bluuebunny/crossref_metadata_2025 huggingface dataset:
Output‐Increase in C.I. Engines
Authors: Kammer G.S.
Published: February 2008

THE output‐increase of the two‐stroke C.I. engine seems to be closely connected with the future possibilities of sleeve valve development. More than any other constructional solution this one offers promising remedies against inherent drawbacks of the two‐stroke cycle.
Design and Production
Authors: Ritter Oberingenieur E.
Published: February 2008

THE construction of an aeroplane is directed by aerodynamic considerations, calculation of mechanical strength, production methods and various other factors.
Modern Precision Grinding Methods
Authors: Brulé R.
Published: February 2008

IN modern machining practice, precision grinding (the operation known in France as “rectification” is carried out on a limited number of parts and the use of the term immediately suggests the type of component usually subjected to this method of working—the gear wheel.
Solid Organic Materials
Authors: de Bruyne N.A.
Published: February 2008

THE life of an engineer is largely a life spent in solving problems of a practical kind; and so his attitude to nature differs from that of the scientist. Confronted with a particular material an engineer will first ask in what way he can use its particular and special properties; whereas the scientist will want to know how those particular and special properties arise. But a good engineer must have knowledge of the scientist's conclusions, so I hope engineers will not think I am wasting time by trying to describe in these articles why wood behaves like wood and why rubber is “rubbery.” I have tried to keep the engineer's point of view in mind, and I have not attempted to give anything more than an outline of the reasons why a given material has its special and peculiar properties.
Welding Technique in Aircraft Construction
Authors: Krieger Karl
Published: February 2008

FOR the welding of light alloys, the flame should be adjusted to a fairly distinct cone having a light aura which indicates a small excess of acetylene. Under no circumstances should there be an excess of oxygen, as this would burn the material. With the longer types of job, the blowpipe should be cooled as often as possible in cold water and the flame should be frequently re‐adjusted.
High‐Output Aero Engines
Authors: Hives E.W. , Smith F. Ll.
Published: February 2008

AT the outset we ought to say that we could probably have done more justice to a paper on the “High Output cf Aero‐Engines.”
The Bases of V.P. Airscrew Design
Authors: Schmidt K.A.
Published: February 2008

THE use of the variable‐pitch airscrew has to‐day become commonplace. Its wide application permits certain facts derived from experience to be postulated and leads to new development problems.
Helicopter Theory
Authors: von Kármán Th.
Published: February 2008

In connexion with the series of articles on rotary‐wing aircraft by Dr. Bennett which concluded last month, our attention was called to this paper by Professor von Kármán. Although it is now to some extent of historical interest only, it did not at the time of its appearance receive the attention it deserved and we believe that this translation will be of interest to those concerned with the subject
Investigations on V.P. Airscrews
Authors: Salzmann F. , von der Mühll A.
Published: February 2008

COMPREHENSIVE research on the stress conditions of the airscrew hub, arising from the centrifugal forces which exceed 30 tons on each blade, have led to important advances in design which, with minimum dimensions and weight, allow the installation in the hub of the pitch‐adjusting mechanism. Some examples show how the basic principles of the design originated in complementary experimental and mathematical research; where calculation was abandoned owing to excessive complication in shape, the gap was filled by practical stress measurements, while, on the other hand, it was possible by calculation to extrapolate the results of experimental tests to points which were not accessible for direct measurement.
The Guidonia High‐Speed Tunnel
Authors: Ferri A.
Published: February 2008

WHEN the Italian Air Ministry decided to build a research station at Guidonia for the study of high speeds, work of this kind had already been initiated at the main aerodynamical centres throughout the world, but as a rule the apparatus had been made by means of adaptations and expedients and in no case had the problem been satisfactorily solved.
German Production Equipment
Authors: Frydag K.
Published: February 2008

AT the time of the advent of the all‐metal aeroplane, there were no machine tools and equipment well suited to the peculiar manufacturing operations required. Save for the necessary machining operations, the mechanical labours were performed on equipment largely borrowed from the fitter's, tinsmith's, and coppersmith's trades.
Standardization in Aeroplane Design
Authors: Thompson John T.
Published: February 2008

JUDICIOUS standardization applied to aircraft design on a large scale co‐operative basis will form one method by which the mass production of aeroplanes may be expedited. This matter is one which has been recognized with increasing importance for many years by the services and the manufacturers, and it is one which, if handled in the proper manner, will at the same time tend both to improve the science of aircraft design and remove the aeroplane from the experimental status.
Gust Load Factor Principles
Authors: Shanley Francis R.
Published: February 2008

A SIMPLIFIED presentation of basic gust load factor theories, designed to supply information requested frequently by pilots, has been prepared by the Aircraft Airworthiness Section of the V.G. Civil Aeronautics Authority.
The Balancing of Airscrews
Authors: Castaing H.
Published: February 2008

EACH blade of an airscrew is submitted to an elementary static balance check after it has been completed. But this operation does not eliminate the necessity to carry out a general balance of the complete airscrew. This is carried out statically, first of all for the hub alone, and then statically and dynamically for the completely assembled airscrew.
The Influence of Span on Wing Flutter
Authors: Leliwa‐Krzywoblocki Zbigniew
Published: February 2008

AS the basis of this examination I have taken the results obtained by H. Roxbee Cox in his “Statistical Method of Investigating Relations between Elastic Stiffnesses of Aeroplane‐Wings and Wing‐Aileron Flutter”, which may be briefly recalled.
The Junkers Constant‐Speed Unit
Authors: Hay Stevens James
Published: February 2008

THIS article is complementary to that on the new Junkers constant‐speed air‐screw and is intended to be read in conjunction with it.
Some Books Recently Received
Authors: PUGSLEY A.G. , KENNEDY O.
Published: February 2008

The publication of a new book by Timoshenko is an engineering occasion which, with the passage of time, and to the surprise and pleasure of British engineers, is becoming more rather than less frequent. Ever since the issue in 1928 of his joint work with Lessells on Applied Elasticity, which quickly became popular among British students, his books have played an important part in both the theory and practice of engineering in this country.
Aeronautical Education in Germany
Authors: Doetsch G. , Seidel J.
Published: February 2008

THE five principal divisions of aeronautical science—military aviation, research, production, operation, and air transport—afford the aeronautical engineer all possible opportunities for employment.
Reducing Wastage of Timber
Authors: Maskew R.
Published: February 2008

Timber is one of the essential products which has to run all the risks attendant upon shipment from overseas; but, even after surviving all these dangers, on arrivalat the sawmill, in being cut up into the required sizes of boards etc. a large percentage is reduced to waste as sawdust. It seems a great pity that we should defeat the enemy's attempts to destroy this essential war material, and then ourselves render such a large proportion waste.
Combustion Research in the U.S.A.
Authors: Fiock Ernest F.
Published: February 2008

A BRIEF discussion of combustion research, which has been in progress for over three hundred years, must be limited to a specific subdivision of the field. For presentation before the Society of Automotive Engineers, it is logical that this report should be confined, in a general way, to that phase of combustion research which is concerned with explosions in gases, and particularly with explosions from which, through the medium of the internal combustion engine, usable power may be derived.
Blackout in Factories
Authors: Beringer A.
Published: February 2008

BLACKING OUT small windows causes no difficulties. Blackout arrangements for large skylights with an area of several thousand square metres, however, become more complicated, especially in steel‐frame buildings, where the attachment of fixtures and the boring of the necessary holes meets with difficulties; not least because of the inaccessibility of the skylights.
Some Notes on the Me. 110
Authors: Thompson James E.
Published: February 2008

AFTER viewing the Messerschmitt Me. 110, one is impressed by the fact that here is an aeroplane provided with terrific striking power, but with practically no defensive armament or armour. The four machine‐guns and two cannon, tightly packed into the nose of the fuselage, provide heavy lire power, and contrast sharply with the single flexible machine gun supported on a primitive mount in the aft cockpit. A quickly detachable, external bomb rack designed to carry two bombs, apparently of the 500 lb. class, is provided for use on missions where attack of ground objectives, such as troop concentrations, would be the principal purpose.
Vibration Tests and Flutter
Authors: Lyman Charles B.
Published: February 2008

MUCH reference is made in the aeronautical field to the flutter problem and the subject is receiving the attention of many persons engaged in research, testing, and design. Many aeronautical engineers are well acquainted with some aspect of the problem, and although only a few are concerned with its several phases it is safe to say that all aeronautical men regard it with some degree of interest. It is fitting, therefore, that although it has been adequately treated by many authors from other points of view, a statement be here made summarizing the flutter problem as one of the aeroplane designer. In order that the exact nature of this problem be appreciated it is first necessary that a few of the fundamentals be reviewed.
Designing for Machinability
Authors: Thompson James E.
Published: February 2008

Machine may bo defined as a machine tool which removes metal by causing the work, securely held in a vice or fixture, to be fed against a revolving cutting tool, called the milling cutter, having one or more cutting edges—usually several.
Standards for Defence
Authors: Stryker C.E.
Published: February 2008

IN speaking of standards I should make clear my interpretation of the term.
Plastics in Aircraft Construction
Authors: DeBell George W.
Published: February 2008

MANY engineers look upon plastics and allied materials as entirely new to the aircraft industry, but such is not the case. Phenol fibre sheet and resin bonded waterproof plywood have been used for years, and acrylic resin sheet has been in use for transparent enclosures for some time past; yet all come under the above category. The primary difference between the past and present uses of these materials is that they are now used in applications where structural loads are involved, while they were previously used only in non‐stressed parts where special characteristics, such as transparency or insulating qualities, were of paramount importance. If these materials are classified according to their major characteristics they fall into three categories; those made with thermosetting resins, those made with thermoplastic resins, and those made with wood veneer. This classification also in a general way divides them according to their principal uses; thermosetting materials being used mostly in the production of relatively small structural parts, the thermoplastics being used mostly for their transparent properties, and the wood veneer materials being used mostly in relatively large structural parts and assemblies.
Improvements in Aeroplane Construction
Authors: Pistor J.
Published: February 2008

RESEARCH is making rapid strides, particularly in aircraft construction. The'results are given practical expression by the designer, who is thus one of the prominent factors in technical development. In the same manner as in science and research; the designer must continually be breaking new ground. Neither lack of time, convenience, nor conservative adherence to excessive safety should induce the retention of an older design if new research and experience are capable of indicating improvements. Each succeeding design should be lighter, simpler, but also stronger than its predecessor, and not only by the use of new and improved materials.
Two Important Books Reviewed
Authors: NIXON F.
Published: February 2008

This notable book gives pleasure from the outset owing to the high standard of its printing and binding, now all too rarely met with these days, and owing to the obvious excellence of its layout. These first impressions are fully borne out by a closer perusal, but only when the author's purpose is kept firmly in mind. For lest its title should rouse false hopes in the breasts of practising designers, leading them to think that here at last is the book for which they have been waiting, it would be as well to refer at once to the author's opening words. Writing from Purdue University, Indiana, he says: “This text has been assembled to aid technical students in bridging the gap between the point (a) where they have a fairly complete knowledge of the fundamentals of mathematics, mechanics, and machine design and (b) the point where they are sufficiently familiar with the application of these fundamentals to the design of aircraft engines to enable them to be of value to the aircraft‐engine building industry.”
Theory of Shock‐Absorber Design
Authors: Burger F.E.
Published: February 2008

THE aim of this paper is to provide a survey of some of the principal theoretical considerations affecting the design of aircraft undercarriages.
Electrical Indicator Drives
Authors: Hempson J.G.G.
Published: February 2008

THESE notes are concerned only with the aspect mentioned in the title, and no attempt is made to add to the vexed and controversial subject of types of indicating unit.
Electrical Measurement of Stresses
Authors: Theis A.
Published: February 2008

ECONOMY in the use of engineering materials calls for a very accurate knowledge of the stresses arising in machinery and structural parts. The forces acting on the part are frequently impossible to determine and vary in their effect according to their static or dynamic nature. The surest method of determining the stresses in time and magnitude, is therefore to measure the resultant elastic deformation. Measurements by mechanical extensometer are, however, of limited usefulness, and, in particular, performed with difficulty on parts in rapid motion or vibration while running.
Stressed‐Skin Wooden Construction
Authors: Stepniewski W.
Published: February 2008

In strength problems of stresscd‐skin constructions, the outside shape of a part to be stressed as well as the loads sustained by it are generally given. Having this data, the designer or stress analyst in most cases has to choose the type of skin and the best distance between ribs or bulkheads to obtain the lowest weight of construction.
Metals at High Temperatures
Authors: de Bruyne N.A.
Published: February 2008

THE marked dependence of the strength of metals on temperature, and on rate of loading at high temperatures, can be explained by assuming that above the equi‐cohesive temperature rupture takes place by plastic flow in a non‐homogeneous medium, consisting of rigid crystallites weakly cemented together. Although the stress concentrations required by the Griffith theory must still be operative above the equi‐cohesive temperature, it is suggested that they produce intergranular flow, rather than the elastic separation that occurs at temperatures below the equi‐cohesive temperature. A theory is developed based on the assumption that the strain energy at rupture reduces the energy of activation of the flow process, and the theory is shown to be in numerical agreement with the experimental results, if the energy of activation of the flow process is about one seventh of the latent heat of evaporation per gram atom. Values of the cohesive strengths and of the stress concentration factors are also derived.
Organization of the Manufacture of Parts
Authors: Tiranti D.
Published: February 2008

THE method of controlling work on the factory varies considerably. It can start from simply telling an operator the quantity required of a certain part, handing him the blueprint and telling him to get on with the job, to a complex breakdown where everything has been considered in advance, an exact line‐up prepared, and an adherence to a fixed production plan.
Control of Fine Finished Surfaces
Authors: Ferdinand Kayser J.
Published: February 2008

THE correct functioning of many pieces of apparatus depends not only upon dimensional accuracy, but also upon the surface finish of contacting surfaces. Practically all engineering establishments have available a microscope suitable for magnifications up to at least 200 diameters and, in any event, such microscopes, even under present circumstances, are in reasonably good supply. By means of such a microscope and readily available accessories, it is possible accurately to measure and control certain types of finish by a method that has recently been perfected. At the outset it will be as well clearly to define the scope of this method. It is only applicable to finely finished convex or flat reflecting surfaces; with increase in scratch depth or roughness the more difficult does it become to interpret the results and, in general, the method is not applicable if the average height of the surface above the mean line exceeds about 20 micro inches.
Lockheed Chain‐Line Assembly
Authors: Wilkin Perry Harry
Published: February 2008

FIRST doubling, then tripling of the rate of production of the Lockheed Lightning fighter without expansion of plant size has been made possible, by ingenious engineering adaptation of automobile chain‐line assembly practice to aircraft manufacture. The accompanying illustrations show clearly some of the features of this system.
Perspective Drawings for Aeroplane Handbooks
Authors: Hay Stevens James
Published: February 2008

THE great intake of unskilled labour into industry and ‐the fighting services during the War has made a heavy demand for perspective drawings; drawings that can be readily understood by those who have not the experience to read the plain engineering drawing. In this country these drawings arc mainly used for instruction and maintenance handbooks, although in the U.S.A. they are also being very largely used for shop assembly drawings.
Design Features of the Mosquito
Authors: McIntyre R.B.
Published: February 2008

THE Mosquito aeroplane is, perhaps, the outstanding achievement of this war. While the latest performance figures are still held secret, it may be told that it is the fastest aircraft in operation in the world. The design was not started until after the war began, so that it represents another world record—time from drawing board to operations against the enemy: 22 months—and the prototype flight, trials took place only eleven months after design began.
Design and Production Technique
Authors: Schroeder A.J.
Published: February 2008

THERE are three principal points which are of special importance in the manufacture of any industrial article:
The Instrument Industry and Aircraft Development
Authors: Barron S.L.
Published: February 2008

THE importance of instruments is nowhere more vital than in aircraft engineering and the science of flying. Indeed, the rapid progress in design made by aeronautical instruments in the last twenty years has to a large extent determined the phenomenal advances made in the achievements that are now being accomplished with aircraft. Not only are a large variety of precise instruments required for researches into the properties of raw materials and alloys, but accurate monitors and gauges are essential throughout every stage of construction from the minutest part to the built‐up member. In the finished aircraft, instruments become the eyes, cars, tongue and nervous system of the machine; as the practice of blind flying, intercommunication and beam landing so adequately demonstrate. A peep into the cockpit of a modern aircraft discloses, to the uninitiated, a collection of instruments of bewildering assortment, and it is for good reason that the Air Ministry, in the training of pilots, lay considerable stress on the instrument side of the science of flying. Not less in control rooms, beam stations, etc., instruments in the hands of skilled operators, play a major part in controlling, guiding, computing and the manifold tasks that are co‐incident with major actions. Although these facts are apparent to all the full extent of the essential nature of instrumental control is not adequately appreciated, except by a few, and we must necessarily wait until the end of the war before a full expression of the manifold uses and high order of precision that has been attained can be permitted to be published.
Practical Application of Stress Strain Theory
Authors: Hoffman F.C.
Published: February 2008

THE first and foremost problem in aircraft production is one of proper design and rapid production of sheet metal forming tools. A full understanding of forming properties of various aircraft materials, the limits of each method of forming, and die design and construction, are of vital importance to every tool designer and tool planner. In view of the great variety of parts to be produced, the expensive and time‐consuming trial and error method of die development should be reduced to a minimum. The problems of production, particularly forming problems, will be greatly simplified by the use of this same knowledge and information in the design of sheet metal parts. If the limits to which parts can be formed by the common methods are known and applied, a very large percentage of parts can be designed so that they may be formed readily and economically using as few operations as possible. If parts are designed so that they take advantage of new simplified methods, it is important that tools be made with close cooperation between the pre‐planned, tool planners, and tool designers.
The I.Ae.S. Annual Meeting
Authors: Klemin Alexander
Published: February 2008

IT was very gratifying to see that in spile of the pressure of the times and the difficulties of travel, the Twelfth Annual Meeting of the Institute was as well attended as ever with as wide a representation as in previous years. Nor was there any lack of excellent papers, although, of course, it was perfectly clear that some of the very best development work in aerodynamics, power plant, and similar fields could not be discussed because of military restrictions. Note‐worthy was the perfectly tremendous attendance at the rotating wing aircraft session at which, after some excellent papers, films were shown of the Piasecki, Sikorsky and Bell helicopters. This session was so. crowded that the audience had to be moved to another hall where standing in the aisles could be avoided. This is another confirmation of the importance which is attached to helicopter development by American aeronautical engineers.
Automatic Power‐Unit Controls
Authors: Lowrey Joseph
Published: February 2008

THE period of 40 years since man first flew with the aid of an internal combustion engine has seen many changes in aircraft power units. Power has increased to an astonishing extent, yet reliability has also been obtained. Unfortunately, however, the amount of skill and knowledge required to obtain the best results from an engine can hardly be said to have decreased.
Canadian Work on Plastics and Laminated Woods
Authors: Gallay Wilfred
Published: February 2008

NO technical development in all our industrial history has been as highly glamorized as the subject of plastics. It has shown an amazing degree of popular appeal for several reasons, including probably the idea of synthesis from “coal, air and water”, the beauty of colour and finish in decorative effects, and the fact that the objects of early manufacture were those of common use by the general public. Feature writers have regrctably enjoyed a general field‐day revelling in the subject, and unfortunately there has been a tendency towards certain misconceptions and exaggerations in such writings. Plastic aeroplanes now flying, plastic automobiles and plastic homes of the future have been described. Actually there is no such thing today as the plastic aeroplane. The plywood airframe has attained great importance owing to the advent of plastic glues, and what might be termed a “plywood plastic” aircraft is still actually a high‐grade plywood. The plastic automobile bodies envisaged today are secondary structures to be built over a metal framework. The post‐war homes will undoubtedly have dozens of items in which plastics will play a part, but primary load‐carrying structures are not among these components as yet. The plastic industry itself has recently become somewhat concerned about the dangers attendant on over‐glamorization and some remedial action has been studied.
Production Control: The Production Plan
Authors: Tiranti D.
Published: February 2008

ONE of the first essentials in the initiation of any work is to organize it to a definite plan; which may be interpreted as follows:
Airscrews as Landing Brakes
Authors: Von der Mühll Dipl Ing. A.
Published: February 2008

SINCE the first successful flight tests were made with the Escher Wyss airscrew some years ago, this type has been distinguished in this sphere by several fundamental innovations . From the beginning a very high speed of adjustment of approximately 8 deg./sec. was attained in normal operation as an automatic, constant‐speed airscrew. This property and the wide range of speed control between 100 per cent and approximately 40 per cent of the rated r.p.m. made it possible completely to release the pilot from control of the airscrew. Thus the problem of the automatic airscrew was finally solved (Fig. 1). That this solution was satisfactory has been proved by many years' service under the most stringent conditions in the Swiss Air Force.
The Ellipse as Applied to Aircraft
Authors: Billings V.R.
Published: February 2008

THE modern aeroplane, while tending to become simpler in general form with every new design, presents ever‐growing difficulties to the drawing office. The accurate establishment of the shape of the aeroplane is by no means the least of these difficulties. Whereas the shape of most aeroplanes built up to 1935 was bounded by a series of flat and simply curved planes, the modern aircraft shape is virtually one plane of a fairly complex nature. Hitherto, most designers have been content to have the complex curves of the aircraft shape made by hand, assisted by several experienced eyes. The logical development of this method has been, in the case of several of the larger manufacturers, the establishment of a mould loft, whose principal duty is to make a full size drawing of the aircraft and from this drawing to establish the shape of all parts of the aircraft exterior and their location relative to some datum line or lines.
Airscrew Thrust and Take‐off
Authors: Franz Roth Ing.
Published: February 2008

IN the mathematical treatment of the take‐off problem it was formerly difficult to define any general relationships for the airscrew thrust. This difficulty was avoided usually by assuming certain mean values, such as, for example, 1 • 1 to 12 kg/h.p. for the static thrust and by using this value in the calculation. This procedure is incorrect in that the airscrew thrust is assumed to be constant for a given output and so ceases to be suitable as a governing factor. As we have shown in a previous article, it is now possible to estimate the static thrust more accurately and by appropriate engine design the static thrust can be made to satisfy the necessary demands within wide limits [11]‡ This makes it possible to adopt new viewpoints in the treatment of the take‐off problem, which it is proposed to examine.
Estimation of Batch Quality
Authors: Lunt T.J.
Published: February 2008

A CERTAIN number of defectives, c, is observed in a sample of n articles drawn at random from a large batch. Nothing else is known about the batch. What inferences can be drawn as to the true but unknown proportion Q of defectives in the lot? In his book An Engineers' Manual of Statistical Methods, Col. L. E. Simon gives several charts which help to answer this question. The basic assumption made is that before sampling one “lot‐fraction‐defective” is as likely as another. The charts are based on the incomplete ?‐function ratio. They make no assumption of homogeneity. From these charts the accompanying alignment charts have been constructed. The degree of accuracy is not, of course, as high as in Simon's charts, but it is thought that it will be high enough for practical purposes.
The Strength of Valves at Closing
Authors: Zalewski W.
Published: February 2008

THE speed at which a valve is coming to rest on its scat at the moment of closing is one of the factors deciding the amount of gases passed through the valve. The inertia forces, however, act for a very short time on the valve at this moment, and this is the reason why normal considerations in the strength of valves are not accurate; it would be better, when designing the valve, to use approximate calculations giving the possibility of orientation among the various factors coming into consideration, than to leave all this to experimental practice.
Negative‐Rake Milling
Authors: Holmes J.Q. , Holloway R.C.
Published: February 2008

SOME truly remarkable results in high‐speed or “hyper” milling of steel forgings have been attained on a production basis at Eastern Aircraft's Linden, N. J., plant. To date, work has been confined to tough 4140 chrome‐molybdenum steel forgings; some annealed and some heat‐treated to 40–41 Rockwell C and 180,000 lb. per sq. in. tensile strength. Milling rates range from about five to nearly IS times those previously attained with conventional cutters run as fast as usual procedure dictated.
Magnetic Crack Detection
Authors: Bell J.E.D.
Published: February 2008

THE demands of war have created an increasing necessity for very strict inspection of component parts of aero and other internal combustion engines ; more particularly with the former, as more and more power is demanded from them.
Magnetic Crack Detection
Authors: Bell J.E.D.
Published: February 2008

In Part I the elementary principles of magnetic crack detection have been discussed, and an endeavour made to explain the elements of a system which has been satisfactorily applied to the inspection of aeroengine components.
The Calibration of Cylindrical Tanks
Authors: Allen C.F.
Published: February 2008

THE writer has had on occasions to calibrate a cylindrical tank, and found that whilst this task presents no real difficulties, a lot of time was spent on the necessary calculations. It was felt that a simple curve could be evolved to cover all cases of cylindrical tanks.
Perforated Tension Joints
Authors: Bowen I.G.
Published: February 2008

MUCH theoretical and experimental data are available on the strength and stiffness of tension joints with perforations. The object of the present paper is twofold: firstly, to summarize some relevant parts of existing data, and secondly, to present the results of recent tests which serve to illustrate some outstanding features of members tested to destruction.
The Importance of Attention to Jig Details
Authors: Moore H.
Published: February 2008

SINCE the design of drill jigs permits the adoption of an almost unlimited range of new ideas it is curious to note the lack of originality in the minor components. Most of the common accessories—clamps, screws, pins, bushings and the like—have remained unaltered for years. And yet, in all of them, there is some room for improvement. It is true that the measure of possible improvement is not great; often it is merely a pin here, a screw there, an alteration of an existing part, or perhaps only a rearrangement of some of the parts. But all these changes are within the scope of the operator himself; he should not wait for the jig producer to furnish him with ideas. As a matter of fact, if any little defect is allowed to continue unchecked it is the fault, not of the producer, but of the jig operator who, because he is using the jig in actual practice, is in the better position to see where it is wrong. At any rate, as far as the present writer can ascertain, nothing on this subject has ever before been published from the jig producing end. It remains, therefore, for someone at the other end—the jig operating end—to point out some of the defects of small accessories and how to correct them. These notes, although they chiefly concern the operator, are directed to the producer as well, because many of the ideas to be mentioned could well be incorporated in the jig before it is delivered to the shop.
The Design of Balancing Machines
Authors: Campbell Rose F.
Published: February 2008

THE balancing of rotating parts can be effected either on a balancing machine, or by means of vibration measurements carried out on the completed assembly.
Two Books Received From America
Authors: WILLIAMS D. , LUSTY IVOR
Published: February 2008

This collection of papers forms a sequel to Volume I which was reviewed in AIRCRAFT ENGINEERING, Vol. XVI, October 1944, p. 297. Again we have a set of contributions of remarkable interest and variety which is well worth careful study by all aeronautical engineers who have to do with experimental stress analysis.
Principal Limitations of Dielectric Heating
Authors: Madsen Carl J.
Published: February 2008

WITH the popularity of high‐frequency heating growing by leaps and bounds, it is desirable to stop for a moment now and then to take stock of the state of the art. This can best be done by breaking down the broad view and reviewing only a narrow phase at a time. This paper is concerned only with dielectric heating (heating of materials by a varying electric field), and reviews the major limitations that prevent universal application.
Making Ignition Faults Visible
Authors: Clark A.
Published: February 2008

UNSATISFACTORY performance of an aircratt engine often leads to the ignition system being suspect without there being positive proof that this is where the trouble lies. A complete change of sparking plugs may have to be undertaken; alternatively other ignition components may have to be removed for substitution, bench test or examination. All this work may be necessary to locate the fault, and, in the end, it might even prove not to be in the ignition system at all.
A.C. Power and Aeroplane Accessories
Authors: Miner J.D.
Published: February 2008

IT is slightly over two years since the U.S.A.A.F. asked some of the leading electrical manufacturers of the country to undertake the development of a wholly new alternating‐current electrical system for aircraft. While some of the details are not ready for publication, enough can be revealed to make this an opportune time to review the progress which has been made, and to evaluate the significance of this highly publicized development.
The Efficient Control of Twist Drills
Authors: Moore H.
Published: February 2008

ONE of the noticeable effects of the extensive application of drill jigs is a steady decline in the number of fully qualified hands. Too many operators are jig specialists and quite unable to handle anything else. This is hardly a matter for surprise. After all, the main function of a jig bushing is to control the movements of the drill, and to anyone accustomed only to this kind of work it is an extremely difficult matter to acquire, in a short time, the entirely different technique of jigless drilling. This awkwardness, however, is not incurable. Actually, it is a question of knowing how to prepare for drilling, as much as the drilling itself. It is because the opportunity of learning from others is not always present that the writer of these notes presents, for the first time, a selection of the methods favoured by himself. They will not miraculously transform an incompetent driller into a competent one, but they will help materially in the process.
Airframe Repairs‐Past, Present and Future
Authors: O'Halloran T.J.
Published: February 2008

THE recent winding‐up of the Owl Repair Organization signalized the end of war‐time conditions in the airframe repair industry. Yet our outlook upon repairs cannot be the same as before the war. What will be the form and scope of repair work in the future? What will be the effect of the experience gained in the past six years? An answer to these questions can only be attempted if we first look back upon the period immediately prior to 1939, when the structures of most aircraft were basically the same as the more orthodox types used during the war.
The Wartime Repair of Bristol Aeroplanes
Authors: Cullum R.D.
Published: February 2008

TWO items which frequently appeared on the repair lists for the Beaufort and Beaufighter, were (i) the main inter‐spar ribs to which the fuselage is attached, and (ii) the ribs carrying the nacelle structure (FIG. 26). The attachment ribs for the fuselage were usually known as the box ribs, a term derived from their form of construction which consisted of inner and outer alclad webs with top booms of extruded angfe section and built‐up bottom booms of box section forming the link between the longerons of the front and rear fuselages. On the Beaufighter the ribs were attached to the spars by means of extruded angles, extruded channels being employed on the Beaufort (FIG. 27). The ribs were further stiffened by inter‐web members of channel section. Each attachment rib for the nacelle structure consisted of an alclad web with a top and bottom boom of extruded angle section and secured to a bracing of square section steel tubes.
The Cold Starting of Aero‐Engines
Authors: Pickering Flight‐Lieutenant C.G.
Published: February 2008

THIS article deals with the cold starting and associated problems of reciprocating engines as distinct from jet engines. The associated problems are those which limit the satisfactory operation of the engine after the initial start, and are included because they form part of the functioning of the unit. The general problem of cold starting may be split up under the following headings and each one will be dealt with separately:
Simplified Statics
Authors: Hadekel R.
Published: February 2008

THIS article has been suggested by an actual problem in undercarriage work, and this problem is used as an illustration.
Design for Repair
Authors: Cullum R.D.
Published: February 2008

HOWEVER good the result, every designer expects, and receives, criticism—mostly adverse. But even the most adverse destructive criticism can be of some value to a designer whose interest is the furtherment and betterment of his work and who does not take criticism as a personal reflection on his ability.
Adiabatic Expansion of a Gas Stream Containing Solid Particles
Authors: Maxwell W.R. , Dickinson W. , Caldin E.F.
Published: February 2008

AN equation of state is derived for a system consisting of a perfect gas containing solid particles in suspension. It is assumed that temperature‐equilibrium is maintained throughout. The results are applied to calculate the kinetic energy obtainable from the adiabatic expansion of a stream of such a system, and related quantities. The assumptions of the treatment are critically examined.
Flying Boat Repairs
Authors: Reynolds I.W.G.
Published: February 2008

REPAIRING aircraft for Imperial Airways, led, at the beginning of the war, to the setting up of a repair organization with its headquarters at Rochester. All the work carried out was category ‘AC’ (repairable on site by contractors' party), except later when the Windermere factory and Short & Harland, Belfast, started to deal with category ‘B’ (repairable by contractor at the firm). At Windermere work was mainly large modifications or major overhauls. Short & Harland organized a separate repair department which dealt with all types of aircraft in Northern Ireland.
The Shear Analysis of Beams
Authors: Noble B.A.
Published: February 2008

THE limitations of the various methods of Beam Analysis are often improperly understood and it is felt that an explanation and criticism of them would be of some value.
Mechanical Seals for Rotating Shafts
Authors: Burger F.E.
Published: February 2008

THE practice of mechanically sealing liquids and gases within machines has shown little tendency to undergo any fundamental change since the earliest days of the art, and apart from the semi‐sealing properties of the elementary labyrinth in which measurable clearances exist as between a rotating shaft and its housing, some variant of the common ‘soft packing’ is the standard method of providing the closest form of contact sealing. This type of seal seems to have been engendered by the concept that only substances having extreme deformability could provide the closest degree of conformity to a circular shaft, and the type is brought into play in many ways, from the simple kind of soft, semi‐elastic ring which is rammed into a housing and thus becomes, due to its transverse elasticity, to some extent preloaded on to its co‐acting shaft, to the more refined rubber ring with its lip held against the shaft through the medium of an encircling garter‐spring of steel.
Conic Lofting of Streamline Bodies
Authors: Liming Roy A.
Published: February 2008

THE problem involved in obtaining satisfactory surface contours for assemblies such as are required in modern aircraft development demands for its successful solution the co‐ordinated, concentrated efforts of all those concerned with both the design and manufacturing processes. Even the casual observer can see that, if optimum performance is to be realized, the external skin or covering, whether made of thin sheet stock or precision machined from heavier plate stock, must be continuously smooth.
The Estimation of Aerofoil Lifting Characteristics
Authors: Bisgood F/O P.L.
Published: February 2008

THE lift coefficient of an aerofoil fitted with a hinged control flap and a tab can be expressed in the form:
Welding in the U.S. Aircraft Industry
Authors: Grimaud R.
Published: February 2008

DURING the War the use of spot welding became general in the United States. It is used in various ways by the different firms visited.
A Fuel System Full‐Scale Testing Rig
Authors: Black A. , Powell G.
Published: February 2008

THE considerable difficulties encountered in designing a test rig which would allow of unbroken fuel supply from tanks whose attitude was being changed continuously was successfully overcome.
The Library Shelf
Authors: WILLIAMS D. , DUNCAN W.J.
Published: February 2008

This latest volume of the proceedings of the Society for Experimental Stress Analysis begins with an interesting account by one of its promoters, Mr R. D. Mindlin, of the activities of the Society since its inception a few years ago. There follow a dozen papers which are well up to the high standard set by previous volumes. Four are devoted to the problem of repeated loading and fatigue, two to the description of instruments for telemetering flight data from the aeroplane to the ground; two papers describe instruments for the accurate measurement of small displacements; there is a paper on dynamic testing, another on accelerometers and lastly a paper on the measurement of stresses in moving parts.
A Recording Instrument for Performance Tests
Authors: Jarvenpaa Paavo
Published: February 2008

THE application of this recording instrument is in fact of very wide range. On flight tests the most varied range phenomena may be simultaneously subjected to research and it is also possible to use the instrument for the investigation of such phenomena as do not belong to the actual sphere of performance tests. The following instances will probably give an idea of the possibilities of employing the recording instrument.
A Further Development in Calculating the ‘Take‐off to 50 ft.’ Distance of an Aeroplane
Authors: John G.
Published: February 2008

A SERIES of laborious calculations of take‐off distance indicated the desirability of expressing propeller thrust as a function of speed in the take‐off range so that the ground run could be integrated directly. Propeller thrusts were estimated from REF. 2 for a wide range of disk loadings, solidities, and tip speeds. Plotting against speed shows that, for practical values, the assumption of linearity introduces a negligible error (see FIGS. 7–39).
L'Exhibition de Farnborough Vue par un Francais
Authors: Charriou André
Published: February 2008

I HAD the great pleasure of visiting for several days the excellent display organized by the S.B.A.C. at Farnborough.
Filtration as Applied to the Aircraft Industry
Authors: Parkinson J.
Published: February 2008

BEFORE the war scientific filtration as applied to aircraft was a little known subject. The prime concern of the people developing aircraft in those days was the attainment of higher power output, ceiling and maximum speed. More streamlining was the cry and, although filters were available, they were rarely used.
The Technique of Wire Locking
Authors: Tomlinson J.W.
Published: February 2008

IN the past designers and draughtsmen have been inclined to regard wire locking as the Cinderella of locking devices. The practical man frowned on the method and looked upon the results as machinery tied together with pieces of wire. In recent years, however, wire locking has without doubt established itself as an important and prominent form of locking in the aircraft world. Today its position is enhanced by the introduction of the gas turbine, which employs wire locking on practically external fuel and oil pipes.
An Airline Maintenance Base in the U.S.A.
Authors: Perry H.W.
Published: February 2008

AIRLINE and military aviation leaders from many countries who have visited the recently completed United Air Lines maintenance base at San Francisco to observe the layout, special equipment and operating system have been greatly impressed with the facilities and efficiency of the new plant. They have proclaimed it the largest and most advanced airline maintenance base in the world.
The Representation of Streamline Shapes
Authors: KIRSTE C.L.
Published: February 2008

To the Editor, Dear Sir, The series of articles in your paper, dealing with the application of conies to lofting, recalls another kind of curves for representing stream‐lined shapes. They are obtained by multiplying the ordinates of a circle by a variable coefficient m. If this is a linear function of the abcissa, the co‐ordinates of the curve are:
A New Tyre, Brake and Undercarriage Testing Machine
Authors: Green J.R. , Wills H.A.
Published: February 2008

DURING the war the young aircraft industry in Australia made great strides. Design and development of new types of aircraft were undertaken and a need was soon felt for an undercarriage testing machine. A small drop tester was built by one of the firms for the undercarriages of small aircraft and a larger one was under construction by the Government when, towards the beginning of 1944, serious operational difficulties were experienced in the South Pacific area due to the short life of the tyres of medium and heavy bombers, complete failure occurring in as few as five or six take‐offs and landings. Thus to the need for an undercarriage tester was added the need for proper facilities for developmental and type testing of tyres and wheel brakes.