Patent GB-373771-A (GB)
Title: Improvements in or relating to aircraft with rotating wing systems
IPC: B64C27/54
Filed: 1931-05-18
Abstract: 373,771. Controlling helicopters and machines with rotary wing systems. BREGUET, L., 24, Rue Georges-Bizet, Paris. May. 18, 1931, No. 14679. Convention date, May 21, 1930. [Class 4.] Helicopters and machines with autorotative wing systems wherein the blades are hinged about horizontal axes at their roots have the blades hinged also about radial axes and controlled in incidence by arms having their forward ends guided by mechanical means. The guiding means described comprise a ring mounted on gimbals so that it can be raised and lowered and tilted in any direction so as to vary the pitch as a whole or cyclically feather the blades to excentre the thrust in any direction, and, in a machine with oppositely rotating blade systems, orientation of the machine may be effected by differentially varying the pitch of the two blade systems, and propulsion effected by causing those blades of both systems that are moving backwards to have the greater incidence. On alighting a pilot weight normally holding the guide ring down against a spring contacts with the ground and allows the spring to effect an increase in the pitch of the blades. Fig. 1 shows diagrammatrically a shaft 2 having a bracket 6 in which is journalled a shaft connected by a cardan joint 4 to a shaft 3 which may carry a blade 1 directly or through another cardan joint 5. An arm 7 having a roller 8 at its forward end with respect to the direction of rotation of the shaft 2 engages the surface of or a groove in a plate 9 mounted on gimbals on a member 10 which can be raised and lowered relative to the shaft 2. The plate 9 can be tilted in any direction by the pilot by means of cords 11, 12 to vary the angle alpha of the blade 1. Since the roller 8 is at the forward end of the arm 7 an increase in the angle # of the shaft 3 due to a gust reduces the angle alpha. Fig. 2 shows means for adjusting two oppositely rotating blade systems, only one blade of each system being shown. The two systems are shown side by side but actually the two systems rotate about concentric shafts as shown in Fig. 3, which also shows a modified means for changing the angle of incidence of the blades. The cords 11, 12, 11<1>, 12<1> of each plate 9, 91 are connected to rings 14, 13, 14<1>, 13<1> pivoted as shown to members 15, 15<1> carrying the members 10, 10<1>. The rings 14, 14<1> are tilted about transverse axes bv connections to a lever 25, a differential gear 27 ensuring equal torques being transmitted to the two rings. The two rings 13, 13<1> are tilted in the same direction about longitudinal axes by lateral tilting movements of the lever 25 acting through the rack and pinion gear shown, a differential gear 26 enabling both rings to be tilted in opposite directions, to effect forward propulsion, by turning a hand-wheel 22 having an elastic connection 23. The members 15, 15<1> are raised and lowered to vary the pitch of the blades differentially by connections to a rudder bar 20 and both in the same direction by connections to a hand-wheel 16 having an elastic connection 17. This hand-wheel may also control the engine by acting on a governor 30 which can act after each setting upon the pitch control. Automatic differential pitch control for steering the machine may also be effected by a wind vane 31 acting, through elastic connections 18, 18<1> on the members 15, 15<1>. Connections to a lever 56 supported by a spring 62 and connected to a pilot weight 54 enables the pitch of the blades to be increased just before alighting. Fig. 3 shows two pairs of blade shafts 3, 31 rotatably mounted in sockets such as 53, pivoted about vertical pins 52, 52<1> to stirrups pivoted about horizontal pins 51, 51<1> on two hubs 40, 40<1>. The hub 40 is driven from a shaft 36 and gearing 37, 38, 39 and the hub 40<1> from an oppositely driven shaft 35 through gearing 37<1>, 38<1>, 39<1>. A fixed casing 43 on which the hubs revolve surrounds the shaft 35 and slidably carries two spherical members 46, 46<1> about which rings 46a, 46<1>a can pivot on axes 10a, 10<1>a. These rings have pivots 10b, 10<1>b about which rings 9a, 9<1>a can tilt. The rings 9a, 9<1>a can be tilted in any direction or moved vertically by rigid rods 11a, 11<1>a, rocking levers 11b, 11<1>b,rods 11c, 11<1>c, levers 11d, 11<1>d and rods 11e, 11<1>e leading to the controls. The rings have ball races about which turn rings 47, 47<1> having arms 48, 48<1> projecting forwardly with respect to the direction of rotation and universally jointed to arms 7, 7<1> pivoted on pins traversing the shafts 3, 31. Specification 352,521 is referred to.