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Aviation History
1951
1951 - 2266.PDF
and AIRCRAFT ENGINEER First Aeronautical Weekly in the World Founded 1909 No. 2234 Vol. LX. FRIDAY, 16 NOVEMBER 1951 ED/TOR MAURICE A. SMITH, D.F.C. ASSISTANT ED/TOR H. F. KING, M.B.E. TECHNICAL EDITOR C. B. BAILEY-WATSON, B.A. ART ED/TOR JOHN YOXALL Editorial, Advertising and Publishing Offices: DORSET HOUSE, STAMFORD STREET, LONDON, S.E.1. : v Telegrams, Flightpres, Sedist, London. Telephone, Waterloo 3333 (60 lines). Branch Offices: COVENTRY 8-10, Corporation Street. Telegrams, Autocar, Coventry. Telephone, Coventry 5210. .....- " BIRMINGHAM, 2 King Edward House, . - . New Street. Telegrams, Autopress, Birmingham. Telephone, Midland 7191 (7 lines). MANCHESTER. 3 : ., ;:': 260, Deansgate. Telegrams, Iliffe, Manchester. Telephone, Blackfriars 4412 (3 lines). Oeansgate 3S95 (2 lines). GLASGOW, C.2. 26b, Renfield Street. Telegroms, Iliffe, Glasgow. Te/e(>hone, Central 1265 (2 lines). SUBSCRIPTION RATES Home and Overseas: Twelve months U3s.0d. U.S.A. and Canada, $10.00 BY AIR: To Canada and U.S.A., six months, $16. IN THIS ISSUE: Himalayan Airlift - - - 6I0 SiPa 902 in the Air - - 616 High-speed Flutter - - 619 Ae-obatic Team - - - 621 Bit, and Pieces- ... 624 Refuelling Requirements 625 Keeping Them Airborne- 627 Lessons from ConvairA LITTLE time having passed, the effects of cerebral indigestion incurred through the recent Anglo-U.S. Aeronautical Conference at Brighton are now beginning to wear off, and one is the better able to assess the relative qualities of the papers pre- sented. Such a task is inevitably invidious, and we shall do no more than state that, in our opinion, the outstanding contribution was the lecture on high-speed hydro- dynamics given by Mr. E. G. Stout. We give this lecture (reported in our issue of October 26th) pride of place because Mr. Stout told of developments at Convair which have not only been proved to relieve the flying-boat of some of the more formidable limitations imposed by adherence to the theories of naval architecture, but which (and far more important) hold excellent promise of making marine aircraft aggressively competitive with their land-based counterparts —or even superior to them. Length beam ratios of the order of 10 and 12 :1, so long thought impracticable, have been demonstrated to be not only feasible but widely advantageous. The discovery of "spray-dams" has at one and the same time reduced the spray-making of a planing hull and rid the aircraft of the incubus of chines. Again, the Convair Skate project is of a kind to shatter the traditional trammels of marine aircraft design, for the hull is blended into the wings and, incredible though it might seem, has buttock sections of high Mach number comparable with those of the wing sections. If th^se revelations by Mr. Stout were not enough to give his audience furiously to think, then his relation of the use of free-body dynamically-similar models was amply sufficient to produce the same effect. By using radio-controlled dynamically-similar modek—a development of the studies initiated in this country of Coombes, Perring, Johnstone and Hutchinson—Convair are able to obtain almost the whole test-flight data of a design before the full-scale prototype even exists. What this means in con- servation of man-hours, materials and money is fantastic. At the present time, a prototype fighter aircraft cannot be built in this country in under about twelve months; it costs tens of thousands of pounds, it may need slight or considerable modifications, which takes up more time; only then, and if no one changes his mind, can production start. But the use of free-body models is not confined to obviating the need for a proto- type—a prototype, that is, in the present meaning of the term. By the use of such model technique, any number of variants of the basic design theme can be explored and their individual characteristics assessed. In this sense, the technique serves as a dynamic physical continuation of the purely theoretical work of the design-study whilst, at the same time, it offers an immeasurable widening of the practical field of design exploration. Mr. Stout told us that the small models take about 1,200 man-hours and the big ones about 4,000 man-hours to build. Cost is thus largely a function of rates of pay. But cost is less important than time. Unfortunately, this country exists today in a state of sub-surface tension engendered by having to re-arm in case it has to fight another war. On this page last week prominence was given to Air Chief Marshal Sir Guy Garrod's statement on the perilous state of Britain's re-armament production resources. There just are not sufficient men working in the vital industries, and the aircraft industry needs the largest single number. The use of dynamically-similar models would not, of course, free many men for other work, for the number of operatives engaged in building experimental types is relatively small. The real importance is the saving in time. Production cannot start until the design is proved, and proving the design takes another six to eight months on top of the j. 2 to 15 months absorbed in building a prototype. A minimum of about two years is thus used up in prototype work before production can start. That two years could, we suggest, be reduced to about twelve months by using the free-model technique. There may be snags—almost certainly there are—but we cannot conceive that they are likely to be comparable with those that now face the aviation industry and the country.
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