Picking this up out of another thread;
Heavy items often need more support than the firewall skin alone can support so here is one method that I used on a battery box.
I used some 1/8x 3/4 aluminum strap for a backup on my firewall The nut plates for the battery box attachment are in those straps. The straps are bolted to the firewall. The lower strap is supported to the air frame with a couple of cushion clamps around the cross tube of the fuselage so that the weight of the battery is carried by the fuselage tubing rather than the thin firewall material.
Smaller items, like the master relay, have a 1/16" aluminum doubler with nut plates riveted to the firewall from the backside.
Heavy items often need more support than the firewall skin alone can support so here is one method that I used on a battery box.
I used some 1/8x 3/4 aluminum strap for a backup on my firewall The nut plates for the battery box attachment are in those straps. The straps are bolted to the firewall. The lower strap is supported to the air frame with a couple of cushion clamps around the cross tube of the fuselage so that the weight of the battery is carried by the fuselage tubing rather than the thin firewall material.
Smaller items, like the master relay, have a 1/16" aluminum doubler with nut plates riveted to the firewall from the backside.
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