Electric Cabin Heat

[Bryan Cotton]

Eons ago I was on my college ski team and I had Lange heated boots. They were awesome. We trained up in VT and it was cold. My team mates were jealous. One day they shorted. Took a minute to realize what was happening. The boots were tight, old tech 80's boots and it took a few moments to get it off and then rip out the wires. I got a good burn. My buddies were delighted. The fun of heated boots was over. I never trusted them again. I guess the motorcycle stuff would be better, at least you could isolate the power. The langes had batteries of their own buried in the sole.

[mike.smith]

I like the idea of not having to cut a big hole in the firewall and fabricate heat muffs and piping for cabin heat.

I installed heat-muff based cabin heat. More time, but not too difficult:
http://www.mykitlog.com/users/display_l ... 680&row=83
http://www.mykitlog.com/users/display_l ... 582&row=70
http://www.mykitlog.com/users/display_l ... 637&row=69
http://www.mykitlog.com/users/display_l ... 811&row=67
http://www.mykitlog.com/users/display_l ... 825&row=58
http://www.mykitlog.com/users/display_l ... 891&row=57
http://www.mykitlog.com/users/display_l ... 758&row=48

No idea how well it works since I haven't flown yet, but I will be starting my engine for the first time this weekend!

Mike Smith

[vigilant104]

Mike,
Thanks for the post and the pictures. That looks like a clean setup. I look forward to hearing how it actually performs (temp rise of air coming into the cabin and how much air there is--ultimately how much warmer does it get inside the airplane vs no heater).
Some questions:
- For the valve on the firewall: SS or aluminum? I know we all want to keep any "fire" on the correct side of the "wall."
- Have you decided where you'll get the air feed from? I've seen some nice scoops added to the cowling for this, but I'd like to avoid having another thing to be disconnected when I remove the cowl, and I'd like to avoid the drag of another opening. I like Mike F's suggestion of tapping into the air right at the opening of the oil cooler duct, I'll need to take a look next time I'm at the plane and see if there's room there. I've got a slightly leaky main bearing seal, I'd need to keep any wayward oil out of the heater (or, heaven forbid, fix the seal!).

Thanks again.

[mike.smith]

Mike,
Thanks for the post and the pictures. That looks like a clean setup. I look forward to hearing how it actually performs (temp rise of air coming into the cabin and how much air there is--ultimately how much warmer does it get inside the airplane vs no heater).
Some questions:
- For the valve on the firewall: SS or aluminum? I know we all want to keep any "fire" on the correct side of the "wall."
- Have you decided where you'll get the air feed from? I've seen some nice scoops added to the cowling for this, but I'd like to avoid having another thing to be disconnected when I remove the cowl, and I'd like to avoid the drag of another opening. I like Mike F's suggestion of tapping into the air right at the opening of the oil cooler duct, I'll need to take a look next time I'm at the plane and see if there's room there. I've got a slightly leaky main bearing seal, I'd need to keep any wayward oil out of the heater (or, heaven forbid, fix the seal!).

Thanks again.

Valve is SS from ACS.

The air comes from the top right (rear) engine baffle. It goes in a scat tube, to the heat muff, through another scat tube and to the valve.
This shows it better:
http://www.mykitlog.com/users/display_l ... 776&row=39
http://www.mykitlog.com/users/display_l ... 290&row=16

I plan to make a cover plate to cover that baffle opening for the warm months when heat isn't needed.

Mike

[vigilant104]

[quote="mike.smith"
I plan to make a cover plate to cover that baffle opening for the warm months when heat isn't needed.
[/quote]
Mike,
Thanks. That's a convenient spot for getting the air. One heads-up: My airplane had a fitting for a 1" SCAT tube at the same spot (was used to feed a blast tube for cooling something else). When that tube was in use the CHTs on that side went up by 20 degrees. That 1" SCAT tube = .78 sq inches, and a 2" SCAT tube = 3.14 sq inches, so we could expect the impact to be more. Anyway, maybe it won't be a problem for you in the cold months, but I just wanted to chime in so you can keep an eye open for this as you get your engine up and running. Thanks very much for the pictures and the help.

Mark

[hickej]

My heat muff has proven to be too small. It keeps me comfortable down to around 50F at night. I had to seal the canopy to keep air out. I may be able to go lower once I seal the air leaks coming in through the wing root. I am looking for a larger area for another heat muff but it is a tight fit. I am going to add a second heat muff to the other 3to1 exhaust to double my heat output and see what happens. I'll post more when I have more data.

[fastj22]

My heat muff has proven to be too small. It keeps me comfortable down to around 50F at night. I had to seal the canopy to keep air out. I may be able to go lower once I seal the air leaks coming in through the wing root. I am looking for a larger area for another heat muff but it is a tight fit. I am going to add a second heat muff to the other 3to1 exhaust to double my heat output and see what happens. I'll post more when I have more data.

I have two muffs, one on each exhaust pipe. I run fresh air from a NACA vent into one, then from that into the other and then into the cabin. I stuffed stainless steel scrubby pads into both to help slow the air and transfer the heat. I'm good down to about 20F. below that and I can see my breath again.

[Rynoth]

This builder has an excellent video of his installation: https://www.youtube.com/watch?v=lcBrMMkRFa0

I like how he vents the heat overboard when not in use, rather than just stopping airflow within the system (and the heatbox.)

[Bryan Cotton]

"This builder" is Jim Hicke, builder/pilot of the silver mini-bonanza. Pretty standard to dump heat overboard rather than dam it up.

[vigilant104]

My heat muff has proven to be too small. It keeps me comfortable down to around 50F at night.

Jim,
It's great to see you here. It looks like your heat muff covers about 3" of the exhaust pipe, you just didn't have much room. I think there's room for a 6"+ muff in my Aerovee/trigear, so maybe that will help. Thanks very much for posting the videos. Having the increased heat transfer area around the pipe (from a spring, SS scrubby, accordion-pleat metal, etc) is a good idea.