Rubber Heat Duct Pattern - CTSW

[tevbax]

Does anyone have a pattern or a print of the heat duct rubber piece that goes onto the muffler scoop? This would be the rubber piece between the "scoop" and the cowling. Ours was just done at annual back in April and is already crumbling apart. Also, looking for a good "known to work" material source for the fiberglass layered high temp rubber. 

Thanks! 

[Tom Baker]

I'm not sure if I have a pattern, but I will look. I do have some material that holds up better, it is fiber reinforced. It is kind of pricey too. Here is the link from AS, https://www.aircraftspruce.com/catalog/pnpages/05-00600.php . I could probably cut a piece and send it to you if needed.

[tevbax]

I ordered some temp reinforced rubber until my sheet comes in from McMaster. I've been thinking about making this duct a two piece that slid together somehow - like when the bottom cowling is set it either slides inside or outside of the existing scoop. The current design seem less than adequate and relies on the rubber to create a "positive seal" between the inlet and the rubber. 

[Roger Lee]

I just wrap it around the aluminum shroud and then rivet it in place. Then take a pair of scissors and cut the slots and trim it. It just has to flare outward to capture and direct air in flight.

[FlyingMonkey]

I just made a rectangular flap for each side and riveted and that worked great.  Roger's wrap method might give fewer gaps and thus a bit better flow through the shroud.