The X-13 was intended to prove that a jet could take off vertically, transition to horizontal flight and return to vertical flight for landing. It was hoped that such a jet would lead the way for submarine-based aircraft and provide offensive capability should conventional runways be destroyed in an attack. This is the second of two X-13s, completing the first full-cycle flight in April 1957 at Edwards AFB and is now on dispaly in the R&D Gallery of the NMUSAF's new fourth building.