The Ki-43 entered service with the Imperial Japanese Army Air Force with the designation Type 1 Fighter “Hayabusa” in late 1941 and served until the end of World War II. It was known as the Army ‘Zero’ though it had a different profile and a much thinner rear fuselage. Model 2 had its first test flight in February 1942, it was equipped with an uprated Nakajima Ha-115 Sakae 2-stage supercharged engine also known from the Reisen. The supercharger air intake was moved to the top of the engine cover while the carburetor’s intake remained on the bottom. The wingspan was reduced by 0,6 meters to boost low and medium altitude combat speed. Self-sealing fuel tanks and 13mm pilot armor plates for the head and back were added. A total of over 2500 Model 2’s were built in Nakajima, Tachikawa, and Hikoki K.K. factories. It was produced until December 1944 when the Ki43-ll version replaced it.