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Aviation History
1928
1928 - 0451.PDF
MAY 31. 1928 drives the oil pumps, magnetos, gas distributor and C.C. gun gear), and the air screw thrust bearing. The rear end of the crankshaft carries the spur gear which drives the induction fan. The front and rear webs of the crankshaft carry the necessary balance weights. Mixture is supplied to the engine by a Claudel-Hobson A.V.T. 100 carburettor through the medium of an induction fan which delivers the mixture into an annular induction casing. Thence the mixture passes to the cylinders by means of induction pipes. Experiments have proved that the use of an induction fan of this kind very considerably increases the volumetric efficiency of the engine and also gives a perfectly even distribution to all cylinders. The carburettor is supported on an induction elbow attached to the rear end of the engine, the controls and air intake pipes being integral with the carburettor and engine. Ignition is controlled by two magnetos of the latest approved type, each having fourteen terminals. The magnetos are accessibly mounted on the front of the engine and are bevel driven from the crankshaft. There are two sparking plugs per cylinder, the braided H.T. cables being supported in a wire carrier mounted on the crankcase. Fine adjustment of the magneto timing is provided by serrated couplings incorporated in the magneto drive. The gas distributor which is mounted on the front of the engine is driven from the crankshaft, the cams for the C.C. gun gear being incorporated in its casing. The oil pumps are mounted on the front of the engine and are bevel driven from the crankshaft. The pressure pump, which has a relief valve to govern the oil pressure, delivers oil under pressure through a filter to the centre of the crank- shaft and thence to the connecting rods and bearings. At the bottom of the crankcase are an oil sump and filter, into which the oil drains from the engine. When the engine is stationary, the surplus oil passes from the crankcase and collects in this sump, flooding of the crankcase and lower cylinders being thus prevented. Oil is drawn from this sump by a scavenge oil pump situated underneath the pressure pump, the scavenge oil pump then delivering the oil to the oil tank on the aircraft. On its way to the oil tank, the oil passes through the jacketing of the carburettor and induction elbow, thereby imparting a positive degree of heating to the induction system. A gear type petrol pump and relief valve of approved design are carried at the rear end of the engine, prolonged tests having proved this pump to be very successful. A tachometer drive which is fitted to the engine is situated just above the petrol pump. The drive points towards the rear of the engine in order to avoid unnecessary bends in the tachometer flexible shaft. The air screw boss is of standard size, the dimensions being given on the installation drawing. Provision for priming is made by fitting a distributing ring at the rear of the engine, the ring having small branch pipes leading to each induction pipe. Each branch pipe terminates with a small atomising jet fitted to the induction pipes. The distribution ring is fed by means of a primer pump, filter and T piece, these parts being supplied loos^ with the engine. Attached to the rear end of the engine is a conical bearer plate, by means of which the engine is mounted in the airshaft. The accompanying installation drawing gives the principal dimensions, usually required by aircraft constructors. Specification Air-cooled Ra.lial Left-hand Tractor. No. of cylinders . . . . 14 Bore . . . . . . 6 in. Stroke . . . . . . . . 7-5 in. Normal B.H.P. .. .. 700 at 1,501) r.p.m. Maximum B.H.P 777 at 1,650 r.p.m. Compression ratio . . . . 5 to 1. Weight : Engine complete for installation including bearer plate, propeller boss, dual ignition, carburettor, air intake, and short exhaust pipes, 1,415 lbs. THE SOUTH AFRICAN SURVEY FLIGHT THE Big Survey Flight round Africa, commenced on November 17 last, which Sir Alan and Lady Cobham have been carrying out is now almost complete ; the Short-Rolls- Royce " Singapore " flying-boat being due at Plymouth today, May 31. It is, however, proposed to extend the flight from Plymouth to include a tour of the big sea ports of this country, in order to show the " Singapore," which has accomplished so much without regularly organised facilities for mooring, refuelling and docking. No doubt, in a few years' time, liners and yachts of the air will set out on similar voyages from most of these sea ports, so that the visit of this machine should be an historic event. The African flight has been one of survey for an aerial trade route which shall bring each territory nearer to its neighbours, and provide a means for development and pros- perity through a more rapid exchange of passengers, goods and mails. Administration, settlement and commerce will gam tremendously thereby, and now that the conditions for operation are known with some certainty and the require- ments of traffic gauged, no time need be lost in establishing the first 'ink in this main trunk route from Egypt into the heart of Africa. A subsidy will be necessary to consolidate the work done and obtain the maximum advantage from experience whilst it is still fresh, but such a subsidy will not be permanent, any more than subsidies have been for other forms of transport in the past. Australia has already been able to reduce her subsidies for air lines, where 5,000 miles are in regular operation over country similarly in need of development, and in the I'nited States, one-third of the air lines are now paying without a subsidy. In Africa, Sir'Alan Cobham has been called the " Flying Ambassador of the British Empire," and the result of his mission, combined with that of his previous flight through Africa, should be the establishment of a permanent British air line, bringing Cape Town eventually within 8 days of London. Sir Alan Cobham has found all British territories in Africa fully alive to the need for a permanent air line and ready to support the scheme submitted by his company (Cobham- Blackburn Air Lines, Ltd.). But final plans and estimates must receive the support of the Home Government before operations can be commenced. In view of the importance to the Empire of closer personal contact, and bearing in mind that other countries may try to forestall us in the establishment of air lines, there is every reason to take advantage immediately of the enthusiasm created in Africa by this flight. The total distance covered in the " Singapore " amounts to about 20,000 miles, in addition to which Sir Alan flew over 3,000 miles by D.H. " Moth " light plane in Kenya, Northern and Southern Rhodesia, while the tour round Britain will add another 2,000 miles. Finally, Lady Cobham's experiences throughout a flight of 20,000 miles, the longest yet made by a woman, must be unique. As a member of the crew, she has had an oppor- tunity of studying from every angle just those points about comfort to which attention must be paid in order to encourage general passenger traffic by air. The final stages of Sir Alan Cobham's flight may be sum- marised as follows :—May 25, Las Palmas-Casablanca ; May 26, Casablanca-Gibraltar ; May 28, Gibraltar-Barcelona The 650 miles were completed in a gale ; May 29, Barcelona- Bordeaux ; May 31 (today), Bordeaux-Plymouth. Subject to re-arrangement, the programme for the tour round Britain will be as follows :—May 31, arrive Plymouth, 12.30 p.m. ; June 1, flying over Thames, 1-2 p.m. ; arrive Hull 5 p.m. June 4, arrive Newcastle, 11 a.m.; arrive Edinburgh, 5.30 p.m. June 5, arrive Glasgow, 11.30 a.m. June 6, arrive Belfast, 12 noon. June 7, arrive Liverpool 12 noon. June 8, arrive Cardiff, 11.30 a.m. (possibly arrive Southampton 5.30 p.m.). June 9, flying over Thames, 12-12.30 p.m. ; arrive Rochester, 1 p.m. Brigands Rounded up by Aeroplanes THE leader of a gang of brigands in Iraq, Ghadhban al Kharjiun, after ignoring a demand to surrender dropped from a R.A.F. machine, was successfully " disposed of " and his gang broken up by the combined action of R.A.F. aero- planes and police forces. 407
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