Patent GB-191304673-A (GB)
Title: Improvements in Stabilizers for Aeroplanes.
Inventor: THAW ALEXANDER BLAIR
IPC: B64C1/00
Filed: 1913-02-24
Granted: 1914-02-24
Abstract: 4673. Thaw, A. B. Feb. 24. Steering and balancing.-The longitudinal and lateral balancing and steering planes of an aeroplane are actuated automatically when the machine tilts, by drums which are connected by clutches, controlled by electro-magnetic means, to a continuously rotating shaft driven by a wind or other motor independent of the driving- power of the machine. Means are provided to prevent overwinding of the operating-cords, and to adjust the angle of inclination of the machine at which the automatic devices become operative in accordance with the degree of control exercised by the aviator. In the form shown, the cords for raising and lowering the elevator and for operating the right and left balancing - planes or warping-devices are respectively secured to drums 14, 16, 15, 17, Fig. 1, freely mounted on a shaft 30 constantly rotated by worm gear from a shaft 33. The shaft 33 is provided with arms 35 fitted with anemometer cups 36 whereby the shaft is rotated when the machine is in flight. Slidably mounted on the shaft 30 are clutch members 39, 40 adapted to be moved by the levers 42, 43 into engagement with the drums. The levers 42, 43 are provided with armatures 46 adjacent to the electro-magnets 47. At the four sides of the plate 18 carrying the drums are mercury switches 51, each provided with a contact pin 54, Fig. 4, electrically connected with one of the electro-magnets. The circuit of one or other of the electro-magnets is closed when the machine tilts, whereby the corresponding drum is engaged by the clutch and rotated to adjust the balancing-member. The contact pin 54 is carried by a cap 50 vertically movable in guides 59 by means of a nut 56 engaging with the threaded internal surface of the cap. The nut 56 is carried by a sleeve 64 surrounding the mercury tube 53 and provided with a pinion 65 gearing with a pinion on a shaft 67. The shaft 67 adjusts the transverse pair of contacts and a similar shaft at right-angles thereto adjusts the longitudinal pair. Each shaft 67 is provided with a pulley around which is passed a belt by which the shaft is moved when the aviator moves his band-lever to control the banking or the inclination of the machine. The machine is then maintained by the automatic mechanism in the attitude set by the band control. In a modified device for varying the sensitiveness of the automatic mechanism, each mercury switch is provided with three contact pins 71, 72, 73, Fig. 6, of decreasing length and electrically connected to wipers 80, 85, 86 respectively. The wipers bear against a disk having a non-conducting part 82 and a conducting part 81 connected by a lead 83 to the battery 84. The disk is rotatable by a cord 88 connected to the steering-levers of the aeroplane, and is arranged so that the longest contacts are in circuit when the levers are in the middle position. The movement of the levers in either direction causes the sector 81 successively to engage the wipers 85, 86, whereby the automatic action is delayed until the mercury rises into contact with the pin 72 or 73. The circuit of each electro-magnet passes through the rim of its corresponding drum, and is arranged to be broken to disengage the drum from the driving-shaft at a predetermined point.