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Aviation History
1950
1950 - 0869.PDF
FLIGHT, 4 May 1950 565 HIGH-SPEED RESEARCH R.Ae.S. Paper on Developments in the Work of the Aerodynamics Division of the N.P.L APAPER entitled Recent Developments in High-SpeedResearch, by J. A. Beavan, M.A., A.F.R.Ae.S., andD. W. Holder, B.Sc, A.C.G.I., D.I.C., A.F.R.Ae.S., was presented last Thursday, April 27th, before the Royal Aeronautical Society, at the Chemistry Lecture Theatre of Manchester University. Of considerable interest to aero- dynamicists, the lecture dealt with the various wind tunnels in the N.P.L. Aerodynamics Division, and the measuring instruments and experimental techniques employed. In a section reviewing recent experiments, the authors sum- marized the test methods and the results obtained, but by the very nature of the work, focused as it is on funda- mentals, much of this information was of interest chiefly to the aerodynamic specialist rather than to the man primarily concerned with the very much broader field of design application. When the Aerodynamics Division took it up in 1935, research on high-speed flow was, as far as aeronautics was concerned, mainly of academic importance and could there- fore be regarded as more suited to the N.P.L. than to the other establishments. * The i2in tunnel, which was then built, was not only the largest high-speed tunnel in the country but was, in addition, the only one devoted to aeronautical work. During the past 15 years, the scene *-' has changed completely, and although new equipment has been built at the N.P.L., the apparatus and staff available (the staff of the high-speed laboratory consists of four scientific and four experimental officers and has been at this level for the past seven years) are only a fraction of the nation's total facilities for research on high-speed flow. It was the authors' contention that, this being so, it was desirable that the N.P.L. should devote most of its resources to investigations of a fundamental nature, leaving tests of supersonic designs and other practical applications to the larger and more suitable tunnels and other facilities available elsewhere. Such fundamental work was urgently needed because, although in recent years there had been a very large output of theoretical work, many of the simplest theories of compressible flow remained unchecked by ex- periment. Such checks were clearly important if further theoretical work was to proceed on a sound basis. Much experimental work had been done at the N.P.L. on the mixed subsonic and supersonic flow past two- dimensional aerofoils, and the physical nature of many of the phenomena which occurred in this regime of flow were now, at least partially, understood. Real progress had been impeded by the absence of a reliable theory, even in the absence of the boundary layer, or of a theory re- lating to the interaction of shock waves with the boundary layer on an aerofoil- surface. It seemed that a major part of the available effort could be devoted more profitably to the study of the flow round finite wings, particularly at MAKING LOADS LIGHTER "CORK trucks, baggage trollies and many other kinds of smallF vehicles of kinds used in airport load-carrying will be on view at the forthcoming (June 6th-i7th) Mechanical HandlingExhibition at Olympia, London. In addition, there will be examples of almost every kind of hoist, small mobile crane.conveyor and vehicle used in factory production work. With a floor space of over 200,000 sq ft, the show—which is organ-ized by the journal Mechanical Handling—is more than twice as large as the first exhibition, held in 1948. Concurrently, the Mechanical Handling Convention will beheld, when, there will be daily discussions and papers by, in all, fourteen experts on various aspects of the subject, the emphasisin each case being on practical applications. A number of films will also be shown. Representatives of a "mechanical aids" team of the Anglo-American Council on Productivity will also attend, and will organize a discussion on the report which they made after arecent visit to America. supersonic free-stream velocities. This problem was of greater practical importance and, moreover, was covered by an extensive theory most of which remained, as yet, unchecked. With this in mind, an extensive series of balance and pressure plotting tests had been planned for the i8in x 14m tunnel on delta wings for which a theory was available. The work on two-dimensional aerofoils would continue in the 2oin x 8in and in other tunnels, not only for its own sake, but because the information thus gained on the interaction between shock waves and boundary layer might be of value in other problems. Detailed tests on systematic family based on a representative modern section were in progress in the 2oin x 8in tunnel which, in addition, had a full programme of other work. The higher Reynolds number that was available in the i8in x 14m tunnel would extend the range over which the problem of shock-wave/ boundary-layer interaction had been investigated in the past in a most useful direction, and it was intended to examine the interaction for a fiat plate as well as for the curved surface of an aerofoil. The problem was also to be investigated in a proposed small tunnel which might be driven either by the direct discharge of compressed air through the working section or by the vacuum pump, thus giving a large range of Mach and Reynolds numbers and enabling them to be adjusted independently. This tunnel and the 18111 x 14m tunnel were, in addition, to be used for explorations of the boundary layer of sub- and super- sonic main-stream flows. Allied to the work on the interaction between shock waves and boundary layers was that involving removal of the boundary layer by suction. This might include work on the high-speed performance of new types of suction aero- foil that had been designed in another part of the Division to improve the low-speed stalling properties, or reduce the drag. These might have slots near the nose or even dis- tributed suction over the whole nose section using porous surfaces. The gjin x gjin tunnel was likely to be devoted for a considerable time to flutter derivative research. This field was of such importance at both sub- and supersonic speeds that one of the 36m x 14m tunnels to be built in the Aero- dynamics Division was reserved for the continuation of these experiments with larger sized aerofoils, perhaps up to one foot chord. It was proposed also to take in the near future Schleiren photographs with a high-speed camera of the flow round an aerofoil performing pitching oscillations. In addition to the pressure measurements on blunt-nosed plates and bodies already mentioned, the gin x 3m tunnel was to be used for tests on families of biconvex and wedge aerofoils at supersonic speeds. R.P.A.F. AT I.A.L. "DEPRESENTATIVES of the .Royal Pakistan Air Force -tv recently" visited the engineering department of Inter- national Aeradio, Ltd., at Bovingdon Airport. They were the Air Commander in Chief, A.V-M. R. L. R. Atcheriey, C.B.E., A.F.C.; the Director of Maintenance and Supply, A, Cdre. R. G. Bowditch; and W/C. M. M. A. Cheema. The visitors inspected work being carried out by I.A.L. in connection with a radio and radar training scheme to be insti- tuted by the Pakistan Government. They saw a synthetic trainer, a high-power ground radar unit and V.H.F. trans- mitters and receivers for ground-to-air communication. They were also shown equipment for a radio teleprinter link in Pakistan which includes a '' packaged" frequency-shift re- ceiver terminal—-the first of its type to be made available in this country. Among those who escorted the party round the department were A. Cdre. E. S. Cadell, managing director, and Mr. G. Scott-Farnie, operations manager.
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