The Hawker 400XP is basically the same as the Beechjet 400A, with some minor changes. The Raytheon Beechjet 400/400A evolved from the Mitsubishi Diamond 2 design that was bought by Beech in the mid 1980s.
The original Mitsubishi MU300 Diamond 1 flew for the first time in August 1978. In the 1986 the Diamond 2 replaced the Diamond 1, only 11 Diamond 2s were built before Beech purchased the design and production rights. The Diamond 2 was renamed the Beechjet 400. Beech equipped the Diamond 2 with JT15D5 turbofan engines, developed a new interior, and made other minor changes
259 cubic feet
1,684 nautical miles
74 cubic feet