GB437521A - Improvements in and relating to aircraft - Google Patents

Abstract

437,521. Aircraft with rotary-wing systems. WILKENING, F. W., Arlington Road, Penn Valley, Pennsylvania, U.S.A. April 27, 1934, No. 12807. Convention date, Feb. 2. [Class 4] A rotating wing system for aircraft comprises a hub 19 on which is mounted a plurality of blades 18 free to vary their pitch, to lag with reference to the hub axis and also to swing in planes through the hub axis, variations in pitch being correlated to variations in lag but swinging in the said planes causing no variation in pitch. Further, the variations in lag are correlated to variations in pitch without the use of intermediate members between the blades 18 and stubs 20 mounted on the hub 19. In one form, the hub member 19 is driven from a crank-shaft 41 from a radial liquid - cooled engine through a shaft 36, reduction gearing 42 ... 42<c> and a freewheel clutch 43 the outer casing of which may form a brake drum. The rotor blades are each hinged to the hub member by horizontally arranged pins 22, the tubular stubs 20 of the blades being shaped as shown to provide stops 25, 25<a> to limit movement of the blades. A tubular spar 26 of each blade is mounted on vertically disposed trunnions 27, journalled in the stub 20 and a thrust-bearing 30 facilitates rotation of the blade about its longitudinal axis relative to the stub 20. The blade 18 is thus free to lag in its plane of rotation and to take up a position of equilibrium under the effects of centrifugal force and drag. This lagging of the blade is adapted to change its incidence automatically through a bevel-gear segment 33 on the spar 26 which meshes with a bevel-gear segment 34 secured to or formed integral with the stub 20. The segments may be replaced by pin and slot or other linkage. Angular displacement of the blades about their longitudinal axis is limited by stops, e.g. by providing blank portions on the segments.