Trim wheel tough to turn in one direction

[OR75]

the trim wheel on my J model is very easy to turn in one direction (trim down) but harder to turn in the other direction.

Anyone experiencing or observed the same ? how did you solve ?

thanks ...

[jetdriven]

We get it too. Its harder to move in the "nose up" direction. Part I think may be the design (it physically lifts the whole tail), and part of it is keeping that trim jackscrew in the tail lubricated every 100 hours.

[201er]

and part of it is keeping that trim jackscrew in the tail lubricated every 100 hours.

Care to elaborate? Is this easy to do DIY?

[jetdriven]

Yes it is. Pull off the tail strip fairings that go between the tail and the fuselage. Then take a very small phililps screwdriver and remove the two tiny screws that hold the boot on the tail pushrod inside. Then pull the boot back, run the trim all the way "nose up". This exposes the jackscrew. Take a small brush (I use the cheap, throwaway acid brushes from Harbor Freight) and liberally wipe the jackscrew with the Dukes actuator grease (You are greasing the actuator every 100 hours, aren't you?) , or Aeroshell Grease #7 as called for in the SMM. Cycle the trim full nose down, then back up to distribute the grease into the jackscrew assy. Then repeat 4 or 5 times more.

Ours got so stiff the electric trim was laboring to move it, and the manual wheel was damn near impossible to move. Your pilot wife / co-owners / and/or electric trim motor will thank you.

[larryb]

I had a similar problem with the pillow bearing in the tailcone near the electric trim motor. Access is through the battery access panel. Trim was hard to turn in both directions. One day it was fine, next day super-stiff. My shop used a little tri-flow spray and it was good to go again. They thought it was the jackscrew also, but in my case the problem was further forward.

Larry

[OR75]

thanks Jetdriven and Larry.

getting to the jackscrew seems easy enough. i am guessing what you call the boot is the "duct, flex instl" in the parts catalog ?

i am thinking that greasing the screw that is under the trim wheel may help too. but that's a pain to get too so i will leave that for next annual.

thanks again

[Marauder]

The upward movement of the trim wheel is definitely harder than the downward. One thing to keep an eye on is if the wrong grease was used. When I had my autopilot installed with electric trim, it faulted. We discovered that the grease in the mechanism had actually hardened causing increased resistance.

[Jeff_S]

That's funny. The thumb switch on my yoke doesn't seem harder to push in one direction than the other. And my auto-pilot auto-trim has never complained. Oh, wait...you mean there's a manual trim wheel somewhere? Like in my old Warrior?

Who'd a' thunk!?

[N201MKTurbo]

If you want to really do it right it is not that difficult to remove the whole jackscrew, disassemble it and completely clean and re-lube it. It will make a huge improvement in your trim system.

First remove the two fairings that cover the gap in the tail and the access covers forward of the gap. Remove the belly panels to access the bottom of the trim wheel.

Run the trim wheel to the nose up stop. Accurately measure the distance between the bottom of the tail and the fuselage, you will use this measurement to re-calibrate the trim.

Loosen the boot and remove the bolt that holds the trim link to the jackscrew.

Remove the cotter pins and clevis pins from the universal joint on the torque tube just behind the trim wheel.

If you have electric trim, loosen the two bolts that tension the chain and remove the chain from large sprocket. Just let the chain hang loose around the torque tube.

Slide the entire torque tube assembly towards the front of the plane, disengaging the square coupling at the back of the jackscrew.

Remove the two bolts holding the jackscrew and slide it out towards the front of the plane.

Completely disassemble the bearing holder and remove the bearings.

Remove the snap rings holding the bearing shields, remove all the balls from the bearings, clean and reassemble with Aeroshell 7.

Clean the jackscrew, working it back and forth in the solvent until it is completely clean, dry with air and then work as much Aeroshell 7 into the screw as possible.

Reassemble in the reverse order. After the jackscrew and torque tube are reassembled, make sure the trim wheel is at the nose up stop, rotate the end of the jackscrew with your fingers and trial fit the link until the gap measurement matches the original measurement and then reassemble the link.

Put your plane back together and marvel at how well your trim works!

[Marauder]

That's funny. The thumb switch on my yoke doesn't seem harder to push in one direction than the other. And my auto-pilot auto-trim has never complained. Oh, wait...you mean there's a manual trim wheel somewhere? Like in my old Warrior?

Who'd a' thunk!?

LOL! I had to find mine again once when the CFI faulted it during a BFR one year.

[N201MKTurbo]

I have electric trim, I only use it for big moves, the wheel is a lot more accurate.

[OR75]

electric trims are not un-common on Mooneys.

if the trim wheel is hard to turn, it may become an issue and I prefer not to hide it behind the electric trim.

[jlunseth]

Also check the simple. There is very little clearance between the bottom of the wheel and the floor, especially if there is carpet. It is possible to get something on the floor and under the wheel that partially or fully binds it in one or both directions. Or something on the sides of the wheel.

[FloridaMan]

There was a fatal accident with a high time Mooney pilot in (I think) Massachusetts a couple years back. No clearly-defined cause was found, but the jackscrew was cited in the accident report as a possible factor.

[201er]

I have electric trim, I only use it for big moves, the wheel is a lot more accurate.

I agree. I end up only using the electric trim on landing or go around but prefer the manual trim all around. However, the electric trim is a life saver on approach cause it allows me to use my right hand to lower flaps while simultaneously keeping my left hand on the yoke while running the electric trim to adjust for flaps. Likewise on a go around I can keep my hands on stick/throttle while retrimming with electric. For takeoff, level off, and cruise, the manual trim gives much better feedback and seems better to use.