The Cessna 120-140 Association Forum

Hello, Recent annual on perfectly flying 120. First flight on roll out of 3 point had tail shimmy. Plane has never done that before in last 3.5 years. Thought maybe I didn’t have the stick back tight enough to keep the tail down. Next flight same thing. Pushing forward to hold the tail up kept it from happening. Mechanic’s trainee serviced the tailwheel. The actual assembly looks like the angle between the ground and the assembly is less than it was. He “tightened up” the chains. I have the old CAA instructions for the Scott 3200 Tail Wheel Installation. The note says tension on connector springs not required or advisable. sUse sufficient chain links to remove slack in each connector assembly on installation. Does anyone have any information on what caused my new problem with my old airplane? I have asked the mechanic to put it back to a no shimmy condition. Waiting week two with wheel landings. THANKS

The nut on the bottom of the fork adjusts the shimmy dampening mechanism. All the related parts must be in place, and the nut properly adjusted.

The chains should be as loose as possible without any significant slack.

Check out these two articles on tail springs and steering:

viewtopic.php?f=10&t=147

viewtopic.php?f=10&t=134

Whoever “tightened up” the chains no your previously perfect tailwheel, did you no favours whatsoever.

Thanks so much for the information!

You can also view videos on the Alaskan Bushwheel website on Tailwheel maintenance.

EAA is having a forum in March, one of the topics is tailwheel shimmy. Check this link, scroll all the way down to register. It's a WINGS program.

https://pages.eaa.org/index.php/email/e ... d_id=21967

I just received an e-mail from Alaska Bushwheel about their new Shimmy Dampener. I was getting ready to post this to the group to see what the response is. https://www.airframesalaska.com/Article ... e6233e4962

FWIW, Just replaced an old Scott 3200 with a brand new Alaskan Bushwheels 3200 clone and shimmy resolved. I did the same thing (got an entirely new tailwheel) in 1997 for the same problem on my 170. That time I first tried rebuilding the 3200, but to no avail. Debating whether should also replace the springs.