Pratt & Whitney Wasp series

The Pratt & Whitney Wasp was the civilian name of a family of air-cooled radial piston engines developed in the 1920s, 1930s and 1940s.

The Pratt & Whitney Aircraft Company (P&W) was founded in 1925 by Frederick B. Rentschler, who had previously been the President of Wright Aeronautical. He brought with him some of Wright's best designers and the new team quickly came up with their first design, the R-1340 Wasp. The name "Wasp" was suggested for the first model by Rentschler's wife, Faye.

Wasp series
R-985 Wasp Junior (1930) R-1340 Wasp (1925) R-1535 Twin Wasp Junior (1931) R-1830 Twin Wasp (1931) R-2000 Twin Wasp R-2180-E Twin Wasp E R-2800 Double Wasp (1940) R-4360 Wasp Major (1942)
 * 9-cylinder single row air cooled radial
 * Bore x stroke: 5+3/16 x
 * Displacement: 985 cuin
 * 9-cylinder single row air cooled radial
 * Bore x stroke: 5+3/4 x
 * Displacement: 1344 cuin
 * 14-cylinder, two row, air cooled radial
 * Bore x stroke: 5+3/16 x
 * Displacement: 1535 cuin
 * 14-cylinder two row air cooled radial
 * Bore x stroke: 5+1/2 x
 * Displacement: 1830 cuin
 * 14-cylinder two row air cooled radial,
 * Bore x stroke: 5+3/4 x
 * Displacement: 2000 cuin
 * 14-cylinder two row air cooled radial
 * Bore x stroke: 5+3/4 x
 * Displacement: 2180 cuin
 * 18-cylinder two row air cooled radial
 * Bore x stroke: 5+3/4 x
 * Displacement: 2804 cuin
 * 28-cylinder four row air cooled radial
 * Bore x stroke: 5+3/4 x
 * Displacement: 4363 cuin

Note: the designations refer to the engine configurations as follows: "R" = Radial, followed by the approximate displacement in cubic inches.