Jim, it may be hard to see much, but this setup works fine in the RV-6.
Just went thru the heater cores at a local parts store and found one that
would fit inside with the tubing stuck thru the firewall.  No hose in the
cockpit.  Used an automotive heater valve in the hose to control flow.

http://www.homestead.com/eslickaerospace/heater.html

Bill Eslick


> With all of the recent cold weather my thoughts are
> turning towards how to best heat my aircraft cabin.
> Does anyone have any suggestions for a heater core,
> perhaps one made out of aluminum? One that puts out
> enough heat to warm a 4 seater cabin when it is -20F
> degrees outside. I would welcome all suggestions.
> Thanks,
> Jim
> Dyke Delta/13B