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Aviation History
1932
1932 - 1230.PDF
FLIGHT, DECEMBER 1, 1932 A UNIQUE AUXILIARY SET ONE of the most interest ing, small and useful auxiliary sets it has been our pleasure to see is that which has been designed by Lord Ridley and produced by A.B.C. Motors, Ltd., of Walton-on-Thames. It consists of a 4-h.p. two- cylinder horizontally opposed four-stroke engine which oper ates no less than live auxiliary units, namely, a dynamo with an output of 50 amps, at 12 volts, a petrol pump delivering 2,250 gallons of fuel per hour, with a suction lift of 16 ft. vertically, through a 1-in. flexible hose against a head of 10 ft. ; an oil pump delivering 300 gallons of lubricating oi per hour, with a vertical suction lift of 16 ft. through a lj-in. flexible hose against a head of M 2 ft. at a temperature of 60 deg. Fah. ; a water pump delivering 2,500 gallons per hour with a suction lift of 16 ft. ; and an air compressor which will charge an air bottle holding 400 cub. in. of air to a pres sure of 200 lb. in 10 min. We imagine that this unit, which has been designed for Air Ministry use, will be installed not only in large flying boats, but also in large aircraft of all types. The engine, as we have already mentioned, is of the horizontally opposed type and parti cularly sweet running. This is probably largely due to the use of a three-throw crankshaft, which entirely avoids the rocking couple so prevalent in normally designed hori zontally opposed engines. The engine is mounted on a bedplate, and connected to the rear side of it is a gear case which houses the clutch arrangement operating the various drives of the auxiliaries. As will be seen from the photographs, these are bolted on either side of this case and driven by spiral gears from the crankshaft. Looking from the front, or the starting handle end of the engine, the air compressor is situated above the left-hand cylinder behind the engine with the fuel pump immediately below it. On the opposite side of the engine opposed to these two units the oil pump is fitted in the upper position and the bilge pump in the lower position. The generator is bolted directlv to the crankshaft extension, and is designed to clCt cLS a flywheel. The set is so arranged that by means of the clutch gear any of these five auxiliaries can be operated sepa rately or together with the generator, mat is, the generator under load and not merely acting as a flywheel. All the auxiliaries can be operated together if required, with the exception of the bilge pump, the working of which requires the whole output of the engine. The engine itself is a small high speed one, developing 4 b.h.p. at 4,000 r.p.m. It is governor controlled, and uses a Zenith carburetter and B.T.H. mag neto. The bore and stroke are 54 mm. and 38 mm. respectively. It has its own pressure feed oil circulating system to all bearings, with its oil supply carried in a sump. The compactness of this engine can be judged from the fact that the whole unit weighs only 102 lb. complete, including 23 lb. for the generator, 15 lb. for the bilge pump and drive and 37 lb. for the engine itself without bedplate. Starting is particularly easy by means of a handle acting through a train of epicyclic gears arranged to turn the engine at four times the speed of the handle. A Ki-gas priming pump is fitted, and the gears are automatically thrown out when the engine fires. As one may imagine from the study of the weights, light alloys have been used extensively in this interesting little design. The crankcase, cylinder heads, and all castings, except the bilge pump, are in R.R.50 (D.T.D.133), the latter being aluminium bronze. The pump blades are nitralloy steel and the cylinder liners are internally case-hardened and ground steel. The connecting rods are duralumin with white metal big ends. The crankshaft is of nickel chrome steel. All three pumps, which are of the eccentric and fan type, were especially designed in the works for use with this unit. The generator, of course, is the standard Air Ministry type and is enclosed in a cowling with a fan giving a 35- m.p.h. draught over it. It only requires 1J h.p. at 4,000 r.p.m. to drive it. The air compressor is also an Air Ministry standard fitting of the Herzmark type. The engine as at present arranged is water cooled and designed to be connected to the main engine cooling system, but a small circulating pump can be fitted if necessary. The complete unit has passed all the Air Ministry acceptance tests, during which it has run some 100 hours, with between 30 and 40 hours on the auxiliaries. The view at the top of the page shows the starting-handle end of the A.B.C. Auxiliary Unit. On the left at the bottom can be seen the air compressor and the fuel pump, and on the right the oil and bilge pump. In these views the generator is shown cowled and uncowled. • B B 8 8 fl Engines at Paris Show PROBABLY greater progress was to be found among the aero engines than among the aeroplanes at the Paris Aero Show, and we have been fortunate to get a promise from Maj. G. P. Bulman, O.B.E., B.Sc, F.R.Ae.S., Assistant Director (Engines) of the Directorate of Technical Development, Air Ministry, to write for the benefit of FLIGHT readers an article describing his im pressions of the progress in aero engine development evidenced by the new types exhibited in the Grand Palais. Maj. Bulman's article will be published in FLIGHT very shortly. 1152
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