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July, 1941 A I R C R A F T E N G I N E E R I N G 179 not have to be scrapped and an entirely new one designed and built when the change-over takes place. It must therefore be Aircraft Engineering designed round a strong framework constituting an adaptable skeleton within which fresh details for forming the parts, and locating Devote d to th e Science an d Practice of Aero the fittings, of a new type can with comparative ease be built up when the discarded inside frame for the production of the old type nautic s and to Allied and Subsidiary is removed. Branche s of th e Engineering Industry It will enormously facilitate production if a jig is mounted on wheels so as to be movable—at any rate where it is used for any Editor: Lieut.-Col. W. Lockwood Marsh, F.R.Ae.S., M.S.A.E., F.I.Ae.S. thing but the larger components of the largest types of aeroplane. This obviously conflicts with the first requirements of solidity and rigidity and considerable ingenuity is called for in the design of Vol. XIII, No. 149 July 1941 a jig which will meet both these needs. Henschel Jigs Over and over again the author calls attention to the interest N this issue is concluded a series of articles on jigging for aero and importance of the ingenious type of jig evolved at the plane production which has been running in AIRCRAFT ENGIN HENSCHEL FLUGZEUGWERKE A.G. Attention was first called to EERING since October last year, with the exception of the first this development in an article, " The Economics of Aeroplane two months of this year when, for reasons outside our control, pub Production," we published in July, 1939 ; which was followed by lication of it had to be temporarily suspended. another, " Henschel Theories on Production," which appeared in The fact that we have seen fit to devote in each of eight issues October the same year. A number of illustrations showing examples an average of some 20 per cent of our, now limited, editorial space, of the use of these jigs are given in the series of articles now con including the provision of no less than 204 illustrations, gives some cluded, with explanations of their convenience and adaptability indication both of the importance we have attached to the subject for the various purposes, in the text. The most striking example is, and the breadth of the survey. The types of aeroplane covered perhaps, the change-over of the same type of jig from production range from a single prototype Canadian experimental light fighter of the Ju 86K to that of the Do 17 and 215 ; but it is necessary to to the large-scale production of machines for the German Luftwaffe, read the articles to get a true idea of the importance of the lessons including a number of American, French and, of course, British to be learnt from a close study of these Henschel jigs. types. Designs Suited to Jigging A Unique Series As is now so well known as to have become a truism—though there We have no fear of contradiction when we say that no information was a time well within living memory when it was not—the designer on the design, construction and use of jigs in the production of must from the inception of a new type have the needs of production any engineering products, let alone aircraft, of equal, or even constantly in view; and prominent among these is the " jiggability " comparable, completeness has even been published before. The of all parts. It is for this reason that the articles call attention series constitutes a mine of information and has involved an enor repeatedly to the merits of two new ideas in construction—the mous amount of painstaking research, investigation and examination Vickers-Wellington " geodetic " system (not the least interesting of sources which reflect the greatest credit on the writer of the arti feature of which is the surprising way in which it has shown itself cles. His present employment necessitates his hiding behind the suitable for rapid production in jigs) and the Arado "barrel" thinly veiled anonymity of initials but all with whom he came in fuselage introducing the element of longitudinal panels constituting contact while on our staff will join with us in congratulating him on a " shell " which arc quick to produce and easily sprung into place an extraordinarily fine and valuable piece of work. He will forgive in a jig. us for saying that not the least important part of his contribution We can only conclude by urging all concerned with aeroplane has been the unearthing and bringing together of a selection of production in England and the United States to read and re-read photographs, ably reinforced by his own sketches, the like of which this series; from every fresh perusal of which we are sure new in catholicity has never been seen before; and will, in all human lessons will be learnt. probability, never be collected again. The devotion with which he has spent a large proportion of his leisure to unceasing search for material, followed by hours occupied in analysis and collation, RUSSIA GOMES IN apart from the labour of compilation in writing the articles, is a The entry of the Union of Soviet Socialist Republics into the war, lasting monument to his assiduity. as the result of the German invasion along a wide front in the early We venture to say that no progress or production engineer can hours of June 22, naturally arouses interest in the efficiency of the afford to neglect these articles, for they present a picture of the Red Air Fleet. At the time of writing, it is too early to express various types of jig—good and bad—in use in all the principle any definite opinion as to how it compares with the Luftwaffe, aeroplane-producing countries from which no one reading with but what little is known of the types of aeroplane available hardly intelligence and desire to learn could fail to derive benefit and points to these being in the same class as the Messerschmidt, inspiration. Heinkel or Dornier fighters and bombers. The Russians have, however, always been remarkably successful in keeping informa Ji g Fundamentals tion secret and it may be that during the last two years or so development has been taking place. Mention has already been The design of jigs is a fundamental basis of all production which made of one new fighter—the 1.18. is very far from being the simple matter it used to be thought. The first desideration is solidity and rigidity ; but even these features I t may be interesting for readers to recall the article "Types of must be used with intelligence, because the jig must not be of such the Red Air Fleet" published in AIRCRAFT ENGINEERING for a nature as to force a light part into the correct shape by mere brute November, 1939; a fully illustrated survey which contained the strength or it will merely distort it into something from which it may best information obtainable at that time—to which, be it said, little spring back on release from constraint. On the other hand, if the could be added to-day. No reports of the results of Russian jig be too light, particularly in relation to a fairly heavy part, it research work have, so far as we can ascertain, been allowed out will itself be distorted in a varying degree. In neither case will the of the country since 1936, so that it is impossible to know what interchangeability of parts, which is to a large extent the ultimate knowledge on aerodynamics or general design problems has been aim of all jigging, be achieved. accumulated in the past five years. We know from our own experience that the Russians are voracious readers and keen students In order to save unnecessary expense and, in these days even of foreign technical literature from which they cannot but have more important, delay in changing over production to a new type assimilated knowledge which will have been useful to them. of aeroplane, a jig must be "adaptable". That is to say, it should
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Jul 1, 1941
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