Pratt & Whitney R-2800 Double Wasp

The Pratt & Whitney R-2800 Double Wasp is an American twin-row, 18-cylinder, air-cooled radial aircraft engine with a nominal displacement of 2,800 cu in (46 L), and is part of the long-lived Wasp family of engines. Produced from 1939 to 1960, the R-2800 saw widespread use in major American aircraft during and after World War II, including the Grumman F6F Hellcat, Vought F4U Corsair, and Republic P-47 Thunderbolt.

Source: Wikipedia — Pratt & Whitney R-2800 Double Wasp (CC BY-SA 4.0)