A friend of mine recently purchased an RV-4 and after getting it home and further inspection, we've discovered his airplane is missing a part that mine has... It's the fillet between the fuse/cockpit area and the tailcone of the airplane.
I went back, looked at my set of plans and sure enough, there it is, F-466. My question is, how many (if any) RV's are flying around out there without this? Is is structural or purely a cosmetic/aerodynamic piece? My RV-4 does have this F-466 piece and it seems to have 15+ rivets holding it on making me wonder if it's structural. If nothing else, it gives my friend and I a reason to bend some sheet metal and learn some building techniques.