Martin Foray (Updated: 5/10/2016):
The IJA went straight to the Nakajima Aircraft Company once more and Mr. Nakajima took on the new requirement and delivered a promising prototype. As in the Ki-27 "Nate" before it, the new design was kept lightweight to make for a more maneuverable mount. As such, important facets such as pilot armor and self-sealing fuel tanks were once again dropped from the equation. Armament consisted of just a pairing of 2 x 7.7mm Type 97 machine guns firing from the upper engine cowl and synchronized to fire through the spinning propeller blades. 250 rounds of ammunition were afforded to a machine gun. Flight tests of the new fighter began in 1939 but soon proved the overall design something of a disappointment, forcing a halt to all further development for the time being. It was not until 1941 that the design was revisited and revised to make up for the inherent deficiencies. The wing surface area was enlarged and the addition of combat flaps helped in maneuverability to the point that the modified airframe proved to have excellent turning capabilities, promising to content with the best Allied fighters that could be fielded. The fighter was formally designated as the Ki-43 "Hayabusa" (meaning "Peregrine Falcon") and accepted into service with the IJA. Serial production of the new mount occurred in June of 1941 and the type entered service shortly thereafter as the Ki-43-Ia.
Outwardly, the Ki-43 was a highly conventional aircraft and, in some ways, decidedly Japanese in origin. She sported fine contoured lines making for an elegant design. The engine was fitted well-forward in the thin fuselage and covered over in a nicely rounded cowling. The spinner was noticeably protruding from the engine compartment and powered a three-bladed propeller system. The cockpit sat just behind the engine and just ahead of amidships. The fuselage tapered off to a point and the empennage was highly conventional in its use of a single vertical tail fin and applicable horizontal planes - all well-rounded at the edges. Wings were set ahead of amidships and initially rounded at the tips. The undercarriage was wholly retractable and featured two main landing gear legs and a diminutive tail wheel (the tail wheel remained exposed in flight). The main legs retracted inwards towards centerline under each wing near the wing roots and were exposed to the elements along one side (the main legs were not covered over by door panels in flight).
Once in service, the Ki-43 proved a capable adversary despite the lack of formidable firepower. In true Allied fashion, the fighter was assigned the codename of "Oscar" to follow suit with other Japanese aircraft names ("Nate", "Sally", "Zeke", etc.... Her turning capability ensured the aircraft would become one of the most feared of the Japanese fighters for a portion of the Pacific War. Her inherent success extended beyond the machine itself for the Ki-43 would go on to produce many of the admired Japanese aces of her time. The ki-43-Ia was followed into service by the Ki-43-Ib which was interestingly armed with 1 x 12.7mm Ho-103 heavy machine gun and 1 x 7.7mm Type 97 machine gun. The Ki-43-Ic came next and was fittingly armed with 2 x 12.7mm Ho-103 heavy machine guns.