Originally posted by Mluvara
AV8TOR-
My firewall is actually nomex honeycomb with glass on both sides, 3/8" of an inch thick. It originated from some floorboard in a 747! I have a friend that works at an airline and gets old floorboard material which he gives to me from time to time. Works great for R/C!
I've seen 1/4" or 3/8" thick endgrain balsa with carbon and glass bagged over it on 75 cc motors. Something in that arena is about right.
How big is your firewall dimensionally?
My firewall is 7.5" x 7.25". This is actually a sub-firewall. On these types of planes they have an extra long cowl (I think to allow for custom smoke systems) that requires a stand off box type firewall as well. The glass at the firewall is 1 layer of 3.2 oz. and 2 layers of 6 oz.