Pratt & Whitney R-1830 Twin Wasp was an engine widely used in American aircraft in the 1930s and 1940s. Produced by Pratt & Whitney, it was a two-row, 14-cylinder, air-cooled radial design. It displaced 1,830 in³ (30 L) and its bore and stroke measured 5.5 and 5.5 in (140 and 140 mm), respectively. A total of 173,618 R-1830 engines were built, a notable figure which makes it the most produced aircraft engine. An enlarged version with a slightly higher power rating was produced as the R-2000.