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Aviation History
1963
1963 - 1112.PDF
FLIGHT International supplement, 28 March 1963 of deflectors in the path of the curtain jet. As shown in the accompanying diagram, the inventor reasoned that cascades of deflector vanes could be employed to intercept the jet and turn it inwards (possibly more than once). Preliminary results with an elementary deflector scheme—more primitive than that shown in the sketch—were reported as "quite staggeringly good." Without deflectors the experimental rig operated at H=1.71R. With the single simple deflector, turning the jet through an angle of 90°, it was found that H=3.13R, and, allowing for the height of the deflectors themselves (0.75in) the theore tical H gain should be 1.98. // is possible that it would pay to feed in a little new high-pressure air to the lower deflectors, enabling more deflector stages to be used, in an attempt to extract the maximum energy from the jet. With my approx 90° deflector, optimum results are obtained when the centreline of the deflector is set at a height of about 0.45H, but it is not very critical, and so far I have not been able to prevent the system "priming" itself, i.e. nothing seems to be critical the jet, which presumably must start when the equipment is being turned on as a single semi-circle, just walks out wards on to the deflector, and is deflected in again presumably the external en trained air is deflected initially). Air-Cushion Vehicles HYDROFOILS <S3(f(((( L DEFLECTORS A suggested configuration for superimposed deflectors arranged in con junction with hydrofoils (see "Letter to Mr Shaw") Ripplecraft Report No. 12/57: July, 1957. In this document Cockerell discusses Uwe H. von Glahn's NACA Technical Note 3982(22), in which it is stated that an annular nozzle will show a thrust- augmentation of the order of 50 per cent for a nozzle/ground ratio (corresponding to Hovercraft H/D) of 0.2. This figure of an augmentation, states Cockerell, is obtained by comparing the experimental figure for the thrust of a certain annular nozzle, not with the experimental figure of thrust for a circular nozzle of equal flow A three-view drawing of a suggested cross-Channel ferry, as described on the opposite page area as would seem logical, but with the theoretical thrust which should be obtain able from a circular nozzle of equal flow area. This so clouds the results that von Glahn is led right off the scent, and so he discards nozzle D which should have led him on to further nozzles and larger values of augmentation. In the remainder of this report Cock erell discusses the experimental results obtained by von Glahn, and suggests improvements to the tatter's mathe matical expression in order to cover a wider range of values of H/D. Cockerell particularly notes there must be a velocity and pressure gradient across the jet, and it was this realiza tion which led to the breakdown of the "thin-wall" theory. Ripplecraft Report No. 13/57; August 14, 1957. In this Note on Possible Hovercraft Development the inventor calls for more rapid evaluation and development, discusses the place of air-cushion vehicles in the overall transport spectrum, com ments on work accomplished at that time and points to possible future craft. One cannot help sympathizing with his restlessness:— A small development research contract is due to be placed with Messrs Saunders- Roe to substantiate and add to the theoretical and experimental data supplied by the writer. There would appear to be (as seen from the outside) not yet a full appreciation of the potentialities of the system, and therefore an entirely inade quate amount of effort. This is not surprising, as it is always difficult to get new ideas taken up, and the extreme new ness of this idea makes it doubly difficult. However, the writer, having lived with the idea for a longer time than anyone else, feels it his job to continue pressing with all the means at his disposal. The writer is precluded from taking the obvious course of making a man-sized model and demonstrating it, because the device was put on the secret list in November 1956. 45
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