bluuebunny/crossref_metadata_2025 huggingface dataset:
Aiding Archæology from the Air
Authors: Crawford O.G.S.
Published: February 2008

FOR some years now air‐photography has been acknowledged as a most valuable accession to archaeological research. It has often been said, and with justice, that for the excavation of an ancient site an air‐photograph is practically a necessity. The reason for this is that, when seen from above, the plan of an archaeological site is revealed in a way which is impossible for an observer on the ground. The actual process differs according to the character of the ground itself. Ancient ruins consist either of earthworks, such as banks and ditches, or of foundations of masonry. In either case, the plan appears to a ground observer as a confused jumble that, when seen from above, is revealed for what it really is. Archaeologists have not many opportunities for flying themselves, at any rate in England, where this new branch of study originated and where it has been developed to a far greater extent than abroad. The pilot naturally has other things to think about when he is flying, and it has been suggested that a few words of explanation might be of interest to readers of Aircraft Engineering. There is a fine field here for the owner of a light aeroplane who might welcome some excuse for cross‐country flying, other than the obvious ones. Old England seen from the air is a book that has as yet only been half‐opened; there are still immense possibilities. In order to bring out some of the ways in which air‐photography works, I have described in this article a few typical air‐photographs of sites in Sussex.
Designed for Aerobatics in Germany
Authors: Beck Waldemar
Published: February 2008

OWING to the various competitions in Germany last year one type was neglected, a moderately high‐powered machine for stunt flying. The Raab‐Katzenstein firm has now filled the gap with the “R.K. 26,” which combines high strength factor with speed and rapid climb. This machine is a cantilever biplane with one‐piece wings. Above the fuselage the top wing is carried on a capotage of steel struts and there is one N‐strut towards the wing‐tip on each side. The American N.A.C.A. M‐12 aerofoil section is used, giving low centre of pressure travel, the wings being constructed of wood and fabric covered. The fuselage is built up of wire‐braced steel‐tubes, the pilot's cockpit being in rear of the passenger seat. The empennage is also constructed of steel tubes. The tubular steel undercarriage has a divided circle supported by M struts for the bottom longerons. Four fuel tanks are provided, three in the wings and a special tank for upside‐down flying in the fuselage, with a total capacity of 210 litres (46 gallons).
The Development of Aeronautical Research in Holland in Recent Years
Authors: Van der Maas Ir. H.J.
Published: February 2008

Industry Foreign machines were used in Holland at the outbreak of the war (type Farman). In the beginning of the war some machines were built by the Spyker Works, which later on developed the Spyker types V.1 and V.3 in which Gnôme et Rhône and Thulin engines were mounted. In 1927 the v. Berkel Works started building float‐seaplanes W.A. and W.B.
Recent Progress of Aeronautical Science in France
Authors: Franck P.
Published: February 2008

THE main objectives of French aeronautical progress have been safety in flight, development of commercial aviation, and metal construction. In every part of aeronautical science we shall find progress along those lines. They concern aerodynamics, building of aircraft, flying boats, motors and aerial navigation.
Aeronautical Research Work in Sweden
Authors: Angostrom Tord. K.
Published: February 2008

THIS paper contains a report on the principal aeronautical reseach work carried out by the Aeronautical Committee of the Royal Swedish Institute for Scientific Industrial Research.
The Dornier Do.X. Seaplane
Authors: Dornier Claudius
Published: February 2008

THE leading thought in the design of the Do.X. was that to lead to the desired goal only that which had been technically proved could be used. Every kind of “experimenting” was ruled out from the beginning. There is no doubt that through this precaution creative work was, to a certain extent, handicapped. The fact, however, that from the commencement of the tests of the Flying‐Boat, up to their completion, only about one hundred working hours were occupied in alterations, proves, in conjunction with the results achieved, that the plan adopted was correct.
Fuels and Dopes for Aircraft Engines
Authors: Dunstan A.E.
Published: February 2008

SIX years ago the present author contributed a paper on “Aviation Spirit: Past, Present and Future,” before the International Air Congress, London, 1923.
Rigid Airship Design and Construction
Authors: Wallis B.N.
Published: February 2008

THERE are two outstanding principles which underlie all airship design, two criteria by which everything undertaken may bo judged. The first is that the body produced shall offer a minimum of resistance to propulsion through the air; the second is that, having shaped a body in that way, it shall give a maximum of disposable lift for a given volume. An airship also, at the present time at least, must be produced for a minimum of cost. For this reason every effort must be made to design the structure as cheaply, as economically, and as quickly as possible.
Compression Ignition Oil Engines
Authors: Schulz R.
Published: February 2008

THE development of the Diesel engine for aeroplanes in Germany was first taken up by the Junker works, in Dessau. Junkers began building oil engines more than twenty years ago with the construction of large Diesel engines. Later on they produced the well‐known stationary “HK” engines, and recently also small high‐speed engines for vehicles. Simultaneously with this began the development of the heavy oil engine for aeroplanes.
The Siemens‐Halske S.H.20 Engine
Authors: Beck Waldemar C.
Published: February 2008

THE Siemens SH.20, which can be supplied with or without reduction gear, has a total swept volume of 31·5 litres and a power output of 500–560 h.p., and is one of the largest and most powerful air‐cooled engines in the world.
Army Air Corps Experiments on Tail Spins
Authors: Sutton Harry A.
Published: February 2008

THE serious nature of difficulties which might be encountered in tail spins, was brought forcibly to the attention of the Material Division of the U.S. Army Air Corps, in the Spring of 1926, when Lieutenant E. H. Barksdale lost his life in attempting to determine the cause of difficult recovery from spins in a military aeroplane being flight tested at Dayton, Ohio. Trouble in recovery from spins had been encountered in several instances in foreign countries, and one or two cases had occurred in the United States: however, the problem was not considered as one generally applicable to all aeroplanes, because, in most cases of previous trouble, the aeroplanes concerned possessed unusual design features which were thought to be mainly responsible for their abnormal behaviour. Prior to this time, general conjectures had been made, regarding probable reasons for difficult recovery from spins, but very little in the nature of systematic investigation had been attempted, consequently no generally applicable principles had been determined. Numerous studies had been made in wind tunnels, and it was recognised that the normal aerofoil would rotate automatically under certain conditions, but the magnitude of the forces involved, and therefore the ability of an aeroplane to recover a normal attitude by use of the controls, could not be readily determined by wind tunnel tests. A few flight tests had indicated that the centre of gravity location, with respect to the resultant air force vector on the lifting surfaces, influenced the type of spin and the case of return to a normal attitude.
The Twelfth Paris Aero Show
Authors: de Marolles R.J.
Published: February 2008

THE Paris Aero Show—the oldest in the world, since it was first held, though unofficially, in December, 1908—took place this year from November 28 to December 14, in its usual quarters, the Grand Palais des Champs‐Elysées. This Salon, the twelfth of the series—as the first official one dates from 1909, there being, of course, a gap from 1914–1918, and after 1922 it laving been decided to hold it in alternate years—is, as usual, conducted by the “Chambre Syndicale des Industries Aéronautiques,” of which M. Fernand Lioré, the well‐known aeroplane and flying‐boat manufacturer, is the present President, M. André Granet being Commissaire‐Général.
The Cooling of Engines
Authors: Nutt Arthur
Published: February 2008

CONSIDERABLE interest has been shown during the last year or two in the use of high temperature liquid coolant for aircraft engines. Both evaporative cooling, which has been used experimentally on automobile and aircraft engines, and the use of high‐boiling‐point liquid have been considered. In England evaporative cooling has received probably more attention than high temperature liquid cooling, while in America the latter has received more attention.
Steel Tube and Strip
Authors: Handasyde G.H.
Published: February 2008

BEFORE describing the methods used in the construction of Armstrong‐Whitworth aircraft, it is necessary to describe briefly both the types built and the conditions under which they are manufactured, so that an allowance can be made when comparing their methods with those of other firms.
Applied Load Factors in Bumpy Air
Authors: Rhode Richard V. , Lundquist Eugene E.
Published: February 2008

FROM the standpoint of the structural design of transport or “non‐acrobatic” aeroplanes, which never need be subjected to manoeuvres more severe than the very mild turns, etc., required to achieve a given destination, the “bumps” experienced in flying through “rough” air are of considerable importance, since they give rise to the structural loads for which the wings should be designed. In the past, practically no quantitative information on the structure of the atmosphere in its relations to applied loads on the aeroplane has existed. To supply this deficiency, the National Advisory Committee for Aeronautics is conducting an investigation of the accelerations obtained in flight through rough air on a number of transport aeroplanes flying regular scheduled trips. Only a small amount of information has been obtained to date. Enough has been accumulated, however, to throw considerable light on the subject of applied load factors in rough air. With the object of presenting this information this note has been prepared.
The Fifth Air Congress
Authors: Piercy N.A.V.
Published: February 2008

The two volumes recording the work of the Congress together run to some 1,700 pages. The presentation is good, and several lecturers have graciously met our peculiar national difficulty by giving their papers in English. The summaries in French are also a great help.
Fabrics in Aviation
Authors: Cleary Charles J.
Published: February 2008

TO attain the maximum in design and performance of a fabricated article requires familiarity with the characteristics and properties of the materials employed. That there is a keen appreciation of these facts is evidenced by the use of new and improved materials and processes throughout the industry. The development of textiles has kept pace with general progress, yet the designer in aeronautics is relatively uninformed as to the characteristics and limitations of textile materials, as compared with his information on metals, heat treatments, protective coatings, and the like. So long as textile materials are used as stressed members, as in the case of wing coverings, semi‐and non‐rigid balloon envelopes, and parachute canopies, they must necessarily be subject to the same careful scrutiny as other structural materials with reference to the design and performance of the fabricated article. Specifications for textile materials are widely known and thoroughly appreciated, thanks to the excellent work of engineering, technical and commercial organisation, and Governmental agencies. The interpretation of these specifications and an appreciation of the limitations of the material specified, however, are apt to be faulty, and it is with the hope of being of assistance in this connection that the following discussion is offered.
Welded Tube Construction
Authors: Handasyde G.H.
Published: February 2008

THE firm of A. V. Roe & Co., of Manchester, is the outcome of the early efforts of the two brothers Roe, of whom A. V. was responsible for all the early practical work, and, with the writer; is the oldest aircraft constructor in Great Britain so far as really practical work is concerned, though there had been several others who had made experiments and had generally toyed with the idea of free flight prior to the serious experimental work undertaken by A. V. Roe. In recent years the actual design of the firm's products has been in other hands, but his original ideas are still easily traceable in the design of the present‐day machines produced by this company; which would seem to prove that some of the early designers knew a good deal more about the subject than the later generation of designers and constructors would care to admit.
A University Wind Tunnel
Authors: Fairbanks Rollin J.
Published: February 2008

ONE of the most recent wind tunnels built in the United States is that at the University of Detroit, officially put into operation in September, 1930, designed under the personal supervision of Professor Peter Altman, director of the aeronautical engineering department of the University.
A New Type of Gyroplane
Authors: Klemin Alexander , Ruffner B.P.
Published: February 2008

SINCE 1929, a number of tests have been made at New York University on a new type of rotating aerofoil system, invented by Walter Kreiser and Walter Rieseler, and developed by E. Burke Wilford, of the Pennsylvania Aircraft Syndicate.
Aeroplane Construction at Bristol
Authors: Handasyde G.H.
Published: February 2008

THE Bristol Aeroplane Company is one of the pioneer aircraft firms in this country, their entry into the aircraft business being clue to the foresight, and strong belief in the future of aircraft, of their first Chairman, the late Sir George White. The firm have always been noted for the high finish and sound workmanship of their products, some of their war‐time designs being still in service in the R.A.F., and though they have from time to time received minor modifications, in the main they still retain the chief features of the original design. That this was sound in principle is borne out by the fact that, even in their most recent productions, there is a strong resemblance to the famous Bristol Fighter. With the march of progress the use of wood in the earlier machines has given way to metal construction, and all their types are now built in this material.
A Radial Engine for Light Aircraft
Authors: Handasyde G.H.
Published: February 2008

IT was with a feeling of uncertainty that the writer entered the offices of British Salmson Aero Engines, Limited, the firm having only been in being about two years, and not being yet very well known. It seemed doubtful, therefore, whether there would be much system to interest the readers of AIRCRAFT ENGINEERING. A certain amount of confidence was, however, at once gained on being shown into a waiting room which contained three complete engines of different horse‐powers, all mounted on stands at a height that made close examination easy. This room gave one the impression of having entered a well established firm, which was confirmed by a tour of the shops, and it is no rash statement to say that these works are one of the most interesting the writer has visited.
Duralumin and Steel Construction
Authors: Handasyde G.H.
Published: February 2008

THE Westland Aircraft Co., of Yeovil, is one of the firms whose entry into the aircraft industry dates back to the times when a few enthusiasts were trying to prove it possible to fly with a heavier‐than‐air machine, and Mr. Bruce, the managing director, was one of the early pioneers of this movement.
The Installation of a Racing Engine
Authors: Pettitt‐Herriot J.
Published: February 2008

THE issue of AIRCRAFT ENGINEERING for October, 1931, contained descriptions of the Rolls‐Royce racing engine and the Schneider Trophy seaplane.
Jigs for Aircraft Construction
Authors: Handasyde G.H.
Published: February 2008

A JIG is a device used to ensure that all the members of a batch of articles are alike. In its simplest form, it is known as a template; which, however, only ensures uniformity so long as each article is accurately made to the shape of the template, the accuracy depending to a considerable extent on the skill of the operator.
Flying in the Stratosphere
Authors: Crocco General G.A.
Published: February 2008

FOR the purposes of this paper the prefixes hyper and super, which, etymologically, have the same essential signification, are given different meanings: to the first a sense of distance, and to the second a sense of altitude.
Flying in the Stratosphere
Authors: Crocco General G.A.
Published: February 2008

Having taken up our position on the above definition of this fundamental point, which closes the long‐standing discussion between upholders of the airscrew and those of the reaction system (just as in earlier days the distinction between impulse and work closed the classic discussion between the followers of Leibnitz and Descartes), we must now admit, without going into details, that this supposed attainment of equal efficiencies cannot be considered easy, if even possible, for the normal speeds of flight. It must also be admitted that a power unit, consisting of engine, compressor and jet, is at first sight a unit more complex, heavier and more bulky than the ordinary engine‐airscrew unit which has now been reduced to a high degree of simplicity and neatness. There is no doubt at all that in the sphere of the sub‐acoustic velocities the airscrew will reign supreme.
The German Aero Show
Authors: Schulz W.R.
Published: February 2008

THE Deutsche Luftsport Ausstellung (German Light Aeroplane Show) which was held in Berlin from October 1 to October 23, was devoted entirely to private and club flying, so that only light aeroplanes, touring aircraft, appropriate engines, and gliders were shown. Unlike the big international aero shows, exhibitors were not restricted to the industry alone; many of the aircraft shown were constructed by clubs or amateur designers. In addition, the organisers had arranged for the production of a few “aircraft of the future” which, although only in model form, were to full scale and embodied some interesting ideas.
The Economics of Weight‐Saving
Authors: Warner Edward P.
Published: February 2008

HOW much is lightness worth? The question is one upon which many engineers have formed their own opinions. Their conclusions range in written expression from the epigrammatic observation of Major Green, of the British Armstrong Siddeley Company, that he would “spend a pound to save a pound any time,” to an estimate of $40 per pound offered by a well‐known American metallurgist. We are going in search of a definite answer, with arithmetic taking the place of speculation.
The Design of Airscrews
Authors: Hollis Williams D.L.
Published: February 2008

FROM time to time alternative methods of generating thrust have been proposed, but for a variety of reasons early promise has failed to mature and the airscrew remains without an important challenger as the best available means of impelling an aircraft through the air.
Hull and Float Maintenance
Authors: Jarvis J.
Published: February 2008

CAREFUL inspection and maintenance of hulls and floats is of the utmost importance, as a forced or heavy landing with a hull or float which is in a doubtful seaworthy condition might easily result in the total loss of the sea‐plane.
The Principles of Air Cooling
Authors: Pye D.R.
Published: February 2008

The Nature of the Boundary Layer The changes of velocity in an air stream at points close to a surface past which it is flowing have been calculated by Blasius and von Karman for the surfaces of a thin plate placed edgewise to the stream; and they have also been directly measured by Fage and Falkner close to the surfaces of an aerofoil, by means of an arrangement of minute pitot tubes, down to distances of a few thousands of an inch from the surface.
The Phenomenon of Knocking
Authors: Taylor E.S.
Published: February 2008

RECENT researches by Withrow and Boyd (reference 1) and by Schnauffer (reference 2) each using a different technique, have shown that the phenomenon of knocking is accompanied by an apparently simultaneous reaction of the last part of the charge to burn. Whether the reaction of this part of the charge is actually simultaneous or whether the reaction zone travels with a very high velocity, has not yet been determined. In any case, it will be conceded that the progress of the reaction zone is too rapid to be dependent upon the transfer of heat energy by conduction from the flame front as in normal combustion. In the light of these researches and others, some of which have been carried out in the Aeronautical Engine Laboratory of the Massachusetts Institute of Technology, I believe it is possible to postulate a very simple and reasonable theory of knocking, which fulfils all present requirements and which may in some degree help to remove the veil of mystery which has surrounded the subject.
The Effect of Turbulence
Authors: Millikan C.B. , Klein A.L.
Published: February 2008

THE extensive series of investigations to be discussed in the present paper has its origin in an attempt to clarify the reason for certain discrepancies, which have long plagued aerodynamicists, between the results of tests on similar aerofoils carried out in different wind tunnels. It has been well known for many years that the Reynolds number has an important influence on aerofoil characteristics. It is therefore highly desirable that aerofoil tests, to be useful for full‐scale predictions, be made at as large a value of the Reynolds number as possible. For several years the variable density wind tunnel of the National Advisory Committee for Aeronautics has been able to employ Reynolds numbers considerably higher than were attainable in any other wind tunnel. Its results have, therefore, very properly been generally accepted as furnishing the standard aerofoil data for aeroplane designers in the United States, and to some extent also in Europe. It appears from the present investigation that another factor, turbulence, may be of the same order of importance as the Reynolds number in determining certain aerofoil characteristics. In discussing the possible effects of this factor, it is desirable that as wide variations in its magnitude as can be obtained should be considered. The turbulence characteristics of the N.A.C.A. variable density tunnel and of the wind tunnel at the Guggenheim Aeronautics Laboratory at the California Institute of Technology (referred to in the figures as Galcit) are as different as those of any two large contemporary wind tunnels. It is for this reason that in the following discussion results obtained in these two tunnels are compared.
Variable Pitch Airscrews
Authors: Folland H.P. , Milner H.C.
Published: February 2008

IN conception, the conventional airscrew is an extremely simple transformer of energy and when constructed with skill can be, under certain conditions, a highly efficient means of propulsion. Its function is to develop thrust, the factors concerned in which are: h.p. of engine, forward speed of aircraft, engine r.p.m. and air density. For any given combination of these factors there is a limiting thrust, obtainable only by an ideal airscrew designed to meet the set of conditions, which cannot be exceeded by changing the geometry of the screw within the limits of diameter usually imposed by other considerations.
An American Cure for Buffeting
Authors: Hood Manley J. , White James A.
Published: February 2008

THE increasing use of low‐wing monoplanes has emphasized the susceptibility of this type of aeroplane to detrimental wing‐fuselage interference. This interference was first indicated by the inferior aerodynamic characteristics of the low‐wing as compared with the high‐wing monoplane.
The Design of Machined Parts
Authors: Marcell R.
Published: February 2008

BROADLY speaking, machined parts as a class are far too expensive for the services they render, when compared with the cost of comparable plate fittings. Consequently, most firms cut down their number to an abolute minimum, sometimes even making up from plate parts which are generally considered more suited for the machine shop.
Commercial Aeroplane Design
Authors: Weyl Alfred Richard
Published: February 2008

ONE of the most important tasks of present‐day aeroplane manufacture is the design of economical high‐speed commercial aeroplanes to provide regular and safe services.
Commercial Aeroplane Design
Authors: Weyl Alfred Richard
Published: February 2008

THE high and economical cruising speed already mentioned depends on the aerodynamic “fineness” of the aeroplane (low drag, high airscrew efficiency) and on the horse‐power per unit wing area.
Timber for Aeronautical Use
Authors: Seeley A.W.
Published: February 2008

ALTHOUGH the modern tendency in aeroplane construction is to produce an all‐metal machine, the time has not yet come when we can definitely say that this or that machine is entirely of metal, there being still a fair proportion of the structure of most light aeroplanes in which wood plays a very important part, both from the point of view of the greater facilities existing for repair and the lesser cost of production.
The N.A.C.A. Seaplane Tank
Authors: Truscott Starr
Published: February 2008

A SURVEY of the information available regarding the application of the results of tests of models in towing basins to the design of floats for seaplanes was made by the National Advisory Committee lor Aeronautics in 1929. It was found that the development of flying boats and seaplanes had been assisted very much in the United States, and possibly more in other countries, by tests of models in towing basins or tanks (References 1 and 2). Some tanks already existed which were designed especially for testing models of seaplane floats and the construction of other tanks for this special purpose was projected (References 3 and 4). There was no such tank in the United States; in fact, there were only two tanks, both constructed before the appearance of the seaplane and designed originally to test models of ships. The construction in the United States of a special towing basin that could be devoted to tests of models of seaplane floats and hulls might reasonably be expected to be of great assistance in the further development of this type of aircraft, the importance of which appeared to be increasing.
Static Wing‐Rib Tests
Authors: Clegg A.W.
Published: February 2008

THE strength of main plane ribs for use on all British aircraft is determined by static tests of single representative ribs under conditions of loading determined from the characteristics of the aerofoil.
A New French Light Aeroplane
Authors: de Marolles R.J.
Published: February 2008

AEROPLANE manufacturers exhibit a growing tendency towards building their own engines; conversely, there are instances of engine manufacturers starting aeroplane construction. This is not exactly true of Société Salmson, the well‐known engine firm, since this concern produced large quantities of military machines during the war and has brought out some new designs since that period. Its directors recently decided to re‐enter the field of aeroplane design with a machine intended to provide for the requirements of the private owner. Hence the Phrygane, as it has been christened after a particular species of butterfly. This high‐wing three‐seater monoplane, fitted with a 135‐h.p. Mk. 9 Nc. Salmson engine, is the forty‐sixth design produced by the well‐known engineer, M. Deville, who, after starting his aeronautical career in 1911 with the Clément‐Bayard firm, later became a member of the technical staff of the Breguet‐Salmson works in England. M. Deville is a very practical man and he contends that small points which are often overlooked by designers of repute are worthy of exhaustive study, as they go a long way towards making all the difference between a perfect engineering job, which is however a nightmare to maintain, and a possibly less ambitious machine which is simple and easy to use or maintain.
Throttled and Full‐Throttle Tests
Authors: Hutchinson J.L.
Published: February 2008

THE fact that the engine power in full‐throttle flight is governed by thermodynamic conditions involving the atmospheric pressure and temperature at the air intake; while the engine power in throttled flight is, by adjustment of the throttle position, entirely at the choice of the pilot, is the cause of certain fundamental differences in the correction of full‐throttle and throttled tests to standard conditions. For, whereas full‐throttle flight, in which the aerodynamic forces are subject to a thermodynamical limiting condition, involves both aerodynamics and thermodynamics, throttled flight is purely aerodynamic. A simple illustration is provided by throttled level flight in which the throttle is adjusted until the airscrew thrust is equal to the drag at the air speed selected by the pilot; that is, the engine power is fixed by aerodynamic conditions alone.
The Third Deutsch Cup
Authors: de Marolles R.J.
Published: February 2008

THE rules for the 1935 Deutsch de la Meurthe Cup Race remained almost identical with those of 1933 and 1934. Briefly, the contest was open to all types of land “aerodynes”; the only limitation being that the total capacity of the engine (or engines) remained under 8 litres (488·20 cu. in.). In other directions, designers were left with an absolutely free hand—the usual Certificate of Airworthiness even being dispensed with. To avoid the participation of machines of doubtful characteristics, each competitor had to qualify between April 2 and May 2 by passing successfully the following tests: a flight of 500 km. (311 miles) in a closed circuit at a speed exceeding 300 k.p.h. (186·5 m.p.h.)—against 250 k.p.h. (155·5 m.p.h.) last year. In addition, take‐off and landing had to be performed in less than 500 metres (1,640 ft.) over a “screen” 1 metre (3·28 ft.) high—against 550 metres (1,801 ft.) last year. Actually, the “screen” took the form of two parallel ropes set at the required height and separated by an interval of 50 metres (164 ft.), so as to ensure correct execution of the test. The wind velocity had to be under 6 metres per second (19·7 f.p.s.) during the take‐off and landing tests.
My Early Experiments
Authors: Blériot Louis
Published: February 2008

WHEN I succeeded in crossing the Channel on July 25, 1909, no one obviously believed that it was simply a matter of good luck. I do not say, especially after so long an interval, that I was not favoured by the chance factor. But it should be remembered that since 1899 I had devoted all my time and money to solving the problem which constantly provided me with fresh difficulties.
Stainless Steels
Authors: Bull H.
Published: February 2008

THERE were two types of stainless steel in 1912–14, and this is still substantially true; the chromium iron alloys and the chromium nickel iron alloys.
The Critical Speed of Crankshafts
Authors: Beilschmidt J.L.
Published: February 2008

AN outstanding feature relevant to the consideration of shaft whip phenomena is that intermediate bearings cannot be depended upon to eliminate whip by reducing the free shaft length, for under these conditions the forces tending to produce whip are still present and are transmitted to the bearings in the form of shocks which are likely to coincide with the maximum inertia load positions and result in overloading. Apart from this, an absolutely rigid bearing supporting structure is a practical impossibility (even if it were desirable) and flexing of the shaft is inevitably communicated to the structure so that if this be excessive, vibration, fatigue and rapid general deterioration must result.
Longitudinal Trim Relations
Authors: Sayers W.H.
Published: February 2008

THE use of the C.G. as the datum to which all moments involved in the trim relations are referred is doubtless the result of a convention widely used in mechanics generally and having one advantage, i.e., that the moment due to gravity is zero. In general mechanical problems where the position of the C.G. is normally a fixed characteristic of the body whose motions are under consideration, the C.G. has a good claim to be a convenient datum. In the case of the aeroplane, where the C.G. of a particular aeroplane is rarely found to be in the position estimated for it—even under carefully defined conditions of loading—it is subject to considerable movement with variation in loading; and, in different aeroplanes, may occupy the most various positions relative to the organs which produce the moments involved—the use of the C.G. as a reference point for trim estimates has very serious disadvantages.
The Fowler Wing Flap
Authors: Fowler Harlan D.
Published: February 2008

THE design of aerofoils, after years of research, has about reached its maximum development. The comprehensive research of the National Advisory Committee for Aeronautics has resulted in several new highly efficient aerofoils. The systematic nature of this research indicates that the possibility of further marked improvement is remote, and would be of comparatively small value and costly to discover. Various attempts have been made to so design an aerofoil that it would develop an especially high L/D ratio, better minimum drag at cruising speed, etc.
The Rocket‐Propelled Aeroplane
Authors: Ley W.
Published: February 2008

THE rocket‐propelled aeroplane demands the successful combination of two conflicting principles. In fact the problem has been compared with the construction of a ship equally suited for travelling on rivers and navigating the high seas. The principle of the rocket, as that of the aeroplane, is to move by reaction against an accelerated mass. There is a great difference, however, in the manner of application of this principle, as the following two examples will show. A powder rocket of a commercial type has an overall, weight of 140 grammes (453 grammes = 1 lb.); the weight of the shell containing the driving charge is 40 grammes, while the charge weighs approximately 15 grammes. The effective burning time of such a rocket was found to be 0.15 sec.; the thrust during this period being 4.8 legs, or approximately 11 lb. The exhaust speed of the gases (“c”) was calculated to be 453 metres per second; the acceleration 314 metres per second (in other words more than 31 gravities): the altitude 110 metres without considering air resistance. Actually the altitude reached was about 80 metres, or 250 ft.
A Property of Synthetic Resins
Authors: de Bruyne N.A. , Maas J.N.
Published: February 2008

SYNTHETIC resins reinforced with fahric have proved in actual service to be not only resistant to disintegration from shocks and vibration but also to have remarkable freedom from “notch sensitivity.” In order to investigate this property measurements were made of the energy absorbed by such materials under torsional oscillation; it was found that the energy absorbed was greater than that of any other comparable materials (such as wood or metal).
Modern Helicopter Theory
Authors: Isacco Vittorio
Published: February 2008

In this article M. Isacco concludes his exposition of what he believes to be the underlying principles of flight by direct‐lift machines. He here surveys the types that have been built up to the present from the point of view of their stability characteristics. This involves a critical description of practically every helicopter built during the last thirty years. His paper therefore constitutes a history of all that has been done in this field of aeronautics in modern times
A Convertible Wind‐Tunnel
Authors: Winter H.
Published: February 2008

THE general arrangement of the wind tunnel shown in Figs. 1 and 3 does not differ materially from the tunnels built up to the present on the plans of Professor Prandtl in Germany, England, America. It is an open jet tunnel with single return flow and two large elliptic nozzles of different design. A single stage helicoidal fan in the return flow provides the air stream. The fan is driven by a synchronous motor across an oil gear, Thoma‐Waldrich type, consisting of two pumps and a motor.
The Calculation of Span Loadings
Authors: Crean J.R.
Published: February 2008

A FUNDAMENTAL method of determining the distribution of lift across the span of, e.g., a monoplane wing is that of Graphical Successive Approximation, proposed originally in 1923 by A. Fage and B. N. Jurieff independently.
The Equilibrium Diagram
Authors: Macleod Norman
Published: February 2008

THE following notes are being written solely for the benefit of ground engineers who are endeavouring to acquire the necessary knowledge to obtain a D licence. A licence in Category D demands a knowledge of the heat treatment of steels. Practical experience is, of course, quite as essential in this as in other and allied branches of engineering, but a theoretical study of the reasons for, and the results of, different heat treatment, is equally essential for a complete understanding of the subject.
The Modern Junkers Wing
Authors: Quick A.W.
Published: February 2008

IF I am to cover the development of the Ju 86 wing in this short paper, it will be obvious that I shall not be able to touch upon all the aerodynamic problems encountered. Thus I shall deal particularly with the modern problem of lateral stability about the longitudinal axis, or “wing‐dropping.”
The Sinking Speed of Aeroplanes
Authors: Lundberg B.
Published: February 2008

IN accurate performance calculations it is usual to calculate the two curves for the horse‐power required and available (against the path velocity), especially in the case where the individual engine and airscrew characteristics are to be considered. With the principles applied in this article it is recommended to use instead the rising and sinking speeds respectively. Here only the sinking‐speed part of the problem is to be studied. It is well known that the calculation of the curves for the horse‐power required or the sinking speed involves considerable labour, especially when the calculations must be repeated for different heights and for different alternatives or assumptions according to the design and aerodynamic qualities of the aeroplane.
Valve‐Spring Wire
Authors: Wood Ernest
Published: February 2008

IT has recently been said by a member of a firm of justly‐famous wire makers (1) that there is probably no finer grade of wire than that designed for aero‐engine valve springs to Air Ministry Specification D.T.D.5A, and despite the fact that this article will deal principally with defects in that wire, the author, from an experience gained from the handling of some hundreds of miles of it, must state at the outset that he can endorse this opinion.
Aeroplane Undercarriages
Authors: Jones E. , Cook F.G.R.
Published: February 2008

Performance Calculations for Oleo‐Pneumatic Shock Absorber Struts Various types of oleo‐pneumatic shock absorbers are shown diagrammatically in Fig. 19. The equations of motion for each type are of similar form, but differing in detail, and the equations for each type are deduced separately. The equations are not directly soluble and a step by step integration process is used with successive approximations for each step. Although the method may appear laborious at first sight, the complete analysis of a shock absorber can be made in about three hours after some experience in the method.
A Polish Engineer On Production
Authors: Cyma Zygmunt
Published: February 2008

PROBLEMS which confront Aviation today have changed so radically and to such a degree in the last few months that, in comparison with methods employed until recently, aeroplane production in practically all branches is undergoing fundamental changes.
Notes on Welding Practice—III
Authors: Waterworth J.G. , Mowbray A.R.
Published: February 2008

THE materials commonly employed in the fabrication of aircraft structures are confined for the main part to steels of low carbon content (i.e., mild steel, manganese steels of a medium carbon) and chrome‐molybdenum steels. The content of carbon steels that are weldable cannot be exactly laid down, since the amount which can be contended with by the oxy‐acetylene process may rise to as much as 0.8 per cent, although this does not occur in the examples given here where only steels within the region of 0.3 per cent carbon exists.
Some Aspects of Engine Wear
Authors: Jackson H.H.
Published: February 2008

OF all modern engineering constructions, it is difficult to imagine a unit the components of which are more liable to general wear than the present‐day internal combustion and compression ignition engines. The performances demanded of aero‐engines in particular, have instigated the enormous amount of research and investigation that has been made on the problem of reducing metallic wear under various conditions of temperature, load, atmosphere, etc. The importance of this problem is manifest when one reflects that the great majority of the components of the aero‐engine (with the exception of details, nuts, bolts, pins, etc.) are subject to continual wear in one form or another. In other words, the serviceable life of any engine is largely a function of the degree to which particular forms of wear have been minimized. While the question of adequate lubrication is undoubtedly of vital importance in reducing friction, the primary causes of wear are dependent upon the properties and surface conditions of the materials at their respective working temperatures. For the majority of components, the selection of material must necessarily be mainly decided by such considerations as yield point, compression strength, fatigue range, specific tenacity, maximum stress, resistance to scaling, thermal expansion, etc., and the question of wear is reckoned rather as a problem for which the metallurgist will find a treatment which can be suitably applied to the material. Thus we have seen evolved the many processes for surface‐hardening, and numerous anti‐friction materials, etc. It is interesting to review the present position of the practical applications of the science of reducing metallic friction, and to note tendencies of future developments.
Surface Defects in Engine Parts
Authors: Kornfeld Konrad
Published: February 2008

AN exceedingly careful control of the surface of aero‐engine parts has beyond doubt become an excellent habit both with manufacturers and those who are to use the engine. A crack on a new part, or one which will cause a fatigue failure in work—these are the defects looked for by inspectors during manufacture, overhaul, or repairs. Cracks are very frequent causes of accidents and this fear often underlies the rejection of parts which are only suspect but which might work quite well until normal wear and tear would cause them to exceed permissible tolerances. In many cases, electro‐magnetic examination or etching reveal defects on the surface of engine parts which cannot be defined: in such cases, for the sake of certainty the part is rejected on the ground that it is cracked or made from faulty material.
The Practical Application of Explosive Rivets
Authors: Butter Otto
Published: February 2008

THE most common joining medium in aircraft construction, ship construction, coachwork, steelwork and the construction of reservoirs generally is the rivet. As, by this means, the shear stresses are transmitted in the simplest and safest way rivets are used in very large quantities. If we reflect that, in an aeroplane of medium size, there are some 300,000 rivets, the application of which occupies a considerable space of time, it will be obvious that the cost of building an aircraft is very considerably affected thereby. Their use is expensive, in so far as two men are necessary for the hammering of the rivets and good accessibility must be provided at both sides. Where the closing head side was inaccessible hollow rivets have been used, up to the present, since they could be hammered from the other side, but this method had many disadvantages. The strength of these rivets was small, in view of the hollow shank, and they were unsuitable for water‐tight and countersunk riveting.
The Manufacture of Hollow Valves
Authors: Balleret A.
Published: February 2008

THE increase of the specific power of aero‐engines in the last few years has been obtained in three ways, namely: by increasing the engine speed and, more particularly, by raising the compression ratio and by adopting supercharging.
Methods of Clamping Sheet Metal for Riveting
Authors: Plock C.H.
Published: February 2008

IN aircraft construction and other industries using kindred materials, it is usual before the final riveting to clamp constructional parts made of sheet‐metal; especially when they are to be finished off in series. The parts are then taken out of the jig coupled together, so that they cannot shift out of place. Then as they are riveted the temporary clamps are taken out one by one.
An Aeroplane for Survey Work
Authors: Warner John H.
Published: February 2008

THE needs of modern aerial survey work become ever more exacting and it was felt that a high performance aeroplane, specialty designed to suit the particular requirements of the work, was required. The engineers of the Abrams Air Craft Corporation of Lansing, U.S.A., therefore started work on an aeroplane which would incorporate all the features required by the aerial photographic industry. Experienced mapping pilots and operators from the several American companies collaborated on the design. The machine developed has been very successful, and today a separate company has been formed to manufacture it.
A New Electro‐Sonic Altimeter
Authors: Jupe John H.
Published: February 2008

THE principle is not new of measuring the actual height of an aeroplane when within a short distance above the earth by generating sound signals in the machine, directing them down towards the earth and measuring the time taken for them to be reflected back again. It has been used successfully for some years in the field of marine sounding and various instruments working on this principle have from time to time been produced for aircraft. A new height‐measuring instrument on these lines has recently been introduced by Henry Hughes & Son, Ltd. Light weight and operation from a low‐voltage d.c. supply were two important points borne in mind in determining the general plan of this new altimeter, which obtains all its power from a 24‐volt accumulator through a motor‐driven alternator.
Torsional Damping Capacity
Authors: Barron S.L.
Published: February 2008

THE introduction and recent development of instruments for the accurate measurement of torsional damping capacity have provided for the metallurgist an accurate indication of this property, while structural changes due to processing can be observed and much valuable information gained. It is proposed to describe some of the latest methods of recording that are available, while accessories for the pre‐stressing of specimens and examination of records are also considered. A final reference is made to the method of calculation from record measurements.
Dornier Stressed‐Skin Structures
Authors: Petzold L.
Published: February 2008

THIS article is intended to give an outline of the experiences of the Dornier‐Werke G.m.b.H. in two important spheres of its work.
Welding Technique in Aircraft Construction
Authors: Queitsch Kurt
Published: February 2008

WHEN metal parts are exposed to alterations of temperature, their outer dimensions undergo a change. With rising temperatures metals expand, with falling temperatures they contract. If different temperatures exist within one and the same metal member, internal stresses begin to act, causing a deformation of the component and thus setting up internal strains. Cracks, buckling, distortion and shrinkage are the external results of such strains.