Firewall doubler on engine side of firewall

[ppakotze]

First post here goes:

Are there any special considerations when mounting a firewall doubler on the engine side of the firewall?

I want to make one large doubler for the MGL RDAC which will also be mounted on the engine side. Doing this will allow me to fix the doubler to one of the stiffeners.

If I make a doubler for the inside I will have to split it intwo smaller ones because of the stiffener running through them. Will also be less sturdy because I won't be able to easily connect to the stiffener.

Regards
P.

[rzbill]

You may notice in the plans that the majority of firewall mounted items designed by Vans are somehow connected to the framework behind the firewall.

If the device you want to mount is heavy, you may want to add some structure (over and above a doubler) that is integrated to the rest of the aluminum angles.

[aerhed]

I know it helps minimize penetrations, but I wouldn't put the RDAC in the engine compartment. Heat and oil can't be good for it. I know it's recommended in the manual, but I think Ranier's point of reference is sort of LSA.

[Mike S]

Originally Posted by ppakotze

First post here-----------



Regards
P.

Pieter, welcome to VAF

[Beancounter]

Pieter
Please consider mounting the RDAC cabin side. I did, and it avoids having to make an enclosure to protect it from the elements. I didn't incorporate a doubler as the unit is light weight.

[scootwoot]

I mounted my RDAC on the engine side, the cowl is the enclosure protecting it from the weather. I have had no issues. I also didn't put any doubler, it is light.
The reason to put it on the firewall side is to prevent you from having you run all the engine sensor wires through the firewall.

Bill

[ppakotze]

Thanks for the feedback and opinions.

My main concern is not the RDAC itself, but the use of a doubler on the front of the firewall. Any special precautions because it is more exposed? Any issues with the nutplates now being riveted on the stainless steel firewall rather on a doubler inside the cabin?

What is also attractive with the doubler on the outside is that I can countersink the doubler and don't have to dimple the thin firewall. Agreed?

Regarding the RDAC. I agree it might not even need a doubler and might be cleaner and more comfy inside the cabin. I am working on a partial completed plane and is guided (constrained) by what has already been done.

However my thinking on the RDAC doubler and position is as follows:
1. That firewall is thin, I like the idea of adding a doubler it removes doubt on my side even if not needed ( a bit like my wife taking the kids to doctor to tell her everything is ok even if I already done so).
2. Having the RDAC itself on the engine side is convenient for wiring and in my mind also keep one more electrically noisy thing behind a metal wall.
3. The RDAC will be mounted in a small enclosure, certainly not waterpoof but enough to provide a little extra protection from heat and fluids.

Thanks for the warm welcome

Regards
Pieter

[terrykohler]

No special considerations.
Terry, CFI
RV9A N323TP