That's a good question. On the two planes I have built, one had a DA-50 with a canister, the second has a 3mm TOC-53. The TOC engine started out with a stock muffler, now it has a canister.

In none of the configurations did I do anything other than just mount the engine. The DA-50's head fins protruded out of the cowl, the TOC's cylinder is completely enclosed except for the plug cap.

It's my feeling that both these setups have run fine with regard to cooling. I've never experienced any fading or loss of power that could be attributed to heat. Hot air exhausts through the gap in the back where the cowl meets the canister tunnel.

I am interested to hear others' experiences in this area.

TF