The Nakajima J1N1 is a twin-engine aircraft used by the Imperial Japanese Navy during World War II. A prototype first flew in May 1941. The first full production variant of the Gekkō, the J1N1-C was a reconnaissance aircraft, although many of these underwent field modification into night fighters; in addition, a night fighter variant, the J1N1-S was later put into production. Towards the end of the war, J1N1 pilots also undertook kamikaze anti-shipping missions. The Gekkō was given the Allied reporting name "Irving".
Design and development
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, much as the Luftwaffe had done with the Messerschmitt Bf 110 Zerstörer, introduced the year before.
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 aircraft machine guns. Four of these machine guns were mounted in two rear-mounted powered turrets. The plane was considered to be overweight, and problems developed with the gearboxes of the propellers, hydraulic system, and ailerons. The turrets were heavy and difficult to bring onto target. In addition, the plane was not considered to be maneuverable enough. These issues brought about the end of the development for a long range fighter. Instead, production was authorized for a lighter reconnaissance variant, the J1N1-C, also known by the Navy designation Navy Type 2 Reconnaissance Plane, which passed flight tests in July, 1942. The J1N1-C had all of its armament removed except for a single 13 mm Type 2 machine-gun at the rear of the cockpit, a reconfigured fuselage, reduced fuel supply (1700 liter down from 2270 liters), and the engines changed from a combination of Sakae-21 and Sakae-22 to just the Sakae-22 without a gearbox. As the need for specialized planes wasn't as urgent as standard types, production of the J1N1-C was slow. 54 J1N1-Cs, including prototypes, were produced by Nakajima from April 1942 to March 1943. The J1N1-C was redesignated as the J1N1-R (C for carrier-based, R for reconnaissance), and a few were fitted with a 20mm Type 99 gun in a turret behind the cockpit. 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 Gekkō (, "Moonlight"). It had a crew of two, eliminating the navigator position. Like the KAI, it had twin 20 mm Type 99 Model 1 cannon firing upward in a 30° upward angle, but added a second pair firing downward at a forward 30° angle, allowing attacks from above or below. Production was quickly ramped up, with 183 produced between April 1943 and March 1944, and a further 204 produced before end of production in December 1944. This arrangement was effective against B-17 Flying Fortress bombers and B-24 Liberators, which usually had Sperry ball turrets for ventral defense. The Gekkō's existence was not quickly understood by the Allies, who assumed the Japanese did not have the technology for night fighter designs. Some planes were equipped with the Type 3 Mk. 6 Model 4 radar in the nose to detect enemy ships at night, while others were equipped with a searchlight in place of the radar. Later models, the J1N1-Sa, omitted the two downward-firing guns and added another 20 mm cannon to face upward as with the other two. Other variants without nose antennae or searchlight added a 20 mm cannon to the nose.<!-- reference -->
|prime units?=met<!-- imp or kts first for US aircraft, and UK aircraft pre-metrification,
met(ric) first for all others. You MUST choose a format, or no specifications will show -->
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General characteristics
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|crew=2
|capacity=
|length m=12.77
|length note=
|span m=16.98
|height m=4.562
|wing area sqm=40
|empty weight kg=4,480
|empty weight note=
|gross weight kg=7,010
|gross weight note=
|max takeoff weight kg=8,184
|max takeoff weight note=
|fuel capacity=
|more general=
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Powerplant
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|eng1 number=2
|eng1 name=Nakajima NK1F Sakae 21
|eng1 type=14-cyl. two-row air-cooled radial piston engine
|eng1 hp=1,130<!-- prop engines -->
|eng1 note= take-off rating<br/>
:: at
:: at
|prop blade number=3<!-- propeller aircraft -->
|prop name=un-handed metal constant-speed propellers
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Performance
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|max speed kts=274
|max speed note= at
|cruise speed kts=180
|cruise speed note= at
|range nmi=1,374
|range note=
|ferry range nmi=2,040
|ferry range note=
|climb rate ms=8.7
|climb rate note=
|time to altitude= in 9 minutes 35 seconds
|wing loading kg/m2=175.3
|wing loading note=
|power/mass= 0.27 kW/kg (0.125 hp/lb)
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Armament
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|guns= 4× 20 mm Type 99 cannon, two upward- and two downward-firing<br/>
:::or 2× 20 mm Type 99 cannon, firing upward only
:::or 3× 20 mm Type 99 cannon, all three firing upward
See also
References
Notes
Bibliography
- Francillon, René J. Japanese Aircraft of the Pacific War. London: Putnam & Company Ltd., 1970 (2nd edition 1979). .