Trim wheel very hard to turn

[leesh]

I just bought my new 1967 M20F and flew it back from West Palm Beach, FL to western Massachusetts this Tuesday (with a CFI for my transition time). Overall, I love the plane so far, but there are a number of little squawks as might be expected. One thing that concerns me is that the trim wheel is hard to turn and gets much harder at higher airspeeds. I found myself wishing i had a pair of gripping gloves on, since it took all my strength to turn it to trim for cruise. I really don't like the metal wheel.

Is this normal for the Mooney?

One thing that may be related is that apparently had a Brittain AP in it at one point. The seller indicated that the guts were still there, but it didn't have Brittain head. I was wondering if that could be causing resistance somehow.

Thanks,

Alisha

[MooneyMitch]

Hello Alisah.

I would certainly recommend you have the situation looked into by a knowledgeable Mooney service person, whether that be a Mooney Service Center or another shop that is quite well versed on Mooneys.

In my opinion, it could be from lack of lubrication at a few key locations along the trim system, including the worm gear located between the fuselage and the empennage.  Just a suggestion to you and welcome to the Mooney world.

Mitch

[N33GG]

My 1968 C-Model trim wheel is feather light.  Couldn't be easier to turn.  Get your aircraft checked out sooner than later.

Congratulations on buying an awesome aircraft, and good luck.  Let us know what you find out.

[GeorgePerry]

Quote: leesh

I just bought my new 1967 M20F and flew it back from West Palm Beach, FL to western Massachusetts this Tuesday (with a CFI for my transition time). Overall, I love the plane so far, but there are a number of little squawks as might be expected. One thing that concerns me is that the trim wheel is hard to turn and gets much harder at higher airspeeds. I found myself wishing i had a pair of gripping gloves on, since it took all my strength to turn it to trim for cruise. I really don't like the metal wheel.

Is this normal for the Mooney?

One thing that may be related is that apparently had a Brittain AP in it at one point. The seller indicated that the guts were still there, but it didn't have Brittain head. I was wondering if that could be causing resistance somehow.

 

the trim system has not interconnetion with the Brittain and the trim wheel should be able to be adjusted with two fingers.  Get it checked soonest.

 

[N201MKTurbo]

Here is what you (or your mechanic if you are not one) need to do;

Run the trim all the way nose up and measure the distance from the tail to the dorsal fin, should be about 1/4 inch. You will need this measurement to get the rigging right when you re-assemble everything.

Remove the clevis pins in the trim torque tube just behind the trim wheel gear box. Slide the tube back till it comes apart then forward till the square coupling in the jackscrew come apart.

Remove the screws to the forward end of the jackscrew boot, slide it back and remove the bolt connecting the jackscrew to the link. Remove the two bolts holding the trim jack screw in place and remove the jackscrew.

Disassemble the jackscrew noting the orientation of the end plates and the shims. Remove the circlips from the bearings, the bearing shields and the balls. Clean everything thoroughly. pack the bearings with grease. Work as much grease as possible into the screw threads, working the screw in and out and applying grease until it will not take any more. Wipe off any excess grease and reassemble.

Bolt the jackscrew back into the tail, connect the link and the boot.

Clean the square coupling and apply a thin coating of grease.

Spin the trim wheel, it should spin freely, if it is stiff it will need to be cleaned and lubricated also, but first just clean and lube the chain and see if that fixes it. If you disassemble it don't remove the stops on the screw.

Spin the trim wheel to the nose up stop, turn the torque tube until the tail to dorsal fin measurement is the same as when you started. re-connect the torque tube to the gearbox.

Your trim system should work great!

[MARZ]

Although I doubt it would not have it done already there is a service bulletin addressing the trim wheel on our vintage birds as well (I own a 66/67 F as well) the SB number is M20-154 - Retrofit of trim wheel sprockets.

More than likely it's as others have suggested - a bit of cleaning and lube does wonders.

All of the service bulletins can be found at this link http://www.mooney.com/servicepdf/index.php

Welcome to the family!!

 Don't forget to post some Pictures!!

Mike  

[piperpainter]

I have noticed in my airplane that in the winter when its cold, or at altitude when its cold it can sometimes get harder. Then when I get down in warm air the trim wheel moves no problem. But I will say that I just had my annual and after I greased all the blocks from the tail to the trim wheel it was much easier. So as stated above....lube!

[Mooney13]

Hi Alisha,

Please take your new Mooney to  a qualified and knowlegeable  Mooney mechanic.  Do not have anyone disassemble your trim system unless they have current manuals and the correct Mooney travel boards for setting and adjusting the trim system.  To allow other wise may lead to an acident.  Disassembling and reassembling the trim system as described in another post assumes that it is or was correct in the first place.

Like so many other Mooney's your's most likely simply needs a bit of attention. Your trim wheel should be operable with the tip of your middle finger while holding a bit of back pressure on the yoke.

Clarence Beintema

Tri-City Aero, MSC

 

[leesh]

Wow! This forum is a wealth of knowledge. Thanks guys! I really appreciate the recommendations. I'll definitely get it in to have it checked out.

Alisha

[Lionudakis]

Hmm, I just checked my trim out during annual, its very tight, the 'driveline' to the tail turns with no effort at all, the trim wheel and gears are another story, Does anyone know if there's parts avail such as bushing for the gear shafts? I didn't see any parts break down in the ipc..... Thanks in advanced !  awesome site.....

[Alan Fox]

I spent a huge amount of time on my b model with the same problem... Here is what we found....  After disassembling and cleaning and and lubing the jack screws in the tail and the wheel , we still had the same problem ... It ending up being a stiff universal joint in the tube up near the trim wheel assy , when we lubed up and freed the u joint the trim was fine ...Wasted a lot of time on that one , hope this helps!! 

[Gilt]

Also by the Trim Control Wheel you should find a friction screw (if thats the name of it)... I need to tighten mine, climbing its turning on its own.

[Lionudakis]

Got it all cleaned up, greased, reinstalled. She feels like new !!

 

No friction type of screw on mine though...

[INA201]

Anyone have a recommendation for a mechanic that would be familiar with our Mooney trim systems near upstate SC? Mine is pretty stiff and I would like it gone through. I've heard mention of a guy at KEHO or KMRN but can't remember.  Thanks in advance.

[carusoam]

The trim screw at one end to the gear box at the other end collect grease for years.  The grease hardens over time and causes the trim to be difficult to operate.  Have your mechanic start in the tale cone inspecting the screw...

This is from the memory of an old PP.

Best regards,

-a-

[Marauder]

Anyone have a recommendation for a mechanic that would be familiar with our Mooney trim systems near upstate SC? Mine is pretty stiff and I would like it gone through. I've heard mention of a guy at KEHO or KMRN but can't remember.  Thanks in advance.

PM Bob Belville on this site. He is based at KMRN and is pretty happy with his mechanic.

Your problem is most likely the grease as Anthony points out. I had mine disassembled and re-greased a few years back for the same reason.

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[1964-M20E]

There are more forces on the tail and trim system at higher speeds.  On the ground I can use a single finger to roll the time wheel completely nose up and nose down however during descents at 180mph IAS it is harder to adjust.  MY $0.02

[Bob_Belville]

19 minutes ago, Marauder said:

PM Bob Belville on this site. He is based at KMRN and is pretty happy with his mechanic.

Your problem is most likely the grease as Anthony points out. I had mine disassembled and re-greased a few years back for the same reason.

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We removed, cleaned and put new grease in the "gearbox" below the trim wheel on my '66E a month ago @ annual. The old grease was very old. I suggest you call Lynn Mace @ AGL Aviation Services - KMRN. 828.216.6482 828.391.8645 lynn@aglaviation.com.

Belly access panel(s) have to be removed, front seats and floor covering have to come out. The actually work on the trim is not that big a deal but that gear box needs to come off and be opened up which is why, I suppose this system get neglected. 

[INA201]

Thanks Bob.  Is Lynn the type guy and is this situation where I could fly up and work with him to get it done in a day then fly back.

[Bob_Belville]

3 minutes ago, INA201 said:

Thanks Bob.  Is Lynn the type guy and is this situation where I could fly up and work with him to get it done in a day then fly back.

Absolutely. (Assuming it is just a lube problem and no parts are needed which I would think is the most likely situation.)

In fairness, I point out that you are about as close to Dalton GA where Joey Cole is a highly regarded MSC. 

I really like Lynn though.

[Guitarmaster]

On December 16, 2010 at 7:22 AM, leesh said:

I just bought my new 1967 M20F and flew it back from West Palm Beach, FL to western Massachusetts this Tuesday (with a CFI for my transition time). Overall, I love the plane so far, but there are a number of little squawks as might be expected. One thing that concerns me is that the trim wheel is hard to turn and gets much harder at higher airspeeds. I found myself wishing i had a pair of gripping gloves on, since it took all my strength to turn it to trim for cruise. I really don't like the metal wheel.

 

Is this normal for the Mooney?

 

 

One thing that may be related is that apparently had a Brittain AP in it at one point. The seller indicated that the guts were still there, but it didn't have Brittain head. I was wondering if that could be causing resistance somehow.

 

 

Thanks,

 

 

Alisha

 

I have the same issue.  In addition, i couldn't get enough down trim at high speeds.  After cleaning out the "booted" part of the jackscrew, I got the full range back.  Now it gets stiff at high speeds.  This will be attacked in the annual next month.

What you are seeing below is chunks of hard grease creating an artificial stop.

Photos_Library.photoslibrary.zip

Edited January 14, 2016 by Guitarmaster

[mike20papa]

There could be several issues...work with your mechanic.  Okay, now that thats been said... Remove the inspection panels at the rear of the fuselage and inspect everything for obvious wear.  Then lift up on the rear of the tail cone and see how much "play" there is.  1/8 inch or so?  Then check the leading edge of horiz. stab at tip for fwd/aft play - SHOULD BE ZERO!  Then remove the AN4 bolt that connects the ACME screw to the tail cone bracket - but have some padded/stable means available to support the tail cone when bolt removed.  (2 person job) Now, lift up on the tail cone and check for binding, free movement, etc.  Now...very important!  DO NOT ALLOW the connector on the end of the ACME screw to rotate (or you will loose the trim reference)..while someone rotates the trim wheel.  Does it bind, move freely.  It should.  Now start chasing down the source of the resistance...either in the empenage/tailcone pivot hinges..or in the trim wheel assembly all the way to the acme screw.  The hinge pivots for the tail are hard to access.  Get a bottle of triflow with the long tube and dose the pivots - along with all the ball joints, etc. 

Also, before you start, sit in the cock pit, pull back all the way on the yoke and see if that helps with rolling the trim wheel "nose up" it should.

[Yetti]

My u joints had that yellow hardened grease on them.  I got some of them Shell 6 grease, but not all.   It helped

[cnoe]

Here's a question for those of you with aerodynamics expertise. And if anybody else wants to chime in your comments will be noted.

Does anybody know "how much" downward force is applied to the horizontal stabilizer during level flight at cruise? And do you believe that said force is "less, equal, or more" than the weight of the tail assembly itself?

My observation has been that when trimming the tail on the ground using the electric trim it seems to struggle just a bit when trimming up because it is effectively "lifting" the weight of the tail. But when trimming down the weight of the tail "assists" the motor.

So the reason for my question is this...

I can't "hear" the trim motor in cruise and I'm wondering if it is still struggling when trimming up, or whether the aerodynamic forces on the tail might lessen the load on the motor.

Any thoughts on this?

[Yetti]

It's a wing, it's flying so would not lift, drag and weight be in play.  If the tail cleanly separated from the plane in flight  I would think it would go up first before down.