23 November 2013

Wings: Aileron actuation. Bellcrank to aileron pushrods.

Since the torque tube to bellcrank pushrods are aluminum, they could be primed with my usual Stuart System's EkoPrime (reminder, don't use a water-based primer on steel).  For the interiors, I taped off one end of the tubes and all the rivet holes then poured the primer down the tube.  After rolling it around for a while, it was well coated.  Curing took more than a week given the absence of airflow and puddling on the bottom of the tube (every day I'd rotate it 90 degrees to spread it around a bit and mitigate puddling).  This is a key point since the VA-111 Threaded Rod Ends were previously sanded to fit snugly without primer, so a puddle of dried primer on the interior just makes fitting that much harder.

Here's the VA-111 Threaded Rod end prior to riveting.  I took this picture to match the image in the plans.  I used Napa 7220 on the rod ends since it's thinner and more compliant when sprayed on threads (Stuart's can gum up threads).


Given all the primer in the tube's interior, it wasn't an easy task to get the VA-111 threaded rod end in there.  I had to pound it in against my workbench fairly violently.


It's key that the holes are well aligned prior to the pounding, otherwise you're left with trying to rotate a piece trapped by a lot of friction.  This happened to me on one end so I had to use the approach shown below to rotate the piece.


Here are the completed ends.  The MSP-42 rivet manufactured heads conform to the tubes' curvature - not something I expected to happen.  Rod ends need a quick touch-up of primer before final install.

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