I was having problems stripping out the inside of the umbrella gear on the main frame end of the tail boom. It looked like the spline on the drive tube was not fully engaging the internal splines there. Because I only saw this on the main frame end I focused on that when trying to find how it was happening. But, I could not find why it would do that. then last night I crashed (got way too brave) and
knocked the tail boom off. When I replaced the boom tube I found what you see int he photo. I had not gotten the tube seated all the way int he metal housing at the tail rotor. I found a small burr that was stopping the tube from going all the way in. I cleaned the burr out, installed a new tail boom tube and all is fine.


