Nakajima Sakae
The Nakajima Sakae (栄, Glory) 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]
| Sakae | |
|---|---|
![]()  | |
| 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 | 
| Developed into | Nakajima Homare | 
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 Ha25 (ハ25) and later versions were designated Ha105 and Ha115, in the Hatsudoki designation system and Ha-35 in the unified designation system, 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.
Variants
    
- Army Type 99 975 hp Air-cooled Radial
 - Long Army designation for the Nakajima NK1 radial engine named Sakae.
 - Nakajima Ha25 (Hatsudoki designation)
 - Short Army designation for the initial production version of the Nakajima NK1 radial engine named Sakae.
 - Nakajima Ha105 (Hatsudoki designation)
 - Nakajima Ha115 (Hatsudoki designation)
 - Nakajima Ha115-I
 - Nakajima Ha115-II
 - Nakajima Ha-35 (unified designation)
 - Nakajima Ha-35 Model 11
 - Nakajima Ha-35 Model 12
 - Nakajima Ha-35 Model 23 - 1,150 hp (858 kW)
 
- Nakajima NK1 (Navy designation)
 - 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 - 1,130 PS (831 kW; 1,115 bhp)
 - NK1E Sakae 31 - 1,130 hp (843 kW), boosted to 1,210 hp (902 kW) with water-methanol injection
 
Applications
    
    
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
    
- Type: 14-cylinder air-cooled two-row radial engine
 - Bore: 130 mm (5.1 in)
 - Stroke: 150 mm (5.9 in)
 - Displacement: 27.9 L (1,687 in³)
 - Length: 1,600 mm (63 in)
 - Diameter: 1,150 mm (45 in)
 - Dry weight: 590 kg (1,300 lb)
 
Components
    
- 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
 
Performance
    
- Power output: 842.64 kW (1130hp) at altitude
 - Specific power: 30.2 kW/L (0.66 hp/in³)
 - Compression ratio: 7:1
 - Power-to-weight ratio: 1.428 kW/kg (0.869 hp/lb)
 
See also
    
Comparable engines
- BMW 801
 - Bristol Hercules
 - Bristol Taurus
 - Pratt & Whitney R-1830
 - Fiat A.74
 - Gnome-Rhône 14N
 - Mitsubishi Kinsei
 - Piaggio P.XI
 - Piaggio P.XIX
 - Shvetsov ASh-82
 - Tumansky M-88
 
Related lists
References
    
    Notes
    
- Gunston 1989, p.105.
 - Nakagawa, Ryōichi (1985). Engine History of Nakajima Aircraft. Tōkyō: Kantōsha. pp. 76–85. ISBN 4-87357-007-7.
 - Seaman, Richard. "Aircraft air shows." richard-seaman.com. Retrieved: 13 October 2010.
 - Flight Demo of Genuine Japanese Zero with ORIGINAL WWII Sakae 31 Engine! on YouTube
 - OPNAV-16-VT#301, p. 852
 
Bibliography
    
- Goodwin, Mike & Starkings, Peter (2017). Japanese Aero-Engines 1910-1945. Sandomierz, Poland: MMPBooks. ISBN 978-83-65281-32-6.
 - 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
 
