Edward “Ed” James Swearingen was an aeronautical engineer based in San Antonio, Texas. Swearingen was notable for developing modifications from existing production aircraft such as the Piper PA-30 Twin Comanche from the Piper PA-24 Comanche single engine series, the Swearingen Merlin turboprop aircraft from the Beech Model 50 Twin Bonanza. Swearingen also developed original aircraft designs such as the SX-300 experimental airplane and Sino Swearingen SJ30-2 executive jet.