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April, 1940 AIRCRAFT ENGINEERING Workshop and Production Section miniu m piston takes the place of the vulcanite one NIQUE technical resources coupled with over used in water meters. Fig. 2 shows the working fifty years of experience in fluid metering U of the piston, which is really a displacer, finished have led to the perfecting of a flow meter t o very fine limits and practically frictionless, which gives th e aeroplane pilot accurate readings of engine fuel consumption. Indication takes the havin g a finite cycle corresponding to the flow of an double form of a dial graduated in rate of flow in exac t quantity of petrol through the meter. For gallons per hour and a 3-figure counter totalling the every such cycle the counter-driving spindle is fuel consumed by each engine. As an alternative, rotate d once and this movement is taken up for the latter reading can be substituted a sub throug h suitable reduction gearing and through a tracting counter giving the quantity of fuel in the gland spindle to a "dry " compartment wherein tank. th e transmitter gear is situated. The essential component of this part of the The meter consists of two separate units con mechanism is a micrometer switch which is operated nected electrically so tha t in effect the term "tele- register" is applicable, which means that the b y a cam wheel mounted on the last spindle of the transmitter unit or units may be installed close to gear train. The meter is geared to give a n electrical each engine, say on the fuel supply between the contac t for each fixed number of revolutions and pump and the Amal regulator, and the receiver unit may , for example, be arranged so tha t it makes one placed on the instrument panel, or where most contac t for every gallon of fuel passing. convenient for the pilot. The wiring diagram is Othe r details of the transmitter arc a strainer elementary, containing only the transmitter, of very generous dimensions, a by-pass valve receiver, switch, panel light fuse and connexion to a 12- or 24-volt battery. The Transmitter The meter and transmitter unit is shown in Fig. 1. The prime mover of the meter is identical with the well-known and proved Kent "M " type water meter, except, of course, that suitable petrol- resisting materials are used. For instance, an alu is arrested by the succeeding impulse. The indicator pointer simultaneously jumps to the position at which the small pointer was arrested and shows th e rat e of flow. The cycle is completed at every third contact , bu t if there has been an y change in the rate of flow since the last cycle the indicator pointer moves to the new position, in which it stays until the rate of flow alters. There is thus continuous indication of rate of flow. The counter is also advanced with each impulse an d therefore adds more or less units in a given time according to the speed of the meter. The ½-in. size is suitable for a maximum consump tion of 100 gallons per hour, the ¾-in. size for 200 an d the 1—in. size for 300. These meters will stand up t o 50 pe r cen t overload without damage. operated by a suitable means of control to be used The combined nett weight of transmitter and if for any reason a meter has to be shut off, and receiver is only 7½ lb. for the ½-in., 8 1b. for the a strong aluminium body casting with fixing lugs ¾-in., an d 9 lb . for the 1-in. meters respectively. an d quick-release bottom cover through which the Th e works of George Kent, Ltd., are equipped straine r can be taken out for cleaning. wit h separate meter-testing shops for water, steam an d air and oil and petrol, where all meters are The Receiver tested with their correct fluids. Every aircraft Th e principal component of the receiver unit is petrol meter is given a careful accuracy test and a special timing gear (Fig. 3), resembling a large mus t read within 1 per cent of the correct flow at split-second stop watch, housed, together with the all normal rates. solenoid, gearing, counter mechanism, etc., in a Ever y meter is also subjected to a pressure test compac t case designed for mounting on an instru of some 20 lb./sq . in. men t panel. This new meter, which has already undergone The rat e of flow scale an d the counte r are operated severe testing by Imperial Airways and the Air by the same electrical impulses previously men Ministry, is now in full production. tioned. Full particulars of this meter, together with There are two pointers on the dial. When an installation details for the various sizes, can be impulse is received by the timing unit a small obtaine d from the manufacturers, George Kent pointe r is allowed to move round the dial until it Ltd. , 199 High Holborn, London, W.C.1. No. 2 of the year 1940 Publication 1208, December, 1937, edition, is now AI R MINISTRY NOTICES available and can be purchased, price 1d. net Civil Aircraft Operation during the War: or 1½d. post free, either direct from His Majesty's Necessity for Strict Compliance with Regulations. to fly the particular type of aircraft that he is Stationer y Office or at any of the following operating. addresses : York House, Kingsway, London, W.C.2; 1. The attention of all owners of aircraft is 3. It is particularly necessary that the require 120, George Street, Edinburgh 2; 26, York Street, called to their obligation to ensure tha t any aircraft ment s of the Air Navigation (Restriction in Time of Manchester 1; 1, St. Andrew's Crescent, Cardiff; operated during the war is flown in accordance War) Order, 1939, should be strictly complied with. 80, Chichester Street, Belfas; or through any with the requirements of the Air Navigation Acts This Order forbids the flight of any aircraft in or bookseller. ted Orders an d the Regulations issued thereunder, over the United Kingdom, except under the Januar y 30, 1940. unless special dispensation from any of these re authorit y of and in accordance with the terms and rements has been granted by the Air Ministry. conditions of a permit in writing issued by the 2. Particular attention is drawn to the following Secretary of State, and imposes restrictions on the points:— flying of aircraft in respect of which permits have A NEW INSPECTION been granted. In view of the military require (1) Loading.—In accordance wit h para . 9 (1) (c) ment s of the present situation, any departure from of Schedule I I of th e Air Navigatio n (Consolida AGENC Y the provisions of this Order may be attended by the tion) Order , 1923, n o aircraf t shall b e flown unless most serious consequences. I t has recently been announced that the sole it is satisfactorily loaded for safety in flight. Januar y 24, 1940. agency for the products of the Bausch and Lomb (2) Licences.—Each pilot must possess the Optical Company, of London, has been granted prescribed certificate of competency and a valid No. 3 of the year 1940 t o A. C. Wickman Ltd., Thames House, Millbank, and current licence. Flying carried out under CIVIL SPECIFICATION London , S.W.1. National Air Communications arrangements is MEMORANDUM No. 30 The measuring instruments falling within the regarded a s "public transport " flying, and it is Amendment List No. 6 to Volume II of the Air scope of this arrangement include a contour- therefore necessary that any pilot engaged on worthiness Handbook for Civil Aircraft measurin g projector, optical protractor, optical this work shall possess a valid and current 1. Amendment List No. 6 to Volume II of Air drill gauge and shop microscope. Class "B " pilot's licence permitting the holder
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Apr 1, 1940
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