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Aviation History
1955
1955 - 0096.PDF
96 FLIGHT, 21 January 1955 THE INDUSTRY Sleeve-valve Ignition Efficiency IN conjunction with the Bristol Aeroplane Co., Ltd., the firm ofK.L.G. Sparking Plugs, Ltd., have designed a new plug for use on Bristol sleeve-valve engines. An "overhead" earth wirereplaces the more orthodox arrangement of "side-fire" earth wires used in plugs having precious-metal electrodes. Thisarrangement, it is stated, has shown in service that it gives longer life and longer periods between scheduled overhauls. One of the principal reasons why side wires have been favouredfor piston engines in the past is that the spark is not screened by the earth wire, so that the ignition of the mixture is normally moreeffective. By experiment, K.L.G. have found that if the body of the plug at the combustion-chamber end is given a bell-mouthform, the utmost use can be made of the excellent swirl charac- teristics in the cylinder of the sleeve-valve engine. This resultsin an induced circulation of the mixture within the plug mouth and makes the overhead gap fully effective by removing anyscreening effect which would otherwise be likely. The use of unequal electrode dimensions has also increased gapstability while providing a partial "side-fire" effect. In this arrangement the diameter of the central electrode is larger thanthat of the earth wire. The new plugs are now undergoing service trials in Centaurus661 engines installed in B.E.A. Elizabethans and in Centaurus 173s in the Blackburn and General Aircraft Beverley. Smiths Aircraft Instruments, Ltd., are the sole sales conces-sionaires for K.L.G. plugs. Preventing Backlash in Gearing THE problem of overcoming backlash in spur gearing is oneA that frequently arises in the design of small mechanical assemblies. In some cases, i.e., servo-mechanisms and indicatingapparatus, the effect of backlash may be a critical factor. A conventional method of overcoming the problem is to employa coiled tension spring to pre-load one of the gear wheels torsion- ally. This method is not an ideal one, and in experiments to im-prove upon it the G.E.C. Research laboratories have evolved a neat device which makes use of a standard circlip. This circlip isaccommodated between two thin spur gears carried on a shouldered bush, one gear being fixed and the other free to revolve, and apin in the face of each wheel registers with a clearance hole in the other wheel. On meshing of both wheels with the mating gearthe free wheel is tensioned by an angular displacement of one tooth. The G.E.C. Laboratories have successfully used the device—which is not subject to patent—over a range of wheels from lin to 3in diameter and have introduced various detail refinements. Fairey Apprentices' Examination Successes "pORTY-THREE members of the apprentice training scheme in•*• the Fairey Aviation Company's group of factories were recently presented with cash prizes in recognition of examination suc-cesses during the past year. The presentation was made, at Hayes, by Mr. G. W. Hall (director, engineering). Two apprentices who obtained Final Certificates in the Cityand Guilds machine-shop engineering course, and 17 who earned Higher National Certificates, each received a cheque for £10.The others were given £5 awards to mark success in the electrical and mechanical engineering sections of the Ordinary NationalCertificate examination, and the City and Guilds intermediate machine-shop engineering and sheet-metal-work courses. In addition to obtaining his Higher National Certificate, D. P.McQuire received the special prize of £5 donated by the Company to Southall Technical College. The citation from MiddlesexCounty Council stated that McQuire was "their most outstanding Interested group at a recent cocktail party held at Londonderry House by Lansing Bagnall, Ltd. (left to right): Air Commodore H. Ford, Director of Armament Research and Development (Air), M.o.S.; R. H. Gluyas of Lansing Bagnall, Ltd.; Mrs. Ford; John R. Sharp, Lansing Bagnall managing director. In the background—Stubbs' life-size painting ('circa 1800) of the race-horse Hambletonian. student." An ex-apprentice, P. J. Bashford, was admitted during 1954 on a County Scholarship to the College of Aeronautics. At present 270 apprentices are under training in the Hayesgroup of factories and 141 in the Stockport group. Most of the Hayes apprentices complete theoretical studies at Southall Tech-nical College. Northern factories attend Stockport Technical College. The Hayes apprentices have their own library, for theupkeep of which the directors make an annual grant. "Know-how" in Packaging THE directors of the 20th Century Joinery and Packing Co.,Ltd., of Thames Ditton, Surrey, a firm which specializes in packaging for the aircraft industry, have announced plans involvingcapital investment of £100,000 in new plant and other projects. Among the latter is development of the company's training centre,plans for which were mentioned in Flight last year. The firm feels that the growing importance of correct packagingof aircraft and guided missile components, for transport and stor- age in all climates, has made it essential to provide proper technicaltraining for those who do the work. For this reason, all opera- tives will receive a thorough basic training at the new centre,followed by refresher courses to keep them informed of new developments. Training methods will include workshop practice, film demon-strations, lectures and visits to aircraft factories. The centre will also include facilities for testing completed packages to the require-ments of the Ministry of Supply. IN BRIEF Aerofilms, Ltd., have moved to new London offices at 4 Albe-marle Street, W.I. The telephone number, Hyde Park 5211, remains unchanged. * * * Jenolite, Ltd., anti-corrosion and metal pre-treatment specialists, announce the appointment of Mr. L. F. Parsons as a new technical sales representative, based in the London area. * * * Among articles in the current issue (No. 30) of Wiggin NickelAlloys is one on "Cutting fluids for machining Nimonic Alloys." The periodical is published by Henry Wiggin and Co. Ltd., ofWiggin Street, Birmingham, 16. * * * Rolls-Royce, Ltd., have recently produced a new edition oftheir excellent conversion tables (principally British, metric and American), in 100-page, hand-somely bound pocket-book form. A limited number are availablefor executives in the industry in response to official applications. Mr. J. A. Grace has joined Folland Aircraft, Ltd., as commercial man- ager. He was previously with de Havilland Aircraft, whom he joined in 1935, becoming their contracts manager five years later. The Vacuum Oil Co., Ltd., tollThe Story of Coryton in a non- technical documentary film de-scribing the construction and opening of their big new refinery on the Essex bank of the Thames. Copies of the film (16 mmsound, monochrome, 30 minutes) will shortly be available on request from the Film Library, Sound Services, Ltd., 269 KingstonRoad, Merton Park, London, S.W.19. * * * Painton and Co., Ltd., of Kingsthorpe, Northampton, publish aleaflet giving technical data on their new multi-contact "winkler" switch. A great variety is obtainable, in one-, two-, three-, andfour-pole types, each of which is available mounted in one to six banks, and may be of either "make before break" or "break beforemake" types. The number of contacts ranges from three to 29.
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