During production of The Empire Strikes Back, designer Joe Johnston conceived a ship that combined the body of an X-wing and the cockpit of the Y-wing. However, this design was scrapped for the T-47, which featured no elements from previous craft. Johnston's designs for the Snowspeeders have influenced later Star Wars designers, such as Tommy Lee Edwards.The models were built in three different scales by Steve Gawley, Charlie Bailey, and Mike Fulmer of ILM, with the smallest (20 inches) used for motion control photography, and the largest (2½ feet) for hero and pyrotechnic shots. All models included motor-controlled flaps to imply maneuverability, and the largest version also possessed motor-articulated crew. Several full-scale props were built in London for the hangar, cockpit, and speeder crash scenes.