One of the most successful twin-engine airplanes in the history of aviation, there are still a large number of Beech 18’s working for a living around the world today. When the airplane started out in the commercial aviation field, it was a little under-powered. However, with the introduction of the 450 hp Pratt & Whitney-powered version, Beech had found a winner. The design was also fortunate in its timing, as the War was looming. With a navigation trainer version (AT-7), a bomber training version (AT-11), a light transport version (C-45), and any number of other lesser used versions, the basic design was one of the most heavily produced transports of the War. The U.S. Navy also used it in service. After the War, Beech went back to its civilian clientele as well, and the ten-place airplane was developed through several other changes. There was even a series of tricycle gear 18’s produced by Beech.