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Cooling for avionics

Jetspud

Member
Just got my Rv 4, i have been flying and it seem the avionics really dont have any cooling air. The "dashboard" were all the steam gauges are gets very warm to touch. I was thinking of putting a naca inlet on the avionics hood, the piece you can take off to see all the avionics.

What do yall think

David
 
Rain

FAR from an expert but I would worry about flying thru rain ....water and electronics seem a bad mix . I know NACA duct is good but invariably going to get water in there I would think . I think some small strategically placed computer cooling fans might be better . Just my two cents. Cheers. Stew
 
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NACA below cowl cheek.

I have a NACA vent below both cowl cheeks with the nozzle put right on back of NACA and no SCAT hose up to panel. I get massive air flow from down by my knees that cools me and the panel backside. I don't recommend any cooling vents "above the water line". i can reach the vents to open/close with out any problem. I also put a NACA under the right wing skin (RV-8 plans) and routed rear seat air through the stick tunnel. No overheating in my cockpit!.
 
Two options:
- Add cooling air or
- Remove heat

The easiest thing to do is add a “defrost fan” on the glare shield. Use a ~3”x3” 12vdc fan mounted to the bottom of the glare shield. Drill a nice hole pattern on the glare shield for air to pass - a separate screen is not required or desired. I typically do a symmetric pattern of 1/4” and 3/8” holes. For the RV-8 I use one fan, for the RV-10 I use two. A box of 10 fans cost me ~$20.

Even with the fan off you will have heated air leaving the area behind the panel. It also works well on those few high humidity mornings when you need some defrost.

Carl
 
Did the same thing as Carl on my -7. There is no cooling to the avionics but the fans pull the warm air out well. On cool, humid mornings as soon as I turn the master on the fans keep the interior of the windscreen from condensing. They are wired directly to the master BUS. No reason to turn them off. On a 1A fuse.
 
Instead of bringing cooling air in from outside, you can create a small negative pressure behind the panel and use that to exhaust cabin air through the panel for cooling.

I am going to put a small reverse NACA inlet with a small tube to scavenge air from behind the panel. That will hopefully also keep any smoke and fumes from any electrical problems out of the cockpit, or at least reduced.

Big airplanes use the same logic.
 
No room ?

Many great ideas here .....I like the Defrost fan idea but sadly I believe RV4 has no room for such with tip over canopy ... would be different with RV8 fixed windscreen
 
Doesn't the RV-4 tip-up canopy leave the bootcowl/glareshied in place? Unless your particular RV-4 tip-up canopy has a glareshield overlay built into the canopy frame itself. The whole top of the boot cowl comes off with a couple of dozen screws providing total access to the back side of the panel and would facilitate installing a muffin/computer fan underneath. The very fact the skin comes off means a nice neat pattern for the fan could be drilled in it on the bench.

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