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Elmer Sperry: Gyroscopic Compass, 1914

Twists and Turns

The concept of precession and its accompanying definition seem rather complex, but if you think about an automobile and apply Sperry's words, an understanding of precession becomes a bit more accessible. Imagine a car driving along a straight, flat road. As it makes its way along this stretch of road, it is in linear motion, and its wheels are not angled in response to a force impressed by an angular motion. If, however, our car reaches a sloping section of road, that curves and climbs as it winds its way around the side of a mountain, its wheels will precess, or turn in response to the new angles of the road. If our car's wheels did not have the ability to do this, the car would run the risk of flipping over each time it encountered a part of the road that did not run straight. The concept of Sperry's automobile stabilizer enables automobiles to hug the road, and to remain upright as their wheels absorb the disturbing energy resulting from the twists and turns they encounter on the road.

For a more detailed description of precession, including diagrams and a video clip, see How Gyroscopes Work.