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General Category => General Helio Discussion => Topic started by: TreeTopFlyer on January 10, 2019, 01:11:43 PM

Title: TailWheel Shimmy
Post by: TreeTopFlyer on January 10, 2019, 01:11:43 PM
I know this is a topic that comes up fairly often and this exact problem MAY have been discussed previously.

I recently had a tailwheel shimmy, it was there with the original square profile tire and then again INTERMITTANTLY when I replaced the tailwheel with a beaver tire and wheel.

So we took everything apart....A frame out AND what we found that inside one side of the pawl (little piece of metal that swings like a gate and has a spring) was sticking....(Jim Metzlar has previously stated DO NOT use too much grease)  Well we actually didn't but enough grease migrated up and that side scraped a little upon testing it and it basically glued it open...hence the shimmy...

We took it apart..used a little emery cloth to smooth the bottom....used VERY VERY little lube...and put it back together....

NO MORE Shimmy!

IF you lift tailwheel off the ground and swing tire back and forth you should hear both sides of the pawl clicking and as per JIM Metzlar back and forth slight movement checking that both pawls actuated should be no more than 3/8 inch.

Jim mine was 3/8 +/-

Hope this helps!
Title: Re: TailWheel Shimmy
Post by: Doug Johnson 1 on January 11, 2019, 11:34:03 PM
Thanks for an interesting post and I'm sure it was helpful to those active pilots.

Here are a couple of links to interesting posts that I found while searching for other posts on shimmy.

your previous post on the beaver tail wheel http://flyhelio.com/smf/index.php?topic=1428.msg6522#msg6522

and one by Louis on the tail wheel lock http://flyhelio.com/smf/index.php?topic=520.msg2766#msg2766
Title: Re: TailWheel Shimmy
Post by: RCarter on January 13, 2019, 04:16:50 PM
I had pronounced shimmy when I initially went with the 500-5 tire.  I did a lot of research on shimmy, tire pressure, caster angle, etc. I could not figure out what the problem was.  When I hoisted the tail of the airplane there was +/- 1inch of play in the tire.  Ended up pulling out the A-Frame and taking everything apart. Installed new bushing, cleaned everything up, lightly greased, and tightened everything. Almost no play now and the shimmy is gone.  Plane tracks straight and turns well.  No arguments here.  Amazing how much better stuff works when it is assembled correctly!