Avionics Cooling on PA24-180

[Frank Brunot]

I recently added an Aspen 2500 System (PDF + 2 MDF's) and a Garmin 430W to my panel. In addition, I already had an STEC 50, 2nd Nav/Com, Xponder, and encoder. Needless to say, I'm now generating a LOT of heat behind the panel. I have a cooling fan for the Garmin 430W, and each Aspen unit has it's own cooling fan built in. The STEC-50 has no cooling. However, the fans are simply drawing in already warm air from behind the panel.

Now, with the warm weather finally here, I'm having problems keeping the units cool enough. Both the 430W and the STEC-50 have "dropped off line" while in flight. Recycling them brings them back online for a few minutes, then they fail again.

My question is this: Does anyone have a suggestion as to how to get FRESH outside air to the space behind the panel? I've called Comanche Gear and Webco, with no results. My one thought is to disconnect the SCAT hoses from the Heat Exchanger to the two firewall mounted boxes, and connect the fresh air scoops directly to them. That gets the fresh air into the interior SCAT tube, where it can be re-directed to the space behind the panel. Normally, the fresh air scoops supply air to floor (pilot's left foot, passenger's right foot).

Any other suggestions, or mods that can be put forward would be of great help. What do you people in the Southwestern US do during the summer months for cooling?

[Kristin Winter]

I am not sure that you need outside air as much as you need air that is not right up under the panel. I would install a three port avionics cooling fan as far away from the heat as reasonably feasible. You might even investigate putting it under the back seat and piping the air forward under the flooring and up to the avionics units.

Have you asked you avionics shop for suggestions?

[Frank Brunot]

Thanks for the suggestion. Although under the rear seat also has "dead" air (wing spar and Baggage compartment bulkhead), moving the cooling fan into the tail cone might just work. Or possibly using the fresh air scoop on top of the fuselage and tapping air from there to bring forward.

Thanks again.