Model Variants (Including Prototypes)
Ki-67 - Bomber Variant on which the Ki-109 is based on.
Ki-109 - Heavy Fighter Bomber Interceptor; fitted with Mitsubishi Ha-104 piston engines of 1,900 horsepower each; 1 x 75mm cannon in nose position and 1 x 12.7mm machine gun in defensive tail gun position; 22 examples produced as armed version only (as in Ki-109b model proposal below).
Ki-109a - Proposed "hunter" version fitted with radar and searchlight to be used in conjunction with "killer" model.
Ki-109b - Proposed "killer" version fitted with heavy armament to be used in conjunction with "hunter" model.