The Twin Comanche was developed from the single-engined Comanche by Ed Swearingen who at the time operated a facility that specialized in the modification of production aircraft.
Ed Swearingen started the developments that led to the Merlin through gradual modifications to the Beechcraft Twin Bonanza and Queen Air business aircraft which he dubbed Excalibur.
Ed Swearingen announced a new design for a light twin business jet in October 1986, the SA-30 Fanjet.