11th September 2009

Pushrods & bellcranks

Hours: 6.2 | Posted in Ailerons

Spent some time monkeying with the internal workings of the wing.  Reamed the bellcrank bushings and turned them down to the proper length, then assembled both bellcranks.  Some of the bolts that came with the autopilot servo install kit are too short, so it looks like I will need to order a few longer bolts…add to the list.  I also need to look up what an appropriate grease is for the bellcrank bushings–the manual says “your favorite multipurpose grease.”  The stuff I have says it is rated to -20F.  Presumably, the possibility exists that the thing could be colder than that at altitude, so is it appropriate?  (Of course, my truck is lubed with the same stuff, and has worked fine in temps colder than -20F…)  I’m sure there’s a common aviation grease of some sort for this purpose, too.

Assembling aileron bellcrank

Cut and drilled the pushrods, making them a bit longer than plans, as I’ve heard of some people wishing they had, when they had a hard time obtaining the required amount of thread engagement on the rod ends.  After dosing the insides with primer, I assembled the short steel pushrods (riveted per plans), but the longer aluminum ones still need to be primed & riveted.  Also had a bugger of a time locating the jam nuts for the rod ends (hint: look in the bag marked “spar bolts & misc”).

Drilling long aileron pushrods Fabricating short aileron pushrods

Temporarily put the bellcranks in the wings (I didn’t realize before that the bellcrank brackets had to come out, as the center bolt is too long to insert with the bellcrank in position.) and set the pushrod length using the straightedge aligned with the tooling holes and the bellcrank alignment tool.  I’ll have to get the protractor out and see if there is enough aileron travel the way it is, or if the spar pushrod holes need to be relieved to allow more clearance; the pushrod swings up/down and in/out as it moves through its travel.

Left bellcrank in wing Left pushrod-aileron attachment (not tightened in photo) Right aileron bellcrank in wing

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