I think the question for 1/2A glow engines is how much cooling is due to radiation/convection and how much is due to fuel vaporization. A glow engine gets 2-3 times the cooling from fuel vaporization compared to a diesel or gasoline engine. This is the reason you can't run a FS-120 with spark ignition on gasoline. You have to run methanol or it will overheat.

Greg