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of a helicopter rotor, or the like, by abiplaneaerofoil assembly 15,16, of small gap/chord ratio, the depth of Month in the Patent Office the duct being equal to the gap of the aerofoils, which are faired into the horizontal duct walls. The biplane aerofoils arc of high fineness ratio and are of the same dimensions and section, having a flat face and a cam These abstracts of British Patent Specifications are taken, by permission, from the officially prepared bered face, the flat faces being disposed parallel to abridgments classified in Groups. Sets of Group abridgments can be obtained from the Patent Office, and facing one another with zero stagger. Fuel for the 25 Southampton Buildings, W.C.2, sheet by sheet as issued, at a subscription of 10s. per Group. Copies duct is supplied through conduits 17, 18 passing of the full specifications are obtainable at the same address, price 1s. each. through the aerofoils 15,16, and blade 10 respectively. 614,102. Controlling aircraft. Lachmann, G. V., empty, or partly or completely filled with sound- and Suppancic, G. O. July 5, 1946, Nos. 20158/46 and absorbing material D such as slag wool or felt. The 614,622. Helicopters. Cierva Autogiro Co. Ltd., 2275/47. (Class 4.) boards B may be protected by acoustically trans Shapiro, J. S., and Pullin, C. G. July 25, 1946, No. In order to impart 'feci' to a power-operated air parent material, and the frame A may be formed by 22155. (Class 4.) (Also in Group XXVI.) craft control system, the control operating member is bending the ends of one of the boards B. In a modifi A rotor blade for a helicopter or other rotary-wing subjected to an elastic reaction, the intensity of which cation, vibratory boards are fixed either close to the aircraft carries a propulsive duct which is so disposed is selectively varied to suit changes in airspeed by insides of the boards B or separated therefrom by that the greater portion of it is markedly displaced means responsive to, or the operation whereof is a small air spaces, or alternatively one vibratory board forwardly or rearwardly of the spanwise plane con function of, the dynamic head. The embodiment may divide the space C into two. Sheets of porous taining the axis of rotation and the maximum thick shown in FIGS 1, 3 (6) and 4 makes use of an infinitely ness of the section at the tip of the blade, the inlet and variable gear mechanism such as is described in outlet of the duct being disposed forwardly or rear Specification 576,536 (Group XXIV), comprising two wardly of the leading and trailing edges of the blade shafts A20, A21 connected to a layshaft A22 by two tip respectively. FIG. 1 shows a construction in which universal joints whose yokes A24, A25 arc 90 degrees out of phase. The shaft A21 is attached to an arm A211, FIG. 4 connected by a link A40 to a nut A41 mounted on a scrcw-thrcaded portion A42 of a push- pull connexion A43 connected by a lever A44 to the pilot's control member, and the arm A211 carries two compression springs A80, A81 between forked arms A201 attached to the shaft A20. The velocity ratio between the shafts A20, A21 is governed by the in clination of the layshaft A22, increasing as it is moved further out of alignment with the shafts A40, A21. The torsional coupling between the latter forms a light-reaction system which functions alone up to a pre-determined airspeed, and the springs A80, A81 a heavy-reaction system which is brought into operation as the airspeed increases above the predetermined value. The inclination of the layshaft A22 is con the inlet and outlet of the duct 6 are disposed rear trolled by an electric actuator A33, no. 3 (b), the wardly of the leading and trailing edges of the blade operation of which is governed by an air pressure tip 5, while FIG. 4 shows the duct inlet and outlet capsule. The increase in inclination of the shaft A22 mounted forwardly of the respective blade edges. with speed results in an increase of the velocity ratio Specification 557,011 is referred to. between the shafts A20, A21, and hence of the rela tive movement between the members A201, A211 and of the degree of compression of one or other of the 614,623. Helicopters. Cierva Autogiro Co. Ltd., heavy-reaction springs A80, A81. Shapiro, J. S., and Pullin, C. G. July 25, 1946, No. 22156. (Class 4.) (Also in Group XXVI.) vibratory material, e.g. wood fibre board or sponge A blade of a helicopter or like rotor is provided 614,404. Silencing gaseous currents. Cementation rubber, may be fastened on the outsides of the boards with a propulsive duct of the continuous flow or Co. Ltd., Neelands, A. R., and Rosen, A. de. Aug. 27, B. In a further modification, FIG. 5, the partition is intermittent type at its outer extremity, the blade 1945, No. 21994. (Class 7 (ii).) built up of vibratory boards or sheets B, B1, B2, B3 being generally straight, except at the portion adja enclosing spaces C. Specifications 461,065, 484,641, Means for reducing the sound effect of the passage cent the duct where it has a pronounced sweep-back 495,699, 504,795, and U.S.A. Specification 2,112,608 of a gaseous current through a conduit comprises or sweep-forward. FIG. 1 shows a blade 5 with a arc referred to. sound-absorbing partitions J, K, L, FIG. 8, arranged in the conduit, the partitions comprising layers, at least two of which are of stiff, sound-absorbing material, 614,621. Helicopters. Cierva Autogiro Co. Ltd., spaced apart to vibrate at specified frequencies or in a Shapiro, J. S., and Pullin, C. G. July 25, 1946, No. range of frequencies. The partitions, which arc sup 22154. (Class 4.) (Also in Group XXVI.) ported horizontally or vertically on joists M, consist A propulsive duct 11 of the continuous flow or of stiff absorbing boards B fixed to a wooden or metal intermittent type of rectangular cross-section is frame A and enclosing a space C which may be mounted beyond the outer extremity of the blade 10 swept-forward portion carrying the duct 6 in an in clined position, as in Specification 614,624. In order to minimize the twisting moment of the blade, the latter may be given a curved form comprising a swept-back portion joined to the straight inner portion of the blade, continued by a swept-forward portion carrying the duct, or the reverse arrangement may be adopted. 614,695. Helicopters. Cierva Autogiro Co. Ltd., Shapiro, J. S., and Pullin, C. G. July 25, 1946, No. 22158. (Class 4.) (Also in Group XXVI.) A blade 4 for a helicopter or like rotor carries at its outer extremity two similar propulsive ducts 5, 6 of the continuous flow or intermittent type mounted on streamlined struts 8,9, one duct being disposed above, and the other below, the blade. The struts serve to convey fuel from a pipe in the blade to the ducts. The gaps between the ducts and the blade arc of the same order as the diameter of the ducts. January 1952 29
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Jan 1, 1952
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