Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser EarthX Batteries Garmin G3X Touch
Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 25

Thread: Cabin heater coolant diagram

  1. #11
    Birdseyeview's Avatar
    Join Date
    Sep 2017
    Location
    Oregon, Ill
    Posts
    198

    Default Re: Cabin heater coolant diagram

    Jim -
    All your comments make sense. Thanks. Where did you get your Thermo Bob thermostat? Do you have a part number or model number?
    Larry Olson
    Kitfox Series 6 - 1st Flight Oct 2021
    Tri-gear, smooth cowl
    912 ULS

  2. #12
    Senior Member
    Join Date
    Apr 2009
    Location
    Chisholm Mn
    Posts
    1,562

    Default Re: Cabin heater coolant diagram


  3. #13

    Default Re: Cabin heater coolant diagram

    Quote Originally Posted by Birdseyeview View Post
    Lots of interesting debate in this thread on air flow through the cabin heat exchanger but has anyone every determined by temp measurements if the cabin heat exchanger itself is actually getting enough coolant flow through it to get it good and hot?

    My cabin heater kit is the one sold by Kitfox with the coolant flow tee'd off the main radiator hoses and with the two computer fans. However, it just doesn't seem to send out much heat into the cabin when it's 30-40 F ambient or colder (in Northern Illinois). In contrast my Toyota's heater will drive me out if I let it go.

    Although the two computer fans do seem to push some air through it that I can feel, its not exactly a hurricane and its just not very warm. I've sealed up air leaks around the firewall and elsewhere to minimize cool ambient air ingress into the cabin but I'm wondering - Is there a way to modify the coolant plumbing somehow to potentially push more coolant flow through this cabin heater to get it hot without negatively impacting the coolant flow to the cylinder heads? The following diagram crudely depicts my current plumbing:

    Attachment 31553

    My CHT seems to always hover around 180 F so it seems that my cylinder heads are getting plenty of coolant flow. Or do I need a coolant thermostat or something else to raise the overall coolant operating temp?

    Does anyone have the standard Kitfox set up that proves its output is more than adequate? If so what do you attribute it to? Any thoughts are appreciated.
    this is EXACTLY why I pulled the fans and went with ducted air. Yes those fans move air, but not much. And with the cabin as poorly sealed as it is, they were pushing enough air to keep anything but the tips of my big toes warm. That issue solved itself with the ducted air, however it took the development of a shroud and mounting etc etc.

    I also just have standard y fittings on the main coolant lines. No thermo bob so no ability to comment there.

  4. #14
    Birdseyeview's Avatar
    Join Date
    Sep 2017
    Location
    Oregon, Ill
    Posts
    198

    Default Re: Cabin heater coolant diagram

    [QUOTE=AvDES LLC;107021]this is EXACTLY why I pulled the fans and went with ducted air. Yes those fans move air, but not much. And with the cabin as poorly sealed as it is, they were pushing enough air to keep anything but the tips of my big toes warm. That issue solved itself with the ducted air, however it took the development of a shroud and mounting etc etc.


    I may have missed some of the discussion history here so please excuse me if you've already explained this in another post. Have you been flying with this set up to prove that it provides plenty of heat into the cabin? Does it ever provide too much heat? If so, how do you plan to regulate the flow to shut it off during the summer?
    Larry Olson
    Kitfox Series 6 - 1st Flight Oct 2021
    Tri-gear, smooth cowl
    912 ULS

  5. #15

    Default Re: Cabin heater coolant diagram

    i have just crossed the 100hr threshold with this setup in my plane and it provides plenty of heat to keep myself and my lady warm in the Reno winters. It does get a bit toasty in the spring / summer months and to solve that I simply put a ball valve on the inlet line. When it’s hot out, close the ball valve and zero coolant flow takes place through the exchanger.

  6. #16
    Senior Member bbs428's Avatar
    Join Date
    Jan 2015
    Location
    SW Missouri
    Posts
    649

    Default Re: Cabin heater coolant diagram

    I weighed a new 8" rad. fan I was thinking of using. It blows a lot of air but it's 1lb 13oz. Plus the amp draw. Ouch!

    I think I'm warming up to your shroud. Weight would be miniscule compared to the bigger, stronger fan plus the savings in amps.
    I might be able to bend up some aluminum sheet but not sure if it would look as good. I don't have much in the way of sheet metal tools/benders/brakes.
    My heater core is 8"x 8" so I'd have to make my own variation. Now would be the time to do it!

    Is that 3" hose from the firewall to the shroud?

    Thanks for posting - really got me thinking in a different tangent.
    Somebody said that carrier pilots were the best in the world, and they must be or there wouldn't be any of them left alive. — Ernie Pyle

    Brett Butler
    Flying: 1998 Model 5 Outback, 912ul Zipper 110hp, G3x avionics, ss7 upgrades

  7. #17

    Default Re: Cabin heater coolant diagram

    Glad it got you thinking outside the normal box. These engines don’t have much for electrical output and sucking some up with a big fan isn’t always the best idea in my
    mind. If you want to aim more for the “certified” approach, you can run a small 2 inch duct to a muffler shroud and have the outlet to that shroud go into a through bulkhead ducting port and into the shroud on your cabin heat heater.

    drop me a pm if you want to discuss shrouds and whatnot. I can steer you in the direction of a possible solution to your dilemma.

  8. #18
    Senior Member jiott's Avatar
    Join Date
    Jun 2010
    Location
    Portland, OR
    Posts
    2,960

    Default Re: Cabin heater coolant diagram

    I can understand some of you wanting to go the "certified" approach with muffler shrouds, etc, especially those who live in very cold climates. But I do want to say that the automotive style hot water heater is one of the great features that drew me to the Rotax engine. Not having to worry about CO leaks from exhaust cracks, and not having to annually do the fairly laborious inspections inside the shroud area is a big deal to me personally. I don't have to worry about what if an exhaust crack occurs 6 months from annual time-better have a very good CO detector in the cockpit. Exhaust cracks are far from uncommon or rare on our Kitfoxes as we all know. Sure, I know the certified world lives with this potential problem very successfully, but it takes eternal vigilance and extra labor. I live in the Pacific Northwest and have never wished for better cabin heat for 10 years now, using the standard Kitfox supplied cabin heat option with two computer fans. Just wanted to throw this other side out there FWIW.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

  9. #19

    Default Re: Cabin heater coolant diagram

    100% agree with the above in the sense that there are many many ways to skin this cat - sadly my cabin is so poorly sealed at the cowl to windshield interface (about a 1 inch wide open gap) that outside air POURS into my cabin and it gets cold as **** pretty quick - that’s the main reason my fan setup was pulled - the power draw was secondary.

    now a word of caution on pulling air from under the cowl -

    yesterday I spent the day installing an oil cooler conversion kit on a Rans S7. Owner has the 912uls with the ball and socket style exhaust. This is a VERY well taken care of plane; the owner meticulous about literally everything. While flying with an instructor the instructor asked why it smelled like exhaust in his cabin and he mentioned this to me while we were working. Upon inspection of the ball and socket fittings it is extremely evident that there are no less than 10 spots in the joints of that exhaust system that are displaying the signs of blow-by.

    this was a first for me. I have the older slip together exhaust and had yet to deal with this ball and socket style before. If you’re planning on ducting air from under the cowling and you have the ball and socket style rotax muffler, I STRONGLY suggest first inspecting that system and ensuring it is very well sealed.

  10. #20
    sonex293's Avatar
    Join Date
    Sep 2013
    Location
    Cary
    Posts
    3

    Default Re: Cabin heater coolant diagram

    Larry, in reference to your diagram in Post #9. Is this the way Kitfox recommends you plumb the coolant lines? (i.e. in parallel to the main coolant radiator).

    Anyone have any thoughts on getting maximum flow through the cabin heat radiator (which uses 5/8" hose) without sacrificing main engine cooling (which uses 1" hose).

    ==
    Michael

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •