GB646867A - Improvements in and relating to multi-rotor helicopters - Google Patents

Abstract

646,867. Multi-rotor helicopters. CIERVA AUTOGIRO CO., Ltd., PULLIN, C. G., SHAPIRO, J. S., and BOLAS, H. April 22, 1948, No. 11089. [Class 4] In a multi-rotor helicopter having at least one pair of sideby-side lifting rotors, control in roll is obtained by transverse differential collective pitch control, and control in yaw by differential inclination in the pitching plane of the lift vectors of the side-by-side rotors and by a rudder or rudders, both yaw control members being operated by the same pilot's control member. Figs. 4 and 5 show a control system for a helicopter with three lifting rotors, as described in Specification 591,982, in which a spider with three arms 47, 48, 49 is mounted for universal tilting and vertical movement by operation of an attitude control lever 38 and a collective pitch control lever 40, respectively, the ends of the spider arms being connected by links 50, 51, 52 to the collective pitch control mechanisms of the respective rotors. Transverse movement of the lever 38 is transmitted to the spider by links 62, 63, 65, 56 to move the links 51, 52 equally in opposite directions, resulting in differential variation of the collective pitches of the side-byside rotors. Fore-and-aft movement of the lever tilts the spider about a transverse axis, through links 61, 53, 55. The rudder pedals 39 are connected by links 86, 87, 82 to a lever 75 whose ends are connected by links 78, 79 to the cyclic pitch control systems of the rear side-byside rotors, and also by a link 92 to pulleys 94, 95 connected by chains 98, 99 to sprockets 102, 103 actuating rudders 36, 37 through links 106, 107. By this arrangement the control exerted by the rudders becomes progressively more powerful as the forward speed increases, and the effect of the rotors is correspondingly reduced, this minimizing the rolling couple resulting from the differential inclination of the rotor lift vectors. In the case of a helicopter with four rotors arranged in diamond plan formation, the three-armed collective pitch control spider is replaced by one with four arms, Fig. 8 (not shown), and the links 78, 79 are connected to the cyclic pitch control mechanisms of the side-by-side rotors, there being no cyclic pitch control of the front and rear rotors. The three-armed spider shown in Fig. 4 may be replaced by a T-bar which may be constructed and power-operated as described in Specification 646,864. All the rotors are preferably driven in the same direction. Specifications 644,524 and 646,866 also are referred to.