There's a history of Pratt & Whitney history at:
http://www.prattandwhitney.com/Content/History.aspIncluding this about P. W. A.
1925 Frederick Rentschler approaches Pratt & Whitney, looking for funds and a location to build his new aircraft engine. Pratt & Whitney loans him $250,000, the use of the Pratt & Whitney name, and space in their building. This was the beginning of the Pratt & Whitney Aircraft Company. Pratt & Whitney's first engine was called the Wasp, completed on Christmas Eve 1925. The Wasp developed 425 horsepower on its third test run. It easily passed the Navy qualification test in March 1926, and by October the Navy had ordered 200 engines. The Wasp exhibited speed, climb, performance and reliability that revolutionized American aviation.
1929 Frederick Rentschler, ended his association with Pratt & Whitney Machine Tool and formed United Aircraft and Transport Corporation, the predecessor to today's United Technologies. His agreement allowed Rentschler to carry the name with him to his new corporation.