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154 AIRCRAFT ENGINEERING June, 1931 A New Series of Engines—"Zontrol" Furnaces—Airway Beacons—Mineral Oil Test—Flexible Bearings Th e illustration (Fig. 1) shows a complete heat Bristo l Mercury Engines essential before a lubricating oil can be accepted as treatmen t plant with two 6 ft. 9 in. by 3 ft. Th e Bristol Aircraft Company announce the fully satisfactory, the Shell Company arranged with "Zontrol " electric furnaces, two control cubicles puttin g into production of their new series of th e "Bristol " Company for such a test t o be carried (of which only one appears in the figure), a patent "Mercury " engines. Although the new engines ou t on one of the "Bristol" Jupiter X.F.B.M. incandescent charging fork, an d beside the furnaces, ar e of the same nine-cylinder air-cooled radial types moderately supercharged geared-type engines. as the Jupite r "F " the introduction of up-to-date a n I.H.C. oil-quenching bath. The temperature A duration of 300 hours was agreed upon as a features has necessitated entire re-designing, and the rang e is from 1.50 to 1,000 deg. C. reasonable period for demonstrating the properties new Mercury will therefore be produced side by side of this oil, and in order to obtain the maximum with the Jupiter, the two being non-interchange Beacons and Floodlights information on the progressive changes in the able . interna l condition of the engine throughout the Th e London Electric Firm of South Croydon, Amon g the improvements introduced are : the test , it was stripped for inspection at the end of Surrey , have recently produced a small floodlight provisio vis n of gas starting, together with inertia 50, 150 and 300-hour periods. of the precision order for wide-angle lighting. starte r of the hand or electrically-energised types, I t is fitted with a novel optical arrangement Th e test included 30 hours on the dynamometer or hand-turning gear; engine-driven petrol pump comprising two silvered glass mirrors and a lens so a t full-rated r.p.m. and 90 per cent full power, and unit, with built-in relief valve ; automatic ignition- positioned that practically the whole of the light th e remainder on the hangar with the engine control to magnetos, and automatic boost control. from the filament of the 500-watt gas-filled lamp opened up for 5 minutes at the end of each 5-hour Subsidiary drives are also provided for oil centri- period to approximately 580 b.h.p . an d 2,200 r.p.m. fuger, electric generator unit, and other equipment Durin g the first 150 hours, the hangar test was such as telemeter, etc . As it is impossible to pu t all carried out under actual cruising conditions of these auxiliary components and drives on the b.h.p . and r.p.m., bu t as th e condition of th e engine Jupite r type of back cover, the attachment of the a t the end of the first 150 hours was particularly engine to the aircraft has been entirely altered, and satisfactory the test was increased in severity for th e Mercury engines are provided with a conical th e final 140 hours on the hangar, starting at mountin g secured by 18 bolts, incorporating rubber 365 b.h.p. a t 1,900 r.p.m. an d increasing t o 428 b.h.p . shock-absorber fitments. a t 2,000 r.p.m. for the concluding 57 hours. Othe r important features of the series are : inter- Althoug h the average oil consumption over the changeability of main components; forged reduc whole of the 270 hours on the hangar was under tion-gear casing ; lighter reduction gear, saving some 40 lb . in weight; lighter enclosed rocker gear of 7 pints per hour (or 0·0019 pints per b.h.p./hour), reduced drag; and the introduction of a special from the excellent condition of the engine-bearing "pusher " type engine. The two ratios of reduction surfaces it was obvious that the desired standard gear standardised are 0∙656 an d 0∙ 5 engine speed. The of lubrication had been maintained, there being a compression ratio for the whole series is 5.3. notabl e absence of sludge with a small amount of carbon deposit observed during the intermediate an d final inspection. Spring s As a supercharged and geared engine of this type Th e Lewis Spring Company, Ltd., of Resilient wit h such a high-power output affords very severe Works , Redditch, and 29, King William Street, tes t conditions, the test of this oil can be considered London , send an interesting booklet on the springs particularl y satisfactory. As a result th e " Bristol " manufacture d by them. A very wide range of Company are satisfied to use this oil in future and types and sizes is covered even in this comparatively t o recommend it for use in their engines. small selection from the hundred and one kinds of springs made a t Redditch. Particularly interesting is the wide range of spring presswork undertaken. Flexibl e Roller Bearings Electri c Furnaces Geo. Salter & Co., Ltd., of West Bromwich, who hav e been makers of flexible roller bearings for Th e Incandescent Hea t Company, Ltd., of British man y years, have recently been carrying out Mills, Cornwall Road, Smethwick, Birmingham, researches which have led to the bringing out of an specialise in electric furnaces for all purposes. improved type, one of the most important features used as the illuminant is utilised and definitely "Zontrol " furnaces are produced in various types of which is the elimination of noise. The firm's directed into the angle of th e beam. an d sizes from the standard portable type for bearings incorporate a number of spiral rollers, Thi s projector can also be used as an airway general heat treatment up to 980 deg. Centigrade, coiled from chrome-vanadium steel, arranged beacon . an d a portable forging furnace specially designed alternatel y in right and left-hand coils around a Th e same firm have also brought out the beacon for accurate heat treatment of aluminium and other centra l hole. The spaces between the coils, together illustrate d in Fig. 2, which is fitted with electric low-melting-point alloys, to a high-temperature wit h the central hole, ensure free lubrication and rotatin g gear. It has a completely-enclosed lamp forging furnace for rapid heating up to 1,300 deg. resiliency. The new bearing permits of the maxi an d lamp-holder gear to suit 1,000-watt projector- Centigrade. The latter furnace incorporates the mu m number of rollers being employed and is also patter n gas-filled lamps, two lamps being carried paten t Incandescent "Defuser" system which fitted with balls to hold the rollers in place. The in mechanism so that if one fails the other is eliminates uneven heating and ensures equal combination of balls an d rollers eliminates friction, immediatel y automatically coupled up and brought soaking. ensures silent running and makes the bearing suit int o the focal position. It can be elevated through able for taking end-thrust. (See Fig. 3). a wide angle an d either project in a forward direction only or be fitted with a special lens to direct a portio n of the light upwards. A Mineral-Oil Test Th e tendency to turn to lubricating oils of the minera l type in place of the vegetable type oils previously used for high-powered high-eflicicncy aer o engines, has led to considerable research on th e part of the oil manufacturing companies in an endeavou r to improve the qualities of mineral oils, particularl y in respect of the anti-sludging and "oilincss " factors. A new oil, known as "Aero Shell, " with a mineral base and a small percentage of fatty matter added, recently developed by Shell Mex, Ltd., has shown excellent promise in these respects. As experience has shown that a prolonged main engine test under service-operating conditions is
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Jun 1, 1931
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