FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1953
1953 - 1177.PDF
FLIGHT, 4 September 1953 333 PROPRIETARY EQUIPMENT New Major Aircraft Components Reviewed Rotol controller for Viscount airscrew. MANY firms in the British air craft industry manufacture major items of aircraft equip ment which, by virtue of their complex nature, warrant more detailed introduc tion than can be accorded them in the extensive directory which follows this section. Accordingly, these pages are devoted to brief descriptions of selected new or recent products of such firms, and serve well to indicate the great strength of the component-manufac turing industry without which no British aircraft could take the air. In addition to these representative products there remain numerous items that manufacturers are unwilling to discuss in detail at this stage but which will be displayed at the forthcoming Show. These new products will be fully described and illustrated in our Farnborough-report issues. Airscrews The Airscrew Company and Jtcwood, Ltd., Weybridge, Surrey (Stand 45), are this year celebrating their 30th anniversary. This thirty years' service will be the theme of their stand at Farnborough, and the principal exhibit will be a moving unit displaying a range of fan units and photo graphs of the aircraft in which they are fitted. This company is concentrating on non- metal, fixed-pitch fans and airscrews, and their products include test fans and wind- tunnel fans. Among aircraft airscrews, that produced for the M.L. pilotless target is typical; driven by a two-stroke piston engine of 65 h.p., this unit is made from laminated wood, with a plastic leading- edge sheath. The diameter is 4ft 6in. De Havilland Propellers, Ltd., Hatfield, Herts (Stand H). These manufacturers employ both the forged light-alloy and hollow steel methods of construction, examples of which continue to be designed for all types of piston and turbine power plant. Examples in the former field are the four-blade unit developed for turboprops of some 1,500-2,000 h.p. and a 10ft diameter airscrew to be shown at Farnborough is suitable for the R.R. Dart. The company continue to develop forged hollow-steel units in large sizes for the most powerful types of aircraft; the four-blade airscrew for the Britannia has now been followed by a similar unit for the Beverley which is six inches less in diameter (at 15ft 6in) but employs the same mechanical prin ciples of reversing, quick feathering and hydraulic pitch-locking. Rotol, Ltd., Cheltenham Road, Glouces ter (Stand 57). Viscount airscrews, of the composite-blade type, in which an elec tric de-icing element is housed inside the rebated leading edge of each blade beneath a sheath of beryllium-copper, are represen tative of latest Rotol practice. Comple- mentaiy to this neat four-blade unit are the associated feathering pump and con troller unit; both will be shown fully sec tioned, as is the drawing of the latter unit on this page. Completely new equipment will include the accessory drives of the Fairey Gannet and de Havilland Comet 2. For the four Avons of the latter aircraft, Rotol have developed a variation of their well-known synchronization equipment, which keeps the main rotating parts of all four engines turning at precisely the same speed. Another new product is a lightweight feathering - pump motor — designed and made by Rotol—which will be exhibited "exploded." A particular feature of this unit is the manner in which silicone com pounds have been used to obtain optimum efficiency at high ratings and temperatures. Cabin Air-conditioning De Havilland Propellers, Ltd., Hatfield, Herts (Stand H), are licence-producing the Hamilton Standard cold-air unit for incor poration in all types of high-altitude cabin systems. Fed with compressor-bleed air at high temperature and pressure, this neat unit cools the flow by expansion across a turbine, the turbine being braked by a fan which draws a separate flow of cooling air through heat exchangers in the cabin- air circuit. The cold-air unit is robust and simple, and has a particularly noteworthy lubrication arrangement; a grease cartridge is used which heats up during running and exudes oil which flows to the bearings; when the unit cools after use tiie oil flow ceases. Sir George Godfrey and Partners, Ltd., Hampton Road West, Hanworth, Middx. (Stand 93), have, since the last S.B.A.C. show, developed a number of additional air-conditioning units. The most im portant are probably the air-turbo drive sets and the TF series of cold-air units. The latter are similar to the well-known BT (brake turbine) units, except that a turbo-fan (TF) is used to load the turbine, instead of a compressor. By utilizing a fan with about twice the capacity of the turbine sufficient cooling air can be drawn through a pre-cooler to ensure proper cabin cooling while the aircraft is on the ground. Two TF sets will be exhibited: the TF-5 and TF-10. The other Godfrey development, the air-turbo drive, is discussed here for con venience, although it is not principally concerned with cabin air-conditioning. The air-turbo drive, one of which is illustrated on page 336, will provide a simple metJiod of driving aircraft auxiliaries which has much to commend it. A primary application for these units is the provision of a constant-speed drive for alternators, the lack of which has until now rather restricted the adoption of A.C. systems. To meet this demand, a Godfrey TG-3 air turbine has been matched to a Rotax six- pole, 15-kVA alternator delivering a three- phase supply controlled to 400 cyc/sec ± 2\ per cent. A later development is a set capable of providing the heavier loads that some aircraft require; unlike the former unit, it will not require a gearbox drive, and will be simpler and lighter. The same supply frequency will be used, but control to within ± 1 per cent will be possible. Normalair, Ltd., Yeovil, Somerset (Stand 47), have designed a number of entirely new items of equipment. Of these, probably the most significant are the Type D pressure controller and the associated Type 30/SC discharge valve, both of which have been developed for the Corpet 3. The pressure controller, illustrated on this page, is purely pneumatic in operation, and thus is very much smaller and lighter than its electric or mechanical predecessors. Another obvious advantage is the reduced likelihood of failure in service. A desirable new feature is the manner in which the cabin-pressure "flight plan" can be pre set before take-off. Unlike previous discharge valves, the 30/SC bellows houses a form of pressure- relay valve which ensures a precise res ponse to the master controller. If a par ticular aircraft system calls for duplicated controller/discharge valves, a second dis charge unit can be fitted in cascade with the 30/SC. This second unit, fitted with a simple integral control unit, can auto matically take over in the event of failure of the master controller or its associated unit. Engine and Fuel Accessories The British Thomson-Houston Co., Ltd., Rugby (Stand 101), make most of the cartridge starters currently in R.A.F. service (with the Canberras). All these units are capable of driving the engine well up beyond its sustaining speed, so en suring a good acceleration to idling speed. The starter is, in each case, a small im pulse turbine driven by the exhaust from a combustion chamber in which is burnt such a fuel as cordite or guanidine nitrate —or other solid or liquid propellants. Depending on the power required and the torque-limit on the drive shaft, the burning time varies between 2 and 15 seconds. Normalair Comet 3 pressure-controller.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
