The USAF needed a small payload bomber that worked in low visability. After some designing, testing, and redesigning, the USAF got what they needed, the V-9. Despite the bombs being mounted on the exterior, it proved useful, and was mostly used to sink ships or render their weapons (or takeoff capabilities if its a carrier) inoperable. After a few years of service a torpedo carrying version was introduced, although it didnt make much of a difference as the torpedoes normally were dropped like regular bombs. -Notes: Don't fly into water AT ALL, it blows up when you do. Yaw does work. It can avoid missles without the countermeasures, but its not recommended.-