Patent GB-191510377-A (GB)
Title: Automatic Means for Stabilising Aircraft.
IPC: B64C1/00
Filed: 1915-07-16
Abstract: 10,377. Sperry Gyroscope Co., [Assignees of Sperry, E. A.]. July 17, 1914, [Convention date]. Gyroscopic apparatus. -The lateral and longitudinal balancing planes of an aeroplane or similar craft are respectively actuated by the relative displacement between a pendulous device stabilized by gyroscopes and two control arms carried on the machine, the pendulous device being corrected for acceleration pressures. The control arms actuate the balancing- planes by controlling pneumatic valves on air cylinders, or by making electric connexions which couple up the balancing- planes to a wind-driven servo - motor. Figs. 1 and 2 show a side elevation and plan of the apparatus, parts being shown diagrammatically. The arrows indicate the direction of flight of the aeroplane. Two pairs of oppositely-rotating gyrostats 7, 8 are mounted in cardan rings 1, 2, with their precession axes vertical, so as to stabilize the rings against lateral and longitudinal tilting. The system is made pendulous by placing the pivots of the ring 1 above the centre of gravity. Each pair or preferably each individual gyrostat is statically balanced about its vertical axis, and the gyrostats of each pair are geared together for equal and opposite precession by gear sectors 9, 11. Springs 10 connecting the frames of each pair centralize the gyrostats after small precessions. The gyrostats are of the type described in Specification 2294/13. To prevent irregular action due to sudden acceleration pressures, the system described in Specification 10,255/15 is employed for introducing a torque in the opposite direction to that due to the acceleration pressure, so as to prevent excessive precession, and centralize the gyrostats after the initial torque is removed. An electric contact 25 is adapted to close a circuit through either of two contacts 26, 27 on the vertical axis of one of the gyrostats 7 when precession exceeds a small amount, so as to energize a motor 20 and apply a torque to the pivot of the ring 1 opposite to the torque which produced the precession. The torque is applied through gearing 23, which is normally free of the motor 20. The motor is clutched automatically to the gearing when energized By bodily movement of the armature. Similar means may be employed for impressing a torque about the other axis, but as acceleration pressures are not so likely to occur about this axis, these means are omitted. To prevent the motor from being clutched to the gearing owing to accelerations of the machine, the inertia of the armature is balanced by that of two weights on pivoted levers connected to the armature spindle. To neutralize the effect of the spring 10 when the motor 20 is in operation, the contact 25 closes a circuit which energizes a solenoid 40 and causes a spring 38 to press a sliding bar 34, Fig. 4, against the rear end of a bar 31 pivoted at its other end to the casing of one of the gyrostats 7. The rear end is guided in a slot (not shown), and, as the gyrostat precesses, the bar assumes an inclined position and applies a force in opposition to the spring 10. A projection 15 on the framework carried by the ring 2 engages a bail 13 pivoted about axes normally co-axial with the pivots of the ring 2. The bail has upward extensions provided with balance weights. The pivots of the ring 1 and bail 13 are provided with pointers to indicate the inclination of the machine, and the lateral and longitudinal stabilizing controls are respectively mounted near these axes. Mounted on the ring 1 near its rear pivot is an arm 41, relative displacement between which and a control arm 42 on the main frame actuates the lateralbalancing planes. The longitudinal-balancing planes are actuated by the relative displacement between similar arms 200, 99 mounted on the bail 13 and the adjacent frame. Anemometers.-An anemometer, for acting on the control mechanism of aircraft when the air speed falls below a predetermined value, consists of a fan 111, Fig. 8, mounted on a shaft 112 so as to tend to wind up a spring 114. A pin 117 on the casing passes into a slot in the fan provided with adjustable stops which engage the pin 117 to limit the motion in both directions. A spring arm 118 is adapted to close an electric circuit through a strip on a drum 119 at the critical wind velocitv. The drum 119 is carried on a plate 121 capable of angular adjustment with respect to the casing.