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Aviation History
1954
1954 - 1280.PDF
7 May 1954 567 BUILDING the HUNTER "Unit Assembly" in Three Countries Described by Hawker Executive Mr. E. H. Jefferson. SOME revealing sidelights were thrown on Hunter pro duction in a recent lecture to the Aeronautical Division of the Society of Automotive Engineers in New York. It was given, shortly after his arrival on a visit to America, by Mr. E. H. Jefferson, who is general manager of Hawker Air craft (Blackpool), Ltd., and a director of the parent company. The British Government, said Mr. Jefferson, ordered the Hunter for the R.A.F. "off the board." The "instruction to proceed" was placed in October 1950 and the contract followed six months later. The first production aeroplane flew in May 1953. Thus, from the date that Hawker Aircraft first knew they were going to receive an order to the time when the first produc tion Hunter was flying, only two years and seven months elapsed. The Hunter was a new aircraft; therefore the company had to start from zero and build up a completely new production set-up —this when production of other types had been allowed to run down, with loss of much skilled labour which sometimes seemed almost impossible to replace. Early Production Methods and Difficulties.—An even more serious aspect was the finding of firms to make large jigs and tools in the numbers required. The Hunter required some 3,250 tool designs, and about 40,000 jigs, tools and fixtures had to be pro vided for. To break the bottieneck the British Government intro duced the "super-priority" scheme. This only partially produced the required results, since priority had to be allocated to so many items that suppliers and sub-contractors were often unable to give any measure of preference. In addition, every effort was being made to maintain exports. Eventually, tool-making difficulties were overcome by a com bination of two methods. The first took care of initial detail and sub-assembly work and involved a compromise—the development and use of "rough tools," prepared not by the virtually unobtain able toolmakers but by skilled fitters. Although capable of manu facturing several hundred parts these tools were intended as a temporary measure. Such methods obviously could not be employed for major assembly jigs; here it was a matter of search ing far and wide until someone with the capacity to accept orders could be found. Eventually a large number of jigs were obtained from such Italian firms as Macchi, Breda and Fiat. Assembly.—To facilitate manufacture, the Hunter was broken down into main assembly units, e.g. front fuselage, centre fuselage, rear fuselage, wings. This was common practice, but with the Hunter it was carried a stage farther. Each major component was not only built as a separate structural unit but was complete in itself, containing all ancillary equipment, services, pipes and runs, as in the finished aircraft. Thus for final assembly it was neces sary only to connect the structural members and plug the pipes and leads together. One reason for this method was the difficulty inherent in build ing an aeroplane in a number of factories some distance apart. During the early days the resources of the entire Hawker Siddeley Group were pooled for difficult items. Hawker Aircraft itself was far from being housed all under one roof. Production plans, therefore, called for the detail parts and main assemblies to be made in several places, with Kingston-upon-Thames as head quarters. There were two other factories in the South of England and assemblies were fed to the final-assembly plant and airfield about 50 miles from Kingston. Certain specialized components were sent 250 miles from Hawker Aircraft (Blackpool), Ltd. Off-Shore Procurement.—Work on the Hunter for the R.A.F. was proceeding at a satisfactory rate when the U.S.A. off-shore procurement order was placed with the British Government early last summer. So far as Hawker Siddeley were concerned, the new contract called for some 450 Hunters to be delivered by June 1956. It was impossible for new factories to be erected in order to build off-shore Hunters alone; that was not, in fact, necessary. The order was being met from the existing organization by con tinuing production at the peak rate which had been planned to meet as quickly as possible R.A.F. requirements. Thus the off shore order assured a longer run of peak production and promised a level of capacity not otherwise possible. As the aircraft were completed, the M.o.S. and NATO representatives would decide between themselves which would go to the R.A.F. and which to other NATO countries. Holland and Belgium.—The many problems were intensified by the fact that off-shore orders were also placed with Holland and Belgium; thus eventually Hunters would also be built by three companies in Holland—Fokker (who are to undertake the majority of manufacture in that country), Aviolanda and de Schelde—and by two in Belgium—S.A.B.C.A. and Avions Fairey. There were the normal array of sub-contractors to each one com pany. The Netherlands and Belgium would between them manu facture some 100 off-shore Hunters by the summer of 1956, and thereafter would produce further Hunters for their Governments. Since the war Holland had made Meteors from raw materials; in Belgium, however, the manufacturing side barely existed, except for Avions Fairey. But the country had an industrial tradition and her machine-tool industry was capable of undertaking any work entrusted to it. A large number of jigs and tools had been ordered through Hawker Aircraft in the United Kingdom for both countries, but Belgium had ordered these items in her own territory as well; S.A.B.C.A. had erected a new factory and were in process of receiving special plant from the U.S.A. Broadly speaking, each of the companies engaged had certain responsibilities, each making various detail parts and sub assemblies. Some factories would then incorporate these into main assemblies and finally the main units would be brought together—by S.A.B.C.A. in Belgium and by Fokker in Holland. In Belgium, Avions Fairey would make only detail parts and sub assemblies and would be provided with some finished parts, and with main assemblies, by Hawker Aircraft—and, later, by Holland. Thus the pattern previously worked out of necessity in Great Britain would virtually be reproduced on the Continent. And such was the degree of standardization that components made any where in the three countries would be interchangeable. Hawker teams were constandy going to both countries to advise and assist, and technicians and operatives were continually coming to England to be trained. Much information and material had been supplied, including complete sets of master aircraft drawings and schedules, pre- production manufacturing information, jig and tool drawings, details of manufacturing processes, and master part schedules. Hawker Aircraft were sending teams to Holland to install the major jigs. To get work started they were supplying 50 initial sets of raw materials and complete sets of master templates, tooling aids and interchangeability media. Holland and Belgium were being provided with sample components—including two complete aircraft, one for each country, and a whole set of specimen detail parts—so that engineers would see the standards to which they would be required to work. Sets of all pipe runs were being sent, as the forms of such parts were difficult to visualize accurately from drawings. The comolete aircraft would help both countries to get accustomed to all that was involved in the construction of a complicated fighter, and to develop the flying, servicing and ground-handling techniques it would necessitate. In addition, Hawker Aircraft were providing components, skeleton components and sub-assemblies. Machine Tools.—Many special machine tools for the Hunter, both on the Continent and in Britain, had been obtained from the U.S.A. Certain machined components for the wing and fuselage attachments were made from forgings of high-tensile steel. In their manufacture a large amount of profile and contour milling was involved, and for this work American duplex milling machines and Hvdro-Tels had been found invaluable. The company also used Hufford and Sheridan stretch-forming machines, Onsrud spar-millers, Farnham rolls, Verson brake-presses and, for pipe manipulation, Pines benders. The great deal of formed sheet- metal work called for at Hawker Aircraft was done on Ceco- stamps, employing light-alloy dies, which could be altered easily and economically in the event of modifications. Provision for Dispersal.—In an emergency, the long lines of production jigs in the Hawker factories could quickly be dispersed to safe areas. All main jigs were erected on rafts made of a struc ture of rising steel joists, welded together and provided with jack ing points for levelling up. This was useful even in peace, for the jigs could be moved to any part of the country where labour was available. The method would also prove invaluable in setting up production on the Continent. In conclusion the lecturer said he would like to emphasize the keenness that was being displayed by everyone concerned with the work on the Hunter in all the three countries. There was a very real feeling that nothing should stand in our way to hold things up for one moment. Barriers had been broken down and understanding and unity was being achieved. This in itself was a very worth-while supplementary benefit arising from off-shore procurement orders.
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