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Aviation History
1951
1951 - 0647.PDF
FLIGHT, 6 April 1951 403 testing. The method by which this was achieved was to base the strength calculations on an early weight estimate and take no account of those fluctuations in total weight which occurred during the design of any aircraft. The airframe was finally put up for structural test with a load distribution based on the actual total weight which the finished aircraft would have. A few local points had to be strengthened, but in due course the airframe was cleared without undue difficulty, and with very satisfactory results as far as structure-weight was concerned. The lecturer's opinion was that this was the most satisfactory method of obtaining a light and efficient structure. The flywheel effect of a turbine, said Mr. Hollis Williams, was considerable, and after shutting the throttle there was an appre- ciable delay before the turbine lost speed. Again, on the open-up —as in a wave-off—it was found that delay in picking up speed was again appreciable. Armstrong Siddeley Motors, Ltd., had made experiments with a single Mamba, fitted with a Rotol air- screw, in a Balliol trainer. This used a constant-speeding system, whereby the turbine was run continuously at constant speed, and variations of thrust were achieved by airscrew-pitch change. The system of control was reported upon most favourably, and, there- fore, was introduced into the Double Mamba power plant. By running the turbines at constant-speeding condition when throt- tling for landing, the flight fine-pitch stops were withdrawn and the airscrew blades were free to take up whatever fine pitch was necessary to satisfy the minimum shaft h.p. In other words, at the "cut", with the turbines running at constant speed, the airscrew approached its ground fine pitch stop. It must be realized that to satisfy starting conditions the turbine fine-pitch setting was much nearer the discing condition thanwas the case with a piston engine. The constant-speeding system gave a satisfactory rate of thrust- loss at the "cut", and at gliding speed entered a condition of nega- tive thrust which provided a useful increment of drag. Of the further development of the anti-submarine aircraft, the author said that those who had been studying anti-submarine warfare realized that the fixed-wing, aircraft, in due course, might give way to the helicopter. A large, load-carrying, all-weather helicopter could solve a number of problems in a much simpler fashion than was possible with a fixed-wing machine. It would not only simplify equipment, but it should be possible for it to operate from a merchant ship, thus removing the necessity for the escort carrier, itself an important and vulnerable target. THE INDUSTRY ANALYSED Aircraft Manufacture in 1935 and 1948 Compared: B.O.T. Census Figures BOTH to those who find such data of value in their work and toothers who like statistics for their own sake, an analysis of the British aircraft industry recently issued by the Board of Trade should be of considerable interest. Extracted from the production census on which the B.O.T. has been engaged, it is published in The Board of Trade Journal for March 24th as preliminary report No. 139 : Aircraft Manufacture and Repair Trade. The report consists of five tables in which each important aspect of the subject is covered comparatively, the census year 1948 being set against 1935. The choice of these two years—which, presumably, applies throughout the industrial census—is interest- ing in view of the fact that in each case a rearmament expansion was about to begin. In a brief introduction to the tables, the Board explains that they refer to "establishments engaged wholly or mainly in the manu- facture and repair of complete aircraft (including gliders, airships and balloons) and frames, and of engines of all types, propellers, undercarriages, and other parts and accessories (except electrical equipment), and which employed more than ten persons on the average during the year." It is estimated that about 99 per cent of the total net output of these establishments for 1948 is covered by the returns compiled. It is further stated that "any establishments in Northern Ireland are excluded in 1948; no production was recorded there in this trade for 1935." (It will be recalled that Short Bros, did not move from Rochester to Belfast until after the war.) Though we do not intend to discuss the figures here, some are TABLE I: GENERAL SUMMARY Value of production (gross output) Receipts from Government Departments Cost of materials, fuel and electricity used Amount paid for work given out Net output Wages and salaries of persons employed .. Average number of persons employed (excluding outworkers) Net value of output per person employed (exclud- ing outworkers) (£) Number of establishments 1948 (Cx 1,000) 115,294 2.676 42,619 6,321 69,030 49,530 134,219 514 192 1935 (£ 1,000) 14,328 5,391 270 8,667 35,890 241 57 The values of production in 1948 and 1935 and of materials, fuel and electricity used in 1948 are derived in the following manner:— Total value of sales or purchases Adjustments for stocks and work in prefrtti Ltis payment for transport by Other firms Output 1948 (t> 1,000) 111,673 + 3,775 115,448 154 115.294 1935 (£\ 1.000) 13,029 <o) + 1,299 <b) 14,328 Materials, etc. 1948 (£x 1,000) 43,522 —903 42,619 particularly worthy of note—as, for example, the revelation that the net value of output per person employed rose from £241 in 1935 to £514 in 1948. Taken literally, a footnote to Table V is amusing—"No working proprietors were recorded for 1948." It would be enlightening to hear, say, Sir Frederick Handley Page's comments on this. II: STOCKS OF FINISHED PRODUCTS, MATERIALS AND FUEL Finished products and work in progress (Cx 1,000) Materials and fuel (tx 1,000) Beginning of Year 1948 58.638 10.722 1935 2,748(o) End of year 1948 62,413 11,625 1935 4,047(o) (a) Work in progress only. Ill: CAPITAL EXPENDITURE—PLANT, MACHINERY, VEHICLES Plant and machinery (£> 1,000) Vehicles (tx 1,000) Total (1*1.000) Acquired during 1948 New 1,516 180 1,696 Second-hand 1,308 114 1,422 Disposed of during 1948 211 44 255 IV: CAPITAL EXPENDITURE—NEW BUILDINGS ACQUIRED Capital cost of new buildings (including extensions, etc.) acquired during the year, excluding site value (£x 1,000) 1948 758 V: EMPLOYMENT, WAGES AND SALARIES No. of males: Under 48 All ages No. of females: Under 18 All ages Total Nos.: Under 18 All ages Total remun- eration (Cr 1,000) Operatives (ov. for year) 1948 2,659 85,250 224 8,879 2,883 94.129 32,975 1935 3,129 28.266 270 1,687 3,399 29,953 Admin., tech. and clerical staff (a) 1948 663 29,411 1.131 10,689 1,794 40,090 (b) 16,555 1935 417 4,719 261 1.218 678 5,937 _ Totals 1948 3.322 114,661 1,355 19.558 4,677 I34,2l?<b)(c) 49,530 1935 3,546 32,985 531 2,905 4.077 35,890 (a) Production for sale. (b) Work in progress only. (o) At September 25, 1948. and October 12, 1935. (b) No working proprietors were recorded for 1948. (c) The employers' share of contributions to all National Insurance Schemes payable during the year in respect of these workers amounted to £1,056,000. In addition to the employees in the above table the firms in this trade em- ployed 9 male outworkers in 1948, the amount paid to them being less than £500. Similar information is not available for 1935.
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