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 A6M Zero, the Shiden Kai could compete against the best late-war fighters, such as the F6F Hellcat, the F4U Corsair and P-51 Mustang.
Despite such capability, it was produced too late and in insufficient numbers to affect the outcome of the war.
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 more need for a fighter to fulfil this role.
Kawanishi N1K Shiden (liittoutuneiden kutsutunnus George) oli Japanissa kehitelty sekä valmistettu toisen maailmansodan hävittäjälentokone. Se saapui taistelutoimiin liian myöhään sekä liian pienissä määrin, voidakseen vaikuttaa ratkaisevasti liittoutuneiden sotilaslentokoneiden massiiviseen ylivoimaan.
Valmistusmäärä oli 1 435 konetta. Konetyypin prototyyppi valmistui vuonna 1943.
N1K Shiden tukeutui lentotukikohtiin, eikä se siis käyttänyt lentotukialuksia. Suurin osa japanilaisista lentotukialuksista oli jo tuhoutunut Tyynenmeren sodan rajuissa meritaisteluissa.
Suoritusarvoiltaan N1K Shiden pärjäsi jotenkuten Grumman F6F Hellcat -tukialushävittäjälle ja Northrop P-61 Black Widow -tyyppiselle raskaalle yötoimintahävittäjälle. Koneen aseistuksena oli neljä 20 mm tyypin 99 tykkiä tasoihin asennettuina ja usein myös niin kutsutusti apuaseina toimineet kaksi 7,7 mm konekiväärit. N1K2-parannusversio pystyi kuljettamaan kaksi 500 kilogramman pommia. Huippunopeus oli 580 km/h ja lakikorkeus 10 600 metriä. N1K2-J oli 10 km/h nopeampi, ja sen toimintamatka oli 1 700 km. N1K Shiden oli ainakin osittain suojapanssaroitu.
Saburō Sakai ei arvostanut tyyppiä lainkaan. Hän katsoi koneen menestyneen siksi, että arvostetusta taustasta tullut lentäjä Minoru Genda ylisti vuolaasti tyyppiä, vaikka se oli Sakain mielestä ”toisen luokan romuläjä, jonka oli koonnut kolmannen luokan valmistaja ja joka vaati ensimmäisen luokan lentäjän toimiakseen.” Muut teeskentelivät pitävänsä koneesta Gendan aseman vuoksi, vaikka hän oli lentotaidoltaan heikko. Shidenissä oli paljon lastentauteja: Kawanishi oli tunnettu vesikoneiden valmistajana, ja Shiden oli alun perin kehitetty N1K Kyōfu ("Rex") -vesikoneesta, mutta Kawanishilla oli vähän kokemusta maatoimintakoneista.
Koneen laskuteline oli heikko, ja Nakajima Homare -moottorissa oli paljon vikoja. USAAF:in pommitukset aiheuttivat ongelmia sekä koneiden tuotantoon että tarvikkeiden toimitukseen, ja kokoonpanolinjoilla oli paljon naisia ja nuoria poikia töissä, koska kaikki asekuntoiset miehet oli määrätty asepalvelukseen. Niinpä koneessa oli paljon laatuongelmia. Japanin laivaston ilmavoimat menetti enemmän Shideneitä onnettomuuksissa kuin amerikkalaisten alasampumina.
Osaavissa käsissä Shiden oli kuitenkin erittäin toimiva lentokone. Shiden oli nopea ja hyvin aseistettu, mutta sen lento-ominaisuudet olivat arvaamattomat; keskitasoisen koneen painopiste oli hyvin korkealla, ja koneessa oli elohopeatoimiset kaartolaipat, jotka avautuivat kun kaarto oli riittävän tiukka. Kokenut lentäjä, kuten Kaneyoshi Muto, saattoi käyttää tätä ilmataistelussa edukseen, mutta kokemattomalle lentäjälle Shiden oli erittäin vaarallinen lentää, ja tappiot onnettomuuksissa olivat suuret. Myöhemmässä N1K2-J:ssä konstruktio oli muutettu alatasoksi, joka muutti sen lento-ominaisuuksia turvallisemmiksi.
Length: 9.3 m
Wingspan: 12.0 m
Height: 3.9 m
Wing area: 23.5 m2
Empty weight: 2,656 kg
Loaded weight: 4,000 kg
Max. takeoff weight: 4,860 kg
Powerplant: 1 × Nakajima Homare NK9H radial engine, 1,850 hp (1,380 kW)
Maximum speed: 658 km/h
Range: 1,716 km / 2,395 km (1,066 mi; 1,488 mi (2,395 km) ferry)
Service ceiling: 10,800 m
Rate of climb: 20.3 m/s
Wing loading: 166 kg/m2
Power/mass: 0.305 kW/kg
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, the the early N1K1-J).
The 20×101 mm round had an effective range of 1,000 m and a muzzle velocity of 700 m/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.
2× 250 kg bombs, + 1× 400 L drop tank
The requirement to carry a bulky, heavy float essentially crippled the N1K against contemporary American fighters. Kawanishi engineers, however, had proposed in late 1941 that the N1K would be the basis of a formidable land-based fighter too, 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 radial engine, replacing the less powerful Mitsubishi MK4C Kasei 13 of the N1K. The aircraft retained the mid-mounted wing of the floatplane, and combined with the large propeller necessitated a long, stalky main landing gear. A unique feature was the aircraft's automatic combat flaps that adjusted automatically based on acceleration, freeing up the pilot from having to do this and reducing the chance of stalling in combat. The N1K did have a vice: If handled roughly, it could easily enter an unrecoverable spin. Its flight characteristics were treacherous and required an experienced pilot.
Only four days after the Shiden's first test flight, a complete redesign was begun, the N1K2-J. The new design 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, the tail redesigned, and the whole aircraft was made much simpler to produce, with over a third of the parts of the Shiden. Construction materials involved the use of non-critical materials. The redesign was approximately 250 kg (550 lb) lighter, faster and more reliable than the previous N1K1 version. Since there was no alternative, the Homare engine was retained, even though its reliability problems had not been fully corrected. A prototype flew on 1 January 1944 and after completing Navy trials in April, the N1K2-J was rushed into production. The variant was named the "Shiden-Kai" (紫電改), Kai standing for Modified.
The N1K1 entered service in early 1944 and proved highly effective against American fighters. The Kawanishi was among the few Japanese fighters that could stand up to the best enemy types, including Hellcats and Corsairs. In the hands of aces, the Shiden could even outfly its American opponents. 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. After the action, reporters fabricated a story in which Muto was the sole airman facing 12 enemy aircraft.However, a close friend of Lieutenant Kaneyoshi Muto, ace pilot Saburo Sakai, states in his autobiography that the one versus twelve combat did take place, but with Muto at the controls of a Zero fighter.
The N1K1-J aircraft were used very effectively over Formosa, the Philippines and later, Okinawa. Before production was switched to the improved N1K2-J, 1,007 aircraft were produced, including prototypes.
Problems resulted in very few N1K2-J aircraft being produced, but the Shiden-Kai proved to be one of the best "dogfighters" fielded by either side. Along with high speed, the fighters were very agile with a roll rate of 82°/sec at 386 km/h (240 mph). Their weaponry, comprising four 20 mm cannons in the wings, was highly effective. As a bomber interceptor, the N1K2-J was less successful, hampered by a poor rate of climb and reduced engine performance at high altitude.
Due to production difficulties and damage caused by B-29 Superfortress raids on Japanese factories, only 415 fighters were produced. Consequently, N1K2-J fighters were mainly issued to elite units like the IJN 343rd Air Group (343 Kōkūtai Naval Fighter Group), commanded by Minoru Genda that was constituted on 25 December 1944. The new 343rd Kōkūtai consisted of the best pilots, including Muto. The unit was issued the best equipment available and was also equipped with the 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, 343 Kōkūtai's Shidens intercepted 300 American aircraft. Many of the 343 Kōkūtai Shiden force were N1K2s. When the Shidens encountered VBF-17 Hellcats, three aircraft were lost on both sides in the initial attack; one Hellcat and two Shiden were shot down by enemy ground fire, two fighters collided in mid-air, and one Hellcat crashed while trying to land. Then the other Shiden dove on the Hellcats, downing another one. In the end, the 407 Hikōtai lost six fighters versus downing eight VBF-17 Hellcats.
In another encounter with VBF-10 Corsairs, two of the Corsairs were separated from the main formations, and then attacked by 343rd Shidens. Four N1K2s were shot down and the Corsairs managed to return to their carrier, USS Bunker Hill. An opportunity for revenge came when VFM-123 Corsairs were surprised by Shidens, initially mistaken for Hellcats. A 30-minute aerial duel ensued in which three Corsairs were shot down and another five were damaged. Three other F4Us which had landed on carriers were so heavily damaged that they had to be pushed into the sea. Of the 10 Japanese aircraft the Americans claimed, not one was effectively downed.
Two Shidens however, were shot down at landing by Hellcats of VF-9. Many other Shidens were destroyed by American fighters over another airport, where they tried to land because they were low on fuel. At the end of the day, 343° declared 52 victories, U.S. fighters 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 had heavy losses, with 14 fighters and seven pilots, and 11 other 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 scored several victories but suffered 12 losses out of 34 machines. On 4 May, another 24 Shidens were sent in Kikusui N.5.
In every case, the Shiden, especially the Kai version, proved to be a capable dogfighter with a great combination of firepower, agility and a rugged structure. The premier unit flying the Shiden, 343 Kōkūtai remained operational until the overwhelming unit losses led to the eventual retirement of the unit. The 343° was disbanded on 14 August 1945, when the Emperor ordered surrender.