TIE fighters are fictional starfighters existing in the Star Wars universe. Propelled by Twin Ion Engines, TIE fighters are fast, agile, yet fragile starfighters produced by Sienar Fleet Systems for the Galactic Empire. TIE fighters and other TIE craft appear in Star Wars films, television shows, and throughout the Star Wars expanded universe. Several TIE fighter replicas and toys, as well as a TIE flight simulator, have been produced and sold by merchandise companies. == Origin and design == Industrial Light & Magic's (ILM) Colin Cantwell created the concept model that established the TIE fighter's ball-cockpit and hexagonal panels design for Star Wars (1977). Star Wars creator George Lucas liked the basic design consisting of two panels connected by a stick with a ball-shaped cockpit, but Cantwell's concept had few details. Joe Johnston created additional details, such as the cockpit window and the attachment points between the solar panels and the hull.Initially given a blue color scheme, the TIE fighter models for the first film were grey to better film against a bluescreen; TIE fighters in The Empire Strikes Back (1980) and Return of the Jedi (1983) shifted back to being a muted blue. Sound designer Ben Burtt created the distinctive TIE fighter sound effect by combining an elephant call with a car driving on wet pavement. In the book The Sounds of Star Wars, the engine roar is likened to German Junker Ju 87 "Stuka" bombers, who used sirens to frighten civilians on raids. This could have been a possible inspiration for the sound.