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Aviation History
1964
1964 - 1694.PDF
FLIGHT International, 4 Juno 1964 933 Letters Letters for these columns are welcomed, though "Flight Inter- national" does not necessarily endorse the views expressed. Name and address should be given, not necessarily for publication in full. Brief letters will have a better chance of early publication. Strengthening the Junior Wings SIR,—You have been kind enough to suggest that I let you know how best I think your generous offer [to assist a "Junior Wings" scholarship winner to continue his training to PPL standard—Ed] should be implemented. Naturally one has plenty of ideas, but it is important to see that the money should go where it would do the most good. I have found, in running various airfields, that one always gets a number of enthusiastic youngsters who often come day after day simply for the sheer pleasure of watching aero- planes; at first they tend to be a bit of a nuisance, and short- sighted people are apt to discourage them because they have no money to spend. But I have found that if you let these boys come, sooner or later you are able to pick out some very good ones—in fact, at Redhill particularly, I don't know what we should do without our volunteer boys. Naturally you have to keep an eye on them but after a bit they become extremely useful. Therefore my suggestion is that your award be given as the result of a citation from the CFI or manager of a flying club. I agree with your correspondent, C.E.H., that the minimum age could well be 21. These citations could then be judged by a panel (as are the Jean Bird Trophy nominees) and as many of these particular scholarships as it is possible to afford, should be awarded annually. Although we have always welcomed the ATC Scheme and will do the same for the Junior Wings Scheme, I agree with C.E.H. that for too many boys this is simply something for nothing. But when a boy has proved his keenness and enthusiasm by sweeping out your hangar, helping push aero- planes, answering the telephone and acting as general "run around" for you, then I think he is entitled to any awards which are going. Clay gate, Surrey NORMAN JONES Swing: Wing-ery SIR,—It is reported that an American sales drive for the TFX is imminent in Europe. While the theoretical advantages of variable-sweep wings are obvious, it is less clear how these are to be achieved in practice, particularly in a tactical air- craft subject to exceptionally heavy aerodynamic stresses. Firstly, the CL will presumably move forward when the wings are extended for slow flying and aft when they are swept back for supersonic flight, producing tail heaviness in the first case and nose heaviness in the second. How is fore-and-aft trim to be maintained ? Secondly, assuming that the pivotal point is some way out from the wing root, as shown in artists' impressions, how is the geometrical problem of producing a clean wing for both flight regimes to be solved? This would appear difficult if not impossible. An alternative would be to sweep the whole wing, in which case a lengthy section of trailing- edge will have to be accommodated in the fuselage in high- speed flight. How could this be done without an unaccept- able weakening of the fuselage structure? Lastly, hinges either at the wing roots or at some point along the leading edge must result in a weak wing structure or a very heavy one. The latter might pay off in a long-iange airliner but hardly, one would imagine, in a tactical fighter; the former, of course, would be unacceptable in any aircraft. On the face of it variable-sweep wings would seem to be a designer's and structural engineer's nightmare. Could not the same performance or better be achieved using fixed fully swept wings and partially vectored thrust? For example, 30° vectoring will provide an extra lift equal to half the total thrust at the cost of a reduction of only 14 per cent of the horizontal thrust component during its operation. It is suggested that the combination of wing lift and vectored thrust, with none of the design problems of variable sweep, will in practice produce the better and less costly solution. Southsea, Hants F. P. U. CROKER [In any aeroplane designed to fly for long periods at both subsonic and supersonic speeds the rewards of variable sweep are considerable. So are the problems, but these should not be regarded as fundamentally different from those imposed by movable flaps or a hinged nose. The forward migration in centre of pressure (c.p. not CL) from subsonic to supersonic speed approximately cancels out the rearward shift due to increasing sweep. If the wing does not have variable sweep something else must be done to preserve longitudinal balance; on the Concord the answer is to pump fuel forwards out of a trimming tank in the tail.—Ed] "Full of Sound—Signifying: Nothing" SIR,—Mr G. C. Scott's article on supersonic flight in your issue of April 30 was so vehemently written that no one could deny that it was Full of Sound; but because it was so anti-progressive I sincerely hope that it is allowed to Signify Nothing. In decrying the pursuit of speed Mr Scott is also decrying progress. While I would agree that speed is only one facet of progress, I hope that man is sufficiently determined to progress that road speeds will rise to 100 m.p.h. and possibly to twice that before the end of the century. Cer- tainly if the railways do not improve their speeds to this sort of figure they will have no passengers, even before there are no trains. Travel is by its very nature uncomfortable and anything which either eases that discomfort or the time for which it has to be endured is beneficial to mankind and therefore to progress. The unusual and inevitably restricted environment is uncomfortable and there is no indication that Concords will be any better than current aircraft in that respect, but it will probably halve the flight time. Of course, it would be progress to reduce the restrictions on the environ- ment, but merely increasing vehicle weight does not require the technological progress required to increase speeds; and, anyway, more people choose speed to comfort and go by air rather than by sea. Progress always brings with it changes in the established order, some of which some people regard as for the worse, but further development almost invariably cures those defects. I would hate to be regarded as callous, but must point out that besides being uncomfortable travelling has always been risky. However, progress has over the long term reduced those risks. Although we still have great sea tragedies we have come a long way from the days of the Viking long-boats and even from the days of the Mayflower. Kings have died from riding accidents, but today accidents caused by mechanical defects within the vehicle are few and far between. Every air traveller takes his life in his hands and trusts bodies such as the ARB and FAA not to licence potentially hazardous undertakings. This places a lot of responsibility on those bodies; and, although they would probably not care to admit it, they have to accept certain risks because nobody knows, nor will know, the answer until it has been tried out in service. These risks are taken in the name of progress. Reliability is also something which is always improving. It has to, because of the high costs of unscheduled removals, but we must not confuse component reliability with system reliability. With improving fail-safe designs, system reli- ability can be higher than the total reliability of its individual components. Even without fail-safe systems the car which • today travels at 70 m.p.h. is more reliable than the old 20 mile-an-hourers, and certainly more reliable than the horse. To Dr Russell I will say now that Concord will be as reliable as subsonic jets, because there is already in existence a group of people whose jobs it will be to make that true. To Mr Tye and Mr Dempsey I would point out that although we have to learn to walk before we can run, we never learn Continued on page 934
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