Bill,
Here is a post I did on RV-10 cabin heat. I offer it does what you want, but is much easier and avoids potentially problems.
One other suggestion, replace the 2” SCAT hose in the tunnel with 1.5” hose. Still plenty big enough for rear heat flow but is easier to route in the tunnel. A 2” to 1.5” reducer at both ends makes it work.
Carl
I used some of this between the cabin heat boxes and the firewall, then had it extend over the top of the boxes, then down the front of the boxes:
http://www.aircraftspruce.com/catalo...clickkey=31128
The result is the hot cabin heat air, when the heat boxes are shut, bounces off the Koolmat then down toward the cowl exit, not right at the engine mounted fuel pump.
I also put a 3/4” restrictor on the back of the baffle 2” cabin heat SCAT hose flanges (a piece of aluminum with a 3/4” hole with some aluminum tape to hold it on the edge of the flange, the SCAT hose slides over it). This does two things:
- Less air to be heated so less hot air dumped into the bottom of the cowl. The RV-10 heat is way more than I’ll ever need. Even with these restrictors I have just the rear heat on part way on the coldest days.
- Less engine cooling air bypassing the engine, but still enough to keep the SCAT hose from getting too hot.
This setup has worked well - and I recommend it.