Mitsubishi Type 97 Heavy Bomber / Ki-21 (Sally)
The Japanese Army Air Force (JAAF) Type 97 Heavy Bomber / Ki-21 (code name: Sally) was the main long range bomber in service at the beginning
of the Pacific War and probably the most famous and well known Japanese Army bomber of the Pacific War. This bomber was a contemporary of the Mitsubishi Type 96 / G3M
Production delays prevented the IJAAF from re-equipping the 60th Sentai and 61st Sentai until the end of 1939. The Ki-21-Ia was first used during the Second Sino-Japanese War in China during the fall of 1938. During the Nomonhan Incident / Battle of Khalkin Gol, the Ki-21 saw service during June-September, 1939. Combat revealed that the greatest weaknesses of the design was the weak defensive armament and lack of self-sealing fuel tanks.
Although outdated after the start of the war, and was replaced by the Ki-49 Helen, which was only a marginally superior, the Sally remained in service and was well liked by aircrews
because of its easy maintenance and handling.
Eventually the Type 97 heavy bombers model 2b was produced with a 12.7mm machine gun in a dorsal turret, armor up to 16mm thick, and other improvements.
Transport version of the bomber, with four crew members, that could carry a maximum of nine additional passengers or cargo.
A total of 2,064 built by Mitsubishi at Nagoya and Nakajima at Ota