Mitsubishi Kasei 21, Ha 32 Model 21, Radial 14 Engine


Display Status:

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.

Collection Item Summary:

Mitsubishi was the first and largest series producer of Japanese engines during World War II, with a 1937 Pratt & Whitney arrangement possibly contributing to this success. The Kasei (Mars) was the largest of the manufacturer’s original 14-cylinder radials, and was widely used in various models. It was geared, supercharged, and had optional water methanol injection. Between 1941 and 1945, a total of 9,323 engines of all models of Kasei 20 series were manufactured.

This Model 21 powered the Mitsubishi G4M twin engine attack bomber (Allied Code Name Betty) built in larger numbers than any other Japanese bomber; it was used from the beginning of the war and also transported the Japanese surrender delegation. A total of 2,446 G4M and the similar G6M1 aircraft were built.

Collection Item Long Description:

Data Source

National Air and Space Museum

Restrictions & Rights

Do not reproduce without permission from the Smithsonian Institution, National Air and Space Museum

Credit Line

Gift of the War Memorial Museum of Virginia.


  • Steel
  • Aluminum
  • Rubber
  • Leather
  • Magnesium?
  • Cadmium Plating
  • Adhesive
  • Copper Alloy
  • Stainless Steel
  • Ceramic
  • Plastic
  • Paint


  • Overall: 175.3 × 134 × 134cm, 780kg (69 × 52 3/4 × 52 3/4 in., 1719 9/16lb.)
  • Storage (On Stand): 182.9 × 157.5 × 154.9cm (72 × 62 × 61 in.)

Country of Origin



Circa World War II

Physical Description

  • Type: Reciprocating, 14 cylinders, 2 rows, radial, air cooled
  • Power rating: 1,825 kW (1,825 hp) at 2,600 rpm
  • Displacement: 42.1 L (2,570 cu in)
  • Bore and Stroke: 150 mm (5.91 in.) x 170 mm (6.69 in.)
  • Weight: 780 kg (1,720 lb)
  • missing carburetor, spark plugs, exhaust collector ring, generator, starter; spark plug wires damaged; on stand.


PROPULSION-Reciprocating & Rotary

Inventory Number