bearhawkproject.com Matt Kunkel's Bearhawk Build Log

24Oct/106 hrs

Counterbalances, Tube Plugs, Trim Tab Hinges

I finished trimming the elevator counterbalances so they are fully recessed within the tubes (won't create bulges in the fabric).  Most of this had been done previously, a little touch up today.

 

The elevator halves were hung with the requisite 1lb weight at 7.5" from the hinge line (as calculated by Russ Erb and verified by other builders).  I drilled the weight until it is just slightly heavy.   An inspection cover over the weight will allow for final balance after covering/finish if necessary (I could add weight too by filling one of the drilled holes with epoxy/shot slurry).  According to the manufacturer and other users, Stewart Systems tends to come out light, so I will likely have to trim the weight further.

 

I also trimmed the epoxy/microballoon tube plugs around the trim tabs and added a little in places where the epoxy ran.  Lastlly, I finished reaming the trim tab hinge tubes to accept a 3/16 hinge pin.  There was quite a bit of welding flash in the hinges and some were mishapen or mis aligned..  I used a drill bit brazed onto a rod for some of the work.  I used a reamer for other parts where the drill bit wasn't making a nice round hole.  To finish things off I assembled the hinge tabs with a 3/16 reamer in place of the hinge pin and rotated them a few times.  This made for a nice snug fit on the hinge pins.

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