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Avionics Fans

About a month ago I asked you guys how to fix the heating problem behind my panel. I took the advise and installed a couple of 4" fans.

DigiKey has a pretty incredible filtering tool on their website and I used it for selecting a couple of fans. I picked a low rpm fan as I didn't
want a lot of noise and they easily exceed the cfm that would be required to displace the air behind the panel. They also have a very large
supply of different style fan screens. My biggest challenge was installing these in a finished panel. What you don't see in the pictures is that
I removed my displays and put towels behind the panel to keep metal shavings from mucking up my avionics.

First I made a template out of a piece of fiber board that I purchased at Hobby Lobby. I cut out the exact size of the fan and then drilled the
holes for mounting the fan.
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I used a 1.5" knock out punch for the holes:
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At this point I cleaned up the circle and reduced the sharp edges. I also made sure my glare shield cover also had matching holes and then attached the screens glare shield and fans together.
The glare shield material is actually a form of velcro that is used on convention displays. It looks really nice and stuff will stick to it.

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Mike,

I did not, although I did think about it. If I recall that glare shield is pretty thick and I was a little concerned about having enough room to even pull it off. The actual body of the fan is pretty thick and I bolted them in. What are your thoughts?
 
Results

Richard,

Have the fans reduced the heat issue?

Did you install an switch on the panel?

Or, are the fans powered with the avionics?
 
That is a trick question!! :)
Although the fans helped with the heat issue behind the panel, they just moved it to the cockpit. I need more air movement as it gets really hot here in Texas. Even at 12K it is pretty warm in the cockpit. Overall it is better for the electronics in the panel.

The fans come on with the master, but I also installed a switch so I can turn them off if I need to.
 
Trick Question

Richard,

It was not a trick question, but I can see that it could be. There's a set of defog fans behind the panel that circulate air to the windscreen & they do seem to lower the ambient air temp.

Subjectively, I've tested temp difference by removing the 5600 immediately after flight (using & not using the defog fan). Temps "seem" to be lower with defog fan use. I use the defog fans on hot days in Florida.

Best,

Chas
 
I'm doing the same on a G3X retrofit and this post was very helpful. Can you please describe the velcro-like covering for your glareshield with source.
 
My old HP server case fan comes on with the Nav lights and makes plenty of noise but is well drowned out by the engine. I have some larger fans out of some old Lucent equipment, if anyone is interested. These are also available on that e-sales site.

I cut small holes so reinforcement should not be needed and there is plenty of airflow.

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Not sure...

why you didn't stop after the four 1.5" knockout punch holes were done. Seems like they would allow plenty of airflow and obviate any worries about needing a perimeter reinforcement ring. The amount of material you still had to remove to get a full-size circle cutout makes me wonder if the four inside tangent circles you punched really helped the process much, aside from a starting point for whatever tool you used to nibble away the remainder.

Just trying to learn. I will be doing the same, but before I install the forward skin and panel structure, avionics or windshield.
 
To build on Carl's comment - a black dress sock is an excellent source for just the right amount of material to cover such antennas. Who knows, you might even have a "spare" sock somewhere if you're like me! *grin*
 
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