The R-4090 Cyclone 22 was an experimental
radial
Radial is a geometric term of location which may refer to:
Mathematics and Direction
* Vector (geometric), a line
* Radius, adjective form of
* Radial distance, a directional coordinate in a polar coordinate system
* Radial set
* A bearing f ...
piston engine designed and built in prototype form in the United States during the 1940s.
Design and development
During the 1940s,
Wright Aeronautical Corporation was constantly in competition with
Pratt & Whitney for new engine designs required for civil and military aircraft. Utilising the
Wright R-3350 Duplex-Cyclone
The Wright R-3350 Duplex-Cyclone is an American twin-row, supercharged, air-cooled, radial aircraft engine with 18 cylinders displacing nearly . Power ranged from 2,200 to over 3,700 hp (1,640 to 2,760 kW), depending on the model. ...
as a basis, Wright developed a 22-cylinder engine, using R-3350 cylinders arranged as a two-row radial engine with 11 cylinders per row instead of 9.
[
The air-cooled R-4090 was rated to deliver at 2,800 rpm for take-off, from a total displacement of , with a compression ratio of 6.85:1. Improved performance was expected from the R-4090 if there had been further development. A two-speed single-stage supercharger helped maintain rated power to higher altitudes.][
The core of the engine was a forged steel crankcase which enclosed the three piece two-throw crankshaft. The cylinders were arranged equally around the crankcase, with each row off-set by 16.3636.° to ensure cooling airflow. Accessories similar to other Cyclone engines were arranged around the rear face of the crankcase and a 0.333:1 planetary reduction gearbox at the front.][
Although there are no records of failings of the R-4090, the engine was abandoned to allow development of the R-3350 Duplex-Cyclone series.][
]
Variants
;XR-4090-1:(790C22AA1), drove a single propeller.[
;R-4090-3:(792C22AA), drove a contra-rotating propeller shaft and was intended to have a two-speed reduction gearbox to maximise efficiency in cruising flight.][
]
Specifications (XR-4090-1)
See also
References
Bibliography
*Gunston, Bill. ''World Encyclopedia of Aero Engines: From the Pioneers to the Present Day''. 5th edition, Stroud, UK: Sutton, 2006.
*White, Graham. ''Allied Aircraft Piston Engines of World War II: History and Development of Frontline Aircraft Piston Engines Produced by Great Britain and the United States During World War II''. Warrendale, Pennsylvania: SAE International, 1995.
*
*
*
{{US military piston aeroengines
1940s aircraft piston engines
Aircraft air-cooled radial piston engines
R-4090