Hale’s System

—The first is exemplified in Hale’s rocket, where rotation is produced around the long axis by the escape of the gas through five small vents situated obliquely to it. In his first arrangement, the inventor placed the small vents in the base, surrounding the central vent, so that the resultant of the tangential forces acted around the posterior extremity of the axis of rotation. In 1855, this arrangement was changed by reducing the number of the small vents to three, and placing them at the base of the head of the rocket. The rocket thus modified is the one now used by the U. S. government for war purposes. A still later improvement in Hale’s rocket consists in screwing a cast-iron piece into the bottom of the case, which is perforated with three vents. A corresponding side of each vent is surrounded with a fence, the opposite sides being open. The gas in its efforts to expand after i uing from the vents, pre es against the fences and rotates the rocket around its long axis.