Jump to content

Trim Jackscrew Binding


PeytonM

Recommended Posts

On ‎1‎/‎26‎/‎2017 at 7:15 PM, Sabremech said:

Peyton and I will reinstall the trim jack crew assembly in a week or so. We'll report back on it's operation after repair. 

David

Any luck on the reassembly David?  My electric trim would not work for me last night and I suspect it is the same issue.  It works fine on the ground, but would not work in the air.  If you have not reassembled yours yet, would you mind taking some photos to document the process so I can wrap my head around how big of a job it actually is?

 

Brandon

Link to comment
Share on other sites

We just got the jackscrew assembly back from a cleaning and relubing. We will put it back in the airplane early next week and we will take pics. 

Can u move the trim wheel manually? Try it from full nose up; that was the real test for me. I could not budge it. 

Link to comment
Share on other sites

2 hours ago, PeytonM said:

We just got the jackscrew assembly back from a cleaning and relubing. We will put it back in the airplane early next week and we will take pics. 

Can u move the trim wheel manually? Try it from full nose up; that was the real test for me. I could not budge it. 

I can move mine manually, but I can tell it is stiffer than it once was.

Link to comment
Share on other sites

Wow! Those poor bearings back there. Not much help lubing them over the years. I had no idea. Is there a hole to squirt something in the bearing cavity?

I wish I had large tubs of CorrosionX, tri-flow, mouse milk, epoxy primer...

-Matt

Link to comment
Share on other sites

Be careful of the thin shims inside the bearing block when you pull it apart  Make sure they go back in the same way they came out.

And, no there is no way to lube the bearings without tearing the unit down.

As Sabermech says, it's way neglected by most everyone.  

I use a 2X4 to hold the tail hinge open when the jackscrew is removed. Just put the "4" side between the two bulkheads. Holds it fine

  • Like 3
Link to comment
Share on other sites

2 minutes ago, DonMuncy said:

I'm not sure I understood all of what took place. Was it just gunked up and needed cleaning? Was it just old dried up grease that caused the problem.

Yes, it was binding up from old hardened grease. Just disassembled and cleaned thoroughly, then reassembled.

 

Link to comment
Share on other sites

1 hour ago, Hank said:

^^^^^ That's often the case. If yours is tight, that's the first place to check. Then refill it with fresh, new grease, and top it off every annual.

If it's tight, remove it and disassemble it for a thorough cleaning. Adding more grease won't solve the issue completely and may come back to bite you when you really don't want it to. 

Link to comment
Share on other sites

When you fly it try to get it to move to extreme ends of use by slowing down and speeding up. See if it loads up at different tail loads.

Also give it enough time up high where it is cold to see if it tightens up with cold air. Did you use a low temp function grease?

Mine changes torque needed at different CGs and speeds. 

Link to comment
Share on other sites

10 hours ago, cliffy said:

When you fly it try to get it to move to extreme ends of use by slowing down and speeding up. See if it loads up at different tail loads.

Also give it enough time up high where it is cold to see if it tightens up with cold air. Did you use a low temp function grease?

Mine changes torque needed at different CGs and speeds. 

That will be up to Peyton if he wants to be a test pilot for a flight, but I suspect he won't as it's back to how it was when new. Grease used was what was called for in the maintenance manual. 

Link to comment
Share on other sites

The problem we have found along this line lately is binding on the trim box.  Electric trim forces the box into a bind when trimmed for landing. Amelia's was so tight it took a pair of vice grips to free ti.  We have another 231 here now with a similar problem.  When I landed it I used the elec trim to trim nose up and when  taking off again it was near impossible to retrim.  I wonder if it would be possible to adjust more nose up and less nose down into the system.  I never had a problem with too much nose down trim.  Of course if it were loaded nose heavy>>>>>>>>>>>>>

Link to comment
Share on other sites

I finally flew today after AOG for 36 days, but who's counting?  Two hours, four TOs and landings, manually trimming for the whole flight. The trim wheel moves easily & smoothly, with even less effort than on the ground.  A special thank you to David Staffeldt and Jason Doscher. I could not have done this project without these two gents. I learned a lot.

Maybe I'll celebrate with a flight to SnF!!

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.