Nakajima Ki-43

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Ki-43 "Hayabusa"
Nakajima Ki-43-IIa.jpg
Nakajima Ki-43-IIa
Role Fighter aircraft
Manufacturer Nakajima Aircraft Company
Designer Hideo Itokawa
First flight Early January 1939[1]
Introduction October 1941[2]
Retired 1945 (Japan)
1952 (China)
Primary users Imperial Japanese Army Air Force
Royal Thai Air Force
Manchukuo Air Force
Produced 1939–1945
Number built 5,919
Developed from Nakajima Ki-27

The Nakajima Ki-43 Hayabusa (隼, "Peregrine Falcon") was a single-engine land-based tactical fighter used by the Imperial Japanese Army Air Force in World War II. The Army designation was "Army Type 1 Fighter" (一式戦闘機); the Allied reporting name was "Oscar", but it was often called the "Army Zero" by American pilots for its side-view resemblance to the Mitsubishi A6M Zero[3] that was flown by the Japanese Navy, using essentially the same radial engine as the Army's Oscar, and with the Oscar having much less framing for its canopy than the Zero used.

Like the Mitsubishi-produced A6M Zero, the radial-engined Ki-43 was light and easy to fly and became legendary for its combat performance in East Asia in the early years of the war. It could outmaneuver any opponent, but did not have armor or self-sealing tanks, and its armament was poor until its final version, which was produced as late as 1945.[4][5] Allied pilots often reported that the nimble Ki-43s were difficult targets but burned easily or broke apart with few hits.[6] In spite of its drawbacks, the Ki-43 shot down more Allied aircraft than any other Japanese fighter and almost all the JAAF's aces achieved most of their kills in it.[citation needed]

Total production amounted to 5,919 aircraft.[7] Many of these were used during the last months of the war for kamikaze missions against the American fleet.[6]

Design and development[edit]

The Ki-43 was designed by Hideo Itokawa, who would later become famous as a pioneer of Japanese rocketry. The Ki-43 prototype was produced in response to a December 1937 specification for a successor to the popular fixed-gear Nakajima Ki-27 Nate. The specification called for a top speed of 500 km/h (311 mph), a climb rate of 5,000 m (16,400 ft) in five minutes and a range of 800 km (500 mi). Maneuverability was to be at least as good as that of Ki-27.[8]

When first flown in early January 1939,[9] the Ki-43 prototype was a disappointment. Japanese test pilots complained that it was less maneuverable than the Ki-27 Nate and not much faster.[10] In order to solve these problems, Nakajima produced a series of progressively modified prototypes through 1939 and 1940. These changes involved a major weight saving program, a slimmer fuselage with the tail surfaces moved further aft and a new canopy. Crucially, the 11th prototype introduced the unique differential "butterfly" (or Fowler-type) maneuvering flaps, which dramatically improved performance in tight turns. The 13th prototype combined all these changes, and tests of this aircraft resulted in an instruction for Nakajima to place the Ki-43 into production, the Ki-27 jigs being transferred to the Mansyu factory at Harbin in Japanese occupied Manchukuo.[11]

The Ki-43 (Oscar) was initially produced in November 1939, given the designation Ki-43-I. Deliveries from Nakajima's Ota factory commenced in February 1941. In addition to outstanding maneuverability, the Ki-43-I had an impressive rate of climb due to its light weight. Power was provided by the Nakajima Ha-25 engine turning a two-bladed, two-position variable-pitch metal propeller.[12] Top speed was 495 km/h (308 mph) at 4,000 m (13,160 ft).[13] The Ki-43 was equipped with two synchronized cowling machine guns in various configurations, with either two 7.7 mm (.303 in) Type 89 machine guns, one 12.7 mm (.50 in) Ho-103 machine gun and one 7.7 mm (.303 in) gun, or two 12.7 mm (.50 in) Ho-103 guns; the aircraft was given various sub-designations to reflect these differences. The configuration that appears to have been most prevalent at the outset of the war was the first configuration with two 7.7 mm (.303 in) Type 89 machine guns, while as the war progressed the heavier combinations gained popularity and the version with the heaviest armament was sometimes given the designation Ki-43-Ic.[14] The Ho-103 was often loaded with explosive ammunition to increase target effect; its penetrative effect against later Allied aircraft armor appears to have been marginal.[14]

A Ki-43-II.

Prototypes for the Ki-43-II flew in February 1942. The Ha-25 engine was replaced by the more powerful Nakajima Ha-115 engine, which was installed in a longer-chord cowling. The new engine turned a three-bladed propeller. The wing structure, which had suffered failures in the Ki-43-I, was strengthened and equipped with racks for drop tanks or bombs. The Ki-43-II was also fitted with 13 mm armor plate for the pilot's head and back, and the aircraft's fuel tanks were coated in rubber to form a crude self-sealing tank. The pilot also enjoyed a slightly taller canopy and a reflector gunsight in place of the earlier telescopic gunsight.[15] Nakajima commenced production of the Ki-43-II at its Ota factory in November 1942.[16] Production was also started at the Tachikawa Hikoki KK and the 1st Army Air Arsenal (Tachikawa Dai-Ichi Rikugun Kokusho), also at Tachikawa. Although Tachikawa Hikoki successfully managed to enter into large-scale production of the Ki-43, the 1st Army Air Arsenal was less successful - hampered by a shortage of skilled workers, it was ordered to stop production after 49 Ki-43s were built.[17] Nakajima eventually ceased production in mid-1944 in favor of the Ki-84, but the Tachikawa Hikoki continued to produce the Ki-43.[18]

Tachikawa also produced the Ki-43-III, which utilized the more powerful Nakajima Army Type 1 Ha-115-II engine. Maximum speed increased to 358 mph.[18] Tachikawa produced 2124 Ki-43-II and -III aircraft between April 1944 and the end of the war.[19] Total production of all versions amounted to 5,919 aircraft.[13]

Operational history[edit]

A Ki-43 III-Ko, piloted by Second Lieutenant Toshio Anazawa and carrying a 250 kg (550 lb) bomb, sets off from the Japanese airfield of Chiran for the Okinawa area, on a kamikaze mission, 12 April 1945. School girls wave goodbye in the foreground.

The Ki-43 was the most widely used Army fighter, and equipped 30th sentai FR,(flight regiment) and 12th chutais IS,(independent squadrons). The first unit equipped with the Ki 43-I was the 59th FR at Hankow Airfield, during June–August 1941. Operational sorties over Hengyang on 29. October 1941.[2][20] The second unit to re-equip with the new Aircraft was the 64th FR, from August to November 1941.[21]

The first version, Ki-43-I, entered service in 1941, the Ki-43-II in December 1942, the Ki-43-II-Kai in June 1943, and the Ki-43-IIIa in summer 1944. The aircraft fought in China, Burma, the Malay Peninsula, New Guinea, the Philippines, South Pacific islands and the Japanese home islands.[7]

Like the Zero, the Ki-43 initially enjoyed air superiority in the skies of Malaya, Netherlands East Indies, Burma and New Guinea. This was partly due to the better performance of the Oscar[22] and partly due to the relatively small numbers of combat-ready Allied fighters, mostly the Curtiss P-36 Hawk, Curtiss P-40, Brewster Buffalo, Hawker Hurricane and Curtiss-Wright CW-21 in Asia and the Pacific during the first months of the war. As the war progressed, however, the fighter suffered from the same weaknesses as the Ki-27 "Nate" and the A6M Zero; light armor and less-than-effective self-sealing fuel tanks, which caused high casualties in combat. Its armament of two machine guns also proved inadequate against the more heavily armored Allied aircraft. As newer Allied aircraft were introduced, such as the Republic P-47 Thunderbolt, Lockheed P-38 Lightning, North American P-51 Mustang, Vought F4U Corsair, Grumman F6F Hellcat and late-model Supermarine Spitfire/Seafire, the Japanese were forced into a defensive war and most aircraft were flown by inexperienced pilots. However, even near the end, the Oscar's excellent maneuverability could still gain advantage over rash Allied pilots. From October to December 1944, 17 Ki-43s were shot down in air combat; their pilots claimed seven C-47s, five B-24 Liberators, two Spitfires, two Beaufighters, two Mosquitoes, two F4U Corsairs, two B-29 Superfortresses, one F6F Hellcat, one P-38, and one B-25.[23] Like most Japanese combat types, many Hayabusas were at the end expended in kamikaze raids.

The Ki-43 also served in an air defense role over Formosa, Okinawa and the Japanese home islands. Some examples were supplied to the pro-Japanese regimes of Thailand, Manchukuo and Wang Jingwei Government as well. The Thai units sometimes fought against the USAAF in southern China.[24]

Hayabusas were well liked in the JAAF because of the pleasant flight characteristics and excellent maneuverability, and almost all JAAF fighter aces claimed victories with Hayabusa in some part of their career. At the end of the war, most Hayabusa units received Ki-84 Hayate "Frank" fighters, but some units flew the Hayabusa to the end of the war. The top-scoring Hayabusa pilot was Sergeant Satoshi Anabuki with 39 confirmed victories, almost all scored with the Ki-43.

After the war, some captured examples served in limited numbers in the French Air Force in Indochina against Viet Minh rebels.[25]


A captured Ki-43-Ib in flight over Brisbane, 1943.
Ki-43 of 6th Group, ROCAF
The Flying Heritage Collection Ki-43 at Rabaul, 1945.
Prototypes and operative prototypes.
Variant armed with 2 × 7.7 mm (.303 in) Type 89 machine guns
Hayabusa Fighter Type 1 of Army (Mark 1).
Ki-43-Ib (Mark Ib)
Variant armed with one 12.7 mm (.50 in) Ho-103 machine gun and 1 × 7.7 mm (.303 in) Type 89
Ki-43-Ic (Mark Ic)
Variant armed with 2 × 12.7 mm (.50 in) Ho-103
Prototypes and evaluative models.
Ki-43-IIa (Mark 2a)
Ability to carry up to 500 kg (1,100 lb) of bombs
Ki-43-IIb (Mark 2b)
Radio equipment added
Fitted with ejector exhaust stacks
Prototypes powered by Nakajima Ha-115-II engine of 920 kW (1,230 hp)
2 × 170 L (45 gal) drop tanks (~3 hour full-throttle endurance)
Ki-43-IIIa (Mark 3a)
Series model
Ki-43-IIIb (Mark 3b)
Variant armed with 20 mm cannons. (Prototype - Only 2 Built)
Ki-62 Project
Advanced interceptor version of Nakajima Ki-43 with a powerful engine and armed with 30 mm (1.18 in) or 40 mm (1.57 in) cannons.


Ki-43 Production: Ota, Nakajima Hikoki K.K [26]
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Annual
1941 3 9 23 5 20 20 5 29 43 157
1942 40 26 47 61 51 57 61 37 56 55 46 79 616
1943 88 77 90 96 102 105 105 120 120 138 140 147 1,347
1944 179 181 167 140 155 125 84 28 11 1,070
Total 3,190

Not included:

  • Ki-43-I's pre-production started with three prototypes completed in December 1938, as well as in February and March 1940.[27] A further ten service trials aircraft were build from Nov. 1939 to Sept. 1940.[27]
  • Ki-43-II's pre-production started with five prototypes completed during Feb. to May 1942.[27] A further three service trials aircraft were build from June to Aug. 1942.[27]
  • Ki-43-III's pre-production started with ten prototypes completed during May 1944 to August 1945.[27]
Ki-43 Production: Tachikawa, Tachikawa Hikoki K.K [28]
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Annual
1943 5 7 10 15 20 30 45 67 199
1944 10 115 100 140 125 147 148 157 210 75 275 180 1682
1945 105 90 155 70 120 93 80 35 748
Total 2629

Not included:

  • A further 49 Ki-43-II's were assembled from Oct. 1943 to Nov. 1944 at Tachikawa Dai-Ichi Rikugun Kokusho arsenal plant.[27]
Total Production:
According to USSBS Report: 5,819 [26][28] Figure includes: 5,819 Ki-43-I, Ki-43-II and Ki-43-IIIa builds
According to Francillon: 5,919 [27] Figure includes: 729 Ki-43-I, 5,188 Ki-43-II and Ki-43-IIIa builds, 2 Ki-43-IIIb prototypes





 People's Republic of China
  • Indonesian Air Force - Indonesian People's Security Force operated derelict aircraft against Dutch colonial rule. On 29 July 1947, Indonesia intended to use a Ki-43 from Maguwo Air Force Base, Yogyakarta for bombing Dutch strategic positions in Ambarawa, Salatiga and Semarang. However, it failed to fly because of mechanical problems. It is currently on display in the Museum Dirgantara Udara Yogyakarta (near Adisucipto International Airport).
 North Korea


Indonesian Ki-43-II
Ki-43 at the Pima Air and Space Museum

The only airworthy Oscar is located at the Tillamook Air Museum. There are seven survivors:[31]

Owned by The Fighter Collection, Duxford UK and awaiting restoration.
Currently on display at the Museum Dirgantara Udara Yogyakarta.
Ki-43-Ib N750N
Owned by Flying Heritage Collection, Everett, Washington, USA. Former ZK-OSC restored to flying condition by the Alpine Fighter Collection in the 1990s, not currently flying.
Seattle Museum of Flight[32]
Pima Air & Space Museum, static display in Hangar 4[33]
Four aircraft under restoration/rebuild at Texas Airplane Factory, Meacham Field, Fort Worth, Texas, USA.
Tillamook Air Museum in Oregon, USA.[34][35]
Chiran Peace Museum for Kamikaze Pilots, Kagoshima, Japan.

Specifications (Ki-43-IIb)[edit]

Nakajima Ki 43-I

Data from Japanese Aircraft of the Pacific War[36]

General characteristics



  • Guns: 2× fixed, forward-firing 12.7 mm (.50 in) Ho-103 machine guns in the cowl with 270 rpg
  • Bombs: 2× 250 kg (551 lb) bombs

See also[edit]

Related development
Aircraft of comparable role, configuration and era
Related lists



  1. ^ Francillon 1979, p. 207.
  2. ^ a b Green, p. 74
  3. ^ Stanaway 2003, p. 33
  4. ^ Ethell 1995, pp. 98–99
  5. ^ Green, pp. 77, 78
  6. ^ a b Ethell 1995, p. 99
  7. ^ a b Glancey 2006, p. 173
  8. ^ Francillon 1979, p. 206
  9. ^ Francillon 1979, p. 166.
  10. ^ Air International January 1980, p. 27
  11. ^ Air International January 1980, pp. 27–28
  12. ^ Air International January 1980, p. 28
  13. ^ a b Francillon 1979, p. 214
  14. ^ a b Dunn, Richard L. "Nakajima Ki-43-I Armament: A Reassessment." Retrieved: 18 October 2009.
  15. ^ Air International January 1980, p. 44
  16. ^ Francillon 1979, p. 210
  17. ^ Francillon 1979, p. 211
  18. ^ a b Air International January 1980, p. 45
  19. ^ Air International January 1980, p. 46
  20. ^ Ikuhiko, Japanese Army Fighter Aces, 1931-45
  21. ^ Izawa, 64th Flying Sentai, p.2
  22. ^ Stanaway 2006, p. 9
  23. ^ Ichimura 2009, p. 50
  24. ^ "Royal Thai Air Force aircraft." Retrieved: 18 October 2009.
  25. ^ Dorr and Bishop 1996, p. 249
  26. ^ a b USSBS, Appendix M., p. 40–42
  27. ^ a b c d e f g Francillon, 1979, p. 214
  28. ^ a b USSBS, Appendix J., p. 29–30
  29. ^ March and Heathcott 1997, p. 75
  30. ^ "French Counter-Insurgency Aircraft, 1946–1965." Retrieved: 18 October 2009.
  31. ^ "Flying Warbirds and Antiques." Retrieved: 18 October 2009.
  32. ^ Pluth, Dave. "The Captured Oscars of Hollandia". Retrieved 15 April 2015. 
  33. ^ "Nakajima Ki-43-IIb." Pima Air Museum. Retrieved: 18 October 2009.
  34. ^ 21st century Oscars
  35. ^ "Oscar." Tillamook Air Museum. Retrieved: 18 October 2009.
  36. ^ Francillon 1979, pp. 213–214


  • Bueschel, Richard M. Nakajima Ki-43 Hayabusa I-III in Japanese Army Air Force RTAF-CAF-IPSF Service. Reading, Berkshire, UK: Osprey Publications, 1970. ISBN 0-85045-022-5.
  • Bueschel, Richard M. Nakajima Ki-43 Hayabusa in Japanese Army Air Force RTAF-CAF-IPSF Service. Atglen, Pennsylvania: Schiffer Books, 1995. ISBN 0-88740-804-4.
  • Dorr, Robert F. and Chris Bishop. Vietnam Air War Debrief. London: Aerospace, 1996. ISBN 1-874023-78-6.
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  • Green, William and Gordon Swanborough. WW2 Aircraft Fact Files, Japanese Army Fighters, part 2. London: Macdonald and Janes's, 1977. ISBN 0-354-01068-9.
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  • Pajdosz, Waldemar, Mark T. Wlodarczyk and Adam Jarski. Nakajima Ki 43 Hayabusa "Oscar" (in Polish), Monografie Lotnicze 48. Gdańsk: AJ-Press, 1998. ISBN 83-86208-97-X.
  • Skulski, Przemysław. Nakajima Ki 43 Hayabusa "Oscar", seria Pod Lupa no.11 (Polish/English). Wrocław: Ace Publications, 1999. ISBN 83-86153-98-9.
  • Stanaway, John. Nakajima Ki.43 "Hayabusa" – Allied Code Name "Oscar". Bennington, Vermont: Merriam Press, 2006 (2nd expanded edition), First edition 2003. ISBN 1-57638-141-2.
  • United States Strategic Bombing Survey Aircraft Division. Nakajima Aircraft Company, Ltd. Corporation Report II, Washington, D.C. 1947.
  • United States Strategic Bombing Survey Aircraft Division. Tachikawa Aircraft Company, Ltd. Corporation Report X, Washington, D.C. 1947.
  • Windrow, Martin C. and René J. Francillon. The Nakajima Ki-43 Hayabusa. Leatherhead, Surrey, UK: Profile Publications, 1965.

External links[edit]