Nakajima Homare 21, Ha 45 Model 21, Radial 18 Engine
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, a total of 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
11th Naval Air Arsenal, Hiroshima, Kure
Designer
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 (1,829 lb)
Dimensions
Overall: 1829.8lb. (830kg)
Other (Engine): 3 ft. 10 7/16 in. × 5 ft. 10 1/4 in. × 4 ft. 6 in. (118 × 178.5 × 137.2cm)
Storage (Stand): 6 ft. 2 in. × 5 ft. 1 in. (188 × 154.9cm)
3-D (Overall): 170.2 × 121.9 × 116.8cm (5 ft. 7 in. × 4 ft. × 3 ft. 10 in.)
Materials
HAZMAT: Cadmium Plating
Wood
Textile
Steel
Aluminum
Zinc Plating
Coating
Fabric
Inventory Number
A19710931000
Credit Line
Transferred from the U.S. Navy
Data Source
National Air and Space Museum
Restrictions & Rights
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