The Wright R-4090 Cyclone 22 was an American experimental radial piston engine designed and built in prototype form by Wright Aeronautical during the 1940s.
| R-4090 Cyclone 22 | |
|---|---|
| Type | 22-cylinder air-cooled two-row radial piston engine |
| National origin | United States |
| Manufacturer | Wright Aeronautical |
| Number built | ~3 |
| Developed from | Wright R-3350 Duplex-Cyclone |
Design and development
editDuring the 1940s, Wright Aeronautical Corporation was constantly in competition with Pratt & Whitney for new engine designs required for civil and military aircraft. Utilizing the Wright R-3350 Duplex-Cyclone 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.[1]
The air-cooled R-4090 was rated to deliver 3,000 hp (2,200 kW) at 2,800 rpm for take-off, from a total displacement of 4,092 cu in (67.06 L), 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.[1]
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.[1]
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.[1]
Variants
editSpecifications (XR-4090-1)
editData from enginehistory.org,[2] Old Machine Press[1]
General characteristics
- Type: Air-cooled 22 cylinder two-row radial piston engine
- Bore: 6.125 in (155.6 mm)
- Stroke: 6.3125 in (160.3 mm)
- Displacement: 4,092 cu in (67.06 L)
- Length: 91 in (2,300 mm)
- Diameter: 58 in (1,500 mm)
- Dry weight: 3,230 lb (1,470 kg)
Components
- Valvetrain: One inlet and one Sodium-cooled exhaust over-head valves per cylinder, driven by pushrods and rocker arms.
- Supercharger: 14 in (360 mm) diameter impeller, single-stage two-speed supercharger; gear ratios: of 5 to 1 and 7 to 1.
- Fuel type: Gasoline
- Reduction gear: 0.333:1 planetary reduction gearbox
Performance
- Power output: 3,000 hp (2,200 kW) at 2,800 rpm for take-off
- Compression ratio: 6.85:1
See also
editRelated development
Comparable engines
References
edit- ^ a b c d e f g Pearce, William (22 March 2013). "Wright Aeronautical R-4090 Cyclone 22". oldmachinepress.wordpress.com. Retrieved 24 September 2015.
- ^ "Curtiss-Wright XR-4090 A 22-Cylinder Radial". enginehistory.org. Retrieved 24 September 2015.
Bibliography
edit- Gunston, Bill. World Encyclopedia of Aero Engines: From the Pioneers to the Present Day. 5th edition, Stroud, UK: Sutton, 2006.ISBN 0-7509-4479-X
- 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. ISBN 1-56091-655-9
- White, Graham (14 February 2006). R-4360: Pratt & Whitney's Major Miracle. Specialty Press. ISBN 1580071732.
- USAF US Navy: Engine model designation system (revised 1 January 1950 ed.). Air Material Command. Retrieved 24 September 2015.
- The Wright Cyclones. Wright Aeronautical Corporation. 1942.