221,006. Gray, J. G. June 1, 1923. Gyroscopic apparatus. - The invention is a development of those described in Specifications 130,697 and 186,655. In apparatus according to the latter Specification comprising an auxiliary gyroscope so mounted on a pivoted system carrying a stabilizing gyroscope that turning in azimuth of the vehicle carrying the stabilizer results in forcible turning in azimuth of the axis of spin of the auxiliary gyroscope and so in the production of a couple opposed to the centrifugal couple which accompanies turning of the vehicle, the auxiliary gyroscope 1<1>, Fig. 1, is mounted on fore-and-aft pivots 2 carried by the system and with its axis athwart the vehicle, and its position relatively to the system is determined by means of centralizing springs 3 and stops 4 so that turning of the vehicle causes the auxiliary gyroscope to move over against the stops, the connections with which serve to make electrical contacts. The stabilizing gyroscope 1 is mounted on cross-pivots 5. In a further construction the auxiliary gyroscope 1', Fig. 2, is rigidly attached to the gimbal frame 6 with its axis of spin perpendicular to the axis of the stabilizing gyroscope 1, the parts being so arranged that the frame 6 is in neutral equilibrium with respect to its fore- and-aft pivots 7, 7. A further improvement consists in driving the auxiliary gyroscope so that its speed, is proportional to the speed of the vehicle. This may, be done by using alternating current from a generator driven from a shaft carrying a screw rotated by the passage of the vehicle through the air or water; or the generator may be driven from a shaft the angular speed of which is proportional to the propeller shaft speed; or the motor circuits may be controlled in accordance with the indications of an air-speed indicator or log. Instead of varying the speed of the auxiliary gyroscope the product (to which the angular momentum of the auxiliary gyroscope is required to be equal) of the mass of the pivoted system, the speed of the vehicle, and the distance of the centre of gravity of the system below the suspension axis is maintained at the proper value by altering the latter quantity by raising or lowering weights 13, Fig. 3, forming part of the pivoted systems, by means of an electric motor 8 controlled bv an observer in accordance with the vehicle speed, a pointer 16 and scale 17 being provided. In place of the electric motor 8 there may be employed a turbine 40, Fig. 5, which may either be controlled by the observer or automatically by the means shown in Fig. 5 to raise or lower a weight 13 on a threaded shaft 12 driven by the turbine 40; nozzles 18 for driving the turbine in either direction are supplied with compressed air from the gyroscope casing and are controlled by screens 19 carried on the pivoted armatures of electromagnets 23 the circuits for which are controlled by means of an arm 34 forming part of a speed indicator and moving over contact-studs of one of two resistances forming part of an arrangement resembling a wheatstone bridge, the other resistance being associated with the weight 13 and the galvanometer of the bridge serving to complete the appropriate magnet-circuits. The speed of the auxiliary gyroscope may be varied by means of a similar arrangement controlling resistances in the motor circuits. The Specification also describes erector systems of the type described in Specification 130,697, and which are not affected by the horizontal accelerations resulting from turning motions of the vehicle, stabilising couples being applied to the pivoted system only about the fore-and-aft pivots. In a construction such as shown in Fig. 6 comprising balls 40, moving around a track under control of pushers 41 and checks 42 the movement of each ball relatively to its pusher and check is limited by a spacing rod 44 which is lifted by the engagement of raised guides 47 on the track with a roller 46 on the spacing rod when the ball is in a position such that it is not effected by transverse ace-elerations. Alternatively the spacing rod may be lifted by means of an electromagnet, which may be supplied with alternating current to act by repulsion upon an aluminium ring attached to the spacing-rod. In another form shown in Fig. 9 weighted pivoted rods 64 mounted on a slowly-rotating boss 62 and controlled by pushers 67 and checks 68 are utilized to complete electric circuits if they are in contact with the checks 68 when brushes attached to the checks are in contact with electrical pieces 69 on a plate 70. The completion of the circuits may be used for producing couples for stabilizing, as by uncovering air-nozzles 72, or moving masses on the pivoted system, or setting a motor in action, or changing the direction of the axis of a reaction fan. A construction of stabilizer comprising two connected gyroscopes as described in Specification 186,655 (see particularly Fig. 11 of that Specification) is shown in Fig. 10; each gyroscope carries an erector of the ball or contact-making type as previously described. The connection to constrain the gyroscopes to swing in opposite directions consists of an arm 81 carried on an extension of a pivot 79 of one gyroscope 78 and bearing a roller 82 working in a slot 82<1> of a similar arm 81<1> of the other gyroscope 78<1>. The compensating couples during turning are supplied by the auxiliary gyroscope 83. No disturbance of the stabilizer results from fore and aft accelerations. Another coupled system is provided with fan erectors. Tilting of the fore and aft pivots in systems of this kind does not result in relative tilt of the gyroscopes on the cross-pivots but both gyroscopes turn within the frame 80 and this movement may be used to bring into action stabilizing couples; Figs. 13 and 13b show electric contacts for this purpose. An arm 96 mounted on a cross-pivot of one of the gyroscopes carries a roller 97 running over contact plates 98, 99 separated by a piece of insulating material 101. To avoid the effect of friction between the roller and plates the contact is rendered intermittent by resiliently mounting the roller on the arm and periodically removing it from the plates by means of an electromagnet 106 intermittently energized by an alternating current so as to repel an aluminium ring 103 secured to the part carrying the roller. In order to prevent disturbance of the stabilizer by turning in azimuth relatively to the vehicle the auxiliary gyroscope casing is attached to the gimbal frame of the stabilizing gyroscopes by vertical bearings and to the vehicle by a universal coupling so that the axis of the auxiliary gyroscope remains athwart the vehicle when the stabilizer turns with respect to the vehicle but is forcibly turned when the vehicle turns.