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Aviation History
1949
1949 - 0035.PDF
JANUARY 6TH, I949 FLIGHT FROM ALL QUARTERS SOUTH AFRICAN VAMPIRES THE latest sale of de Havilland Vampires is to South Africa.A contract for ten Mark 5 fighter bombers equipped to R.A.F. standards, and powered with Goblin 2 furbojets, has been signed, it is learned as we go to press. SUPERSONIC SUCCESS AFTER a series of disappointments and failures a Vickerstransonic rocket-propelled research model, launched from 1" Mosquito over the Atlantic, has achieved controlled super- sonic flight. A Mach Number of 1.36 has been mentioned unofficially. The American Bell X-i piloted research aircraft may already have attained Mach 1.4. AVIATION FUEL PROBLEMS IN AMERICA THE latest expression of concern regarding supplies of aircraft-L fuels comes from America where the industry's supply of 100 octane petrol in particular may fall short of military re-quirements. The supply difficulties result in the main from Air Force expansion plans, and it may be necessary to drawErom civilian supplies. An aggravating factor is the Berlin lir lift, which uses some 143,000 barrels a month. It is reported that the Armed Forces Petroleum PurchasingAgency has asked the industry for 14,000,000 barrels of avia- tion petrol and 1,658,000 of aviation kerosene. A barrel con-tains 42 gallons. The oil industry can offer all the gas turbine fuel and 33,000 barrels of 115 octane petrol, but of the9,600,000 barrels of 100 octane only some 8,300,000 are offered. The U.S. Air Force expects that 23 of its 70 Groups to beavailable by July 1st, 1950, will be equipped with jet aircraft, and although the high grade kerosene known as JP-i, whichthey will burn, is easier to produce than high octane petrol, there are fewer refineries to do so. Storage of JP-i fuel,particularly in the Navy's carriers, is a problem. BLACKBURN A.G.M.—A TURBINE PROTOTYPEI X his speech to the annual general meeting of BlackburnAircraft, Ltd., on December 20th, Mr. R. Blackburn, O.B.E., A.M.I.C.E., M.I.Mech.E., F.R.Ae.S., the chairman,confirmed that the net profit for the year, reported in Flight, December 2nd, was ^125,395. After referring to the order forPrentices and the modification of a large number of Firebrands Mr. Blackburn said that it was hoped that the prototype ofa new naval aircraft, powered by gas turbines, would be ready for flight testing early in 1949. Mr. Blackburn then referred to changes of members of theboard of directors which resulted from the amalgamation of Blackburns and General Aircraft, Ltd., reported in Flight,December 2nd and December 9th; Major Bumpus remains managing director of Blackburn Aircraft (Dumbarton), Ltd.,who have been engaged on the production of aluminium houses; Mr- F. F. Crocombe, previously technical director ofGeneral Aircraft, Ltd., becomes cne of the principal designers and technicians of the new company; the resignation was an-nounced of Mr. W. S. Farren and Mr. A. F. Jopling from the Blackburn board, the latter being succeeded as secretary byMr. E. Turner, Blackburn's chief accountant in 1946. On December 31st, the date before the merger of Blackburn'sand General Aircraft was due to become effective, it was an- nounced that the design staff of General Aircraft, Ltd., intendedto go on strike in support of a claim for the reinstatement of 26 of their colleagues who were dismissed for extending theirChristmas holiday by one day without permission. A ballot was held to ascertain whether the majority of the members ofthe Association of Engineering and Shipbuilding Draughtsmen were in favour of the strike; 92 per cent voted against it. GAS TURBINE SELF-STARTER SYSTEM '"PHE U.S. Navy has recently announced that a successfulJ- self-starter for jet aircraft has been developed. Described as "relatively simple," the new system has emerged as thejoint effort of the Navy Bureau of Aeronautics and the Airesearch Manufacturing Co., Los Angeles. At the moment, few details on the system have been re-leased, but the rather sketchy data so far available give rise to some comment. The self-starter is said to comprise a smallgas turbine engine and a high-speed turbine starter, the original power being obtained from a light 24 v. battery and a f h.p.motor. It is further stated that "the gas turbine builds up a highly compressed air supply bled from the turbine to thejet starter device." There is certainly .little to go on in arranging these barefacts into a constructive picture of the system; however, we interpret the information to mean that the J h.p. motor is likely to be an electric motor which, supplied from the battery,is used to spin up a small auxiliary gas turbine which acts as a gas producer unit for a further auxiliary turbine, thepurpose of the latter being to provide torque for spinning up the main turbojet engine. That is to say, we envisage it asbeing a cumulative power-conversion chain system which, from small beginnings, builds up the requisite power supply for start-ing, whilst converting the form of power to that most readily applicable to the end to be served. The Airesearch Manufacturing Co. are, of course, well-knownas being at the top of the American tree in their particular field of specialized pneumatic and turbine equipment, andamong the more notable of their recent achievements has been the air cycle turbine cooler unit for ultra-high-speed aircraftcabin cooling (Flight, November 4th, 1948). In point of fact, the new starting system is said to involve a number of separateutility features vital in aircraft design, in that the turbine unit which powers the starter can be used for cabin condition-ing, wing de-icing and other power-consuming services. The provision of self-starting in a turbojet aircraft is aconsiderable problem, the high inertia in the rotating system of a gas turbine engine making necessary a fairly high andsustained starting torque. Then, having overcome the initial inertia, the unit has to be accelerated up to, in some cases, asmuch as 250 per cent idling speed in order to attain sufficient flow through the compressor to support combustion. In thisregard, the starting speed requirements of engines with axial- flow compressors are somewhat higher than those utilizingcentrifugal flow. The Americans have, of course, shown a pre- disposition towards axial-flow types. WESTLAND ANNUAL GENERAL MEETING THE annual general meeting of Westland Aircraft, Ltd.,took place on December 7th. The chairman, the Rt. Hon. Lord Aberconway, C.B.E., in his speech, stated that theyear under review had been largely occupied in the develop- ment of production with a consequent substantial increaseof work actually in process of manufacture. He referred to certain settlements which had been reached on contracts ofprevious years resulting, after agreement over amounts due for income and excess profits tax, in a credit of £84,051 beingcarried to the profit and loss account. The year's profit, after providing for depreciation, taxation and a loss shown byWestland Engineers, Ltd., amounted to ^93,279 compared with ^32,763 profit in the previous year. A dividend of 7!per cent per annum free of income tax was recommended. Lord Aberconway stated that high priority was being givento research and development, and helicopters being built under licence from the United Aircraft Corporation were flying;deliveries of these aircraft to the Ministry of Supply and civil customers would begin shortly. The chairman concluded byreferring to the activities of Normalair, Ltd., and Westland Engineers, Ltd., and said that the terms of purchase of landfor the extension of Yeovil airfield had been arranged. GASKETRY IN automobile circles the squeezing of a little more powerfrom an engine still seems to invite and regularly to intro- duce gasket troubles. The same is not true of aircraft powerunits, but there is nevertheless room for improvement. Such things as firing after switching off a hot engine can often betraced to the cylinder head gaskets. A new company, Plexeal, Ltd., is now being formed atHaddenham, Bucks, to produce a gasket material of the same name. Patents in France and this country are involved, andthe material itself comprises very thin aluminium laminations separated by skins of plastic resin. Experiment and trialin a number of engines has shown that the resin flows to the points of least pressure between laminations and there sets,the whole forming a virtually perfect seal capable of with- standing extremely high pressures. In addition a plasticbeading which forms on the edge of the gasket is presented to the combustion chamber, and pre-ignition and over-runningtroubles due to hot metal edges are thus mitigated. It is early to record results, but claims regarding reducedtendency to "pink" seem likely to be substantiated, and there are certainly other good talking points, notably: cheap-ness of manufacture—one press operation only being required —very good heat transference from head to block, lightness,and the ability to cut a single-permanent gasket or washer under emergency conditions much as if the material were corkor cardboard. The intention is to provide both finished units and stripmaterial to allow manufacturers to press their own gaskets.
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