Patent GB-171711-A (GB)
Title: An improved method of and means for the combined steering and stabilization of flying machines of the helicopter type
IPC: B64C27/32
Filed: 1921-11-21
Abstract: 171,711. Pateras Pescara, Raul, Marquis of. Nov. 20, 1920, [Convention date]. Screw and like propellers. -A helicopter having oppositely rotating lifting propellers is provided with means for feathering the propeller blades, to decentralize the thrust of the propellers in any direction, operated by a single hand lever which also operates adjustable surfaces for effecting lateral and longitudinal control when the machine is moving horizontally, the propeller control being normally cut out and used only when necassary. An additional control lever for varying the relative reactive torque of the propellers or for actuating a rudder, at will, may also be provided. The means for decentralizing the propeller thrust described in Specification 146,257 are referred to. Fig. 1 shows a tubular lever 21 connected to a fixed post 23 by a cardan joint having its centre at 24. A ring 39 is mounted on a spherical bearing 38 in the plane of the cardan joint and is normally engaged by a dome 34 on the lever 21 so as to move therewith. Four equidistant cleats are provided on the circumference of the ring 39, as represented in Fig. 4 at 51, which are connected by the system of cords shown to two rings 57, 58 in the planes of the propellers in such a manner that the rings 57, 58 always remain parallel to the ring 39. The rings 57, 58 are mounted on gimbals and form the inner rings of ball races of which the outer rings rotate with the propellers. The outer rings of these ball races are connected as shown in one instance at 63 to cords 64, which pass over pulleys 67, 69 and 68, 70 to opposite ends of a strut 73 connecting the upper and lower blades of a biplane type of propeller. A strut 74 connects the pulleys 69, 70. When the rings 57, 58 are tilted the cords 64 cause a cyclic variation in the incidence of the blades of both propellers and the thrust is correspondingly displaced. The lever 21 has a handle 25 which can be rotated about the axis of the lever to turn a shaft 28. The shaft 28 has two screwed portions 29, 30 connected by a cardan joint centred at 24. A nut 32 on the screw 29 is connected by screws 33, passing through slots in the tubular lever 21, to the dome 34 so that the dome can be raised out of contact with the ring 39 to leave it free of the lever 21. Simultaneouslv a nut 35 on the screw 30 effects the upward movement of a dome 37 on the pillar 23 until the dome contacts with the under surface of the ring 39 and holds it stationary. Movement of the lever 21 in this case effects only the movement of the surfaces 75, 76. Fig. 5 shows a modification in which rigid connections to the propeller blades are used and means are provided for operating a rudder 108 and for varying the relative reactive torque of the two propellers by a differential variation of the pitch. A handle 114 is mounted on a cardan joint 113 connecting two members 111, 112 which normally engage two levers 115, 116. The lever 115 is pivoted at 130 to a shaft 131 mounted in bearings 132, 133 and terminating in a. ring 134 which is connected by transverse pivots to the outer ring of a ball race 135. An extension of the lever 115 is connected by a pair of rods 137 to levers 139 on the outer ring of the ball race 135. The inner ring of this ball race is connected by rods 140, in front of each blade of the lower propeller 101, to the inner ring of a ball race 143, and connections are arranged as shown to the warping means of each propeller blade, those of the lower propeller being connected directly to the rods 140, and those of the upper propeller to the outer ring of the ball race 143. Movement of the lever 115 thus effects a cyclic variation in the incidence of each propeller blade, the plane of the ball race 135 remaining perpendicular to the lever 115. By lowering the handle 114 the member 111 is disconnected from the lever 115, and by lowering a handle 161 a dome 163 on the lever is brought into contact with a member 164 of the frame and the plane of the ball race 135 is locked in the horizontal position. A rudder bar 165 is mounted on a box 166 containing a three-way clutch operated by a handle 167 and the transmission gear 169, 170. When the handle is engaged with the top notch, the bar 165 is coupled to a quadrant 175 engaging a pinion 176 on a shaft 177 which is geared at its upper end to pinions 179, 180 forming nuts for screws 182, 181. These screws support the bearings 132, 133 of the shaft 131 so that it is caused to rise and fall when the shaft 177 is rotated. Consequently the ball race 135 is raised and lowered and the pitches of the two screws 100, 101 are varied in opposite directions. The unbalanced torque so produced is transmitted through the propeller hubs 102, 103 and gearing 104, 105 to the pinion 106, which is journaled in bearings fixed to the frame.