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Workshop and Production Section AIRCRAF T ENGINEERING June, 1942 Copies of the following Specifications may be obtained, and dimensions for the necessary plug, ring and Th e application of th e Code is fully practicable in at the prices indicated, from the British Standards calliper gauges. Similar gauge designs are being th e cases where solid or liquid fuels, town' s gas, blast Institution, 28 Victoria Street, London, SAV.l. prepared for splines and will shortly be available furnace gas, coke oven gas, mixed gases, or other as Part 2 of the spline specification. clean gases are used. When hot raw producer gas B.S. A. 19 Serrations and Serration Ganges. Th e Ministry ot Aircraft Production is desirous is employed difficulties arise, although it is a more B.S.A.20 Spline Shafts and Holes for Aircraft. tha t these new British Standards be used for all new or less simple matter to ascertain the heat input Th e British Standards Institution has recently designs and that for aircraft purposes the 1929 when the gas producer is an integral part of the issued new specifications relating to splines and editions of B.S.46 Part 2 be regarded as obsolete furnace. serrations and their gauges. except for replacement parts. In th e case of a furnace fired b y its own remot e gas I t has long been apparen t tha t th e existing B.S.46, Prices : A. 19, 2s. 3d. post free. A.20, Is. 3d. producer plant, but connected thereto b y gas mains Par t 2, 1929, Splines and Serrations, has been in post free. or ilues, th e furnace and producer ma y b e considered need of revision, in order that it might be repre a s one unit and the thermal statement be based on sentativ e of current practice. The need for a B.S. 992.— Testing of Fuel Fired Melting Furnaces th e fuel supply to the producer, unless satisfactory British Standard relating to gauges for splines and used in the Non-Fcrrous Metals Industry. mean s ar e available for measuring th e raw producer serrations also became particularly obvious during in the actual mains supplying the furnace. Even th e present war emergency and, a t the request of I n th e past the lack of an agreed standard testing when gas quantities can be measured directly, the th e Controller of Gauges of the Ministry of Supply, procedure and technique has occasioned many efficiency of the gas producer plant should be con a Committee of the Society of British Aircraft difficulties and misunderstandings in th e correlation sidered and du e allowance mad e for : Constructors was set u p t o investigate th e matte r in an d comparison of results obtained in different tests (a) The thermal value of the tars and carbon collaboration with the Ministry of Aircraft Pro t o evaluate performance and efficiency of these aceous dus t deposit in th e mains or ilues connect duction and the British Standards Institution. furnaces, and in 1935 the Gas and Solid Fuel ing th e producer to th e furnace. On consideration being given t o th e a tablishmcnt Industr y Committees of the Institution appointed (6) The loss of sensible heat of the gas in its of gauge tolerances it was apparen t th a neither the representative committees to prepare standard trave l from th e producer to th e furnace, existing British Standard B.S.46, Part 2—1929, method s of carrying out the tests. ln.th e case of a furnace fired by raw producer gas nor the draft revision issued for comment in 1939, Thi s Test Code has, therefore, been framed to from a main or flue common to other furnaces, and laid down work tolerances which were appropriate cover the testing of furnaces for the melting of supplied with gas from a single producer or battery for war-time production, and it was considered non-ferrous metals. of producers, it is difficult to determine th e thermal desirable that new specifications be prepared for I t provides for two forms of test:— inpu t to the furnace with the preciseness essential splines and serrations for aircraft. Pari 1. A short, simple code for carrying out, for recommendation in a British Standard. Never Th e present specifications, prepared by the a t minimum cost, simplified industrial tests for theless, with the equipment now available, it is S.B.A.C. Committee and endorsed by the British evaluating the performance of furnaces as possible under favourable conditions of application Standard s Institution, cover those types and sizes effective and economic units. t o make a reasonable check on the thermal input of splines and serrations which are commonly used Part 2. A comprehensive code for the complete t o the furnace, provided due allowance is made for in aircraft production. evaluation of th e performance and the efficiency th e errors likely to occur when measuring the flow Th e variety of fits provided in th e 1929 standard of furnaces. an d hea t content of raw producer gas. ha s been considered unnecessary for aircraft pur Amongs t other furnaces the code is applicable to : Price 3s. 9d., post free. poses and the new standards provide for one class Crucible furnaces. Copper melting. of fit only for serrations, namely, a sliding fit Brass melting. B.S. 907-1940.—Dial Gauges for Linear Measure intermediat e between the easy and close sliding Gu n metal melting. ments. Amendment No. 1. fits of the 1929 standard, and two classes of fits for Aluminium melting. splines, namely, easy sliding and close sliding fits. Po t furnaces, cast iron Aluminium melting, A Standard has recently been issued for th e shape I t was considered desirable as a war emergency or plumbago. Type, lead and stereo- of teeth in gear wheels in clockwork mechanisms. measure, and has been found possible, to relax meta l melting. I n order to take advantage of this standard an th e tolerances from those of the 1929 British Heverbcrator y or potless Amendmen t Slip has been issued to the British Standar d and of its 1939 draft revision. Whilst furnaces. Standar d for dial gauges (B.S. 907) which adopt s th e therefore specifications are being issued primarily I t is also applicable to certain furnaces used in standar d form of gear teeth given in B.S. 978, for aircraft components, the fact that it has been othe r industries.. " Gears for Clockwork Mechanism", which also found possible to relax certain of the tolerances Th e Test Code ha s been so framed to make it as standardizes the module for the gears and sizes of makes the specifications equally applicable to all comprehensive as possible in regard to general wheels for th e mechanisms. those fields ol engineering for which th e former issue information and design, and although various Copies of the amendment may be had gratis on of the specification was suitable. specific types of furnace are provide d for, it must be receipt of a stamped addressed envelope. Such precise engineering products as serrated and realized tha t other types exist and still more will be B.S. 907.—Dial Gauges for Linear Measurement, sinpled shafts and holes demand adequate gauging evolved in th e future. an d B.S. 978.—Gears for Clockwork Mechanism, if interchangeable assembly is t o be assured. The Th e Code may not, therefore, be applicable to all cost 2s. '3d. each, post free. new specification for serrations includes full details such furnaces, but nevertheless will serve as a guide.
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Jun 1, 1942
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