The Wright R-3350 Duplex Cyclone was a twin-row, 18-cylinder, radial piston engine that powered by B-29 Superfortress and the Douglas A-1 Skyraider aircraft. It was also originally used on the Douglas XB-19. Developed from the Wright R-1820 that powered the B-17, this piston engine could generate 2,000 horsepower at cruise speed, and 2,200 HP at 2,600 rpm for take-off. Gasoline with the 100-octane rating was used in this power plant. The engine was equipped with a four-bladed, full-feathering propeller.
Technical Description
The Wright R-3350 Duplex Cyclone engine consisted of four sections: nose, power, supercharger, and accessory. The nose section had a planetary-type reduction gear, which reduced the propeller shaft rpm to .35 that of the crankshaft speed. A propeller governor was mounted on top of the nose section. The power section comprised two staggered rows of 9 cylinders each mounted in a circular pattern around the central hub; cooling fins were integrally cast into the aluminum alloy cylinder heads and they were also located on the steel cylinder barrels.
In the supercharging section, a pair of General Electric B-11 exhaust-driven turbo-superchargers enabled the engine to keep constant sea-level horsepower up to 33,000 feet. Each unit consisted of a single-speed blower with 6.06-to-1 impeller to crankshaft gear ratio. This supercharged induction air was then directed through a Chandler-Evans Type 58 CPB-4 pressure carburetor that was mounted on top of the supercharger. This system could keep a pressurized fuel-air mixture at approximately 17 inches of mercury at 2,400 rmp.
In the accessory section, a series of gear trains operated the fuel pump, generators, vacuum pump, oil pumps, starter, and hydraulic pump.
Specifications (R-3350-C18-BA)
Type: twin-row, radial, piston engine
Weight: 1,210 kg (2,670 pounds)
Length: 1.93 m (76.26 inches)
Diameter: 1.42 m (55.78 inches)
Stroke: 160.2-mm (6 and 1/16 inches)
Bore: 155.6-mm
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| Above, front quarter view of the Wright R-3350 Duplex Cyclone. |
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| Back quarter view of engine. |
