The subsequent two prototypes were powered by the turbo-supercharged Mitsubishi Ha-211-I Ru [Ha-43-II]; these experienced teething troubles and the following thirteen pre-production machines substituted the Ha-211 Ru engine for the lower-powered but more reliable turbo-supercharged Mitsubishi Ha-104 Ru (Army Type 4 1,900 hp Air Cooled Radial). The aircraft was fitted with self-sealing fuel tanks, armor and a pressurized cabin for its crew of 5.
The subsequent two prototypes were powered by the turbo-supercharged Mitsubishi Ha-211-I Ru [Ha-43-II]; these had initial issues and the following thirteen pre-production machines replaced the Ha-211 Ru engine with a lower-powered but more reliable turbo-supercharged Mitsubishi Ha-104 Ru (Army Type 4 1,900 hp Air Cooled Radial). The aircraft was equipped with self-sealing fuel tanks, armor, and a pressurized cabin for its crew of five.