Pratt & Whitney R-2270
The Pratt & Whitney R-2270 was an American air-cooled radial aircraft engine. Displacing, it was Pratt & Whitney's first two-row radial engine, developed using parts from existing Wasp and Hornet engines to produce an experimental engine. Design of the engine was begun in January 1929; it first ran on May 14, 1930, and in April 1931 was test-flown in a Boeing Model 40B aircraft. The R-2270 was intended as a purely experimental engine; studies indicated a smaller engine would be more favored by the market, and Pratt & Whitney began development of the R-1830 engine in April 1931.