J1N Gekkou
Nakajima J1N at the Steven F. Udvar-Hazy Center
Role	Fighter Aircraft
Manufacturer	Nakajima Aircraft Company
Designer	Mitsubishi and Nakajima
First flight	May 1941
Introduction	1942
Retired	1945
Primary user	Imperial Japanese Navy
Produced	from 1942 to 1944
Number built	479

The Nakajima Aircraft Company J1N1 Gekkou was a twin-engine aircraft used by the Japanese Imperial Navy during World War II and was used for reconnaissance, night fighter, and kamikaze missions. The first flight took place in May 1941. It was given the Allied reporting name "Irving", since the earlier reconnaissance version the J1N1-C, was mistaken for a fighter.

Design[link]

In mid-1938 the Japanese Imperial Navy requested a twin-engine fighter designed to escort the principal bomber used at the time, Mitsubishi G3M "Nell". The operating range of the standard Navy fighter, the Mitsubishi A5M "Claude", was only 1,200 km (750 mi), insufficient compared with the 4,400 km (2,730 mi) of the G3M. Moreover, at the time, the potential of the "Zero", then still under development, remained to be evaluated, stressing the need for a long-range escort fighter.

In March 1939, Mitsubishi and Nakajima began the development of a project 13-Shi. The prototype left the factory in March 1941 equipped with two 843 kW (1,130 hp) Nakajima Sakae 21/22, 14-cylinder radial engines. There was a crew of three, and the aircraft was armed with a 20 mm Type 99 cannon and six 7.7 mm (.303 in) Type 97 machine guns. Four of these machine guns were mounted in a powered turret, the weight of which reduced the performance of the aircraft considerably. Because of the sluggish handling, being used as ae escort fighter had to be abandoned. Instead, production was authorized for a lighter reconnaissance variant, the J1N1-C, also known by the Navy designation Navy Type 2 Reconnaissance Plane. One early variant, the J1N1-F, had a spherical turret with one 20 mm Type 99 Model 1 cannon mounted immediately behind the pilot.

Operations[link]

In 1943, Commander Yasuna Kozono（小園 安名） of the 251st Kokutai in Rabaul came up with the idea of installing 20 mm cannons at 30 degree angle in the fuselage. Against orders of central command which was skeptical of his idea, he tested his idea on a J1N1-C as a night fighter. The field-modified J1N1-C KAI shot down two B-17s of 43rd Bomb Group attacking air bases around Rabaul on 21 May 1943.

The Navy took immediate notice and placed orders with Nakajima for the newly designated J1N1-S nightfighter design. This model was christened the Model 11 Gekko (月光, "Moonlight"). It required only two crew and like the KAI, had a twin 20 mm pair of Type 99 Model 1 cannon firing upward in a 30° upward angle and a second pair firing downward at a forward 30° angle, placed in the fuselage behind the cabin, similar to the German Schräge Musik configuration, but also in a ventral mode-the original German Schräge Musik mount was strictly upward-firing only. Development of both Japanese and German night fighters were independent of each other. This arrangement was effective against B-17 Flying Fortress bombers and B-24 Liberators, and its existence was not quickly understood by the allies who assumed the Japanese did not have the technology for night fighter designs. Early versions had nose searchlights in place of radar. Later models omitted the two lower-firing guns and added one 20 mm cannon to face upward as with the other two (J1N1-Sa Model 11a). Other variants without nose antennae or searchlight added a 20 mm cannon to the nose.

The J1N1-S was used against B-29 Superfortresses in Japan, though the lack of good radar and insufficient high-altitude performance handicapped it, since usually only one pass could be made against the higher-speed B-29s. However, some skillful pilots had spectacular successes, such as Lieutenant Sachio Endo, who was credited with destroying eight B-29s and damaging another eight before he was shot down by a B-29 crew, Shigetoshi Kudo (nine victories), Shiro Kuratori (six victories), and Juzo Kuramoto (eight victories); the last two claimed five B-29s during the night of 25–26 May 1945. Another Gekko crew shot down five B-29's in one night, but these successes were rare. Many Gekkos were also shot down or destroyed on the ground. A number of Gekkos were relegated to "Tokko" missions, the Japanese term for kamikaze attacks, using 250 kg (550 lb) bombs attached to the wings.

Survivors[link]

Only one J1N1-S Gekko "Irving" survives today. Following the occupation of the home islands, U.S. forces gathered 145 interesting Japanese aircraft and sent them to the United States aboard three aircraft carriers. Four Gekkos were in this group: three captured at Atsugi and one from Yokosuka. Serial Number 7334, the aircraft from Yokosuka, was given Foreign Equipment number FE 3031 (later changed to T2-N700). Records show that after arriving aboard the U.S.S. Barnes, air intelligence officials assigned Gekko 7334 to Langley Field, Virginia, on 8 December 1945. The airplane was moved to the Air Materiel Depot at Middletown, Pennsylvania, on 23 January 1946.

The Maintenance Division at Middletown prepared the Gekko for flight tests, overhauling the plane's engines and replacing the oxygen system, radios, and some flight instruments with American equipment. Mechanics completed this work by 9 April. The Navy transferred Gekko 7334 to the Army in early June, and an army pilot flew the Gekko on 15 June 1946, for about 35 minutes. At least one other test flight took place before the Army Air Forces flew the fighter to an empty former Douglas C-54 factory at Park Ridge, Illinois, for storage. The remaining three Gekkos were scrapped.

In 1949, the Gekko was given to the Smithsonian's National Air Museum, but remained in storage at Park Ridge, Illinois. The collection of museum aircraft at Park Ridge numbered more than 60 airplanes when the war in Korea forced the United States Air Force to move it to the Paul E. Garber Preservation, Restoration and Storage Facility in Suitland, Maryland. Gekko 7334 was dumped outside the restoration facility in a large shipping crate in 1953 where it remained until building space became available in 1974. In 1979, NASM staff selected Gekko 7334 for restoration.

Following restoration of the museum's Mitsubishi Zero in 1976, the Gekko became the second Japanese aircraft to receive the skilled attentions of NASM restoration craftsmen. The airframe was found to be seriously corroded from having remained outside for twenty years. At that time, it was the largest and most complex aircraft restoration project the NASM had ever undertaken. Work started on 7 September 1979, and ended 14 December 1983, following 17,000 hours of meticulous, dedicated labor. Today, Gekko 7334 is fully restored and on display in the Steven F. Udvar-Hazy Center in Chantilly, Virginia the sole remaining example of Japan's innovative line of night-fighting Gekkos.

Variants[link]

• J1N1 : Prototype.
• J1N1-C : Long-range reconnaissance aircraft.
• J1n1-C KAI :Night Fighter converted from J1N-C
• J1N1-R : Later redesignated J1N1-F.
• J1N1-S : Night fighter aircraft.
• J1N1-Sa :Night Fighter same as above except added extra 20MM gun

• 

  J1N1-F Reconnaissance modified with 20mm gun turret

• 

  J1N1-S Night fighter with airborne radar although no armament is pictured here

• 

  J1N1-S of the 210th Kokutai with drop tanks

Specifications (J1N1-S)[link]

Data from Japanese Aircraft of the Pacific War^[1]

General characteristics

• Crew: 2
• Length: 12.77 m (41 ft 11 in)
  

J1N1: 12.18 m (40 ft)

J1N1-C: 12.18 m (40 ft)

• Wingspan: 16.98 m (55 ft 9 in)
• Height: 4.562 m (15 ft 0 in)
• Wing area: 40 m² (430 sq ft)
• Empty weight: 4,480 kg (9,877 lb)
  

J1N1: 5,020 kg (11,067 lb)

J1N1-C: 4,852 kg (10,697 lb)

• Gross weight: 7,010 kg (15,454 lb)
  

J1N1: 7,250 kg (15,984 lb)

J1N1-C: 6,890 kg (15,190 lb)

• Max takeoff weight: 8,184 kg (18,043 lb)
  

J1N1: 8,030 kg (17,703 lb)

J1N1-C: 7,527 kg (16,594 lb)

• Fuel capacity: 1,700 l (373.9 imp gal)

J1N1: 2,270 l (499.3 imp gal)

• Powerplant: 2 × Nakajima NK1F Sakae 21 14-cyl. two-row air-cooled radial piston engine, 840 kW (1,130 hp) each take-off rating
  

820.3 kW (1,100 hp) at 2,850 m (9,350 ft)

730.8 kW (980 hp) at 6,000 m (19,685 ft)

J1N1: 1x Nakajima NK1F Sakae 21 + 1x Nakajima NK1F Sakae 22 handed engines

• Propellers: 3-bladed un-handed metal constant-speed propellers
  

J1N1: handed 3-bladed metal constant speed propellers

Performance

• Maximum speed: 507 km/h; 315 mph (274 kn) at 5,840 m (19,160 ft)
• Cruise speed: 333 km/h; 207 mph (180 kn) at 4,000 m (13,123 ft)
• Range: 2,545 km; 1,581 mi (1,374 nmi)
• Ferry range: 3,778 km; 2,348 mi (2,040 nmi)
• Rate of climb: 8.7 m/s (1,710 ft/min)
• Time to altitude: 5,000 m (16,404 ft) in 9 minutes 35 seconds
• Wing loading: 175.3 kg/m² (35.9 lb/sq ft)
  

J1N1: 181.3 kg/m² (37.1 lb/ft²)

J1N1-C: 172.3 kg/m² (35.3 lb/ft²)

• Power/mass: 0.27 kW/kg (0.125 hp/lb)
  

J1N1: 0.21 kW/kg (0.128 hp/lb)

J1N1-C: 0.226 kW/kg (0.137 hp/lb)

Armament

• Guns: 4× 20 mm Type 99 cannon, two upward- and two downward-firing
  

or 2× 20 mm Type 99 cannon, firing upward only

or 3× 20 mm Type 99 cannon, all three firing upward

J1N1:

1x forward firing fuselage mounted 20mm Type 99 Model 1 cannon

2x forward firing fuselage mounted 7.7mm Type 97 machine guns

4x 7.7mm Type 97 machine guns in two remotely controlled dorsal barbettess

J1N1-C:

1x rearwards firing, manually aimed 13mm Type 2 machine gun

J1N1-C-KAI:

4× 20 mm Type 99 cannon, two upward- and two downward-firing

J1N1-R:

1x rearwards firing, manually aimed 13mm Type 2 machine gun

1x 20mm Type 99 Model 1 cannon in a dorsal turret

J1N1-Sa:

2× 20 mm Type 99 cannon, firing upward only

1x optional forward firing fuselage mounted 20mm Type 99 Model 1 cannon

See also[link]

Wikimedia Commons has media related to: Nakajima J1N

Aircraft of comparable role, configuration and era

• Kawasaki Ki-45
• Messerschmitt Bf 110
• Bristol Beaufighter
• Northrop P-61 Black Widow
• Heinkel He 219
  

Related lists

• List of aircraft of World War II
• List of aircraft of Japan, World War II
  

References[link]

Notes[link]

Bibliography[link]