Elevator Trim Tab Bushings

[6643]

Deja Vu....

[8434]

Ah shoot, I didn't realize the bushing was captured within the aluminum horn. Looks like someone made a quick fix by drilling my ears to 1/4" and using an AN4.

Thanks for the specs John, I'll make some bushings so when I do replace the horn I have all the pieces.

[6643]

Yeah, otherwise the bushing (or bolt) turns in the horn and wears the hole bigger. The rudder hinges are the same way.

[edidin]

If the AN-4 bolt fits in there then the holes on the trim tab bracket are enlarged. The purpose of the bushing is to provide a surface that doesn't rotate as it is captured between the two ears of the bracket.

IIRC, the dimensions are 0.510 long and nominally 0.250 diameter. Material is steel. It has to be slightly longer than the width of the control rod fork and the diameter is a loose fit in the holes of the fork.

This part is now no-bid, so Cessna furnished dims in case need to make. MIL spec appears to map to AMST6736 for CrMo seamless aircraft tubing. Haven't figured out what oakite is, but presumably appropriate corrosion protection.

S-15-50 Bushing Dims.jpg (61.74 KiB) Viewed 7821 times

[6643]

Haven't figured out what oakite is, but presumably appropriate corrosion protection.

https://www.gracoroberts.com/lubricants ... l-variant/
Only $454.72 for a 16kg pail... (Cosmoline?)

Spray it with LPS-3?

I think that's only to preserve it while it's in storage. Once installed in the plane I'm guessing AN-0-6a general purpose light machine oil is all you need.

You can get 4130 tubing 1/4" OD, 0.028 wall, which is very close (probably close enough) to what the bushing needs to be, or, if you're good with a lathe, get 5/16-0.065 wall tubing and have at it...

[edidin]

Stick of tubing on way. Turn .004'' off diameter, face, and cut off at correct length.

Agree regular lubrication should suffice since it's CrMo.