Heater - December 2001

Ok, well enough is enough.  I've flown through two Michigan winters without a heater and made it but the question is... why?  So, I was ordering materials for the new engine baffling and thought; "Why don't you just buy the stuff for a heater while you're at it.  Besides, my wife was wondering what to get me for Christmas and what better present than a nice warm cockpit?

Heat Muff

Both my exhaust pipes are long and straight enough to accept one of those "clam shell" heat muffs.  It simply clamps around one of the pipes and has a 2" inlet and outlet.  Air comes in from a vent in the back of the cylinder baffle and out to the heat box... collecting hot air along the way.

Heat Box

The heat box has one 2" inlet and two 2" outlets and a lever to control which outlet the heat goes through.  One outlet is simply routed out the bottom of the plane and the other is passed through the firewall.  

Installing the Heat Box

Ok, this should be easy...  Right.  Pulled the cowl off and found the perfect location for the heater.  Unfortunately, someone had the nerve to put part of the frame right behind where I wanted to put the heat box.  A little lower and nothing would fit, a little higher and it would interfere with the rudder pedal.  Humm... Ok, move it down and to the outside a bit, cock it sideways, and it looks like the "perfect" location to me.

Routing the SCAT Ducting

I routed the SCAT ducting under the floorboard so it showed as little as possible and would come up under the front seat and fill the cabin with warm, warm air... Ok, well anyway I was hoping that it swirl around and warm me up before it all rushed out the pilot's opening.  As you can see it just fit with full left rudder and the toe brake fully down.

Installing the Heat Muff

Now, we know where the heat box will go and its nice and close to the exhaust pipe.  So I put the heat muff over the exhaust pipe and no dice... pipe was too big.  Ok, it fits on the right pipe 1.75" diameter but not the left, which is the one I want.  So I had LeForge Pipe and Fabrication in Ypsilanti make another pipe.  I'm not sure why it wasn't the same anyway... besides the new one will have smooth bends and not be all lumpy... lumpy can't be good.

Connecting Heat Muff to the Baffling

I connected the input port of the Heat Muff to the baffle with SCAT ducting.  A 2" hole and 2" aluminum flange did the trick... After moving the spark plug wires of course.   I think the previous owner must have changed his mind a couple of times because there were a couple of extra holes.  No matter, I'm going to replace the baffling next so it doesn't have to look perfect.  I did have to take off the top cowling to get to everything, but the top comes off in a snap.

Installing Control Cable

Ok, this should be easy enough.  First question: Should it push or pull the heat on... 

Ok, pull it is.  Now, where to mount the control handle... somewhere out of the way yet accessible.  Well, I bought a dash mount control... how about on the instrument panel?  Sometimes I amaze even myself.  One little hole in the bottom left corner of the instrument panel and that's it.  

The cable runs behind the frame tubing between the frame and skin (see thumbnails below).  A few cable ties to hold it steady and we're ready to connect.   I'll have to wait because I forgot to order the control end "B" nut to connect the wire to the lever.  

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