1932, Pratt & Whitney introduced the R-1535 Twin Wasp Junior.
The R-1535 used fourteen Wasp Junior
cylinders arranged in two rows. Starting out at 600 hp, this
engine was producing 825 hp by World War II.
Compared to the Hornet it
gave similar power, was heavier and more expensive but with a
smaller diameter resulted in less drag and improved pilot view in a
single engine aircraft. Not sold in large numbers, Howard
Hughes used the R-1535 to power his H-1 Racer to set the world
absolute speed record in 1935.
|14-cylinder, twin-row, air-cooled radial|
|displacement: 1,535 cubic inches (25.2 liters)|
|Bore x stroke: 5 3/16 x 5 3/16 in|