Tail play

[bonal]

Subject came up on another thread and was discussed on Mooney flyer also when I asked a Mooney mechanic about play in the tail it seems it is not uncommon and was wondering if there is an acceptable limit. I seem to recall that when measured at the top forward edge of the vertical stabilizer it should not exceed 1/4 inch. I was wondering about others and if you have some play or not. When I test left right it's zero movement but up down there is a bit of play.  Going to remove inspect panels and see if I can locate where the play is. 

Thanks in advance for information 

[Sabremech]

When I purchased my Mooney the tail was off to replace both of the bolts that hold the tail on as they were bent from encountering severe turbulence. Since then, I don't accept any play in the horizontal stabilizers, my personal choice. 

David

[Yetti]

maybe an 1/8 inch.  Two mechanics have said that is normal

[gsxrpilot]

When I first bought my C, Don Maxwell was going over it with me and showed how to grasp under the tail cone and lift. There is just the tiniest bit of movement. He suggested this check should be on every walk around pre-flight and it should always be the same. He's done two annuals on the plane since then and it's always the same.

[carusoam]

Data point...

On my old C, there was near a 1/4” vertical play... Grab the bottom and lift. See the motion, hear the clunk

On my much newer O, there is near unperceptible vertical play... The clunk sound is very similar to the C...

The bolt that is responsible for the play, wears at a very slow rate.  It can be replaced.  I have never replaced one that I remember.  If the material of the bolt is wisely selected.  It will wear in preference to what it is mounted in.

Reminder: This one is really important to replace with the proper hardware...

Best regards,

-a-

[Chocks]

Gxsrpilot, its so funny how the things we just talked about end up on here - it seems like - the very next day. Ha! I actually ended up pulling an exploded diagram of the tail up so I could see what you were showing me that day

Sent from my iPhone using Tapatalk

[Raptor05121]

Mine also has the play and is one of the items that should be getting replaced.

[carl]

2 hours ago, gsxrpilot said:

When I first bought my C, Don Maxwell was going over it with me and showed how to grasp under the tail cone and lift. There is just the tiniest bit of movement. He suggested this check should be on every walk around pre-flight and it should always be the same. He's done two annuals on the plane since then and it's always the same.

This is what I learned at this annual , My tail had some play. I wanted it removed and inspected , but you should be able to change the bolt without removing the whole tail.

[carl]

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

 

Here is a article 

[N201MKTurbo]

It is unlikely that slop in your tail would ever cause a problem. The jack screw would need to wear the threads compleatly away to fail. I have seen screws that were very sloppy and were replaced that still had 90% of their thread left. The link between the screw and tail can get worn. A severely worn bolt or link has still only lost maybe 10% of its metal. There is no reason not to replace them, they are not very expensive. The only part of the tail that would get me excited would be the pivots. If they became loose I would take care of that right away. I've never seen the pivots get sloppy. 

The tail always has a great deal of down force. The tail is always pushing on the jack screw removing any slop from the system, so the slop has no effect on the flying qualities of the plane. 

Has anybody ever heard of a failure of the jackscrew or link that ever caused an inflight problem?

Edited January 3, 2016 by N201MKTurbo

[Sabremech]

The two pivot bolts were what got bent on mine as a result of a severe turbulence encounter. 

David 

[N201MKTurbo]

9 minutes ago, Sabremech said:

The two pivot bolts were what got bent on mine as a result of a severe turbulence encounter. 

David 

I've been in turbelance that literally scared the hell out of me. Life changing event. But it didn't hurt the plane. That must have been one hell of a ride.

[Sabremech]

The tail was off when I did the pre buy and I saw the two bolts and they were not straight. It must have been one heck of a jolt or two! Everything has been tight since and I intend on it staying that way. 

David

[DaV8or]

It's not just the bolts and bushings that can cause the play, but also the screw jack itself. The tail has to come off to replace/rebuild that. Not a super huge job, just some time. The thing to do is, pull the access panels, get a friend and flashlight and find out what is moving where. Changing the bolts is super easy. Replacing, or rebuilding the screw jack is moderately difficult. Replacing he bushings if they are gone is bitch.

[Andy95W]

57 minutes ago, DaV8or said:

It's not just the bolts and bushings that can cause the play, but also the screw jack itself. The tail has to come off to replace/rebuild that. Not a super huge job, just some time. The thing to do is, pull the access panels, get a friend and flashlight and find out what is moving where. Changing the bolts is super easy. Replacing, or rebuilding the screw jack is moderately difficult. Replacing he bushings if they are gone is bitch.

I don't think the tail has to come off for that.  See post 11 from the following thread:

 http://mooneyspace.com/topic/16503-trim-sticking/#comment-233888

"Removing the jack screw isn't that hard. After it is out, it isn't that hard to take apart and clean and lube. The only challenge is getting it synced with the front gearbox. That isn't hard with a little forethought. 
Run the trim to the nose up stop. Remove the sheet metal that covers the tail gap and the tail inspection plates. Measure the gap at the bottom of the tail and write it down. Take apart the universal joint just aft of the trim wheel. Slide then torque tube forward until the square coupling on the jack screw comes apart. If you have electric trim you have to remove the drive chain. Remove the trim link in the tail gap. Remove the boot. Remove the two bolts that hold in the jackscrew, they are at the four access holes in the sheet metal. Slide the jack screw forward and remove. Take it all apart and compleatly clean. You can disassemble the bearings by taking the circlips off and removing the balls. Repack the bearings with #6 grease and work as much grease into the screw and nut as possible. Reassemble in the reverse order. Rotate the torque tube until the gap is the same as before you took it apart and put the U-joint back together."

Please note I'm not speaking from experience.  I'll be tackling this exact project either this spring or the next.

[ryoder]

This kind of thing should be part of a Mooney illustrated owners manual. I am still not sure what to do to test this.

[N201MKTurbo]

Its not part of the owners manual because it is not a big deal.

[Guest]

The tail section play limits are in the maintenance manual for the model. Free play and wear in the trim control (jack screw and link and bolts) is different than free play at the stab tips caused by wear in the two pivot bolts, bushings and fittings.

Clarence 

[Yetti]

go to the back of the plane.  with a hand gently pick up on the center cone type area.  Feel how much the tail moves.  Should give just a bit.

[cliffy]

As mentioned there are limits detailed in the Mx manual for all 3 movements of the tail.  Stabilizer outboard tip up and down and fore and aft. Rudder trailing edge moving up from static down. 

Stab tip movement will be bolts and bushings in the hinge. Lots of time just new (correct) bolts will do the job.  Usually lack of lubrication is the cause. Had one that had 1/2" either way and bolts fixed it.

Rudder up from static down can be either the screw itself or just the link between the screw and the tail. The bolts and link can be changed easily with new parts and not too expensive as a try first but usually you can see the play in the link and bolts as the tail is moved up and down. 

Bill Wheat flew the Mooney without any bushings installed as test. It flew, he didn't like but it flew.  

[bonal]

So instead of flying to the west coast get together due to the crap weather we had locally I went to the hangar and pulled the inspection panels for the tail including the side covers and with the help of my wife was able to determine the play was in part the jack screw into the block and also the square coupling between the block screw and the drive shaft. We then measured the play as described in the attached document provided by Carl and found it to be between 1/8 and 5/32 about half the spec allowed. 

[N201MKTurbo]

See, it is good for another 40 years....