Wright Cyclone R-3350-91TC, Radial 18 Engine

Type: Reciprocating, 18 cylinders, 2 rows, turbocompound, radial, air-cooled

Power rating: 2,424 kW (3,250 hp) at 2,900 rpm

Displacement: 54.9 L (3,350 cu. in.)

Bore and Stroke: 156 mm (6.1 in.) x 160 mm (6.3 in.)

Weight: 1,674 kg (3,690 lb)

The major airframe application of the Wright R-3350 engine was the Boeing B-29 during World War II. This engine continued to give useful commercial service after the war, one version of which was the first of its type to have its exhaust turbines (3 of them) geared into the power system. This engine, called the Wright Turbo-Compound Cyclone, was the last and the most highly developed piston engine to be widely used in large military and commercial airplanes. It was used in commercial aircraft such as the Douglas DC-7 and Lockheed Super Constellation.

The R-3350-91 powered the U.S. Air Force Lockheed C-121 (the military version of the Lockheed Constellation). A total of 4,653 of the -91 engines were built between May 1955 and August 1956.