This Japanese Navy and Air Force engine is the type that powered World War II Allied Code Names George, Sam, Rita, and Frank aircraft. After overcoming some initial reliability problems including vibration and difficult servicing, the Nakajima Homare became the most important 18-cylinder Japanese engine toward the end of the war. Between 1941 and 1945, 8,771 engines of all models of the Homare 10 and 20 series were manufactured.

A very compact design, it had a very high specific output, but had difficulty providing rated power at altitude. For the first time in a Japanese engine, it incorporated a steel crankcase, dynamic balancers, a dual magneto with a remote distributor (on the nose), and a nose sump pump. Its supercharger drive followed the Wright Aeronautical design, with a planetary reduction gear in series with the high gear for obtaining a lower compression ratio, and was equipped with water-methanol injection.

 Display Status

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
Object Details
Date Circa World War II Country of Origin Japan Type PROPULSION-Reciprocating & Rotary Manufacturer Nakajima Hikoki K. K.
 Physical Description Type: Reciprocating, 18 cylinders, 2 rows, radial, air-cooled Power rating: 1,491 kW (2,000 hp) at 3,000 rpm Displacement: 35.9 L (2,195 cu in.) Bore and Stroke: 130 mm (5.1 in.) x 150 mm (5.9 in.) Weight: 830 kg (1,830 lb) Dimensions Diameter 118.0 cm (46.4 in.), Length 178.5 cm (70.25 in.)
 Materials HAZMAT: Cadmium
Non-Magnetic Metal
Ferrous Alloy
Unknown Coating
Aluminum
Plastic
Copper Alloy
Rubber
Possible Leather
 Inventory Number A19670077000 Credit Line Transferred from the U.S. Army Air Forces, Wright Field, Dayton, Ohio Data Source National Air and Space Museum Restrictions & Rights Usage conditions apply
For more information, visit the Smithsonians Terms of Use.