Most planes designed for electric power have provision to allow air to flow through the fuselage to keep the ESC, and battery packs cool.

Given that the Sky Raider II was designed for glow, it does not have the openings.

You can either open an intake oval on the bottom of the firewall, and then a larger exhaust opening further back on the fuselage to deal with all of this.

Some people also resort to placing the ESC right under the motor, exposed to the airflow, on planes like these.

A larger ESC will still build up heat, but it is not likely to get AS warm for a given power level, because of larger components and heat sinks that take longer to heat up...

However you are best off treating it as if it they were all the same... all requiring a degree of cooling airflow.

You don't have to go nuts about it, but do something.

If you cannot expose the ESC, I've used clear material taken from commerical package "bubble" packaging... the stuff you normally have to open with scissors to get to the merchandise.

You can often cut one or two suitable clear intake scoops from a package.

Then I can open a hole in the covering or fuselage, and put the 1/4 egg shaped plastic scoop over the hole, wide side forward, to pull in air.

Remember though that the exhaust needs to be 2 to 3 times LARGER than the opening or pressure will build inside the fuselage permitting no airflow.

Better to have a small intake and a large exhaust, than a large intake and a small exhaust.