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Aviation History
1956
1956 - 0412.PDF
412 FLIGHT, 13 April 1956 LAMINAR FLOW AT RADLETT . . . third glove in place. Most of the flying has been done at around10,000ft at about 250 kt i.a.s. (300 kt has been reached), and no trouble has been experienced as a result of flying in all kinds ofBritish weather conditions. It is true, however, that the company have not yet tested the system in excessively dusty atmospheres—such as might occur during Middle East sandstorms—in which conditions it is conceivable that the suction holes could becomeblocked by induced solid matter. It is known, however, that no sudden breakdown of flow would occur were the suction systemto fail. Tests have been carried out in which the suction system has been suddenly shut off after the Vampire had been trimmedto fly straight and level, hands off, with the system in operation. The pilot had no difficulty in maintaining complete control ofthe aircraft, although there was a pronounced rolling tendency as a result of the decrease in lift of the experimental glove. Results to date amply justify all the expectations of Dr. Lach-mann and his research team A remarkable reduction in boundary- layer thickness has been achieved as a result of suction: the tur-bulent layer, 1.76in thick, has been replaced by a laminar layer only 0.18in thick. Typical results for drag per foot run of the test surface are: turbulent skin drag, 3.98 lb; laminar skin drag,0.325 lb; and drag equivalent of pump work, 0.390 lb. This means that the total laminar drag amounts to no more than0.715 1b per foot run, which is less than one-fifth of the original skin drag without suction. Put in another way, Handley Pagehave succeeded in reducing the skin friction over the glove by 82 per cent by maintaining laminar flow across the test section. Admittedly it would be more difficult to achieve such resultson a highly swept wing. The flow over swept wings is of a more complex nature, since other types of boundary-layer instabilityare involved and, in consequence, rather more suction power would be needed to achieve comparable results. The company look upontheir work in this sphere as being of an essentially long-term nature. It is expected that the next stage will be to fit an aircraftwith complete experimental wings, which should enable even more convincing results to be obtained. Nevertheless, HandleyPage do not envisage boundary-layer control of this type being applied to existing aircraft as a modification. Its primary applica-tion is foreseen in the long-range transport sphere. It is expected that, by employing such an arrangement to maintain laminar flowacross the wings, the system could reduce the size and weight of transatlantic jet transports by over 30 per cent, provided the air-craft were designed to include the system from the outset. TWO AMERICAN FLYING FILMS WITH offerings such as Twelve O'Clock High and The Bridgesof Toko Ri the Americans have established a reputation for first-class films about flying. This reputation they unfortunatelyjeopardize at regular intervals with some very bad material. Two new films which, for different reasons, are well worthseeing are about to be shown in London. One Man Mutiny (gen- eral release May 7th) starring Gary Cooper as Gen. "Billy"Mitchell, gives a supposedly historically accurate account of that personality's court martial and dismissal from the U.S.Army Air Corps in the 1920s. The acting of Gary Cooper as Mitchell and of Rod Steiger as the Army's prosecutingcounsel is superb, and the story of the court martial and the events which led up to it are well set out. But those whoseek accurate flying material in terms of vintage aircraft will be to some extent disappointed. In the early part of thefilm, the period being about 1922, Gary Cooper flies in a Grumman single-float amphibian, whereas this type of aircraftdid not see service till many years later. He then leads a flight of so-called bombers for the fateful attack on the German battle-ship which he sank as a demonstration. But instead of Martin M.B.2s these turn out to be a D.H.9 and a Curtiss JN-4D "Jenny"(the latter re-engined with a Ranger in-line which makes it some- thing of a spotter's headache)—and these aircraft are supposedlyeach carrying two 2,000 lb bombs! Nevertheless, the film is well worth noting by those who would like to see vintage aircraftflying for a short time and a very fine dramatic performance for the remaining 60 minutes or so. The other film, due to open yesterday, April 12th, at the Rialtocinema, Coventry Street, is called On the Threshold of Space and deals with the research being carried out by U.S.A.F. aero-medical authorities into the physiological problems of baling out at very high altitude and sonic speeds. It is in Eastman Colourand CinemaScope, and quite outstandingly good. The main theme is the development of pilot-escape equipmentfor the X-125 rocket-powered, supersonic, high-altitude research aircraft, in which the use of a capsule is not possible. The air-craft itself is hypothetical but by no means far-fetched and the stages of research into the problems of escape from it are thoseactually undertaken by the U.S.A.F. for other projects. In fact, the final sequence deals with a test with a balloon capable ofcarrying a man to a height of 100,000ft so that he can make a delayed-opening parachute descent; and such a test is in fact tobe made later this year from just such a balloon with just such a purpose. The film gives accurate details of U.S.A.F. researchso far carried out, first with the downward ejection of the bom- bardier of the B-47, then with the rocket-propelled sled andfinally with the balloon. Superb photographs of B-47s, downward ejections and bodiesin free fall are followed by a sight as impressive as anyone wishes to see—the rocket sled hurtling past the camera (and straight atit) as it accelerates to about 900 m.p.h. and then roars and screeches to a standstill in the water brake. There is plenty of"five, four, three, two, one, whoosh . . ." about this film, but— relief for the science-fiction weary—the material is solid fact andexcellently presented. Apart from omissions presumably made for security reasons, it shows the difficulties met and gives an ideaof the calibre of men who have done the "guinea pig" work. The background story, at Hollywood strength, is to the formulaof "girl marries guinea pig and reluctant scientist vindicates his courage"; but it is not so sickly as to make the film wearisomeand does give a leitmotif which holds the story together well. It is, incidentally, pretty forcefully demonstrated that neither theresources nor the climate and scenery for either a film of this calibre, nor even for such research, are available in this country.For aviation interest and fine photography On the Threshold of Space should definitely not be missed. LONG-RANGE WEATHER COMPUTING "pOLLOWING successful experiments with an electronic com--"- puter for daily predictions of weather and computing flight- paths for commercial aircraft (Flight, March 23rd, page 320), theUnited States Weather Bureau has formes' a special research unit to predict weather several days or even weeks in advance. Instructions to the electronic computer (an IBM 701) for therequired calculations have been coded during recent weeks and the unit is shortly to be in full operation.The first trial model computer for the new service was designed by Dr. Norman A. Phillips, of the Institute for Advanced Study,at Princeton University, and has been successfully giving weather patterns for up to three weeks ahead. Certain changes intendedto improve accuracy are now being made, and once the machine is "instructed" on how to perform its calculations, it is expectedthat it will be able to make forecasts for at least 30 days ahead, or possibly through one period of what meteorologists call theindex cycle—that is, long enough for the general characteristics of air flow to repeat themselves at least once. Dr. Joseph Smagorinsky, chief of the Weather Bureau's generalcirculation research section, who is in charge of the experimental project, explained that at one point in the index cycle atmospheric flow is zonal, or relatively parallel to the Equator. This patterngradually breaks down until large troughs and ridges are formed and the atmosphere is comparatively turbulent. The time requiredfor these changes from smooth to turbulent flow and back again is not predictable. If the time required to complete an indexcycle were known, long-range forecasting would be facilitated. Dr. Smagorinsky said the unit's work was twofold: (1) Toconstruct, with what was now known, a mathematical model of the atmosphere that would reflect its actual state over a periodof weeks as accurately as possible; and (2) to make fundamental investigations of such phenomena as the effects of changes in solaroutput on weather, and of the formation of clouds, with the aim of being prepared to make more accurate numerical predictions. The research unit, operated by the U.S. Weather Bureau,receives financial support from the Office of Naval Research and the Geophysics Research Directorate. Its activities are guided byan advisory committee consisting of Dr. Harry Wexler, the Weather Bureau's director of meteorological research, and Drs.John von Neumann and Jule Charney, of the Institute of Advanced Study, Princeton University, where studies on numerical weatherforecasting were pioneered.
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