Aileron friction?

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soarer20
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Aileron friction?

Post by soarer20 »

DA-20 Aileron circuit has developed lots of friction out of no where. The Diamond maint manual points to a possible bad bearing somewhere.

Any advice on tracking down the source of the friction and fixing it? This seems like it could turn into a big project.
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Karl
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Re: Aileron friction?

Post by Karl »

The bearings most likely to be the cause are the ones where the controls connect to the ailerons. Disconnect them, one at a time, and see if anything improves. As it is flight controls I would suggest you get the help of an aircraft technician.
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soarer20
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Re: Aileron friction?

Post by soarer20 »

After disconnecting both ailerons from the bell crank, the friction seems to be isolated to the aileron controls inside the fuselage.

1. Right control stick pushrod rod end bearing is nearly frozen.

2. Nylock was very tight connecting bell crank to aileron push rods. This is the connection under the fuel tank. Most likely over tightened when the wings were reinstalled after an inspection.

3. Both pilot and copilot control stick pivot nylocks were very tight. Also found a split shim washer on the pilots control stick.

A&p doesn’t think the Rod end bearing would create the friction.

The system is very simple, diamond used bushings, shoulder bolts and nylocs.

I’m ordering a rod end bearing and new nylocks to replace the ones we removed. A&p is supervising the work and will do the final tightening on the nylocks.
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Aileron bell crank to aileron push rods
Aileron bell crank to aileron push rods
Right control stick Rod end bearing
Right control stick Rod end bearing
BAF6E01C-FC09-438A-8F76-EAAF6661203E.jpeg
Left control stick shim washer and nyloc
Left control stick shim washer and nyloc
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krellis
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Re: Aileron friction?

Post by krellis »

I think you should replace the bolts as well. If they were tightened so much as to bind up the pushrods and bearings, they may have been weakened. AN3 bolt torque is surprisingly low (like 20-25 lb-in, plus the drag of the nyloc). I also suggest that you try to source the bearings from Aircraft Spruce or similar - they are probably just Aurora bearings, so why pay the huge Diamond markup if you can avoid it?
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