Tail Free Play

[Mark942]

I have a 64 M20E.  I've owned it four years now and since day one, there is about a half inch of free play if I lift up on the tail cone during pre-flight inspection.  I asked my first AP if that was normal and he confirmed that it was, but to just keep an eye out that it didn't increase.  The plane flies hands off.  When on autopilot and in altitude hold it is rock solid.  Just finished my fourth annual and nothing has changed but I have a new AP. I asked him what he thought and he said he just didn't know.  We did not change anything but I wanted to ask the group if this is normal and okay.  If the play should be taken out, is it done by tightening the two nuts at the very end of the tail to take clearance out of the "what looks like" bungees in a tube" at the end of the tail.

Thanks everyone,

Merry Christmass

[PT20J]

Here’s some info

https://www.knr-inc.com/25-shoptalk/34-200103-free-play-in-the-mooney-tail

Skip

[EricJ]

There should be free play specs in the maintenance manual for the E model.   For my J the allowed up/down spec at the rudder is only 0.08", so much less than what you're describing.  It may be worth looking into where the play is coming from.  

 

[N201MKTurbo]

I seem to recall the limit is 1/4 inch. 1/2 inch seems like a lot. It isn't going to be a safety issue until you wear clean through the threads on your trim actuator. There are a number of places to check to reduce the slop.

• The bolts, bushings and link that connect the screw to the airframe.
• The shims in the trim screw. Make sure the bearings don't move back and forth in the block.
• The screw itself. Wear in the screw threads and nut leads.

See past posts about how to easily remove and replace the screw without losing the adjustments.

Edited December 14, 2021 by N201MKTurbo

[N201MKTurbo]

1 hour ago, Mark942 said:

I have a 64 M20E.  I've owned it four years now and since day one, there is about a half inch of free play if I lift up on the tail cone during pre-flight inspection.  I asked my first AP if that was normal and he confirmed that it was, but to just keep an eye out that it didn't increase.  The plane flies hands off.  When on autopilot and in altitude hold it is rock solid.  Just finished my fourth annual and nothing has changed but I have a new AP. I asked him what he thought and he said he just didn't know.  We did not change anything but I wanted to ask the group if this is normal and okay.  If the play should be taken out, is it done by tightening the two nuts at the very end of the tail to take clearance out of the "what looks like" bungees in a tube" at the end of the tail.

Thanks everyone,

Merry Christmass

Tightening the nuts in the bungees is a bad idea. At the very least it will make your plane slower, at worst it can restrict the elevator travel. You should put them back where they were. 

[Skates97]

There is a bushing and a bolt where the jack screw attaches to the tail. Over time it will get wallowed out and allow more and more play. Remove the covers on the sides to expose the hinge and the jack screw. Have someone lift up and down on the tail and watch what moves. Pay attention to where the jack screw attaches and you will likely see play there. You can get the bolt and busing from Lasar. After letting it go for a number of annuals my AP/IA finally decided he wanted to have it replaced so we did that a year ago.

[David Lloyd]

Part 38, the trim link will wear adding to the slop.  $450 or so for the bolt bushing and link.  

[N201MKTurbo]

33 minutes ago, David Lloyd said:

Part 38, the trim link will wear adding to the slop.  $450 or so for the bolt bushing and link.  

Holy crap, the last time I bought that stuff, was about 2003 and it all cost about $120!

[Skates97]

48 minutes ago, David Lloyd said:

Part 38, the trim link will wear adding to the slop.  $450 or so for the bolt bushing and link.  

Part 38 for reference.

[StevenL757]

49 minutes ago, N201MKTurbo said:

Holy crap, the last time I bought that stuff, was about 2003 and it all cost about $120!

Yeah, true.

Today, they give you the Covid-enhanced reverse-discount.

[Browncbr1]

I have an extra link, bolts, and bushing on the shelf if needed.  It’s the short link version.  I can’t remember the part numbers.  

Edited December 14, 2021 by Browncbr1

[cferr59]

5 hours ago, Skates97 said:

There is a bushing and a bolt where the jack screw attaches to the tail. Over time it will get wallowed out and allow more and more play. Remove the covers on the sides to expose the hinge and the jack screw. Have someone lift up and down on the tail and watch what moves. Pay attention to where the jack screw attaches and you will likely see play there. You can get the bolt and busing from Lasar. After letting it go for a number of annuals my AP/IA finally decided he wanted to have it replaced so we did that a year ago.

I replaced this bushing (914017-000) and the related bolt.  It resolved most of my freeplay issue.

[Guest]

7 hours ago, Mark942 said:

I have a 64 M20E.  I've owned it four years now and since day one, there is about a half inch of free play if I lift up on the tail cone during pre-flight inspection.  I asked my first AP if that was normal and he confirmed that it was, but to just keep an eye out that it didn't increase.  The plane flies hands off.  When on autopilot and in altitude hold it is rock solid.  Just finished my fourth annual and nothing has changed but I have a new AP. I asked him what he thought and he said he just didn't know.  We did not change anything but I wanted to ask the group if this is normal and okay.  If the play should be taken out, is it done by tightening the two nuts at the very end of the tail to take clearance out of the "what looks like" bungees in a tube" at the end of the tail.

Thanks everyone,

Merry Christmass

You have to distinguish play at the tip which is wear/play in the two pivot bolts and bushings and play while lifting the tail at the rudder trailing edge.

Clarence

[MikeOH]

There used to be about 1/8" of play when I lifted up the tail cone; I thought it was okay because I'd 'been told' that 1/4" was okay, and had flown a rental Mooney for many years that had about 1/4"

After repair (I think the jack screw was replaced) I have an undetectable amount of play when I try to lift the tail cone.

Until this thread I had actually never heard of the measurement/play in PT20J's cited reference!

[Mark942]

Just got home from another day at the hangar reassembling the Mooney.  Thank you to everyone for your responses.  Tomorrow I will share this with my AP.  He allows me to do all the actual work, but I rely on him not to make mistakes.  I plan to pull the panels back off and take a look at the things you guys have mentioned. Trying to wrap up the annual but it's a busy time of year.

Thanks again, I'll report back what I find and hope to take a couple photos or a video.

-mark