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Aviation History
1964
1964 - 1706.PDF
FLIGHT International, 4 June 1964 943 Most of the RAE's high supersonic speed research dates from 1961, when the 4ft x 3ft Mach 5 tunnel came into service. Though at present limited to Mach 4, the tunnel is soon to be given the flexibility for operating from Mach 2.5 to its design limit. The picture shows some of the waverider shapes and intake models studied with the aid of this facility Undoubtedly the star attraction of Bedford as far as popular imagination was concerned was the high-speed vehicle research programme which has thrown up the extremely apt name of "waveriders" for vehicles (previously known as carrot-winged vehicles) shaped to take advantage of the pressure field behind a shock wave. Working on the theory that the quest for higher flight speeds within the Earth's atmosphere is not likely to end with the 1,400 m.p.h. Concord, Dr John Seddon's team working with the 4ft x 3ft Mach 5 tunnel have been engaged, since 1961, on investi- gations into the sort of aerodynamics and efficiencies that will apply to vehicles operating in the Mach 4 to 5 speed range. One fundamental problem concerns the shape of the wing that can be used at hypersonic speeds. The Concord's slender delta planform was chosen so that the leading edge sweep would be more than that of the front shock wave. If this principle is followed into the hypersonic range it results in a shape that would be difficult or impossible to handle at low speeds. The waverider solution is to align the bow shock wave with the wing leading edge and by carefully concaving the underside, to actually derive lift from the associated high pressure region behind the shock wave. Some of the aerodynamic objectives for long-range transport aircraft operating at high supersonic speeds were summarized in the display featuring various vehicle shapes shown in the top photograph on this page. The table is reproduced below. Rangen.m. 3,000 4,750 5,500 Principal incentive High utilization Short journey time Long range Adequate values Mach 4 5 4.5 L/D 7 8 8 C 2 2.1 1.6 Weights (%) Empty 56 52 52 Fuel 39 44 44 Pay- load 5 4 4~ Centre right, model of hypothetical waverider—one of the first actual vehicle shapes to be tested by the RAE. Right, the Hand ley Page HP.II5 staged a convincing demonstration of the controllable qualities of the s(ender wing's natural high-incidence dutch-roll characteristics
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