Nakajima Ki-43-IIa Oscar
The Ki-43 Type 1 Hayabusa (Peregrine Falcon) was the most widely flown fighter of the Japanese Army Air Force during the war (Allied code name Oscar). Entering squadron service shortly before the Pearl Harbor attack, the Oscar was highly maneuverable with a good rate of climb, but somewhat under powered and, despite updates, unable to compete effectively with U.S. fighters in the latter stages of the war. An official US AAF analysis, however, described later models as "an increasingly dangerous opponent." The Oscar saw combat in all Pacific areas where the Japanese Army conducted air operations, and most Japanese Army Aces scored most of their kills in this aircraft. At the end of the war the Oscar was employed with the Army's Taiatari (suicide) units.
In December 1939 Nakajima was instructed by the Imperial Japanese Army to initiate development of a more advanced fighter to supersede the company's own Ki-27, the first of three prototypes making its maiden flight during January 1939. A cantilever low-wing monoplane, this Nakajima Ki-43 had retractable tail wheel landing gear, seated its pilot in an enclosed cockpit and was powered by Nakajima's new supercharged Ha-25 Sakae radial engine with a take off rating of 975 hp (727 kw). Service testing of the prototypes showed that the type met the specification, but maneuverability was so poor that, at one time, it seemed the new fighter was unlikely to be accepted by the army. However, 10 pre-production aircraft were ordered and in attempts to improved maneuverability, modifications were introduced. These included increased wing area, weight reduction and finally, the incorporation of maneuverability or so-called combat flaps. This proved to be the answer to the problem, to the extent that the type was ordered into production as the Army Type 1 Fighter Model 1A Hayabusa (Peregrine Falcon), company designation Ki-43-1a.
This version was armed with two 7.7 mm (0.303 in) machine guns and carried two 33 lbs (15 kg) bombs on external racks, but two sub-variants differed in armaments, the Ki-43-1b having one 7.7 mm (0.303 in) and one 12.7 mm (0.50 in) and the Ki-43-1c two 2.7 mm (0.50 in) machine guns. Production started March 1941 and when the K-43 began to reach operational units it proved to be by far the most maneuverable fighter in the army's inventory, enjoying considerable success in the early stages of the Pacific war. With the advent of more effective allied fighters, however, the Ki-43's shortcomings became apparent, leading first to the construction of five Ki-43-II prototypes for evaluation. These introduced the more powerful Nakajima Ha-115 engine, some armor protection for the pilot, and an early form of self sealing fuel tanks.
Satisfactory testing brought construction of the initial Ki-43-IIa production version which had reduced wing span, a modified canopy, machine gun armament as for the Ki-43-Ic, and two under wing racks each able to carry a 551 lbs (250 kg) bomb. Late series aircraft, designated Ki-43-IIb, were generally similar but for some equipment changes, and the final production Ki-II-KAI incorporated the progressive modifications introduced on the Ki-43-IIa and Ki-43-IIb aircraft. Further development followed with the construction of 10 Ki-43-IIIa prototypes, which which were similar to the Ki-43-II KAI except for introducing the 1,150 hp (858 kW) Nakajima Ha-115-II to give improved performance at rated altitude, and two Ki-43-IIIb interceptor prototypes with the 1,300 hp (969 kW) Mitsubishi Ha-112 engine and forward firing machine armament of two 20 mm cannon, but neither of these versions entered production before the Pacific war ended.
The Hayabusa remained in service from the beginning to the end of the war. Production had totaled 5,919 by wars end, with (3,239) built by Nakajima, (2,631) built by Tachikawa and 49 aircraft built by the Army Air Arsenal at Tachikawa.
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Nakajima Ki-43-IIa Oscar
Specifications |
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Type |
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Power Plant |
1xHa-115 1,150 hp (858 kw) Nakajima 14 cylinder radial air cooled |
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Unladen weight |
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Laden weight |
5,710 lbs (2,590 kg) |
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Max Speed |
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Max Speed (13,125 ft) |
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Cruising Speed |
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Climbing Rate |
2,818 ft (859 m)/min |
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Max range |
1,988 mi (3,300 km) w/drop
tanks |
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Service Ceiling |
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Armament |
2x12.7 mm (0.50) machine guns, fuselage |
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Wingspan |
35 ft 6.75in |
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Length |
29 ft 3.75in (8.92 m) |
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Height |
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Wing Area |
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