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Aviation History
1954
1954 - 2263.PDF
218 FLIGHT, 13 August ;954 THE INDUSTRY Annular-piston Disc Brakes y-A NEW type of Goodyear aircraft brake—introduction at the new aviation products factory of die j3oodyear Tyre and Rubber Co., at Wallasey—is now going inM'service on the fleet of six Vickers-Armstrongs Viscounts for/Trans-Australia Airlines, the first of which was recently cqjrfpleted. Though of single-disc construction, the new brake differs from the orthodox type in that the ijsdal group of individual operating pistons is replaced by a single annular piston. This is the first introduction of the annular-piston design to aircraft braking. Con- Part-sectioned view of the new Goodyear single-disc brake, showing construc tional details. A—Linings. B—Single disc. C—Annular piston. D—Automatic adjust ment. tained entirely within the wheel, die new brake is claimed to effect a weight saving and to give ease of maintenance and enhanced reliability by reason of its constructional simplicity. T.A.A. already have considerable operating experience with other types of Goodyear single-disc brake. Other equipment by the same makers on the new Viscounts consists of the wheels and tyres, and the master cylinder and relay valves for the braking system. Precision Revolution Counter A NEW precision revolution counter—and one which should be **• of considerable interest to gas-turbine engineers—is announced by the Plessey Co., Ltd., Ilford, Essex. - It is, in essence, a precision tachometer which counts the number of elec trical pulses generated in a period of one second and, utilizing a frequency-multiplier unit, gives a visual reading in r.p.m. Normally the pulses are counted for oa^ second, the answer is displayed for 0.8 sec, and the apparatus is then returned to zero for the cycle to be repeated. Alternatively, the instrument may be operated manually by mean«^of a push-button; when this is pressed, the previous coyrft is cleared to zero, then the incoming pulses are counted for one second. This count is then displayed until the btifton is again operated, whereupon the sequence is repeated."' Accuracy is stated to be 0.1 per cent, rising to 0.03 per cent for high rates of jaunting, e.g., at 3,000 pulses/sec. Longer counting periods oi^. sec or 4 sec can also be selected, providing an accuracy better than 0.01 per cent. MR. W. S. HAGGETT, who, as executive assistant to the president, will be in charge of the Winnipeg plant of MacDonald Brothers Air craft, Ltd. The new president is Mr. R. J. Reynolds, executive vice- presidentofthe Bristol Aeroplane Co., Ltd., in Montreal. As we reported last week, the MacDonald business has been acquired by the parent Bristol company. Mr. Haggett became sales manager of the Canadian Bristol company in 1951. Preventing Cockpit Condensation CONDENSATION on the interior walls of aircraft flight-decks has long been a problem, of greater or less severity in rela tion to operating conditions (outside air temperature, rate of let down, etc.) and the relative efficiency of different cabin air con ditioning installations. In some circumstances the phenomenon is particularly marked, e.g., when condensed moisture, frozen at operating altitude, melts quickly as the aircraft descends into warmer layers. It is seldom practicable to apply the remedies established in other fields—for example, the familiar rough-surfaced finish used on ships' deck-heads—even assuming their efficiency to be such as to meet the very severe conditions obtaining in aircraft. A new finish prepared for domestic and industrial use, and found equally efficacious in aircraft, is Seculate anti-condesa- tion compound, a product of British Lead Mills, Ltd., Byron House, St. James's Street, London, S.W.I. Smooth-surfaced, it is not an absorbent material; instead, it depends for its effective ness on establishing a thermal-insulatietn coating on the surface to which it is applied. Its properties-are not exhausted by pro longed exposure to moisture-laden atmospheres. British Lead Mills state that peculate has been ordered by an operator of Stratocruisers on transatlantic services, and that it is also being employed on production aircraft by the makers of a well known fighter. Pilots' reports during a series of tests of the finish have spoken of a complete lack of condensation in a pressurized civil aircraft flying for an extended period in an outside air temperature above —15 deg C and "very slight" condensation in temperatures down to — 24 deg C. Untreated areas in the same aircraft produced a steady dripping. Another of the reports mentioned that at 25,000ft, with an O.A.T. of -34 deg C, "no water fell from above the pilots' heads ... it is considered that the treatment gives a great improvement." For aviation purposes, Seculate is applied over a metal primer to a thickness which varies, according to likely operational requirements, between ^in and -^in. Weight of a A in film is about 2 oz/sq ft. The compound is applied by brush ing on two or three liberal coats. It is off-white in colour, but a top coat of Seculate decorative finish, available in 16 pastel shades, can be applied. A black finish is available for use in night fighters. The surface is easily washable, and is not harmed by detergents. Seculatt is stated to be quick-drying, to be fire-retardent in accordance with B.S.S. 476-1932 and to have exceptionally high resistance to vibration; extended vibration tests of the compound were carried out on an aero-engine test-bed. IN BRIEF Mr. Ray Langmead, until recently senior liaison representative of the de Havilland Enterpjase'in France, has been appointed tech nical services manager^ Smiths Aircraft Instruments, Ltd., and their aviation associates. * * * A number of sailplanes in the International Gliding Champion ships—including the Jugoslav Kpt^va. placed first in the two-seater class—used Venner lightweight silver-zinc batteries for such pur poses as gyro-mstrumen^^clrives. These batteries were of the 12-volt 25 a.h. type, weighing 7 lb. APPOINTED EXECUTIVE DIRECTORS of the Plessey Co., Ltd., are Mr. John Hilton, O.B.E., M.I.Mech.E., and (right) Mr. C. D. H. Webb, A.I.E.E., A.I.Mech.E. Mr. Hilton was appointed general manager of Plessey's aircraft mechanical division in 1951 and Mr. Webb similarly promoted in the electrical division in 1947.
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