G3X: GSU25 in enclosed area?

From the G3X installation manual:

"Do not mount the GSU 25 in an enclosed area, it should be mounted in a location that provides adequate airflow"

My question then is - how enclosed is too enclosed, and what is adequate airflow? Is this for heat dissipation from the electronics, or are there other considerations?

Specifically, I considered attaching it to the F-1015B-L (it's a -10), since that's right next to where the pitot/AoA tubes come in from the wing, and that'd save me from running some of the tubes all the way to the panel:

That location is essentially between the skin and another rib, with a panel covering the gap above that rib - shall I assume that this is too enclosed?

Thanks

rdamazio said:

From the G3X installation manual:

"Do not mount the GSU 25 in an enclosed area, it should be mounted in a location that provides adequate airflow"

My question then is - how enclosed is too enclosed, and what is adequate airflow? Is this for heat dissipation from the electronics, or are there other considerations?

Specifically, I considered attaching it to the F-1015B-L (it's a -10), since that's right next to where the pitot/AoA tubes come in from the wing, and that'd save me from running some of the tubes all the way to the panel:

That location is essentially between the skin and another rib, with a panel covering the gap above that rib - shall I assume that this is too enclosed?


Thanks

Click to expand...

Interesting question Rodrigo,
I too don't want to run the 3 lines up to the panel if I can avoid it.
My current plan is to bolt it to the front of the spar under the seats.
Your idea looks interesting provided the airflow is adequate. General wiring congestion in there would also be an issue.
I suspect fresh air circulates via the pushrod holes and the f1005C but I'd be curious as to what others think.

My RV-8 has dual GSU 25s behind the panel as part of the G3X Touch install (put in before G5 existed for backup data). With AOA there are plenty of tubes but it isn't unwieldy even forward of a tandem panel.

If your panel layout includes a G5 then at a minimum pitot and static lines will have to be routed to the panel. Also goes for similar 3rd party mini backup EFISs. Also any alternate static air valves install means static line needs to be routed to the panel for in-flight acess. Finally your local repair station Sparky will want easy acess to your static system during pitot static test and transponder certification.

That doesn't necessarily mean you can't have your GSU near the wing root area; it will save some space but perhaps not save routing pitot/static lines forward of the panel.

Jim

location

I don't think you will have room mounting it in there, if you consider the fittings required for the tubing and the space required for the wiring connectors...

rdamazio said:

From the G3X installation manual:

"Do not mount the GSU 25 in an enclosed area, it should be mounted in a location that provides adequate airflow"

My question then is - how enclosed is too enclosed, and what is adequate airflow? Is this for heat dissipation from the electronics, or are there other considerations?

Specifically, I considered attaching it to the F-1015B-L (it's a -10), since that's right next to where the pitot/AoA tubes come in from the wing, and that'd save me from running some of the tubes all the way to the panel:

That location is essentially between the skin and another rib, with a panel covering the gap above that rib - shall I assume that this is too enclosed?

Thanks

Click to expand...

Regardless of airflow it's a bad idea from a maintenance standpoint, bring that to me for a bi-annual P-S check and I'd probably suggest you find someone else to do it. ALL LRU's should be readily accessible for maintenance.

You can also mount the GSU back by the battery (ADHRS shelf), and run the Pitot/AOA line rearward. The Static line is already back there....

I suspect the note is mostly about temperature. The biggest error contributors to MEMS gyros and accelerometers are temperature effects. So, best to keep them in a benign temperature area. Like the cabin area, not FWF.
But yeah, always be thinking maintenance!