Replies to This Discussion

Permalink Reply by Louis W. Ott on December 2, 2016 at 1:02pm

I use the waste heat from my firewall mounted oil cooler to heat the cabin. No heat muff around the exhaust. No extra SCAT tubes. It does have a rotating flap.

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Permalink Reply by John Austin on December 2, 2016 at 4:45pm

The Jabiru cabin heat box dumps the heat when not diverting it to the cabin:

It uses a control cable to turn the heat on and off. Spruce sells something identical - they even have 2 versions as to where the hot air duct comes in.

John

N750A

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Permalink Reply by Jerold Ebke on December 2, 2016 at 11:49pm

I used the Vans TG10 with my UL heat muff. Has an exterior NACA vent into the muff and then to the vent.

Dumps the heat out bottom of the cowl when not in use.

Works great..

Flew last winter when outside temps in teens at altitude and very tolerable in cockpit.

Jerry

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Permalink Reply by James R Depfer Sr. on December 3, 2016 at 10:35am

Thanks for the info. I've been looking at the Vans boxes and the similar ones at Aircraft Spruce. 

Jim

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Permalink Reply by James R Depfer Sr. on December 3, 2016 at 10:39am

John,

The boxes I've looked at do not have anything like the triangle and vertical arm making up your actuator. I believe something like that would be desirable no matter which box I get. Did you make those parts, or did they come with your box ? I could probably make something similar. Of the 4 bolts shown, is the right bottom one anchored to the box ? Could you possibly tell me what makes up each pivot point (bolt, spacer, nuts, etc) ?  

Thanks,  Jim

P.S. I just realized my reply to you is not going directly under your reply, or getting indented like my reply to Jerold. I deleted and tried it twice. The only difference is that my reply to Jerold was the last in the thread so it had to go under his reply, but it did also get indented. Is this a problem ? I never noticed this happening before.

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Permalink Reply by John Austin on December 3, 2016 at 11:03am

You're correct - I made the triangular bellcrank and linkage arm myself.  Looking at the photo of my installation, the short black arm in the left lower corner of the heat box is the original lever to activate the valve.  The way it is positioned, you'd have have a sharp 90 degree bend in the cable to actuate it - no good!  The linkage I added allows the cable to come straight through the firewall to actuate the linkage - much better!

The bolt on the lower right of the bellcrank is a pivot that is anchored through a hole I drilled in the box and secured with a jam nut against the box and the bellcrank is secured with a castellated nut.  The remainder of the bolts are pivots with washers and metal lock nuts (could use castellated nuts since these are rotating parts, but hey, it's not a F-16 and this isn't exactly a critical assembly! Ha!) - you can just use washers for spacers as necessary to keep the linkage aligned.

The Jabiru 750 Firewall-Forward instruction guide has several pictures of a similar cabin heat linkage:

STOL 750 Firewall-Forward Instructions

John

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Permalink Reply by James R Depfer Sr. on December 3, 2016 at 11:35am

John,

Great design. I was concerned about the way I would connect my heater cable. You solved that problem. The link you have listed gives me a "404 Not Found Error", although it gets to a Jabiru web page.

Thanks Again,

Jim

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Permalink Reply by John Austin on December 3, 2016 at 11:44am

I fixed the link - should work now!

John

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Permalink Reply by Timothy D. McCall on December 3, 2016 at 2:44pm

James

I have this cabin heat box installed on my 750:

http://www.aircraftspruce.com/catalog/eppages/homebuilderscabinheat...

I have the heat box connected to a full muffler wrap heat muff which is supplied with outside air via naca duct.  Lots of heat.

Tim

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Permalink Reply by James R Depfer Sr. on December 4, 2016 at 9:33am

Thanks for all the replies. I put one of the Vans Stainless Steel boxes on my letter to Santa. If he comes through, I'll copy John's bellcrank design to use with the control.

Jim

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