Wright R-3350-23 Duplex-Cyclone The Wright R-3350 Duplex-Cyclone was one of the most powerful radial aircraft engines produced by the United States. Based on the earlier Wright Cyclone engines, the R-3350 first ran in May 1937, and its first major military use was to power the Boeing B-29. Air-cooled with eighteen cylinders arranged in two rows, it has a displacement of 3,350 cubic inches. Horsepower ranged from 2,200 to over 3,500, depending on the model-the B-29 Bockscar for example used the R-3350-41 variant with 2,200 horsepower. Produced until the 1950s, thousands of these engines powered both military and commercial aircraft. The long list of aircraft using the R-3350 includes the C-119, C-121, and A-1 Skyraider. This engine is displayed as it would have been when delivered to a maintenance unit. The additional parts would have come from the engine it was replacing. Click here to return to the World War II Gallery.