Going operational from autumn 1941, the Ki-49 first saw service in
China. After the outbreak of the
Pacific War it was also active in the
New Guinea area and in raids on
Australia. Like the prototype, these early versions were armed with five machine guns and one cannon. Combat experience in China and New Guinea showed the
Donryū to be underpowered, with bomb capacity and speed suffering as a result. Thus, in the spring of
1942 an up-engined version was produced, fitted with more powerful Ha-109 engines and this became the production
Army Type 100 Heavy Bomber Model 2 or
Ki-49-IIa. The Model 2 also introduced improved
armor and
self-sealing fuel tanks and was followed by the
Ki-49-IIb in which 12 mm caliber|
Ho-103 machine guns replaced three of the
Type 89 machine guns. In spite of these improvements, losses continued to mount, as the quantity and quality of fighter opposition rose. In early 1943, further power increases were delayed, owing to development difficulties with the
Nakajima Ha-117 engines, and the Ki-49-III never entered production, with only six prototypes being built. In the face of its increasing vulnerability to opposing fighter aircraft while performing its intended role, the Ki-49 was used in other roles towards the end of the Pacific War, including
anti-submarine warfare patrol, troop transport, and as a
kamikaze. After 819 aircraft had been completed, production ended in December 1944. Fifty of these were built by
Tachikawa. ==Variants==