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Aviation History
1937
1937 - 0862.PDF
d FLIGHT. APRIL I, 1937. Floodlight and Beacon FOR the permanent lighting of landing grounds lamps are .used which direct a lan-shaped beam of light which has a large divergence in a horizontal plane but a small one in a vertical plane. It is some times required to use this lighting as a beacon, in which case the fan-shaped beam is tilted about a horizontal axis and then caused to rotate about a vertical one. By this means a series of one or more flashes will be observed for each revolution. De pending on the axis about which the beam is tilted the beacon may present different characteristics to different observers depend ing on their respective .heights. ft has been lound, however, that if the axis about which the beam is tilted is suit ably chosen not only are the number of flashes seen per revolution the same when observed from all heights, but the light of the beam is used to the greatest advan tage. Thus, if the fan-shaped beam is tilted about an axis coincident with or only at a small angle to one of its edges, the desired result is obtained. Means for carrying this out are described in which an elongated re flector is tilted by gearing about the de sired axis.—Patent No. 452933: General Elec tric Company, Ltd., and E. L. B. Damant and W. A. Villiers. Oil Cooling A METHOD of cooling oil, particularly applicable to aircraft, consists of the use of two concentric tubes of nearly the same diameter so that the annular space between them is very narrow. Oil is passed through this annular space and is cooled by the stream of air which passes through the inner tube and over the outer one. In order to improve the cooling effect, corrugated metal fins are inserted in the annular space, and these contact with both tubes. This increases the conducting surface and also causes a turbulent action to be set up in the oil.—Patent No. 450261: Serck Radia tors. Ltd.. and H. E. Upton. Cowling and Cooling I N order to prevent the air which is used to cool the engine cylinders from acquiring heat from the exhaust ring, thereby im pairing its cooling efficiency, the Bristol Company proposes in this patent to divide the air into two separate streams, an outer one for the purpose of cooling the exhaust ring, and an inner one for the engine cylin ders. In the construction described, the ex haust ring, which is of streamline form, is fitted just inside of the engine cowl, the outer wall of the ring being in contact with the inner surface of the cowl. In the front opening of the cowl is fitted a circular baffle which splits the incoming air into two streams. The major central portion of the air flows past the engine cylinders. The air entering between the edge of the baffle and the outside edge of the cowl, flows past the exhaust ring and escapes through the annu lar space round the exhaust ring and through ducts along some of which the ex haust tail pipes also pass. By these means both the engine cylinders and the exhaust system are maintained at low temperatures with a consequent increase in general effici ency.—Patent No. 451296: Bristol Aero plane Company, Ltd., and A. H. R. Fedden. Automatic Pilots I N automatic steering gear for aeroplanes provision is made for maintaining the aeroplane on a given straight course, or, alternatively, for following a given curve. In general the steering is effected by an electric motor actuating the rudder, the motor being controlled by a relay. The relay may be connected to either the course- steering apparatus or the curve-steering ap paratus as required. Ii the change-over to the curve steering is The TREND of INVENTION Recent Aeronautical Patents Reviewed made when this is set for an extreme posi tion, the craft would turn abruptly to an altered course. This is prevented by a means described in a patent whereby the proper connections of the relay to the resist ances which control the steering can be made only when the curve-steering appara tus is in the neutral or central position. If the curve-steering is switched in with the control set for some curve previously steered, blocking means prevent the control working and thus a sudden change in the course of the aircraft is avoided.—Patent No. 452728: Siemens Apparate und Mas- chinen G.m.b.H. Wheels ASIMPLE construction of a wheel which is easy to manufacture and which, it is claimed, satisfies all the requirements of an aircraft wheel is described in two Bendix patents. As will be seen from the illustration, the wheel consists of a hub member, mounted on bearings on a spindle, on one side of which is a load-carrying disc which also incor porates the brake drum. On the other side is a second load-carrying disc and between these two discs the tyre rim is carried. The hub, disc, brake drum and one tyre flange are all formed in a single casting. The rim is formed from sheet metal, as is also the second disc, and these are connected to gether by a retaining ring which forms the second tyre flange. In the second patent the entire wheel is formed from sheet-metal parts, the rim, tyre retaining flange and one load-carrying disc being in one piece whilst the other disc and brake drum are built up from several parts, the whole being welded together.— Patents Nos. 455625 and 455687: Bendix Aviation Corporation. A section through the Bendix wheel and brake. Differential Braking IN Flight of September 10, 1936, another patent of the Bendix Aviation Cor poration was reviewed; it related to hydraulic braking in which equal braking was applied to each wheel when the brakes were applied by a hand lever, but in which the braking on the two wheels could be varied when applied from the rudder bar control. Similar results are obtained in the scheme covered by the patent No. 453797, which relates to cable-operated brakes. The hand control operates a lever which moves about a fixed pivot and on the lever are mounted two pulleys round which pass the cables to the brakes of the two wheels. The ends of these cables are anchored to the two sides of a rocking bar which is pivoted at its centre and which is capable of being turned about this pivot by the rudder bar, which thus tensions one cable and releases the other so as to give differen tial braking. The cables are arranged so that they are initially slack, with the result that move ments of the rudder bar do not normally affect the brakes and the cables do not interfere with rudder operations. A slight tensioning of the cables by the hand con trol brings the differential unit into opera tion.—Patent No. 453797; Bendix, Limited, and P. E. Hall. Boost Control WHEN a supercharger can be driven, at will, at more than one speed with respect to the engine speed, then the boost control pressure required will depend upon the relative speed of blower to engine, if the most favourable results are to be obtained. An arrangement is shown whereby a variable-datum boost control is set by a mechanical linkage which is connected to the variable speed gearing of the blower. By this means the datum of the boost con trol is automatically set when the gear is selected for driving the blower. There is a second patent with the same object in view. In this case the fuel supply to the carburettor is varied according to the altitude of the machine by a capsule acted upon by the atmospheric pressure. An interconnection is now suggested be tween this mixture-strength control and the change-speed control for the blower, so that the mixture strength is automatically varied with the speed of the blower.— Patent Nos. 453915 and 454154: Bristol Aero plane Co., Ltd., A. H. R. Fedden and C. 0. Anderson. Rotor Drive I N rotating-wing aircraft, the rotor blades may be temporarily connected to the engine through suitable reduction gear ing. When taking off it is necessary to drive the rotor blades at a certain predeter mined speed for a limited period without at the same time making the airscrew rotate at such a speed as to cause the aircraft to take off, and without producing unnecessary stresses in the transmission system. A trans mission gear by which these results can be satisfactorily obtained is described in patent No. 452922. The engine drives a shaft which is coupled by a hydraulically operated clutch to the driving member of a hydraulic coupling. The driven member of this hydraulic coupling is connected to the input shaft of a change-speed gear box, the output shaft of which is connected to the rotor blades. To drive these the hydraulic clutch is engaged and a suitable gear selected. The hydraulic coupling drives when the engine speed reaches a suitable value and brings the rotor up to the required speed, after which it can be disconnected trom the engine by the operation of the hydraulic clutch. The engine is then speeded up to drive the airscrew.—Patent No. 452922: /. Yoxall and Propello Inventions. Limited.
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