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Aviation History
1931
1931 - 0130.PDF
FLIGHT, FEBRUARY 6, 1931 BOULTON & PAUL PATENTED CLOSED-JOINT TUBES. ONE of the more interesting of the Boulton & Paulproducts developed in connection with their schemefor standardised aircraft components, is the closed-joint tube. The Boulton & Paul system manufactures these tubes from strip by a patented process, whereby lengths up to 70 ft. (in thicknesses down to 0-005 in.) can be produced in almost any material. In the case of steel, a range varying from ordinary mild steel to 100 tons per square inch steel may be used. The high-tensile properties of the latter is established after the formation of the section by the Boulton & Paul patented heat-treatment process. Closed-joint tubes made of duralumin, aluminium, monel, etc., have all been successfully produced in diameters ranging from i in. o/'d. In standardising the circular tubes of this class, the Boulton and Paul system provides for sizes between 1 in. and 3 in., ascending from the 1-in. diameter in J-in. steps. A few small sizes are made, i.e., J-in. o/d, $-in. o/d and £-in. o/d, in 0 007 and 0 010 in. thickness materials for use in such members as the bracing posts on ribs. The advantages claimed for these tubes made from strip compared with the solid-drawn tube may be summarised as follows :— (a) Cheapness.—These closed-joint tubes are generally cheaper than the equivalent solid-drawn tubing, the difference being most pronounced in the case of the thinner gauges. (b) Concentricity.—As they are made from strip, for which the tolerance across the width is something quite small, the bore of these tubes is practically concentric. Quite a large tolerance is permitted in the specification for solid-drawn tubes, which adversely affects their design strength, as the design of any strut must be based on the assumption of maximum eccentricity permitted by the specification. In other words, these closed-joint tubes carry, it is claimed, greater end loads than the equivalent area solid-drawn tube of the same material. (c) Adaptability.—The process by which these tubes are made is equally applicable to steels or light alloys such a> duralumin, etc. Also, by the combined patented process of forming the tubing from the soft strip and afterwards heat treating, it is possible to obtain these tubes in vcrv thin gauges and in very high-tensile strength material. An example occurs in the case of lf-in. o/d by 27 gauge stainless steel of about 100 tons per square inch tensile strength, which can be made in 70-ft. lengths and which were, in fact, used in the airship R 101 structure in lengths of 45 ft. (d) Lengths available.—As these tubes are made from strip, the length of tube which can be produced is in general limited by the draw-bench length, which in the case of the Boulton and Paul system is 70 ft. There are few occasions, of course, when such long lengths are required, but the fact that they are produced in these lengths and afterwards cut to suit customers' requirements enables designers to dispense with joints so far as other conditions permit. (e) Stainless Steel.—As indicated in (c) above, this process of tube manufacture is equally applicable to the manufacture of stainless steel tubes, which can be produced in the whole of the range referred to above. (/) Special Sections.—In addition to the circular tubing described above, the Boulton and Paul system of manufac- ture enables a similar type of member to be made in a variety of shapes. Particularly noteworthy amongst these shapes- are :— (1) Square tubing. (2) Streamline tubing. These members in general have all the advantages of the circular tubing. The company will be pleased to supply further details concerning the range of sizes available, etc., on application to Boulton and Paul, Ltd., Norwich. An Interesting Engine As our readers will know, the Pobjoy engine has now gone into production at the new works of Pobjoy Airmotors, Ltd., Hooton, Cheshire, and those who are interested in it should make a point of seeing an engine now being exhibited at Selfridge's. This particular model has done over 400 hr. flying, including a large amount of racing and full throttle work and has stood the test perfectly. It is an extremely- interesting engine, as in spite of its low weight it is geared and therefore gives manufacturers of small aircraft a chance to build something fast and efficient.The Royal Air Force Display THIS year's Royal Air Force Display, the Twelfth, will be held on Saturday, June 27th, at Hendon. As before, the gates open at 10 a.m., and the programme is completed at about 5.30 p.m. Details of the programme are not, of course, available just yet—but please note the date. It may be of interest to record that the attendance in 1930 surpassed all previous years—154,120 persons and 10,837 cars were admitted to the aerodrome and official car parks.British 'Planes for Japanese Newspaper THE de Havilland Aircraft Co., Ltd., has received instructions to supply two " Puss-Moth " cabin aeroplanes to The Asahi, one of Japan's most important newspapers, published in Osaka and Tokio. It is understood that these 'planes will bs used for the rapid transport of reporters, papers and photographic negatives, and perhaps also for aerial photography.Gipsy Moths in Switzerland THE de Havillmd Company has received an interesting letter from Ebrr R. Hsrzig, Assistant Manager of the aero- drome at Basle, of which the following is a summary :— (a) The " Moth," with " Gipsy I " engine, supplied to the Basle Aero Club in 1928, has now completed 467 hours flying, during which 4,071 landings have been made. Although the de Havilland Aircraft Co., Ltd., as manufacturers of the " Gipsy " cng ne, recommend a complete overhaul after 450 hours flying, the " Gipsy " engine of this " Moth " has never been completely overhauled. So far it has given no trouble whatsoever, (b) The " Moth," with " Gipsy I " engine, privately owned by Horr Schetty, has completed 111 flying hours and has made 703 landings. It has had no overhaul of any kind, and no replacements have been effected. The owner reports it to be " working to his full satisfaction.Autogiro Developments As a result of demonstrations with an American-built Autogiro, given recently to Mr. David S. Ingalls, Assistant Secretary to the Navy for Aeronautics, the U.S. Navy have purchased an Autogiro fitted with a 300-h.p. Wright " Whirl- wind " engine. It is thought that the Autogiro presents many possibilities as regards operation with ships at sea. owing to its ability to take-off from and alight on confined areas. We understand that this side of the Autogiro's qualities is also bdng considered in this country. Another sphere of activity in which the Autogiro is thought to possess possibilities is that of aerial fire-fighting. Col. L. Coil, Chief Fire Warden of the State of New Jersey, is, we learn, investigiting the matter following a demonstration on one of the latest Autogiros produced by the Pitcairn-Cierva Autogiro Co. of America.British Empire Trade Exhibition THE Department of Overseas Trade calls our attention to the fact that a memorandum entitled " Hints for Com- mercial Visitors to the Argentine Republic " has been pre- pared by the Commercial Counsellor to His Majesty's Embassy at Buenos Aires. The memorandum, which is numbered C 3451, can be obtained from the Department of Overseas Trade, 35, Old Queen Street, London, S.W.I. The following points should be borne in mind by those intending to visit the Argsntine specifically in connection with the Exhibition in 1931 :—The weather in Buenos Aires at this time of the year is generally comparable to English Summer weather, and similar clothing should, therefore, be brought. The vaccination regulations usually enforced will be waived for visitors to the Exhibition travelling 1st and 2nd class or by Tourist ship. Special arrangements have been made by the Exhibition Authorities to enable the introduction, free of duty, of samples and propaganda materials and literature, provided these are intended solely for use or distribution at the Exhibition. Further details of these arrangements can be obtained at the London Office of the Exhibition, 5, Parlia- ment Mansions, Victoria Street, London, S.W.I. Advance hotel bookings are already heavy, and intending visitors are advised to make the necessary arrangements in this connection as quickly as possible.Bert Hinkler's Loss IT is reported that Mr. Bert Hinkler has suffered the loss of all the medals and trophies he has won. They wrc stolen in Detroit, on January 30, while he and his wife were dining in a restaurant. Gold Medal for Miss Amy Johnson , THE Society of Engineers has awarded the President s gold medal to Miss Amy Johnson for her paper on " i"nfr attention that I gave to ' Jason's ' engine during my flight- 126
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