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Aviation History
1935
1935 - 0584.PDF
288 FLIGHT. MARCH 14, j^,. on its drive and opens neutralising cocks to each end of the servo cylinders; this permits the pilot to over-ride the auto matic pilot without actually disconnecting the mechanism. A fine adjustment is provided as a dashboard fitting. By means of flexible cables and small leaf springs it enables a bias pressure to be exerted on either pair of valves, so as to deflect the axes ot the gyro wheel up or down, or laterally, and therefore, through the aircraft controls, to raise or lower the nose of the machine or deflect it to the right or left. This enables small adjust ments to be made to the course of the aircraft, but for serious alterations or large and quick turns the over-riding mechanism should be brought into play, so that the pilot can control the machine regardless of the automatic pilot. This, then, is the operation of the automatic pilot as applied to two axes. When required, a similar instrument, consisting of a gyro wheel with its axis running parallel to the wing spars of the aeroplane, can be fitted to control the aileron movements, and therefore to take charge of the machine laterally. Both the two- and three-axes types have been tested out in many kinds of aircraft, and from the short trial which Flight has been able to make, it would appear that the P.B. pilot cer tainly does its work admirably in both rough and smooth weather. Mr. Philip Bailey, who does all the makers' test work, has made long flights from the Continent to this country ina" Puss Moth," and reports that the equipment's accuracy as regards course-keeping was all that could be desired, and that during some 400 hours' flying he has experienced no serious trouble at all. In general, the P.B. automatic pilot is both reasonably small and light. The assembly for controlling the rudder and elevator is contained in an oil-tight case, the outside dimen sions of which are i6£ in. by 9| in. by 10 in., and the weight is 28 lb. To this must be added 5 lb. for tank and pipes, 3 lb. for a small windmill pump (this oil-pressure pump can, if re- A general view of the apparatus controlling the rudder and elevators. In this case there are two sets of valves, as the movement is in two planes. (Flight photograph.) quired, be operated from the engine), making 36 lb. in all, or with the oil, 42 lb. The apparatus for controlling the ailerons is slightly smaller, measuring 12^ in. by g£ in. by 7 in., and weighing approxim ately 18 lb. FLYING-BOATS OF 134 TONS? (Continued from page 283) eludes the tail unit, lateral stabilisers, controls, internal hull structure, etc., probably amounts to about 13 per cent, of the total weight, bringing the total structure weight up to 40 per cent. If the reasonable assumption can be made that the weight of the power-unit installation would be approximately the same percentage of the all-up weight as for existing flying- boats, then this weight would represent about 17.3 per cent, of the total. For the design of boat we are considering this would result in the following weights: — Complete structure Power Unit ... Equipment, say lb. 120,000 Tj'i.OOO 10,000 182,000 leaving for fuel, paying load and crew an amount of 118,000 lb. For a boat of this weight it would probably be necessary to install engines developing a total horse-power of about 24,000 b.h.p. For continuous cruising about 16,000 b.h.p. could be employed, which would give a cruising speed of about 165 knots. With the present-day cruising consumption of 0.5 pints per b.h.p. hour the amount of fuel consumed per hour would be 1,000 gallons or roughly 8,000 lb. weight per hour Assuming the paying load to be in the neighbourhood of 50,000 lb., then the range of the boat under these conditions would be about 1,600 statute miles. This particular example of what might be expected from future development is, of course, only my own personal views and is based on our present rate of progress. Of course, there is the possibility that with the advent of new methods of construction, improved materials and better aerodynamic knowledge we may improve on this—at any rate, sufficient to make regular crossings of the North Atlantic with a reasonable pay load. As far as I can foresee it will be at least a matter of ten years before we see regular Plymouth-New York crossings in a large flying-boat carrying passengers. This may seem unduly pessimistic taking into account the number of times the Atlantic has been crossed, but it must be borne in mind that all these flights have been carried out with machines loaded far beyond their normal Certificate of Air worthiness weight, and it is a far different proposition to run a regular service carrying passengers with a standard of con fort exceeding that now obtained on the London-Pans route. However, the science of aeronautics is still in its infancy and I think it only reasonable to assume that the developing of the large aeroplane,'' and particularly the flying-boat « attain a stage of perfection which has now been reached oy the mercantile marine. FOR AIR FRANCE. The Potez 62, a fourteen-passenger commercial adaptation of the maker's m-iU!place de com .. ^ jn(j the two 900 h.p. " Mistral Major " two-row radials give a cruising speed of 175 m.p.h. The normal range is 62S ffll ceiling 26,000 ft.
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