S-foils/Legends

"Lock S-foils in attack position."

- Unidentified clone trooper pilot

S-foils, also known as Strike foils or Stability foils, and on occasion as X-foils, were movable wings attached to the port and starboard sides of a starship, sometimes mounted with weaponry. Normally the foils were locked in a "closed" position close to the ship for landing and usually for normal flight, but during high-stress situations the foils were folded out. The Incom Corporation manufactured several starfighters with S-foils, including the ARC-170 starfighter and, later, the X-wing starfighter.

Heat dispersion
Historically, S-foils had been developed to address overheating issues on wing-based starfighters. Because of the proximity of engines and weapons systems to narrow wiring that fit inside the thin wings, an excess of heat could cause mechanical meltdowns that would be devastating to the capacity of the fighters to function. S-foils like those seen on a number of Republic starfighter models during the Clone Wars held radiator panels that dispersed heat and cooled the interior mechanisms of the ships. S-foils were used when stress was being put on a ship's systems, usually when it was traveling at high speeds or locked in a dogfight. This idea would eventually evolve into the radiator panels of the Galactic Empire's TIE series.

Atmospheric stabilization
Stabilization was a key issue, especially with larger craft. For shuttles, which were often used to transport dignitaries or sensitive cargo, maintaining stability in flight was pivotal. Large folding wings served to reduce turbulence and protect the craft's contents.

Weapon range
With the advent of newer starfighters like Incom's X-wing, the workhorse of the Alliance Fleet during the Galactic Civil War, S-foils took on a new purpose. Designers realized that they could increase spread coverage of weapons if they mounted them at the tips of the foils. Unfortunately, the new design had the side effect of decreasing the reaction time of patrol fighters. On most models with S-foil mounted laser cannons, the weapons could not fire with the foils in locked position. As such, a pilot would have to switch to attack mode before they could defend themselves. Even in fighters where that was not the case, accuracy was usually improved with the S-foils in attack position.

Starfighters with S-foils

 * Alpha-class Xg-1 Star Wing
 * Aurek-class tactical strikefighter
 * Basilisk war droid (later Mandalorian variants)
 * StarViper-class attack platform
 * Delta-7 Aethersprite-class starfighter (Saesee Tiin's modified starfighter)
 * Eta-2 Actis-class light interceptor
 * V-19 Torrent starfighter
 * Aggressive ReConnaissance-170 starfighter
 * Sentinel-class landing craft
 * Delta-class JV-7 escort shuttle
 * Imperial assault shuttle
 * Imperial loader shuttle
 * T-65 X-wing starfighter
 * T-65B X-wing starfighter
 * T-65BR X-wing reconnaissance starfighter
 * T-65XJ X-wing starfighter
 * T-65XJ3 X-wing starfighter
 * B-wing starfighter
 * TIE Hunter
 * Z-95 Headhunter (variant model)
 * X-83 TwinTail starfighter
 * CF9 Crossfire starfighter
 * GAT-12 Skipray Blastboat

Behind the scenes
The Delta-7's use of S-foils occurs only in Hasbro's toy line and is therefore likely non-canon, except in the case of Saesee Tiin's modified fighter.