinating portion of the fight to pass the heat barrier in the design and performance of aircraft and their power plants. The materials available for service in this temperature range are restricted. The considerations of designing structural components involve many more problems than the old criteria of strength to weight ratio and fabrication costs. Such properties as thermal expansion, heat conductivity, surface emissivity and scaling resistance are as important in determining which metal should be used for a given application as are the various measurements of strength heretofore the primary considerations in material selection.
Structural Features of The Fokker Friendship
Authors: Schliekelmann R.J.
Published: February 2008

AT Schiphol Airport the first Dutch airliner to be built since the war is nearing completion. The Royal Netherlands Aircraft Company Fokker, which was responsible for a large number of successful airliner designs in the period between the wars, has designed this latest aircraft as a medium size ‘Dakota replacement’. Called the Fokker F.27 Friendship, it carries 28–36 passengers and a liberal amount of luggage on stage lengths up to 1,000 miles. It is powered by two Rolls‐Royce Dart propeller turbine engines installed in the high‐aspect‐ratio high wing. The advanced design incorporates a number of interesting structural features which contribute to efficient production and economy of operation.
Polynomial Characteristic Equations
Authors: Morris J. , Head J.W.
Published: February 2008

IN the investigation of stability problems in physical science it is essential that ‘stability criteria’ be available to ensure that the characteristic equation, which is usually an algebraic polynomial equation, is such that the roots, if real, are negative; and, if complex, have their real parts negative.