Wright R-1820 Cyclone. The Wright R-1820 Cyclone 9 is an American radial engine developed by Curtiss-Wright, widely used on aircraft in the 1930s through 1950s.  It was produced under license in France as the Hispano-Suiza 9V or Hispano-Wright 9V, and in the Soviet Union as the Shvetsov M-25.

Design and development
The R-1820 Cyclone 9 represented a further development of the Wright P-2 engine dating back to 1925. Featuring a greater displacement and a host of improvements, the R-1820 entered production in 1931. The engine remained in production well into the 1950s.

The R-1820 was built under license by Lycoming, Pratt & Whitney Canada, and also, during World War II, by the Studebaker Corporation. The Soviet Union had purchased a license for the design, and the Shvetsov OKB was formed to metricate the American specification powerplant for Soviet government-factory production as the M-25, with the R-1820's general design features used by the Shvetsov design bureau for many of their future radials for the Soviet air forces through the 1940s and onwards. In Spain the R-1820 was license-built as the Hispano-Suiza 9V or Hispano-Wright 9V.

The R-1820 was at the heart of many famous aircraft including early Douglas airliners (the prototype DC-1, the DC-2, the first civil versions of the DC-3, and the limited-production DC-5), every wartime example of the Boeing B-17 Flying Fortress and Douglas SBD Dauntless bombers, the early versions of the Polikarpov I-16 fighter (as the M-25), and the Piasecki H-21 helicopter.

The R-1820 also found limited use in armored vehicles. The G-200 variant developed  at 2,300 rpm and powered the strictly experimental M6 Heavy Tank.

D-200 Diesel
The Wright R-1820 was converted to a diesel during World War II by Caterpillar Inc. as the D-200 and produced  at 2,000 rpm in the M4A6 Sherman.

Variants

Notes: Unit numbers ending with W indicate engine variants fitted with water-methanol emergency power boost systems.

Hispano-Suiza 9V
The Hispano-Suiza 9V is a licence-built version of the R-1820. 
Hispano-Suiza 9Vr9V with reduction gear
Hispano-Suiza 9Vb
Hispano-Suiza 9Vbrvariant of the 9Vb with reduction gear
Hispano-Suiza 9Vbrsvariant of the 9Vb with reduction gear and supercharger
Hispano-Suiza 9Vbsvariant of the 9Vb with supercharger
Hispano-Suiza 9Vdvariant of the 9V
Hispano-Suiza 9V-10 driving fixed-pitch propeller
Hispano-Suiza 9V-11as -10 but RH rotation
Hispano-Suiza 9V-16 driving variable-pitch propeller, LH rotation
Hispano-Suiza 9V-17as -16 but RH rotation

Applications

Vehicles
 M4A6 tank
 M6 heavy tank

Engines on display
Preserved Wright R-1820 engines are on display at the following museums:
 American Airlines C.R. Smith Museum
 Fleet Air Arm Museum
 Delta Flight Museum
 National Air and Space Museum
 National Museum of the U.S. Air Force
 Wings of Freedom Aviation Museum

Specifications (GR-1820-G2)

See also

References

Bibliography

 Bridgman, L, (ed.) (1998) Jane's Fighting Aircraft of World War II. Crescent. .
 
 Eden, Paul & Soph Moeng, The Complete Encyclopedia of World Aircraft. Amber Books Ltd. Bradley's Close, 74-77 White Lion Street, London, NI 9PF, 2002, .
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.  
 
 

Aircraft air-cooled radial piston engines
R-1820
1930s aircraft piston engines