bearhawkproject.com Matt Kunkel's Bearhawk Build Log

24Apr/104 hrs

Tail Re-Assembly (corrected), Cleaned Torque Tube Bushings

Today started with the discovery that things were not 100% correct on my previous tail assembly attempts.  The holes lined up laterally, but there was some twist to the alignment around the tube (bolts wouldn't drop though even after removing the primer).  The holes looked like cat eyes or (). I ended up rotating the carry-through tube about the long axis (keeping left=left, right=right) and the holes lined up perfectly.  I had the stab halves on the correct sides, only the mount tube orientation was amiss.  Correcting this made it even harder to get the left stab half on, but removing a little primer build up made it possible.  The right side slips on pretty easily now and I fastened it in place with correct hardware.

I was asked for more info and provided it in the comments but decided to update the post also:

As mentioned in previous posts the stabilizer halves are supposed to be marked left and right.  I cannot find those markings and according to Mark Goldberg they may have been on the inside of the tubes where I  have sanded to remove primer.  The best way to ensure proper stabilizer component orientation is to lay it out on the floor or a flat bench.  The holes will line up and don't just accept horizontal alignment.  Go ahead and drop in the correct hardware.  Also, don't ream out a "cat eye" hole as it will just elongate and enlarge match drilled hole (this is bad).  I ran a reamer through each part individually to get the primer out of the bolt holes.  Even after going through this exercise things were close,  but re-work was still in order because I only looked at the lateral hole alignment and pinned it together with punches instead of real hardware.

Stacey and I finished the day by cleaning primer out of the torque tube bushings (a Dremel tool made quick work of it).  We greased the torque tubes and slid them in place with the bell-cranks bolted on.

Filed under: Empennage Leave a comment
Comments (2) Trackbacks (0)
  1. Congrats, Matt and Stacey! Any suggestions on how other QB users could correctly identify which parts go where or is it basically trial-and-error?

  2. The stabilizer halves are supposed to be marked left/right, however I cannot find it. Mark said it might be on the inside of the tube but I sanded primer out of there so if it was marked, it’s long gone. The carry though tube is marked, but it does not say what’s up and down. Best bet is to assemble on a level bench or the floor and drop bolts in place. Ream the primer out of the holes while apart, not together, so you don’t accidentally drill through when it’s mis-aligned. The holes should line up perfectly both along the tube around the tube.


Leave a Reply

No trackbacks yet.