S-foils were made famous by Star Wars' X-Wing star fighter.
But why were they needed in-universe aside from "Lock S-foils in attack position" sounding cool?
S-foil Wookiepedia has this to say:
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.
Q1: Where exactly in canon is there such an explanation? ("radiator panels")? Wookiepedia isn't providing a cite.
Q2: Since when do the small radiator panels work in vacuum? They typically need to be pretty large (see discussion here for ISS/shuttles), due to lack of air serving as heat transfer agent; and S-foils on a small startfighter don't seem to add all that much extra size.
Was this somehow ever retconned in canon to conform to "reasonable" physics? (even fictional)?