Nakajima G8N

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G8N Renzan
Nakajima G8N1.jpg
Role Heavy bomber
Manufacturer Nakajima Aircraft Company
First flight 23 October 1944
Introduction early 1945
Retired August 1945
Primary user Imperial Japanese Navy Air Service
Produced 4

The Nakajima G8N Renzan (連山, "Mountain Range") was a four-engine long-range bomber designed for use by the Imperial Japanese Navy. The Navy designation was "Type 18 land-based attack aircraft" (十八試陸上攻撃機); the Allied code name was "Rita".

Design and development[edit]

In February 1943 the Imperial Navy staff asked Nakajima Aircraft Company to design a four-engined bomber, capable of meeting an earlier specification set for a long-range land-based attack plane. The final specification, issued on 14 September 1943, called for a plane with a maximum speed of 320 knots (590 km/h; 370 mph) able to carry a 4,000 kg (8,800 lb) bomb-load 2,000 nmi (3,700 km; 2,300 mi) or a reduced bomb-load 4,000 nmi (7,400 km; 4,600 mi).[1]

Nakajima's design featured a mid-mounted wing of small area and high aspect ratio, a tricycle landing gear and a large single-fin rudder. Power came from four 2,000 hp Nakajima NK9K-L "Homare" 24 radial engines with Hitachi 92 turbosuperchargers and driving four-bladed propellers. The engines were cooled by counter-rotating fans positioned just inside the engine cowlings.[1] Defensive armament included power-operated nose, dorsal, ventral and tail turrets along with two free-swiveling machine guns at the beam positions.[2]

Operational history[edit]

A captured G8N with a C-45 and T-6

The initial prototype was completed in October 1944 and delivered to the Navy for testing in January 1945, a year after the Navy ordered development to start. Three further examples were completed by June 1945, with the third prototype being destroyed on the ground by US carrier aircraft.[2]

Other than minor problems with the turbosuperchargers, the Renzan performed satisfactorily and the Navy hoped to have a total of 16 prototypes and 48 production-version G8N1s assembled by September 1945. But the worsening war situation and a critical shortage of light aluminium alloys led to the project's cancellation in June.[2]

One proposed variant was the G8N2 Renzan-Kai Model 22, powered by four 2,200 hp Mitsubishi MK9A radial engines and modified to accept attachment of the air-launched Ohka Type 33 Special Attack Bomber.[2]

Just before Japan's surrender in August 1945 consideration was also briefly given to producing an all-steel version of the aircraft, to be designated G8N3 Renzan-Kai Model 23, but the cessation of hostilities precluded any further development.[2]

After the war, one prototype was taken to the United States[3][4] and scrapped after testing. None are in existence today.


  • G8N1 : Four-engine heavy bomber. Production version.
  • G8N2 : Modified to carry Ohka Type 33 Special Attack Bomber. Four Mitsubishi MK9A radial engines.
  • G8N3 : All-steel airframe.



Specifications (G8N1)[edit]

Nakajima G8N1 Renzan - 3D drawing.svg

Data from Japanese Aircraft of the Pacific War[2]

General characteristics



  • 6× 20 mm Type 99 cannon - 2 each in the dorsal, ventral, and tail turrets
  • 2× 13 mm (.51 in) Type 2 machine guns in nose turret
  • 2× 13 mm (.51 in) Type 2 machine gun in fuselage sides
  • Up to 4,000 kg (8,818 lb) of bombs

See also[edit]

Aircraft of comparable role, configuration and era


  • Collier, Basil. Japanese Aircraft of World War II. New York: Mayflower Books, 1979. ISBN 0-8317-5137-1.
  • Francillon, Ph.D., René J. Japanese Aircraft of the Pacific War. London: Putnam & Company Ltd., 2nd edition 1979. ISBN 0-370-30251-6.
  • Thorpe, Donald W. Japanese Naval Air Force Camouflage and Markings World War II. Fallbrook, California: Aero Publishers, Inc., 1977. ISBN 0-8168-6583-3. (hc.) ISBN 0-8168-6587-6 (pbk.)
  • Unknown authors. Famous Airplanes of the World: Nakajima Shinzan / Renzan (Volume 11, no.146). Japan: Bunrin-Do, Nov. 1984.