Heater fan filled cockpit with smoke

[rocketman2tm]

Had an issue with on e of my heater fans. I had taken off and got up to pattern altitude. I then turned on the heater and a few seconds later the cockpit got a little smoky and I could definitely smell burning. After landing I did not find anything wrong with wiring. I did notice that I had one fan that was not running. I took the fan out and removed the blades and found that the smoke had been let out.
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This is one of two of the fans that came with the heater kit. Has anybody else had any issues with these? One thing I will note is that they are generic PC cooling fans and probably are designed for 12 volts and not much more. I know on my airplane, the electrical system gets up to around 13.8 volts. I've been trying to see if there are fans out there that would be able to work in this range.

[Dave S]

Probably has more to do with the fact the fan was hand crafted in the far east by artisans of dubious distinction more so than the voltage of the system.

Junk parts from china.......?

Don't recall but I think my fans came from a different company - been working fine since new.

Maybe not much help, but there are lots of muffin fans that have been delivered which have worked well, leading me to believe they get along with the normal Kitfox system voltage.

With the degree of corporate incest we have it is just about impossible to figure out if all units from a particular brand were ever made in the same non-US factory or multiple different factories with who knows what degree of QC variablities. Suppliers change in a heartbeat.

Or the failure might just be an individual flaw in that particular fan; and, a replacement might be fine.

If you want to search around, a place like Digikey might be good to check - they seem to have thousands of just about everything electronic/computer related; and, usually you can determine the design limits of a particular unit.

[desertdave]

Agreed on the origin of the part. Plenty of inexpensive 12v pancake fans available online. Good luck finding one made in North America.

[rocketman2tm]

I just ordered two new fans that are rated for 12V at 0.5A each. I'll wire them up in parallel and put a 2 ohm power resistor in series with the combo to bring it down to where it should be.

[TRegli]

I actually had one of my fans seize up a couple months ago. When the fan was switched on, it would stay stuck in a single position. Off, and it would spin easily and freely. I tried cleaning it but to no avail. Thankfully it was during the build and everything was still open so I could easily replace it (I ended up replacing both for good measure)

[Delta Whisky]

I had the same occurrence and replaced both of the fans with ones rated high with computer geeks. So far, so good.

[AvDES LLC]

You could always go the fanless route....

And for those that continue to state that pulling air from under the cowling is unsafe or “would never happen with a certified aircraft” please review the attached photos of my stock Cessna in which the heating system for the cabin heat and cabin air functions identically.

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