Kawanishi N1K

N1K/N1K-J
Kawanishi N1K2-J Shiden Kai
Role	Fighter
National origin	Japan
Manufacturer	Kawanishi Aircraft Company
First flight	N1K1: 6 May 1942 [1] N1K1-J: 27 December 1942 [2] N1K2-J: 31 December 1943 [3]
Introduction	1943
Retired	1945
Primary user	Imperial Japanese Navy Air Service
Number built	1,532 [4]

The Kawanishi N1K Kyōfū (強風 "strong wind", Allied reporting name "Rex") is an Imperial Japanese Navy floatplane fighter. The Kawanishi N1K-J Shiden (紫電 "Violet Lightning") was an Imperial Japanese Navy Air Service land-based version of the N1K. Assigned the reporting name "George", the N1K-J was considered by both its pilots and opponents to be one of the finest land-based fighters flown by the Japanese during World War II.^[5][6]

The Shiden Kai possessed heavy armament as well as surprisingly good manoeuvrability, due to a mercury switch that automatically extended the flaps during turns. These "combat" flaps created more lift, thereby allowing tighter turns. Unlike the Mitsubishi A6M Zero, the Shiden Kai could compete against the best late-war Allied fighters, such as the F6F Hellcat, F4U Corsair, and P-51 Mustang.^[7]

Design and development

Kawanishi N1K1 "Rex" floatplane fighter photographed by the Japanese Navy prior to 1945

Kawanishi's N1K was originally built as a single pontoon floatplane fighter to support forward offensive operations where no airstrips were available but by 1943 when the aircraft entered service Japan was firmly on the defensive and there was no longer a need for a fighter to fulfill this role. It was powered by the Mitsubishi MK4C Kasei 13 14-cylinder radial engine.

The requirement to carry a bulky, heavy float essentially crippled the N1K against contemporary American fighters. However, Kawanishi engineers had proposed in late 1941 that the N1K would also be the basis of a formidable land-based fighter and a land-based version was produced as a private venture by the company. This version flew on 27 December 1942 powered by a Nakajima NK9A Homare 11 18-cylinder radial engine, replacing the less powerful MK4C Kasei 13 of the N1K-1. The aircraft retained the mid-mounted wing of the floatplane and combined with the large propeller this necessitated a long, stalky main landing gear. A unique feature was the aircraft's combat flaps that automatically adjusted in response to acceleration, freeing up the pilot's concentration and reducing the chance of stalling in combat. The N1K did have temperamental flight characteristics, however, that required an experienced touch at the controls.^[8]

The Nakajima Homare was powerful but had been rushed into production before it was sufficiently developed and proved troublesome. Another problem was landing gear failure due to poor heat treatment of the wheels. Apart from engine problems and the landing gear the flight test program showed that the aircraft was promising. Prototypes were evaluated by the Navy, and since the aircraft was faster than the Zero and had a much longer range than the Mitsubishi J2M Raiden, it was ordered into production as the N1K1-J, the -J indicating a land-based fighter modification of the original floatplane fighter.

Only four days after the Shiden's first test flight a complete redesign was begun. The N1K2-J addressed the N1K1-J's major defects, primarily the mid-mounted wing and long landing gear. The wings were moved to a low position, which permitted the use of shorter, conventional undercarriage. The fuselage was lengthened and the tail redesigned. The production of the entire aircraft was simplified: over a third of the parts used in the previous Shiden could still be used in its successor while construction used fewer critical materials.^[9] The N1K1 redesign was approximately 250 kg (550 lb) lighter and was faster and more reliable than its predecessor. The Homare engine was retained even though reliability problems persisted as no alternative was available. A prototype of the new version flew on 1 January 1944. After completing Navy trials in April the N1K2-J was rushed into production. This variant was named the "Shiden-Kai" (紫電改), with Kai meaning modified.

Operational history

Kawanishi N1K2-J, probably N1K4-J Shiden Kai Model 32. Only two prototypes were built.

The N1K Shiden entered service in early 1944. The original N1K1 and the N1K2 Shiden-Kai released later that year were among the rare Japanese aircraft that offered pilots an even chance against late-war American designs such as the F6F Hellcat and the F4U Corsair,^[10] and either could be a formidable weapon in the hands of an ace. In February 1945 Lieutenant Kaneyoshi Muto, flying a N1K2-J as part of a group of at least 10 expert Japanese pilots, faced seven U.S. Navy Hellcats of VF-82 in the sky over Japan. His group shot down four Hellcats with no loss to themselves.^[11] After the action reporters fabricated a story in which Muto was the sole airman facing 12 enemy aircraft.^[12] A close friend of Lieutenant Kaneyoshi Muto, ace pilot Saburō Sakai, states in his autobiography that a one-versus-twelve combat did take place, but with Muto at the controls of a Zero fighter.^[13]

The N1K1-J aircraft were used very effectively over Formosa (Taiwan), the Philippines, and, later, Okinawa. Before production was switched to the improved N1K2-J, 1,007 aircraft were produced, including prototypes. Production difficulties and damage resulting from B-29 raids on factories led to only 415 of the superior N1K2-J fighters being produced.

The N1K2-J Shiden-Kai proved to be one of the best dogfighting aircraft produced by either side. Along with high speed the Shiden-Kai offered pilots an agile aircraft with a roll rate of 82°/sec at 386 km/h (240 mph) backing four powerful 20 mm cannons in the wings. As a bomber interceptor the N1K2-J fared less well, hampered as it was by a poor rate of climb and reduced engine performance at high altitude.^[14][15]

343 Kōkūtai

Captured Kawanishi N1K2-Js having their Homare engines run up by former IJNAS groundcrew

The N1K2-J Shiden-Kai offered a formidable if demanding aircraft in limited quantities. As a result, the planes were distributed to elite units such as the IJN 343rd Air Group (343 Kōkūtai Naval Fighter Group) constituted on 25 December 1944 and commanded by Minoru Genda. The new 343rd Kōkūtai claimed Japan's finest fighter pilots such as Muto and Genda. The unit was issued the best available equipment and new Nakajima C6N Saiun, codenamed "Myrt" long-range reconnaissance aircraft.

On 18 March 1945 one of the "Myrts" managed to spot U.S. carriers en route to Japan. The following morning, Shiden aircraft flown by the group intercepted 300 American aircraft. Many of the 343 Kōkūtai Shiden force were N1K2s. When the Shidens encountered Grumman F6F Hellcats from the Fighting Bombing Squadron 17 (VBF-17), three aircraft were lost on both sides in the initial attack: one Hellcat and two Shidens were shot down by enemy ground fire, two fighters collided in mid-air, and one Hellcat crashed while trying to land. Another Shiden dived on a Hellcat group and downed another one. In the end the Hikōtai lost six fighters versus eight VBF-17 fighters on the other side.

The Shiden's bulletproof glass

Another noted encounter pitted the N1K against the Vought F4U Corsair. Two Corsairs from VBF-10, accidentally separated from their main formations, were attacked by Shidens from the 343rd. Four N1K2s were shot down. The Corsairs managed to return to their carrier, USS Bunker Hill. A second encounter took place when pilots flying Shidens initially mistook Corsairs from Marine Fighter Squadron 123 (VMF-123) for Hellcats and attacked. A 30-minute aerial duel ensued in which three Corsairs were shot down and another five were damaged. Three other F4Us returned to their carriers but were so heavily damaged that the planes were scrapped. No Shidens were lost to Corsairs in that aerial battle. Losses for the Japanese N1K pilots did occur in related action, however. Two Shidens were shot down upon returns for landing by Hellcats of Fighting Squadron 9 (VF-9), while many more Shidens were destroyed by American fighters over another airfield where, low on fuel, their pilots tried to land. At the end of the day the 343rd claimed 52 kills and the U.S. squadrons 63. The actual losses were 15 Shidens and 13 pilots, a "Myrt" with its three-man crew, and nine other Japanese fighters. The U.S. also took heavy losses: 14 fighters and seven pilots, plus 11 attack aircraft. Five days later an unofficial award was sent to 343 Kōkūtai for the valour shown on 19 March.

On 12 April 1945 another fierce battle involved 343°, during Kikusui N.2. The Japanese recorded several kills but suffered 12 losses out of 34 aircraft. On 4 May another 24 Shidens were sent in Kikusui N.5.

In every encounter with enemy fighters the Shiden, especially the Kai version, proved to be a capable dogfighter with a potent combination of firepower, agility, and rugged structure. The premier unit flying the Shiden, 343 Kōkūtai, remained operational until overwhelming unit losses obliged the group to stand down. The 343rd was disbanded on 14 August 1945 when the Emperor ordered surrender.

Variants

N1K1 Kyofu

• N1K1: Standard type as floatplane, which was used from early 1943, with Mitsubishi MK4C Kasei 13 engine.
• N1K2: Reserved name for an intended model with larger engine, not built.

N1K1-J Shiden

• N1K1-J Prototypes: development of fighter hydroplane N1K1 Kyofu, with 1,820 hp Homare 11 engine.
• N1K1-J Shiden Model 11: Navy Land Based Interceptor, first production model with 1,990 hp Homare 21 engine and revised cover, armed with two 7.7 mm Type 97 machine guns and two 20 mm Type 99 cannons. Modified total-vision cockpit.
• N1K1-Ja Shiden Model 11A: without frontal 7.7 mm Type 97s, only four 20 mm Type 99s in wings.
• N1K1-Jb Shiden Model 11B: similar to Model 11A amongst load two 250 kg bombs, revised wing weapons.
• N1K1-Jc Shiden Model 11C: definitive fighter-bomber version, derived from Model 11B. Four bomb racks under wings.
• N1K1-J KAIa Experimental version with auxiliary rocket. One Model 11 conversion.
• N1K1-J KAIb Conversion for dive bombing. One 250 kg bomb under belly and six rockets under wings.

N1K2-J Shiden-KAI

• N1K2-J Prototypes: N1K1-Jb redesigned. Low wings, engine cover and landing gear modified. New fuselage and tail, 8 built.
• N1K2-J Shiden KAI Model 21: Navy Land Based Interceptor, first model of series with a Nakajima Homare 21 engine.
• N1K2-Ja Shiden KAI Model 21A: Fighter Interceptor version: 2,000 hp Homare 21-18 engine with a low wing and larger prop design with four 250 kg ground bombs. Fixed problem with teething pains of N1K2 J at high altitude.
• N1K2-K Shiden Kai Rensen 1, Model A: Fighter Trainer, modified from N1K-J Series with two seats, operative or factory conversions.

Further variants

• N1K3-J Shiden KAI 1, Model 31: Prototypes: Engines displaced to ahead, two 13.2 mm Type 3 machine guns in front, 2 built.
• N1K3-A Shiden KAI 2, Model 41: Prototypes: Carrier-based version of N1K3-J, 2 built.
• N1K4-J Shiden KAI 3, Model 32: Prototypes: 2,000 hp Homare 23 engine, 2 built.
• N1K4-A Shiden KAI 4, Model 42: Prototype: Experimental conversion of N1K4-J example with equipment for use in carriers, 1 built.
• N1K5-J Shiden KAI 5, Model 25: High-Altitude Interceptor version with Mitsubishi HA-43 (MK9A) with 2,200 takeoff hp, project only.

Surviving aircraft

The 343 Kōkūtai's Shiden-Kai, discovered on November 18, 1978 in Jyoen Hisayoshi Bay. The aircraft is displayed at Nanreku Misho Koen, Ehime Prefecture, Japan.^[18] It is possible that the one was flown by ace-pilot Kaneyoshi Muto.

At least three Shiden Kai aircraft survive in American museums. One is at the National Naval Aviation Museum at Naval Air Station Pensacola, Florida.

The second N1K2-Ja (s/n 5312), a fighter-bomber variant equipped with wing mounts to carry bombs, is on display in the Air Power gallery at the National Museum of the United States Air Force, at Wright-Patterson Air Force Base near Dayton, Ohio. This aircraft was displayed outside for many years in a children's playground in San Diego, suffering considerable corrosion, and had become seriously deteriorated. In 1959 it was donated to the Museum through the cooperation of the San Diego Squadron of the Air Force Association.^[19] In October 2008 the aircraft was returned to display following an extensive eight year restoration. Many parts had to be reverse engineered by the Museum's restoration staff. Four different aircraft serial numbers were found on parts throughout the airframe, indicating reassembly from three different wrecks brought back to the U.S. for examination, or wartime assembly or repair from parts obtained from three different aircraft. Serial number 5312 was found in the most locations, and is the number now cited. The N1K2-Ja is painted as an aircraft in the Yokosuka Kōkūtai, an evaluation and test unit.^[20]

The third example is owned by the National Air and Space Museum but was restored by the Champlin Fighter Museum at Falcon Field, Mesa, Arizona, in return for the right to display the aircraft at Falcon Field for 10 years after restoration. It currently is on display at the National Air and Space Museum's Steven F. Udvar-Hazy Center ^[21]

An authentic Shiden-Kai from the 343 squadron is displayed at a local museum in Shikoku, Japan. After the aircraft was damaged in battle, its pilot landed on July 24, 1945 in the waters of the Bungo Channel, but he was never found; by the time of the aircraft's recovery from the seabed in the 1970s, he could be identified only as one of six pilots from the 343 squadron who disappeared that day. Photographs of the six—including Takashi Oshibuchi, commander of the 701 Hikōtai, and Kaneyoshi Muto—are displayed under the aircraft engine.

Specifications (N1K1-J)

Data from TAIC 107 A1 Report^[22]

General characteristics

• Crew: 1
• Length: 9.3 m (30 ft 7 in)
• Wingspan: 12.0 m (39 ft 4 in)
• Height: 3.9 m (13 ft 0 in)
• Wing area: 23.5 m² (253 ft²)
• Empty weight: 2,656 kg (5,855 lb)
• Loaded weight: 4,000 kg (8,820 lb)
• Max. takeoff weight: 4,860 kg (10,710 lb)
• Powerplant: 1 × Nakajima Homare NK9H radial engine, 1,850 hp (1,380 kW)

Performance

• Maximum speed: 656 km/h (408mph) (6100m（20,000ft）)
• Range: 1,716 km / 2,395 km (1,066 mi; 1,488 mi (2,395 km) ferry)
• Service ceiling: 10,800 m (35,500 ft)
• Rate of climb: 20.3 m/s (4065 ft/min)
• Wing loading: 166 kg/m² (34 lb/ft²)
• Power/mass: 0.305 kW/kg (0.226 hp/lb)

Armament

• 4× 20 mm Type 99 Model 2 Mk 4 cannon in wings. 200 rounds per gun (up from 100 rounds per gun internally and 70 rounds per gun in underwing boots for the early N1K1-J). The 20×101 mm round had an effective range of 1,000 m (3,280 ft) and a muzzle velocity of 700 m/s (2,297 ft/s). The 128 g shell had 6–8% HE. Rate of fire was about 500 rounds/min per gun. The guns were harmonized to converge at 200 m (656 ft).
• 2× 250 kg (551 lb) bombs
• 1× 400 L (105 gal) drop tank

See also

Aircraft of comparable role, configuration and era

• Focke-Wulf Fw 190
• Grumman F6F Hellcat
• Hawker Typhoon
• Kawasaki Ki-100
• Lavochkin La-7
• Mitsubishi J2M
• Nakajima Ki-84
• North American P-51 Mustang
• Republic P-47 Thunderbolt

Related lists

• List of aircraft of Japan during World War II
• List of aircraft of World War II
• List of fighter aircraft
• List of military aircraft of Japan

References

External links

Wikimedia Commons has media related to Kawanishi N1K.

• TACI 107A1 Report "George 11"
• Kawanishi N1K2-Ja Shiden Kai (George) – National Museum of the United States Air Force