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J1N "Gekko / Irving"

Night Fighter


J1N  Gekko / Irving

The Night fighter Gekko (Moonlight), Nakajima. Twin-engine long-range escort fighter (J1N1), reconnaissance aircraft (J1N1-C and J1N1-R) or night fighter (J1N1-S and J1N1-Sa). All-metal construction with fabric-covered control surfaces.

Accommodation: Crew of three (J1N1, J1N1-C and J1N1-R), or two (J1N1-C KAI, J1N1-S and J1N1-Sa) in enclosed cockpit.

Night fighter and reconnaissance aircraft J1N "Gekko" ("Moonlight"), American code designation "Irving". After nine months of fighting in China, the senior aviation officers of the Japanese fleet began to receive demands for the creation of a long-range escort fighter, on the basis of which the naval headquarters began to prepare a task for a new aircraft. The reason for such demands was a peculiar tactic used by the Chinese - they diverted their fighter aircraft beyond the range of the Japanese Type 96 fighters, as a result of which the uncovered Type 96 bombers suffered heavy losses.

On the basis of these requirements, in the spring of 1938, the aviation bureau of the naval headquarters formulated the requirements of the 13-Ci, which were generally written off from the French twin-engine fighter "Potez" -63, which had just entered service with the "Air Army" of France. After studying the opinions of the most experienced pilots of the 12th Kokutai and making changes to the specifications, the requirements of the 13-Ci were directed to Mitsubishi and Nakajima. The mission called for a three-seat, twin-engine fighter capable of primarily maneuvering combat against single-engine fighters. The speed was set at 520 km / h, the flight range was 2400 km with a normal supply of fuel and 3700 km with the maximum, the armament was to consist of a 20-mm cannon and 7.7-mm machine guns forward and on a defensive installation back.

For this assignment, Katsuji Nakamura designed an aerodynamically clean low wing aircraft with a number of interesting features. For the aircraft, two Nakajima Sakae air-cooled engines with a power of 1130 hp were chosen, but in order to eliminate the negative effect of the reactive torque of the propeller, the engines were of two modifications Sakae -12 and Sakae -22 with opposite rotation of propellers.

The first "experimental three-seat escort fighter 13-Si" (or "short" designation - J1N1) took off in May 1941. To improve maneuverability, the second prototype aircraft was equipped with flaps that deflected 20 ° during combat maneuvering and 40 ° during landing. Automatic slats were also installed. Both aircraft were handed over for official testing to the fleet in August 1941. The tests were unsuccessful, as the aircraft was generally overweight, problems arose due to the opposite rotation of the propellers and a complex hydraulic system. The remote-controlled turrets proved to be too heavy, and their targeting was inaccurate. In addition, on turns on the J1N1 there was a strong shaking of the ailerons. Maneuverability was considered insufficient, although it was quite high for a twin-engine aircraft. A comparison with the Mitsubishi A6M2 single-engine fighter showed that the J1N 1 was inferior to the first in almost all aspects except for the flight range. As a result, in October 1941 the fleet decided to reject the long-range escort fighter. But since the aircraft was practically not inferior to the A6M2 in speed, Nakajima was asked to convert several almost ready-made machines into a long-range coastal-based high-speed reconnaissance aircraft.

When redesigning the aircraft, special attention was paid to reducing weight and improving reliability. So, the fuel supply was reduced from 2270 liters to 1700 liters, and all weapons, including unreliable towers, were removed. Also, the reliability of the operation of the aircraft was increased by the replacement of engines with opposite rotation of the Sakae-21 and -22 propellers only on the Sakae-22, which did not have gearboxes. To maintain the flight range while reducing the fuel supply, it was possible to suspend two 330-l additional tanks under the center section. The fuselage was reconfigured. The pilot and gunner-radio operator were located in the forward fuselage. The latter had at his disposal a 13 mm Type 2 machine gun on a mobile mount at the end of the cockpit. The navigator was located in a separate cabin behind the wing. The modified aircraft received the designation J1N1-C and successfully passed flight tests in July 1942, after which it was put into production under the designation Marine Type 2 reconnaissance aircraft. Since the need for a specialized aircraft was not as urgent as compared to the main combat types, the pace of production was low - from April 1942 to March 1943, Nakajima delivered only 54 J1N1-Cs, including prototypes.

'Gekko' Specification
J1N1 J1N1-C J1N1-S
Crew 3 3 3
Wing span, m 16.98 16.98 16.98 (55 ft. 8¼ in.)
Wing area, m² 40.0 40.0 40.0 (430.57 sq. ft.)
Length, m 12.18 12.18 12.77 (41 ft. 10¾ in.)
Two Nakajima NK1F Sakae Maximum, hp 1,130 1,100 594
Altitude, m take-off 2850 (9,350 ft) 6000 (19,685 ft)
Weight, kg:
Empty weight 5,020 4,852 4,850 (10,692 lb)
Loaded weight 7,250 6,890 7,010 (15,454 lb)
Maximum takeoff weight 8,030 7,527 8,184 (18,045 lb)
Wing loading*, kg/m² 181.3 172.3 175.3 (35,9 lb/ft²)
Power loading, kg/hp 3.6 3.3 3.7 (8.16 lb/hp)
Speed, km/h maximum 507 530 507 (315 mph)
at altitude, m 5000 6000 5800 (19,030 ft)
Speed, km/h cruising 330 278 330 (205 mph)
at altitude, m 4,000 4,000 4,000 (13,123 ft)
Climb - 5min 37sec 9min 35sec
Service ceiling, m - 10,300 9,320 (30,580 ft)
Normal range, naut miles - 1,457 1,374
Maximum range, naut miles - - 2,040

* - at normal flight weight.

Armament: One forward-firing 20 mm Type 99 Model 1 cannon, two forward-firing 7.7 mm Type 97 machine-guns and four 7.7 mm Type 97 machine-guns in two remotely controlled dorsal barbettes (J1N1).

One rear-firing hand-held 13 mm Type 2 machine-gun (J1N1-C and J1N1-R).

One 20 mm Type 99 Model 1 cannon in a dorsal turret (some J1N1-R).

Two fuselage-mounted upward-firing 20 mm Type 99 cannon and two 20 mm Type 99 downward-firing cannon (J1N1-C KAI and J1N1-S).

Two fuselage-mounted upward-firing 20 mm Type 99 cannon and, optional, one forward-firing 20 mm Type 99 cannon (J1N1-Sa).

Photo Description

Drawing J1N1-Sa (J1N3)

«Gekko» Мк.23 J1N3

J1N. Combat Use.

It was decided to send the first three aircraft for trial operation to the front in the spring of 1942. On April 19, the fifth, sixth and seventh production aircraft took off from Japan in the direction of Rabaul. In the Yokohama area, the leader of the group, Satoru Ono, saw explosions of anti-aircraft shells. Since it was in the deep rear, the intrigued pilot directed his plane in their direction and saw a twin-engine aircraft, which turned out to be an American B-25 bomber! It was an aircraft from the Doolittle group that made the first raid on Japan during the war. Since there were no weapons on the scout, the pursuit of the enemy had to be abandoned. Arriving at the front, the machines became part of the Tainan kokutai (aviation detachment). The first sorties were made for reconnaissance of Port Moresby, over New Guinea and even Australia. There were no losses until September 1942, when the plane under the control of Takunaga ran into a group of American B-26 bombers, escorted by P-39 fighters from the 41st division. "Aircobras" did not miss the opportunity to shoot down a stranger. The victory was chalked up to Elbert Shintsa. The remaining two aircraft were used for reconnaissance during the fighting on Guadalcanal. In particular, they photographed the airfield. Henderson, who then fired at the ships of the Japanese fleet at night.

En masse reconnaissance began to enter combat units in the fall of 1942, and the Americans initially considered him a fighter and gave him the code designation "Irvine" at a time when scouts received female names.

Later, the aircraft was renamed J1N1-R, (the "C" suffix was left for carrier-based reconnaissance), and a small number of them received a turret with a 20-mm gun "type 99 model 1" behind the cockpit. In the spring of 1943, the commander of the 251st Kokutai, Yasino Kozono, proposed installing guns in the fuselage of the aircraft at an angle to the horizon, thereby converting the reconnaissance aircraft into a night fighter. The service personnel at the Rabaul airfield, instead of the equipment of the navigator's cabin, installed two 20-mm cannons obliquely upwards at an angle of 30 "and two more downwards. The modified aircraft received the designation J1N1-C KAI. Soon, the boatswain Shigetoshi Kudo on the J1N1-C KAI intercepted over Rabaul and shot down two B-17 bombers from the American 43rd Bombardment Group, thus proving the suitability of Kozono's idea Kudo later shot down three more B-17s and one Australian Hudson patrol bomber, becoming an ace. fighters forced the fleet headquarters to issue an order to Nakajima to switch from reconnaissance to interceptor.

Production of the J1N1-S "Gekko" (Moonlight) "model 11" fighter began at Nakajima Hikoki K.K. at Koizumi in August 1943. The pace of production immediately increased - from April 1943 to March 1944, already 183 J1Ns (mostly fighters) were produced, compared with 54 in the previous 12 months. Before the end of production in December 1944, another 240 aircraft were produced. The new J1N1-S received weapons similar to the J1N1-C KAI, but the ledge behind the cockpit was smoothed out and the keel root was changed. The first unit to be re-equipped with the new night fighter was the 251st Kokutai, which received 24 Gekkos before the end of 1943.

Later, these machines received the 381st Kokutai, as well as the 321st Kokutai, the first unit in Japanese naval aviation that specializes in night interception. All of them fought in New Guinea and the Solomon Islands. Somewhat later, already in 1944, J1N1-S appeared in the Philippines and Indonesia (141st and 153rd detachments). They covered oil fields and large cities, flying both day and night. They were also used as attack aircraft. To do this, part of the aircraft again received a gun in the nose. At the end of 1944, Gekko was stationed in Northern Japan and the Kuril Islands.

Combat experience showed the inefficiency of guns firing downwards, and soon they were no longer installed. Such machines were called J1N1-Sa "Gekko". Most J1N1-Sas and some J1N1-Ss were equipped with a radar antenna in the nose of the aircraft, and a few aircraft received a small searchlight in the nose. The first "Gekko" received a "type 3 mk. 6 model 4" radar, designed to detect surface targets. From a height of 3000 m, the detection range of enemy ships could reach 50 km. "Gekko" with this locator were used for night patrols over the sea - that is, in the role of a scout. At the end of 1944, there was an urgent need to install a radar to detect air targets. The FD-2 locator used on the Gekko was noticeably inferior in performance to the German and British models - the maximum target detection range was only 3000 m, and the minimum was 600, which was clearly more than the visual detection range of an enemy bomber at night. Even the best version of the Toshiba locator had a minimum range of 470 m, and then the pilots had to rely on "fighter instinct". As a result, in the 70-kg combat units, the locator equipment was most often simply dismantled. Sometimes, instead of a locator or a searchlight, a 20-mm "type 99 model 2" gun was placed in the bow. Only in the spring of 1945 did the first success come - pilot Yuzo Kuramoto and cameraman Shiro Kurotori discovered an enemy bomber at a distance of 3000 m using a radar, which turned out to be a Boeing B-29, and shot it down.

By the end of 1944, the surviving Gekkos were pulled to the metropolis, to the 332nd and 352nd squadrons, beyond the reach of enemy fighters. They were stationed at Kure Air Base, from where they patrolled the Sasebo-Nagasaki-Omura area at night. A small group, commanded by the "father" of "Gekko" Kozono, was located at the Atsugi airfield near Tokyo.

In battles, the Gekko proved to be a fairly effective interceptor for American B-24s, but due to its low speed reserve, it could rarely make more than one attack on a more modern B-29. So, during a raid on Tokyo on October 24, 1944, 111 B-29 bombers that launched to intercept 18 Gekkos were able to damage only one Super Fortress. Sometimes, however, the pilots announced major successes. So on November 3, Gekko from the 302nd Kokutai, together with J2M Raiden, allegedly shot down nine B-29s, and on the night of May 26, 1945, as many as 16 American bombers. One of the pilots - already familiar to us from the first real interception with the help of the locator - Kuramoto announced five B-29s shot down that night, but in reality such losses were not recognized by the Americans.

In battles with Hellcat and Mustang fighters, Gekkos were usually destroyed. Therefore, as soon as from April 1945 the Americans switched to covering their bombers with fighters over the entire territory of Japan, Gekko began to fly only at night.

Production of the J1N was discontinued in December 1944 with a total of 479 vehicles:

2 J1N1 prototypes in the spring of 1941.

7 pre-production J1N1-C (1941-42)

470 pcs. J1N1-C, J1N1-R, J1N1-C KAI, J1N1-S and J1N1-Sa (July 1942 - December 1944)

At the end of the war, most of the remaining Gekkos and J1N1-R reconnaissance aircraft were used as kamikaze aircraft armed with two 250-kg bombs - a logical result for all obsolete Japanese aircraft.

Among the trophies "Gekko" subsequently fell into the hands of the Americans. This already obsolete aircraft, of course, did not arouse much interest and was not tested.

J5N "Tenrai"

J5N1 Tenrai

"Nakajima" J5N1 "Tenrai" ("Heavenly Thunder") is an experimental heavy twin-engine fighter-interceptor of the fleet.

Beginning in 1942, more and more reports began to come in from the front about the low effectiveness of Japanese fighter attacks against multi-engine American bombers. The situation became even more serious when intelligence obtained information that the United States was preparing for mass production of even more advanced machines designed specifically for the strategic bombing of the Japanese islands. The aviation of the army and navy of Japan was absolutely not ready to oppose this threat. It was urgent to take action, and in early 1943, Kaigun Koku Hombu developed the 18-Ci "B" specification for a heavy interceptor fighter.

The technical requirements were formulated in a general form and did not impose on the developers either the design scheme of the aircraft, or purely engines, or their type. The developers had to create an aircraft armed with at least two 30-mm Type 5 cannons, developing a speed of 665 km / h at high altitude and gaining an altitude of 8000 m in 9 minutes. Another additional requirement was to ensure the ease of the mass production process, allowing over time the transition to the maximum use of non-strategic materials. At the beginning of 1943, the specification of the 18-Ci "B" was transferred on a competitive basis to the firms "Nakajima" and "Kavanishi", part of the work was taken over by the technical department of Kaigun Koku Hombu.

After receiving the requirements, Nakajima specialists led by Katsuzi Nakamura and Kazuo Ono in a short time on the basis of an earlier aircraft of this company - J1N Gekko - the N-20 project was created. The new machine was built according to the scheme of a single-seat twin-engine cantilever mid-wing with a working duralumin skin and a laminar profile wing. The fuel tanks were tested, and the front of the pilot was protected by armored glass 50 mm thick. The armament consisted of four cannons placed in the forward fuselage, two 30 mm Type 5 and two 20 mm Type 99 Model 2. Two Nakajima Homare 21 engines with a capacity of 1990 hp were chosen as the power plant. With.

At the end of 1943, the project was approved by the customer and received the military index J5N1 "Tenrai" (Heavenly Thunder). The prototype aircraft was completed in early March 1944, and in July it made its first flight. Due to the fact that the Homare 21 engines installed on it had not yet been completed and did not develop the declared power, the characteristics of the J5N1 could not be considered satisfactory. The maximum speed of the aircraft - 603 km / h - was much lower than required. A number of other indicators did not correspond to the task, with the exception of the rate of climb: the J5N1 climbed to a height of 8000 m in 9 minutes. In addition, in flight, "Tenrai" was characterized by insufficient longitudinal stability and poor controllability at low speeds, especially in turns. Additional problems were delivered by unfinished engines.

While the prototype was being tested, five more prototypes were built. Two of them were double options, them. obviously, they planned to adapt it for the installation of a radar. In 1944, the first prototype was modified to the J5N1 KAI variant. The main difference was the transfer of two 30-mm cannons behind the cockpit and their installation at an angle of 60 °.

Despite the introduction of a large number of changes in the design of experimental machines, the flight characteristics of the J5N1 did not improve significantly. That, however, did not prevent one of the aircraft from intercepting an American Boeing B-29 Superfortress bomber flying at an altitude of 000 m during a test flight and shooting it down.

In early 1945, having lost hope of obtaining an effective interceptor, Kylie Koku Hombu ordered that work on the Tenrai be stopped. Of the six J5N1s built, one aircraft crashed during flight tests, two were destroyed during an enemy air raid, and the remaining three were captured by the Americans after the war.

J5N1 Specification
Crew 1-2
Length, m 11.46
Height, m 3.50
Wing span, m 14.50
Wing area, m² 32.00
2 × PE Nakajima NK9H Homare 21, power hp 2 × 1,990
Weights, kg
Empty weight 5,090
Loaded weight 7,040
Gross weight 8,035
Maximum speed, km/h 621
Cruise speed, km/h 464
Maximum rate of climb, m/min 750
Service ceiling, m 10800
Service range, km 925

Armament. Four cannons were installed in the lower forward part of the fuselage: two 30 mm type 5 and two 20 mm type 99 model 2.

Construction. Trapezoidal all-metal wing J5N had a laminar profile and a simplified design. Since the surface area of the wing was only slightly larger than that of the single-engine A6M fighter, the developers had to equip it with effective mechanization tools: wide flaps and slats.

The all-metal fuselage of the J5N featured a small cross-sectional area and very clean aerodynamic lines. Armament was concentrated in its bow, consisting of two 30 mm Type 5 cannons and two 20 mm Type 99 Model 2 cannons.

The teardrop-shaped canopy of the J5N cockpit, which consisted of armored glass with a thickness of 50 and 20 mm, provided the pilot with a high degree of security.

The J5N's main landing gear was fitted with large diameter, low pressure tires that allowed the aircraft to operate from poorly prepared field airfields. The tail landing gear retracted into the fuselage in flight.

Photo Description

Drawing J5N1


  • "Japanese Aircraft of the Pacific War " /Rene J Francillion./
  • "Japan Warplanes of World War II" /Oleg Doroshkevich/