Nakajima Sakae

The Nakajima Sakae (, Prosperity) was a two-row, 14-cylinder air-cooled radial engine used in a number of combat aircraft of the Imperial Japanese Navy and Imperial Japanese Army before and during World War II.[1]

Nakajima Sakae engine on a Mitsubishi Zero
Type Piston aircraft engine
Manufacturer Nakajima
First run 1939
Major applications Mitsubishi A6M
Nakajima Ki-43
Kawasaki Ki-48
Number built 30,233
Developed from Nakajima Ha5

Design and development

The engine was designed by Nakajima Aircraft Company with code name NAM, as a scaled-down and advanced version of the previous NAL design (Army Type 97 850 hp radial engine, Nakajima Ha5).[2] The Imperial Japanese Army Air Force called the first of the series the Ha-25 (ハ25) and later versions were designated Ha35, Ha105 and Ha115, while the Imperial Japanese Navy Air Service designation was Nakajima NK1, with sub-types identified by Model numbers; thus Nakajima NK1 Sakae 10, 20 and 30 series.

A total of 21,166 were made by Nakajima; 9,067 were manufactured by other firms.


Army Type 99 975 hp Air-cooled Radial
Long Army designation for the Nakajima NK1 radial engine named Sakae.
Nakajima Ha25
Short Army designation for the initial production version of the Nakajima NK1 radial engine named Sakae.
Nakajima Ha35
Nakajima Ha35 Model 11
Nakajima Ha35 Model 12
Nakajima Ha35 Model 23 - 1,150 hp (858 kW)
Nakajima Ha105
Nakajima Ha115
Nakajima Ha115-I
Nakajima Ha115-II
Nakajima NK1
NK1C Sakae 12 - 925 hp (690 kW) , 940 hp (701 kW) , 975 hp (727 kW)
NK1D Sakae 11 - 970 hp (723 kW) , 985 hp (735 kW)
NK1F Sakae 21 - 1,115 hp (831 kW) , 1,130 hp (843 kW)
NK1E Sakae 31 - 1,130 hp (843 kW) , boosted to 1,210 hp (902 kW) with water-methanol injection


Surviving engines

A small number of original Sakae powerplants are on display in aviation museums, usually mounted into the airframes of restored Mitsubishi A6M Zeros - only one airworthy Zero worldwide still flies with a restored Sakae powerplant, the Planes of Fame Museum's A6M5 example, bearing tail number "61-120".[3][4]

Specifications (Sakae 21)

Data from TAIC Manual [5]

General characteristics


  • Valvetrain: Overhead valve
  • Supercharger: Gear driven, two speed.
  • Fuel system: 2 BBL D.D. Float Carb. automatic mixture and boost control.
  • Fuel type: 92 Octane
  • Cooling system: Air-cooled


See also

Comparable engines

Related lists



  1. Gunston 1989, p.105.
  2. Nakagawa, Ryōichi (1985). Engine History of Nakajima Aircraft. Tōkyō: Kantōsha. pp. 76–85. ISBN 4-87357-007-7.
  3. Seaman, Richard. "Aircraft air shows." Retrieved: 13 October 2010.
  4. Flight Demo of Genuine Japanese Zero with ORIGINAL WWII Sakae 31 Engine!. YouTube. 2009. Event occurs at 2:10. Archived from the original on December 14, 2009. Retrieved May 6, 2013.
  5. OPNAV-16-VT#301, p. 852


  • Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9
  • Jane's Fighting Aircraft of World War II. London. Studio Editions Ltd, 1989. ISBN 0-517-67964-7
  • Peattie, Mark R., Sunburst: The Rise of Japanese Naval Air Power 1909-1941, Annapolis, Maryland: Naval Institute Press, 2001, ISBN 1-55750-432-6
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