Wright R 1820 Cyclone

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 produce the engine 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 armoured vehicles. The G-200 variant developed 900 hp (670 kW) at 2,300 rpm and powered the M6 Heavy Tank. The Wright RD-1820 was converted to a diesel by Caterpillar Inc. as the D-200 and produced 450 hp (340 kW) 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 9Vr

9V with reduction gear

Hispano-Suiza 9Vb

Hispano-Suiza 9Vbr

variant of the 9Vb with reduction gear

Hispano-Suiza 9Vbrs

variant of the 9Vb with reduction gear and supercharger

Hispano-Suiza 9Vbs

variant of the 9Vb with supercharger

Hispano-Suiza 9Vd

variant of the 9V

Hispano-Suiza 9V-10

429 kW (575 hp) driving fixed-pitch propeller

Hispano-Suiza 9V-11

as -10 but RH rotation

Hispano-Suiza 9V-16

480 kW (650 hp) driving variable-pitch propeller, LH rotation

Hispano-Suiza 9V-17

as -16 but RH rotation

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

Specifications (GR-1820-G2)

Data from Tsygulev

General characteristics

Type: Nine-cylinder single-row supercharged air-cooled radial engine

Bore: 6  ¹⁄₈ in (155.6 mm)

Stroke: 6  ⁷⁄₈ in (174.6 mm)

Displacement: 1,823 in³ (29.88 L)

Length: 47.76 in (1,213 mm)

Diameter: 54.25 in (1,378 mm)

Dry weight: 1,184 lb (537 kg)

Components

Valvetrain: Two overhead valves per cylinder with sodium-filled exhaust valve

Supercharger: Single-speed General Electric centrifugal type supercharger, blower ratio 7.134:1

Fuel system: Stromberg PD12K10 downdraft carburetor with automatic mixture control

Fuel type: 87 octane rating gasoline

Oil system: Dry sump with one pressure and one scavenging pump

Cooling system: Air-cooled

Performance

Power output: 1,000 hp (746 kW) at 2,200 rpm for takeoff

Specific power: 0.46 hp/in³ (20.88 kW/L)

Compression ratio: 6.45:1

Specific fuel consumption: 0.6 lb/(hp•h) (362 g/(kW•h))

Oil consumption: 0.35-0.39 oz/(hp•h) (13-15 g/(kW•h))

Power-to-weight ratio: 0.84 hp/lb (1.39 kW/kg)