In Thunder Force VI, the Sub Units are used on the RVR-00 Phoenix to form a major Extra Body Equipment known as the "Phoenix Brigandine".

List of Sub Units used on the Phoenix

• Sub Unit A-Parts: It is the first part attached to the RVR-00. This unit includes the Photon Rifle, an Enhanced Radar dish, and Warp Engine used by the Phoenix to warp-cruise.
• Sub Unit B-Parts: The Booster Engine, attached behind the A-Parts, ostensibly used for reaching orbit. It is also the Power Plant of the Over Weapons used by the Phoenix Brigandine. Once it is detached it can fire a destructive "rain" of laser beams on enemy forces.

Appearance

The Sub Units of the Phoenix only make an appearance in the Opening and Phoenix Take Off cutscenes. During both sequences, the Sub Unit B-Parts is used to launch the Phoenix Brigandine into space to support the Sword Fleet against the invading ORN forces. The RVR-00 detaches from the B-Parts, which unleashes a barrage of lasers in the midst of the battle, inflicting heavy damages on the ORN fleet. As the RVR-00 leaves the battlefield and activates the Warp Engine heading to the Galaxy Federation homeworld, then the A-Parts detach from the Phoenix, leaving the Photon Rifle and the radar dish equipped on the ship.