Page:Aerial Flight - Volume 2 - Aerodonetics - Frederick Lanchester - 1908.djvu/447

Rh there is no continued precession such as would be necessary to put an end to the efficiency of the apparatus.

The gyroscope is put in action automatically immediately after launching, the initial spin being given by a toothed segment D (Fig. 208), actuated by a spring, and initially in gear with the pinion teeth on the axle of the fly-wheel. The friction on the ball-bearings is so small that the initial spin imparted in this way lasts for upwards of 20 minutes.