Nakajima Ki-43 Hayabusa Explained

The Nakajima Ki-43 Hayabusa (Japanese: 隼, "Peregrine falcon"), formal Japanese designation is a single-engine land-based tactical fighter used by the Imperial Japanese Army Air Service in World War II.

The Allied reporting name was "Oscar", but it was often called the "Army Zero" by American pilots because it bore a certain resemblance to the Mitsubishi A6M Zero, the Imperial Japanese Navy's counterpart to the Ki-43. Both aircraft had generally similar layout and lines, and also used essentially the same Nakajima Sakae radial engine, with similar round cowlings and bubble-type canopies (the Oscar's being distinctly smaller and having much less framing than the A6M). While relatively easy for a trained eye to tell apart with the "finer" lines of the Ki-43's fuselage – especially towards the tail – and more tapered wing planform; in the heat of battle, given the brief glimpses and distraction of combat, Allied aviators frequently made mistakes in enemy aircraft identification in the heat of a dogfight, reportedly having fought "Zeros" in areas where there were no Navy fighters.

Like the 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 initially have armor or self-sealing fuel tanks, and its armament was poor until its final version, which was produced as late as 1945.[1] Allied pilots often reported that the nimble Ki-43s were difficult targets but burned easily or broke apart with few hits.

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

Design and development

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 an interceptor/escort fighter successor to the popular fixed-gear Nakajima Ki-27 'Nate'. The specification called for a top speed of, a climb rate of in five minutes and a range of . Maneuverability was to be at least as good as that of Ki-27.

When first flown in early January 1939, the Ki-43 prototype was a disappointment. Japanese test pilots complained that it was less maneuverable than the Ki-27 and not much faster. 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" maneuvering Fowler 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.

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. Top speed was at The Ki-43 was equipped with two synchronized cowling machine guns in various configurations, with either two Type 89 machine guns, one Ho-103 machine gun and one gun, or two 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 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. 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.[2]

Prototypes for the Ki-43-II flew in February 1942. The Ha-25 engine was upgraded with the 2-stage supercharger, thus becoming 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 a 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. This was later replaced by a 3-layer rubber bladder, 8mm core construction; with 2mm oil-proof lamination. The bladder proved to be highly resistant against bullets, but was not as effective against larger calibers.[3] The pilot also enjoyed a slightly taller canopy and a reflector gunsight in place of the earlier telescopic gunsight. Nakajima commenced production of the Ki-43-II at its Ota factory in November 1942. Production was also started at the Tachikawa Aircraft Company Ltd (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. Nakajima eventually ceased production in mid-1944 in favor of the Ki-84 Hayate, but the Tachikawa Hikoki continued to produce the Ki-43.[4]

Tachikawa also produced the Ki-43-III, which utilized the more powerful Nakajima Army Type 1 Ha-115-II engine. Maximum speed increased to .[4] Tachikawa produced 2,124 Ki-43-II and -III aircraft between April 1944 and the end of the war. Total production of all versions amounted to 5,919 aircraft.

Operational history

The Ki-43 was the most widely used Army fighter, and equipped 30 sentai FR (flight regiment) and 12 Dokuritsu Dai Shijugo Chutai ("Direct command fighter squadron" - independent squadrons not incorporated into sentais). The first unit equipped with the Ki 43-I was the 59th FR at Hankow Airfield, during June–August 1941 and began operational sorties over Hengyang on 29 October 1941.[5] The second unit to re-equip with the new Aircraft was the 64th FR, from August to November 1941.[6]

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.

Like the Zero, the Ki-43 initially enjoyed air superiority in the skies of Malaya, Dutch East Indies, Burma and New Guinea. This was partly due to the better performance of the Oscar 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 slower, fixed-gear Ki-27 "Nate" predecessor to the Oscar, and the more advanced naval 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, Yakovlev Yak-9, Yakovlev Yak-3U 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 Consolidated B-24 Liberators, two Spitfires, two Bristol Beaufighters, two de Havilland Mosquitoes, two F4U Corsairs, two Boeing B-29 Superfortresses, one F6F Hellcat, one P-38, and one North American B-25 Mitchell.[7] Like most Japanese combat types, many Hayabusas were at the end expended in kamikaze strikes.

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.[8]

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 Nakajima Ki-84 Hayate "Frank" and Kawasaki Ki-100 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.

Ki-43s abandoned in the Netherlands East Indies were taken over by the newly declared Indonesian government and put into service during the fight against Dutch forces.

Variants

Ki-43
  • 13 Prototypes/pre-production aircraft.
    Ki-43-I "Ko" (Mark 1a)
  • Variant armed with 2 × Type 89 machine guns.
    Ki-43-I "Otsu" (Mark 1b)
  • Variant armed with one Ho-103 machine gun and 1 × Type 89.
    Ki-43-I "Hei" (Mark 1c)
  • Variant armed with 2 × Ho-103, plus ability to mount 2x30kg bombs under wings. All earlier Ki-43-Ia "Ko" and Ki-43-Ib "Otsu" were gradually upgraded to this version as more Ho-103 became available.
    Ki-43-II
  • 5 Prototypes, introduced the Ha-115 engine with two stage supercharger, shorter and stronger wings,[9] self-sealing fuel tanks, of pilot armor, reflector sight, three-bladed fixed pitch propeller, and an improved canopy.
    Ki-43-II "Ko" (Mark 2a):
  • First Ki-43-II production model. Improvements of the 5 prototypes added into the design. Ability to carry up to of bombs.
    Ki-43-II "Ko" upgraded
  • Oil ring cooler changed to honeycomb type mounted under the nose. Improved landing light.
    Ki-43-IIb "Otsu" (Mark 2b)
  • Fuel cooling system added on some examples. Both exhaust pipes were angled backwards for slightly increased thrust. Universal drop tank racks mounted outboard of landing gear on later examples. (earlier models sometimes had mounting points slightly inboard of the landing gear or on the centerline)
    Ki-43-II-KAI (Mark 2 improved)
  • Later examples could carry bombs on the drop tank mountings. This variant was tested with skis for operations from snow in Manchuria. Fitted with ejector exhaust stacks (adding approximately 30 hp) and additional 540L fuel tank in fuselage.
    Ki-43-III
  • Prototypes powered by Nakajima Ha-115-II engine of 920 kW (1,230 hp) Exhaust stack configuration slightly modified. Water-methanol injection added.
    Ki-43-III "Ko" (Mark 3a):Only produced by Tachikawa plant.
  • Series production model, some fitted with skis for operations from snow.
    Ki-43-III "Otsu" (Mark 3b)
  • Variant with the Mitsubishi Ha-112-II radial engine and armed with twin Ho-5 cannon. (Prototype – only 2 Built)
    Ki-62 Project
  • Advanced interceptor version of Nakajima Ki-43 with a more-powerful engine and armed with or cannons.

    Production

    Ki-43 Production: Ota, Nakajima Aircraft Company[10]
    Year
    Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Annual
    19413 9 23 5 20 20 5 29 43 157
    194240 26 47 61 51 57 61 37 56 55 46 79 616
    194388 77 90 96 102 105 105 120 120 138 140 147 1,347
    1944179 181 167 140 155 125 84 28 11 1,070
    Total3,190

    Not included:

    Ki-43 Production: Tachikawa, Tachikawa Aircraft Company Ltd[11]
    Year
    Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Annual
    19435 7 10 15 20 30 45 67 199
    194410 115 100 140 125 147 148 157 210 75 275 180 1682
    1945105 90 155 70 120 93 80 35 748
    Total2629

    A further 49 Ki-43-II's were assembled from October 1943 to November 1944 at Tachikawa Dai-Ichi Rikugun Kokusho arsenal plant.

    Total Production:
    According to USSBS Report5,8195,819 Ki-43-I, Ki-43-II and Ki-43-IIIa builds
    According to Francillon5,919 729 Ki-43-I, 5,188 Ki-43-II and Ki-43-IIIa builds, 2 Ki-43-IIIb prototypes

    The number of Ki-43s actually delivered and accepted by August 1945 was 5,751; 3185 from Nakajima, 22 from Rikugun, and 2544 from Tachikawa.

    Operators

    Wartime

    Postwar

    Surviving aircraft

    References

    Bibliography

    Book: Nohara, Shigeru . 中島一式戦闘機「隼」 . Nakajima ichishiki sentōki hayabusa . 2000 . Aero Detail Volume 29 . Dai Nihon Kaiga. 4-499-22735-6. Tokyo. 166435828.

    External links

    Notes and References

    1. Green, pp. 77, 78
    2. Dunn, Richard L. "Nakajima Ki-43-I Armament: A Reassessment." warbirdforum.com. Retrieved: 18 October 2009.
    3. Web site: Ki-43 "Hayabusa" by Thomas Bush.
    4. ,
    5. Ikuhiko, Japanese Army Fighter Aces, 1931–45
    6. Izawa, 64th Flying Sentai, p.2
    7. Ichimura 2009, p. 50
    8. http://www.j-aircraft.com/research/jan_forsgren/j-aircraft_royal_thai.htm j-aircraft.com/research "Royal Thai Air Force aircraft."
    9. Nohara, 2000
    10. Book: United States Strategic Bombing Survey . Appendix M., pp. 40–42 . Nakajima Aircraft Company, Ltd. . Corporation Report II . Washington, D.C. . 1947.
    11. Book: United States Strategic Bombing Survey . Appendix J., pp. 29–30 . Tachikawa Aircraft Company, Ltd.. Corporation Report X . Washington, D.C.. 1947.
    12. http://worldatwar.net/chandelle/v3/v3n1/frcoin.html "French Counter-Insurgency Aircraft, 1946–1965."
    13. Web site: NAKAJIMA KI-43 HAYABUSA (OSCAR). Flying Heritage Collection. Friends of Flying Heritage. 7 February 2016. dead. https://web.archive.org/web/20160214184610/http://www.flyingheritage.com/TemplatePlane.aspx?contentId=21. 14 February 2016.
    14. Web site: Taylan. Justin. Ki-43-I Oscar Manufacture Number 750. Pacific Wrecks. Pacific Wrecks Incorporated. 7 February 2016.
    15. Web site: Nakajima Ki-43-II Hayabusa 'Oscar' : Imperial Japanese Army Air Force . Australian War Memorial . 11 November 2018.
    16. Web site: Taylan. Justin. Ki-43-II Oscar Manufacture Number 5465. Pacific Wrecks. Pacific Wrecks Incorporated. 7 February 2016.
    17. Web site: HAYABUSA (OSCAR). Pima Air & Space Museum. Pimaair.org. 7 February 2016. 13 February 2016. https://web.archive.org/web/20160213071705/http://www.pimaair.org/aircraft-by-name/item/nakajima-ki-43-iib-hayabusa-oscar. dead.
    18. Web site: Pluth. Dave. The Captured Oscars of Hollandia. j-aircraft.com. 15 April 2015.
    19. Web site: Nakajima Ki-43-IIb Hayabusa (Peregrine Falcon) Oscar . Smithsonian National Air and Space Museum. National Air and Space Museum. 31 December 2023.
    20. Web site: Nakajima Ki-43-IIIa Hayabusa "Oscar" Reproduction . The Museum of Flight . 7 February 2016.
    21. Web site: Nakajima Ki-43 II "Oscar". GossHawk Unlimited. GossHawk Unlimited, Inc.. 25 February 2016.
    22. Web site: Nakakima Ki-43 Oscar. Erickson Aircraft Collection. 7 February 2016.
    23. Web site: Taylan. Justin. Ki-43-IIIa Oscar Manufacture Number 15344 (Replica). Pacific Wrecks. Pacific Wrecks Incorporated. 7 February 2016.
    24. Web site: Taylan. Justin. Texas Airplane Factory. Pacific Wrecks. Pacific Wrecks Incorporated. 7 February 2016.
    25. Web site: Nakajima Ki-43 II "Oscar". GossHawk Unlimited. GossHawk Unlimited, Inc.. 25 February 2016.
    26. http://www.kamikazeimages.net/museums/chiran/
    27. News: Chiran Peace Museum for Kamikaze Pilots. 13 February 2018. Kamikaze Images.
    28. Web site: News . Vintage Aviation . 2013-10-09 . Nobuo Harada To Rebuild The Nakajima Ki-43 Hayabusa . 2023-08-19 . Vintage Aviation News . en-US.
    29. Web site: H45 | Nakajima Ki-43-II Hayabusa | Indonesia - Air Force | Arjun Sarup. 20 March 2020.
    30. http://www.japantimes.co.jp/news/2013/10/08/national/japanese-collector-restoring-rare-wwii-plane/ Japanese collector restoring rare WWII plane October 8, 2013
    31. News: Nobuo Harada To Rebuild The Nakajima Ki-43 Hayabusa. 25 February 2016. Warbirds News. Warbirds News. 9 October 2013.
    32. Thompson, Paul J-HangarSpace – Aviation Museums Retrieved 8 September 2016

    This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Nakajima Ki-43 Hayabusa".

    Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2024, A B Cryer, All Rights Reserved. Cookie policy.