RE: Diving on downwind?
I found the firewall is able to flex when I grab the engine and move it. Haven't pulled the cowl off yet to determine the exact cause. Partly, the design has, I think, a weak link in that the firewall is open on the top with a long ABS cockpit sitting on top. Would changing the downthrust/sidethrust cause this problem, if the prop is 'loading' and unloading?