Automatic Pilots in History

Stability augmentation goes back only to about 1945, while the history of airplane and missile automatic pilots, or autopilots (that word happens to be a trademark of a par­ticular manufacturer), actually begins before the Wright brothers, with Sir Hiram Maxim’s 1891 designs. That history has been told by several authors, including Bollay (1951) and the scholarly but very readable account of automatic pilot development in the first chapter of Aircraft Dynamics and Automatic Control by McRuer, Ashkenas, and Graham, dated 1973.

An additional historical account of airplane automatic pilots is that ofW. Hewitt Phillips, in his Dryden Lecture in Research (1989). All of these authors refer to the remarkable 1913— 1914 demonstration of the Sperry “stabilizer,” which provided full automatic control of a Curtiss Flying Boat. However, the present chapter deals only with stability augmentation.

Gust-alleviation systems are a specialized form of airplane automatic pilots, designed to reduce structural loads and to improve ride quality in rough air. These systems are of less interest now than formerly because modern airplanes can fly above turbulence or use weather radar to avoid storms. A complete historical review of gust-alleviation systems is available in a NASA Monograph (Phillips, 1998).