[Mr Frost]

I have it (mostly) cold due to the mayhem hot (let alone hot and forceful) exhaust would create at very busy ports . It is just light that would create heat if allowed to just stay inside the ship .

In my designs the colour of the exhaust does tell you something of the engines' behaviour : blue means it is thrusting , red is reverse thrust (and purple means something has gone very very wrong) with shade and brightness varying with performance . With practiced observation you can tell which direction the ships' thrust is vectored and how hard .