Tail cone wiggle...m20k

[DaveAnderson]

Hi everyone, quick question. I've had my plane a few months now and so far except for a few minor things,it's been a ton of fun and runs extremely well.

Yesterday for the first time during preflight, I grabbed the back of the tail cone where the strobe light is and gently wiggled it up and down and noticed a 1mm movement in it when lifting up and down. The whole vertical stabilizer is what's moving. Is that acceptable, or should I get it inspected and tightened?

Thanks, Dave

[KSMooniac]

Your tail attachment bolts are wearing... there is a published amount of acceptable movement in the service manual, but I cannot remember off the top of my head.  It is normal wear, but you should start thinking about getting those bolts changed and the attachment fittings inspected.  I also can't remember if there is a bushing in the assembly or not.

 

And good for you for checking that movement!  It should be on the pre-flight inspection list for all of us.

[N201MKTurbo]

It is usually play in the trim jack screw. The limit is 1/4 inch. It is nothing to worry about.

[DaveAnderson]

Brilliant, thank you gurus.  I'll get it checked out next time I drop by the mechanic and keep an eye on it until then.

 

Thanks!

David

[Jerry 5TJ]

The play limit is measured at the top of the vertical stabilizer fin (at least for the Vintage Mooney family).   Unless you have a plumb bob hanging right there it is hard to measure accurately.

 

Qualitative Suggestion -- start wiggling the tails (gently) on Mooney aircraft you see and you'll soon find out what it should feel like (and you will find a bunch with excess play)

 

 

 

[Alan Fox]

There is a link that wears between the jack screw , about 80.00 ....  There will always be a little play.....

[jetdriven]

All 4 of the Mooneys we maintain at the shop have zero discernible play. That said, unless the huck bolts are loose in the hinge way, it's not a critical item. IIRC Bill Wheat dived a Mooney to 300 MPH with the tail bushings not installed, the tail had a few inches of play in all directions. He said the controllability was a little strange because the elevator was acting as a trim tab for the whole tail. But otherwise no big deal so they said 1/4" of play to give it a number.

[Hank]

 

Qualitative Suggestion -- start wiggling the tails (gently) on Mooney aircraft you see and you'll soon find out what it should feel like (and you will find a bunch with excess play)

 

Careful, grabbing tail at the airport can induce AIDS if you aren't careful!  Aviation-Induced Divorce Syndrome. 

 

Seriously, the ends of the horizontal stabilizer shouldn't wobble more than 1/4", and I'm not tall enough to grab the top of the rudder, but reach up and wiggle it vertically and watch the tippy-top. Mine moves, but less than 1/8", which is probably pretty common. Bolts first, then bushings, but it never hurts to clean old, dry grease out of the trim jackscrew and re-lube, either.

[Guest]

I just logged on to the Mooney site, the K model manual says that the vertical play limits at the rudder trailing edge is 0.080" 1/4" is way over limits and is worn out. You will have to support the tail tie down to differentiate between play and the airplane bouncing. If you remove the tail close out panels on each side of the tail you should be able to locate the play in the tail trim link and the two bolt which connect the trim screw to the trim fitting.

You will also want to be sure that your free play is not the trim fitting coming loose, see S/B M 20-313 and the FAA AD on the same fitting.

Clarence

[bonal]

During my annual we saw about 1/8th inch play in the tail. We replaced the bolts that connect the saddle to the block and another trick my mech showed me was to flip the saddle and you start with fresh holes. Zero play after the change cleaned and lubed all joints. Nice and tight now.

[bonal]

So I brought up this thread on a search of jack screw and wouldn't you know it mine was the last post. Day three a Lake Aero and all was well until we grabbed the tail and found (more like heard) some play. After looking at the components it was decided that the screw assembly was warn and needed service. Once we had it out you could see some slop in the screw but the threads look good. Looking at the design I can see that this system would have to be extremely worn ou to fail. What I can't figure out is this, if you read my last post you see where we replaced saddle bols and eliminated play last year and ever since I have checked tail on EVERY pre flight with NO movement or play I mean NONE and that includes the test flight before the annual. I can't figure out why it would start doing it during the airframe inspect. Only thing different is the plane is on jacks and the engine is supported on a cherry picker. I'm not about being unsafe and I want an airworthy plane but at the same time I am not trying to do a concours restoration.

[carusoam]

Isn't that a measurable amount that is no longer acceptable?

My R barely budges...

My C's travel was measured in 1/10ths of an inch...

See if you can find the spec.

Best regards,

-a-

[bonal]

There was no visible movement of the tail it doesn't really matter at this point cause the block is on the bench so might as well fix it up. I was just upset cause I was / am so close to not having any issues this annual. I'm just wondering if they're being a bit picky. Oh well maybe next year.