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July, 1929 AIRCRAFT ENGINEERING 183 [At the request of the British Engineering Standards Association the following brief references to British Standard Specifications for Aircraft are published for the information and guidance of those interested. It is proposed to make this a regular feature of AIRCRAFT ENGINEERING, as British Standards for Aircraft are issued from time to time. Copies of the specifications, at the prices given, may be obtained from the Association's Offices at 28, Victoria Street.—Ed.] This specification gives the variations in sections:—Section 1, Provisions applicable to 3A.1.—Bolts and Nuts (Low-Tensile). thickness allowable in duralumin sheets of all sections of this specification. Section II, (Price 8d.) various dimensions. It also gives details of S. 80-A, Bars and Billets for Forging and This specification gives complete tables of th e tensile and reverse bending tests the sheet Drop Forging. Section III, S. 80-B, Bars for standard sizes of bolts and nuts (steel, brass and is expected to pass. In an appendix is a note Machinery. Section IV, S. 80-C, Forgings east iron). It also provides for the anti- on the heat treatment of sheets of this material. and Drop Forgings. Section V, S. 80-D, corrosion coating of all finished parts in Finished Machine Parts. Attention is directed S.1 steel with zinc or cadmium, and gives the in a preliminary note to the importance of 2L.25 . Wrought Aluminium Alloy Bar cold bend test for bolts so treated. surface condition on the liability to corrosion. (Heat Treated). "Y " Alloy. (Specific The heat-treatment temperatures specified are 3L.1 . Wrought Aluminium Alloy Bar Gravit y not more than 2·8 5 per cent.) (Price: representative of average figures used intended (Specific Gravity not greater than 2·85). 6d.) as guides only. (Price : 6d.) The chemical composition of the alloy is A revised standard cancelling B.S. Specifica given as:—Copper, 3·5 to 4·5 per cent. tion 2L.1. This specification covers the alloy 3V.3 . Plywood. (Price: 6d.) Nickel, 1·80 to 2·30 per cent. Magnesium, 1·20 generally known as Duralumin. The chemical This specification covers the requirements of to 1·70 per cent. Aluminium, the remainder. composition of the alloy is given as : Copper, plywood to be used for structurally important Impurities : Iron, not more than 0·75 per cent. 3· 5 to 4· 5 per cent. Manganese, 0·40 to 0·70 part s of aircraft. It is divided into the follow Silicon, the same. Lead, zinc and tin, not more per cent. Magnesium, 0·40 to 0·70. Alumin ing parts: Part I, Kinds and qualities of tha n a total of 0·10 per cent. ium, the remainder. Iron impurities, not more timber. Part II, Construction of three-ply tha n 0·75 per cent. boards. Part III, Construction of multi-ply S.80. High Chromium Steel (Non-Corrod 3L.3—Wrough t Light Aluminium Alloy boards. Part IV, General provisions applying ing)—55 tons per square inch. (Price: 6d.) Sheet s and Strips. (Specific gravity not t o all plywood. Part V, Testing: (a) Three- A new standard, divided into the following ply boards; (b) Multi-ply boards. greater than 2.85.) (Price: 8d.) Air Ministry Notices to Ground Engineers No. 7 of the Year 1929.—Ground engineers moved so that the whole of the cable can be bolted and sweated to the bottom of the sump responsible for the inspection of British aircraft seen. If there are any signs of wear the cable for elbow fixing. tha t are used for private flying only (i.e., not is to be replaced forthwith in accordance with (c) The wire gauze at the bottom of the tank, flown for carrying passengers or goods for hire para . 3 of this Notice. Any four-strand cable above the sump, is to be pierced with 3 -in. no t required to be so replaced is t o be frequently or reward*) are strongly recommended to take holes all round the stack pipe; these holes examined, and any Bowden sheathing is to be action to ensure that a complete record of the can be conveniently made with a pointed moved on each of these occasions to enable inspection by competent persons of all repairs steel rod through the filler. th e covered portions of th e cable to be examined. and overhauls is maintained, preferably in (d) The fuel filter is to be of Air Ministry type aircraft and engine log books. I n future the cable used in flying-control (A.G.S. No. 600) with cleaning connections. systems must be of the seven-strand construc This record is particularly valuable when the Fuel-Tank Supporting Cables.—All existing tion to current B.E.S.A. specification, and no aircraft has to be examined for renewal of its 5-cwt. cables supporting the fuel tank in the certificate of airworthiness. It will not only certificate of airworthiness will be issued or mainplane are to be replaced by standard 10 facilitate consideration of the owner's applica renewed unless cables of this type have been cwt. cables at the earliest opportunity. tion for renewal, but will obviate the difficulties fitted. No certificate of airworthiness will be issued and consequential delay which are likely to Cables of the type mentioned in para. 3 or renewed in respect of any Westland arise when particulars of repairs and overhauls above that are protected at points by Bowden "Widgeon " aircraft unless the above-men have to be obtained from the firms who have sheathing should also be examined imme tioned modifications have been satisfactorily carried out such work since the aircraft was last diately by moving the sheathing so tha t the incorporated. examined. whole of the covered portion can be seen, and this operation must be repeated on each occasion The aircraft log book (C.A. Form 27) and No. 10 of the year 1929.—The attention of all tha t an aircraft is inspected for renewal of engine log book (C.A. Form 28) can be pur concerned is called to the revised requirements certificate of airworthiness. chased from H.M. Stationery Office, either for Certificates of Airworthiness as recently directly or through any bookseller, at a cost of Cancellation,—The above information is sub published in the "Airworthiness Handbook 2s. 6d. each (exclusive of postage). Refills for stituted for that contained in Notice to for Civil Aircraft." either book can similarly be purchased at a Ground Engineers No. 6 of 1929, which is I t is not the intention of the Air Ministry cost of 1s. 3d. each (exclusive of postage). hereby cancelled. to apply these revised requirements retrospec tively in the case of aircraft which are already No. 8 of the Year 1929.—It has been found No. 9 of the Year 1929.—The modification in possession of a Certificate of Airworthiness tha t cables of four strand construction, e.g., described herein must be satisfactorily in during the currency of that certificate. When, corporated in all Westland "Widgeon" air 4 x 19, wear rapidly in aircraft flying control however, the certificate comes up for renewal, craft before any such aircraft is submitted for systems, especially at those points where the and it is found that the aircraft does not comply inspection for issue of renewal of a certificate with the revised conditions, a special report on cables are protected by Bowden sheathing, the of airworthiness. each aircraft will be furnished by the Director cause of this being the relative movement of cable and sheathing. of Aeronautical Inspection, and the question The fuel tank is to be modified in accordance of renewal, in each case, will be considered on Existing cables of four-strand construction are with Drawing No. A.R. 1418. This modifica its merits. With regard to "subsequent" t o be examined immediately, and for this tion, which is necessitated by the possibility, aircraft, which are the subject of application purpose any protective sheathing is to be with the present arrangement, of a stoppage of the fuel flow, due to the collection of vapour for original certification (as distinct from on the fuel tank gauze, may be briefly described renewal of certificate), as from June 1, 1929, * NOTE.—Aircraft and engine log books are as follows:— such aircraft will normally be required to con required to be kept for all aircraft intended or form with the revised requirements in order to (a) A stack pipe is to be sweated into the used for carrying passengers or goods for hire or qualify for the issue of a Certificate of Air existing elbow of the tank sump. reward . (See para. 1 (b) of Schedule III to the worthiness. Air Navigation (Consolidation) Order 1923.) (b) A 22 S.W.G. re-inforcing plate is to be
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: May 1, 1929
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