Pratt & Whitney initiated design and development of the R-2800 Double Wasp in 1936, and first displayed it in 1939 at the New York World’s Fair. With water injection and turbo-supercharging, the R-2800 produced more than one-horsepower per 16.4 cc (cubic inch). Thin, highly pitched cooling fins machined directly from the head forging solved the heat dissipation problem. When introduced, it produced the greatest output at altitude of any engine in the world.
During World War II, it powered the Grumman F6F Hellcat, Vought F4U Corsair, Republic P-47 Thunderbolt, and other combat aircraft. After the War, it was chosen to power the Douglas DC-6 and other airliners. When production ended in 1960, more than 125,000 R-2800s had been manufactured by Pratt & Whitney and it licensees, one of the largest production runs of any single aircraft engine model.
This R-2800-43 model powered the Martin AT-23A, B-26B/C/E/F/G, XB-26D, TB-26G, XB-26H, and Curtiss C-46.