represented in rig. 2ro. As in the precearng case, the two gyroaxles are coupled together by two gear segments so that the precessional velocities are equal in magnitude and opposite in direction. Suppose that owing to motion around a curve, or any other cause, the side A of the car is moved downward. Then the two gyro-axles will precess in the directions indicated by wp and wp', respectively. If, now, these precessional velocities be accelerated to the same degree, equal torques will be developed on the two gyros, and on the attached car, in the directions opposite those indicated by L and L', Fig. 216. If the constants of the gyros are of the proper value, the car will be righted.*
162. The Schilovsky Monogyro Monorail Car of 1915. - Consider a monorail car on which is mounted a single statically unstable gyro spinning about an axis that normally is vertical and capable of precession about a horizontal axis transverse to the rail. When the car tilts to one side, the spin-axle of the gyro precesses either forward or backward. Suppose that a motor accelerates the precession. There is now a torque which opposes the present tilting of the car and tends to make the car tilt in the opposite direction (Art. 158). This overbalancing torque sets up a counter
* Cousins, " The Stability of Gyroscopic Single Track Vehicles," Engineering (1913), pp. 678, 711 and 781, is a noteworthy analytical treatment.