GB506404A - Improvements in and relating to helicopters and gyroplanes - Google Patents

Abstract

506,404. Aircraft with rotary - wing systems. CIERVA AUTOGIRO CO., Ltd., and BENNETT, J. A. J. Nov. 26, 1937, Nos. 32731/37 and.7367/38. [Class .4] . In a helicopter or gyroplane having pairs of oppositely-rotating rotors, each having two or more blades, the rotors are coaxial or spaced and non-intermeshing and the rotors are so geared together that when a blade of one rotor lies in the direction of forward flight a blade of the other rotor lies in a direction making with the first named blade an angle of half or approximately half the blade-spacing angle. The rotors may have a single counterweighted blade, the blade and the counterweight being free to flap either independently or as a unit, and in this case when one blade lies in the direction of flight the other lies in a direction substantially perpendicular to it. In one form, laterally spaced rotors, each comprising two blades mounted on coaxial flapping axes are mounted on laterally-projecting pyramidal bracing-structures 18, 18a. The rotors are driven in opposite directions through bevel wheels 36, 35, 35a, shafts 28, 28a including universal joints 34, 27, 27a, and bevel wheels 25, 26, 25a, 26a. The blades of the rotors are displaced 90‹ relatively to each other. A splined joint 32 is provided in the shaft 28 to facilitate adjustment, by trial and error, of the phase displacement in order to effect balancing of the bouncing vibrations of the two rotors. Drag pivots may be provided 'and these may be so disposed as to cause change of pitch angle of the blades with movement on the drag pivots. In gyroplanes and helicopters in which the drive to the rotors may be disconnected such disconnection is arranged to take place between the shaft 37 and the engine. The rotors may be tilted to effect control of the machine. In a modification, a helicopter is provided with a closed cockpit, tail stabilizing surfaces and further laterally extending stabilizing surfaces 44. The rotors are carried by a single mast, the closely overlapping rotors being rotatable about upwardly and outwardly diverging axes. The mast 48 carries a rotor supporting-beam 49 rockable about a universal joint 53. The rotors comprise single counterweighted blades 83, 83a, rotatable about the inclined axes A A, B B. In a specific example the rotors have a diameter of 35 ft. are spaced 20 to 24 inches apart; the rotor blades have a maximum droop angle of 4‹ and the included angle between the rotor axes is 16 to 20‹. The pitch of the rotor blades may be adjusted cyclically.