Elevator bungee

[1964-M20E]

Has anyone here ever heard of a procedure that requires adding grease to the elevator bungee? I have in the past sprayed them liberally with LPS-2 at annual verified they are working correctly and moved on.

 

The required procedure is to remove them grease them and the replace them requiring rigging the elevator again. I’m not keen on doing extensive work like this for an annual too much chance of maintenance induced problems.

 

I’m asking because my mechanic is saying it needs to be done at annual. I do not see this in the maintenance manuals.

 

[orionflt]

I do not pull them unless they are not operating properly, I will spray them down with a degreasing type solvent to clean them before relubricating them.

 

Brian

[DS1980]

If it's not in the MM, how is it a required procedure? Was an AD/SB/SIL issued for it?

[N201MKTurbo]

I don't understand the re-rigging. UN-bolt them clean them and replace them, it doesn't change the rigging. If you want to completely disassemble them, just count the number of threads and mark the nut flat that lines up with the tab and put it back to the same position. A lot of work for little benefit.

 

If you are going to do all that you might as well strip and re-paint them. It'll make her private parts look much nicer...

[cliffy]

Unless you change the depth of the threads in the forward Heim joint you won't change the adjustment. The rear nut only tightens on the internal sleeve/bushing that sets a predetermined tension on the double bungee springs. It can be removed , the springs removed, cleaned, lubed and reassembled without disturbing the elevator setting. One could also use a "brake cleaner" spray can to clean the springs without disassembling them. If you live in a dusty area like I do, oil and grease attract dirt. I just use silicon like on the rod ends for the control surfaces.

[N201MKTurbo]

If you did change the length it would only change the yoke position slightly.

If you changed the tension it would change the trim to elevator relationship slightly and make your plane go slightly slower or faster.

[jetdriven]

Unless you change the depth of the threads in the forward Heim joint you won't change the adjustment. The rear nut only tightens on the internal sleeve/bushing that sets a predetermined tension on the double bungee springs. It can be removed , the springs removed, cleaned, lubed and reassembled without disturbing the elevator setting. One could also use a "brake cleaner" spray can to clean the springs without disassembling them. If you live in a dusty area like I do, oil and grease attract dirt. I just use silicon like on the rod ends for the control surfaces.

SMM says use triflow for all the rod ends on a Mooney. It leaves Teflon behind and doesn't attract dust.

[cliffy]

Just to verify what I said, by changing the depth of the rod into the inner (fwd) rod end it will vary the angle that the elevator sits at in relation to the stabilizer centerline at a neutral bungee pressure setting. As is called for in the TCDS, this angle is set at a specific setting of the stabilizer in relation to the center line of the of the fuselage. It will vary for all other settings of the stabilizer.

[Andy95W]

Does anybody know why our older Mooneys have the bungee springs but the newer (long body) Mooneys don't?