Country of origin:

Japan

Description:

Three-seat twin-engine escort and reconnaissance fighter

Power Plant:

Two 843 kw (1,130 hp) Nakajima NK1F Sakae fourteen-cylinder two-row air-cooled radial engines

Specifications:

Armament:

One 20 mm forward firing Type 99 Model 1 cannon and two 7.7 mm (0.303 in) machine guns in nose; one rear firing 13 mm Type 2 machine gun

History:

The J1N1 Gekko (moonlight) was conceived by the Japanese Naval Bureau of Aeronautics in June 1938 for a twin-engine fighter. The Nakajima Hikoki K K put forward a proposal designed by a team lead by Katsuji Nakamura, which was accepted, a contract being awarded in 1939. The prototype first appeared in May 1941 and flew for the first time on 2 May.  It was a slim, low-wing, all metal monoplane with a fixed forward firing armament comprising one 20 mm and two 7.7 mm (0.303 in) machine guns, and a pair of remotely-controlled barbettes each housing two 7.7 mm (0.303 in) machine guns mounted aft of the cockpit and operated by the navigator. Power was provided by two 843 kw (1,130 hp) Nakajima Nk1F Sakae 21 and 22 engines driving opposite rotating three-blade constant-speed metal propellers. However, many control difficulties were experienced during testing and the Navy was forced to abandon its proposed long-range escort fighter.

The J1N1 was ordered into production as the J1N1-C type 2 Reconnaissance Model 11 and by early 1943 it was entering service in the Solomon Islands. By this time it was a three-seater and the remotely-controlled gun barbettes had been removed, as had the opposite rotating propellers.  Attention was given to reducing weight and improving reliability, the internal fuel capacity being reduced from 2,270 litres (499 Imp gals) to 1,700 litres (374 Imp gals). In this new form it passed service trials in July 1942. The type was first encountered in the Solomons and was identified as a fighter, receiving the Allied code-name ‘Irving’.

In 1943 the Japanese Navy found it had a requirement for a night fighter due to the regular bombing of bases in the islands by Boeing B-17s and Consolidated B-24s of the USAAC. At this time the 251st Kokutai equipped with the type was based at Vanakunau airfield, Rabaul. It was suggested that a system of obliquely mounted cannon be experimentally fitted to several J1N1-C aircraft and these aircraft had some success in the area against bombers, becoming known as the J1N1-C KAI. Subsequently all existing J1N1s were converted to the night fighter role as the J1N1-S Gekko, as well as aircraft on the production line being converted to this configuration.

Production aircraft then had two fixed 20 mm cannon amidships firing forward and upward at an angle of 30 degrees from the horizontal, and the crew was reduced to two.  A total of 183 J1N1s, mostly night fighters, was produced between April 1943 and March 1944, and a further 240 completed up to December 1944 when the type was phased out of production. In all a total of 486 was completed. Production was slow; between April 1942 and March 1943 only 54 examples were completed.

Following its success as a night fighter a small number were retained for the long-range reconnaissance and attack bomber roles, a few being fitted with a manually operated dorsal turret housing a 20 mm cannon. Late production aircraft were fitted with airborne interception radar with an antenna attached to the nose and used in the night defence of Japan in the Chubu and Kanto provinces, operating against B-29 Superfortresses. Towards the end of the war surviving J1N1-R reconnaissance aircraft were expended in kamikaze attacks, carrying two 250 kg (551 lb) bombs.

Units which operated the type included the 133rd, 141st, 153rd, 251st, 302nd and 322nd Kokutais. The wrecks of a couple which operated with the 251st Kokutai survive in the Rabaul area, serials noted including 664 and 251-16.

In May 1943 USAAF B-24 Liberators were operating from Australia on missions to Rabaul and up to that stage had not met with much opposition from Japanese night fighters. However, on one occasion two B-24s were shot down by a J1N1 of the 251st operating in the night fighter role. In the months that followed the J1N1 became one of Japan’s most successful night fighters. On the night of 21 May 1943 a J1N1 shot down two Boeing B-17s.

On the night of 2 August 1942 a J1N1-C took off from Lae, NG to reconnoiter the Kokoda Trail, flown by Warrant Officer Tokunaga Tamotsu, when it was attacked by Bell P-39 Aircobras of the USAAF 41 Fighter Squadron, the Gekko (‘Irving’) being shot down by 2nd Lt Elbert Schinz. The Aircobras were protecting Martin B-26 Marauders on a bombing mission and left the latter to attack the Gekko. Subsequently the P-39s were attacked by a formation of Mitsubishi A6Ms, one of the latter being shot down and two P-39s being lost. At the time Japanese forces were operating C5M2s and the J1N1-Cs on reconnaissance missions relating to the intention to capture Port Moresby, NG. Records indicate the Tainan Naval Air Group operated three J1N1-Cs from Lae and Rabaul from June to October 1942, these aircraft having tail numbers V-1, V-2 and V-3 (c/ns 15, 16 and 17).

The type was also flown over Australia. On 20 July 1942 a J1N1-C, flown by Warrant Officer Satoro Ono, flew a reconnaissance mission over Horn Island operating from Lae. The surviving J1N1-Cs continued to operate from Lae and Rabaul until US forces invaded Guadacanal. On 7 August 1942 the J1N1-Cs flew reconnaissance missions from Rabaul over Guadacanal, the two aircraft on this occasion having an escort of nine A6Ms from the Tainan Kokutai.

Flying the Gekko in the defence of Japan Lt Sachio Endo was credited with destroying eight Boeing B-29s and damaging another eight before being shot down. Many Gekkos were shot down, destroyed on the ground, or lost in Kamikaze attacks.

One example of the J1N1-S (serial 3-102 – c/n 7334) survives at the Udvar Hazy complex, part of the Smithsonian, in Washington. This was one of 145 captured aircraft conveyed on board aircraft carriers from Japan to the United States for testing. Three J1N1s were included, two found at Atsugi and one at Yokosuka. It was given Foreign Equipment No FE3031 (later T2-N700), restored to airworthiness, and flown on at least two occasions, once on 15 June 1946. The other aircraft were broken up and 3-102 was placed in storage, eventually being restored for display.

In the 1980s a New Zealander located and recovered the complete mount assembly for the oblique mounted cannons in a J1N1 wreck at Vanakunau and this was conveyed to and placed on display at the Kokopo Museum in New Guinea.