Last weekend, my Hangar 9 F6F Hellcat crashed when the firewall separated from the fuselage. Once the wreckage was recovered, to my surprise, the firewall was hot glued to the fuselage instead of being epoxy. Therefore, you may want to reinforce the firewall to the fuselage. I must agree, that the Zenoah G20ie is the right engine for this airplane. The Hangar 9 F6F Hellcat is a smooth flying airplane. I really enjoyed flying it.