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Doubler needed for 120mm defrost fans?

sritchie

Well Known Member
Hey folks,

I've decided to install 2 120mm defrost fans in a spot very similar to Brian and Brandi's:

IMG7303-M.jpg


Do y'all suggest installing a doubler around these holes on the underside of the skin? An .032" doubler with a single row of rivets and corner holes for the #8 screws doesn't feel overkill, but a 1" thick doubler like Vans suggests for the radio stack hole DOES feel overkill.

What are other people installing here to support their fans?
 
Pretty large fans. Mine are much smaller, and lighter and don't see any need for a doubler. Don't need to move much air to be effective.
 
Doublers

I installed fans this size in 2 different Slider 9's. Since I wasn't able to do the structural analysis myself (and it is structure) I used the repair patch part of 43:13 as a guide. The doubler was about 1" wide and got a double row of flush 3/32 rivets. Also made my own "grille" by drilling a hole pattern in a square of .032" which will add in a bit of strength as well. If I'm going to go off the plans a little overkill that hardly weighs anything works for me.

Don Broussard
RV9 Rebuild in Progress
57 Pacer
 
I used the 120s and put a 1" doubler in place with flush rivets...

I ended up doing this as well, with a 0.75" doubler to accomodate the fan flange. Here's the result:

19932342_212861152571176_5476164455807057920_n.jpg


It was obvious when I finished sanding out the cut that it needed a doubler. With just the doubler it's nice and still again, and especially with the fan in place it feels great. Thanks all!
 
I also installed 120mm fans in this location. I purchased the mounting plates shown at: https://www.newegg.com/Product/Prod...Infinity_Fan_mount-_-9SIA8J23270009-_-Product

This grill made for a very easy install, and comes with both a very solid square aluminum plate (doubler) and a nice grill to fit the round hole. I used flat head screws to mount the plate, and can either leave it open for natural ventilation, or can mount the fans for forced ventilation which is my intent.
 
No grill, no backing plate option

An option is to not use a grill at all, just drill an interesting pattern of holes in the glare shield instead of one big square hole. This strengthens the area so no backer plate is needed, and eliminates the ugly grill.

Sorry, didn't set up for photos but is anyone wants them PM me your email address.

Carl
 
An option is to not use a grill at all, just drill an interesting pattern of holes in the glare shield instead of one big square hole. This strengthens the area so no backer plate is needed, and eliminates the ugly grill.

Sorry, didn't set up for photos but is anyone wants them PM me your email address.

Carl

+1. This is what I did. No flex in the glare shield. (In the -10 this is best done prior to installing the windscreen, depending on the exact location of the fan).
 
An option is to not use a grill at all, just drill an interesting pattern of holes in the glare shield instead of one big square hole. This strengthens the area so no backer plate is needed, and eliminates the ugly grill.

Sorry, didn't set up for photos but is anyone wants them PM me your email address.

Carl

+2. Drilled some holes for airflow.

r3phY6jl.jpg
 
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