The heat muff I made previously was 100% from another person's design, and it was for a Jabiru engine. When I made it my engine was not on the airframe yet, but now that it is, it became apparent that having the inlet and outlet on opposite faces wasn't going to work.
So I remade the muff, putting both openings on the same face. The air will still wash over the hot exhaust and onto the cabin, but this is the only way to get the SCAT tubing to work.
Again I split the end caps so I can get them over the exhaust pipes. I also dispensed with the 16 or so tabs at the end holes. 4 on each should be enough to hold it in place with a clamp.
Cutting the holes with a fly cutter
All the muff's bends can be made with a small brake
