Aileron Bell Cranks (2)

2 hours

On to the aileron bell cranks, which will attach to each #9 aft wing rib that I started a while ago.  The first step was to press the bronze bushings into each bracket.  The holes are way to small to start with, so I drilled them up to the closest size I could and still have an interference fit.

The bronze bushing OD is 0.440"

My closest drill bit (marked 27/64") measured 0.435"

The bushings still seemed a little tight to just force in, so I put the bushings in the freezer for a little while, and heated up each bracket with a heat gun just prior to installing.  They went right in with a few good whacks with the rubber mallet.

The next step was to get these steel bushings to go through the bronze bushings and spin freely but without slop.

The steel bushing OD is 0.314"

The bronze bushing ID is about 0.309"

The steel bushings initially didn't fit at all.  I tried reaming the bronze bushings to 5/16" (0.3125"), but they still didn't quite fit.  After some messing around I finally tried drilling the bronze bushings out to 21/64" (my bit measured about 0.325").  This allowed the bushings to finally fit and turn freely, but there is a tiny bit of play in the fit.  I'm going to have to do some research and see if it's too much play or if it's OK.  Worst case I'll have to replace the bronze bushings!

The RH bell crank turns a lot more freely than the LH, but I can make them even by shimming and/or sanding down the spacer blocks between the brackets.  I'm more concerned about the radial play between the bushings though.

Here's a video showing the RH first, then the LH:

Anyway, some adjustments required still, but here's what they'll look like on the ribs: