moving the firewall back on a CG Ultimate..?
ALL the cabane mounting points need to be beefed up. I learned this on my first one. It's very easy if you simply put a small patch of 1/32 ply on both sides of the mount point. This includes the ply ribs and the fuselage. I also added a short piece of triangle stock under the fuselage points and omitted the lightening holes in the ply ribs. For a 150, it would not be a bad idea to beef up the firewall attachment. I used a 1/2" wide strip of lite-ply to double the fuselage sides where the firewall attaches. Do not use CA to attach the firewall. Use a nice sloppy layer of epoxy and scrape off the excess. You can also run a layer of glass all around the firewall/fuselage joint. That's what I did on my Sukhoi. I also omitted the firewall lightening holes for strength and to better accommodate my engine mounting system.
Later