TheMitsubishi Kinsei (金星,Venus) was a 14-cylinder, air-cooled, twin-rowradial aircraft engine developed byMitsubishi Heavy Industries in Japan in 1934 for theImperial Japanese Navy. The Mitsubishi model designation for this engine wasA8 while it was an experimental project; in service, it was known as theMK8 "Kinsei" by the Navy. In 1941 the engine was adopted by Army, receiving designationHa-112^[1] (laterHa-112-I, 1,300hp Army Type 1). In May 1943 it receivedHa-33unified designation code.^[2]

Early Kinsei models (1 and 2) hadA4 internal designation and their cylinder and detail design was based on the single-row, 9-cylinder air-cooledPratt and WhitneyR-1690 Hornet.^[3]

In 1933 engine underwent a major redesign and redesignatedA8. Head layout was reversed to allow exhaust exit to the rear, reducingback-pressure and allowing for a cleaner installation.Compression ratio increased from 5.3:1 to 6.0:1. These changes resulted in a significant performance uplift, compared to previous variants.^[4]

Kinsei 41 saw ever further increase in compression ratio from 6.0:1 to 6.6:1, and a largersupercharger. It's also the first variant to receive a two-digit model numbers. 40 series remained in production from 1936 till the end of the war.

Kinsei 50 series saw the final compression ratio increase to 7.0:1. Indirectfuel injection was fitted as well as a larger two-speed supercharger.

Kinsei 60 series was introduction of direct injection and later, aturbo-supercharger. Its development was run parallel to 50 series. Production started in 1940 and lasted till the end of the war.^[5]

Data from Goodwin^[6]

Kinsei 1

820 hp (610 kW) at 2300 rpm at takeoff

650 hp (480 kW) at 2100 rpm at sea level

Kinsei 2

830 hp (620 kW) at 2350 rpm at takeoff

630 hp (470 kW) at 2100 rpm at 1,000 m (3,300 ft)

Data from Goodwin^[7]

Kinsei 3

790 hp (590 kW) at 2150 rpm at 2,000 m (6,600 ft)

Kinsei 41

1,075 hp (802 kW) at 2500 rpm at 2,000 m (6,600 ft)

990 hp (740 kW) at 2500 rpm at 2,800 m (9,200 ft)

Higher compression ratio, supercharger

Kinsei 42

1,075 hp (802 kW) at 2500 rpm at 2,000 m (6,600 ft)

990 hp (740 kW) at 2500 rpm at 2,800 m (9,200 ft)

Air pump

Kinsei 43

1,000 hp (750 kW) at 2400 rpm at sea level

990 hp (740 kW) at 2400 rpm at 2,800 m (9,200 ft)

De-rated for economy

Model 44

1,070 hp (800 kW) at sea level

1,080 hp (810 kW) at 2,000 m (6,600 ft)

Machine gun synchroniser

Kinsei 45

1,075 hp (802 kW) at sea level

1,000 hp (750 kW) at 4,180 m (13,710 ft)

Kinsei 46

930 hp (690 kW) at sea level

1,070 hp (800 kW) at 4,200 m (13,800 ft)

De-rated for extreme economy

Kinsei 51 (MK8A)

1,200 hp (890 kW) at 2500 rpm at 3,000 m (9,800 ft)

1,100 hp (820 kW) at 2500 rpm at 6,200 m (20,300 ft)

Redesigned cylinder head, added indirect fuel injection, larger two-speed supercharger

Kinsei 52 (MK8B) (Ha-112-I)

1,200 hp (890 kW) at 2500 rpm at 3,000 m (9,800 ft)

1,100 hp (820 kW) at 2500 rpm at 6,200 m (20,300 ft)

Addedwater injection

Kinsei 53 (MK8C)

1,200 hp (890 kW) at 2500 rpm at 3,000 m (9,800 ft)

1,100 hp (820 kW) at 2500 rpm at 6,200 m (20,300 ft)

Higher pressureoil pump

Kinsei 54 (MK8D)

1,200 hp (890 kW) at 2500 rpm at 3,000 m (9,800 ft)

1,100 hp (820 kW) at 2500 rpm at 6,200 m (20,300 ft)

Addedmachine gun synchroniser

Model 61 (Ha-112-II)

1,350 hp (1,010 kW) at 2,000 m (6,600 ft)

1,250 hp (930 kW) at 5,800 m (19,000 ft)

Added direct fuel injection

Kinsei 62 (MK8P)

1,350 hp (1,010 kW) at 2600 rpm at 2,000 m (6,600 ft)

1,250 hp (930 kW) at 2600 rpm at 5,800 m (19,000 ft)

Kinsei 62 Ru (Ha-112-II Ru)

1,350 hp (1,010 kW) at 2600 rpm at 2,000 m (6,600 ft)

1,370 hp (1,020 kW) at 2600 rpm at 7,700 m (25,300 ft)

1,240 hp (920 kW) at 2600 rpm at 11,000 m (36,000 ft)

Ru-102 turbo-supercharger

• Aichi D3A
• Aichi E13A
• Aichi E16A
• Aichi M6A2
• Kawanishi H6K
• Kawanishi N1K5-J
• Kawasaki Ki-96
• Kawasaki Ki-100
• Kawasaki Ki-102
• Mitsubishi A6M8
• Mitsubishi B5M
• Mitsubishi G3M
• Mitsubishi Ki-46-III
• Nakajima/Mahshu Ki-116
• Showa/Nakajima L2D2-L2D5
• Yokosuka D4Y3-D4Y4

Data fromJane's.^[8]

• Type: 14-cylinder air-cooled twin-row radial engine
• Bore: 140 mm (5.5 in)
• Stroke: 150 mm (5.9 in)
• Displacement: 32.3 L (1,970 cu in)
• Length: 1,646 mm (64.8 in)
• Diameter: 1,218 mm (48.0 in)
• Dry weight: 545 kg (1,202 lb)

• Valvetrain: Overhead valve, one inlet and one exhaust valve per cylinder, pushrod operated.
• Supercharger: Centrifugal, single speed.
• Oil system: Triple section pump, one pressure pump, two scavenge pumps.
• Cooling system: Air-cooled
• Reduction gear: Planetary gear, 0.7:1 ratio.

• Power output: 1,075 hp (802 kW) at 2,500 rpm at 2,000 m (6,560 ft) maximum.
• Specific power: 24.8 kW/L (0.56 hp/cu in)
• Compression ratio: 6.6:1
• Power-to-weight ratio: 1.5 kW/kg (0.9 hp/lb)

Related development

• Mitsubishi Shinten
• Mitsubishi Kasei
• Pratt & Whitney R-1690 Hornet

Comparable engines

• BMW 801
• Bristol Hercules
• Bristol Taurus
• Fiat A.74
• Gnome-Rhône 14N
• Nakajima Sakae
• Piaggio P.XI
• Piaggio P.XIX
• Pratt & Whitney R-1830
• Shvetsov ASh-82
• Wright R-2600

Related lists

• List of aircraft engines

• Goodwin, Mike & Starkings, Peter (2017).Japanese Aero-Engines 1910-1945. Sandomierz, Poland: MMPBooks.ISBN 978-83-65281-32-6.
• Matsuoka Hisamitsu, Nakanishi Masayoshi. The History of Mitsubishi Aero Engines 1915–1945. Miki Press, Japan, 2005.ISBN 4-89522-461-9
• Gunston, Bill.World Encyclopaedia 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

• Aircraft air-cooled radial piston engines
• 1930s aircraft piston engines
• Mitsubishi aircraft engines

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