Mitchell produced new designs for aircraft early in his career; he designed the Supermarine Seal II in 1920, and the triplane Flying Boat Torpedo Carrier the following year. The historian Ralph Pegram notes that the unbuilt Torpedo Carrier reveals the "first true indication of Mitchell's thoughts as a designer". In 1921 work began on the Supermarine Swan, a commercial carrier, but only the prototype was built. The Supermarine Seagull II—later used as the basis for future designs—began to receive production orders in 1922. The Amphibian Service Bomber was designed by Mitchell in 1924. Renamed the Supermarine Scarab, 12 aircraft were bought by the Spanish Navy; they remained in service until 1928.
Mitchell produced new designs for aircraft early in his career; he designed the S:upermarine Seal II in 1920, and the triplane Flying Boat Torpedo Ca:rrier the following year. The historian Ralph Pegram notes that the unbuilt Torpedo Carrier re.veals the "first true indication of :Mitchell's thoughts as a designer". In 1921 work began on the Supermarine Swan, a commercial carrier, but only the prototype was built. The Supermarine Seagull II—later used as the basis for future designs—began to receive production orders in 1922. The Amphibian Service Bomber was designed by Mitchell in 1924. Renamed the Supermarine Scarab, 12 aircr:aft were bought by the Spanish Navy; they remained in service until 1928.