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Dick B in KY
05-15-2015, 04:50 PM
I have just picked up a tail wheel shimmy (Matco tailwheel) on my SS7. Nothing has been changed, tension on springs is the same as it has always been (no slack in chains), air pressure is the recommended by Matco. Bearings are good and tailwheel is greased and in good shape. Any thoughts or suggestions. Problem really manifest itself upon landing with severe shaking, otherwise no problem.

Dick B
HighWing
05-15-2015, 06:02 PM
Dick,
Controversial in many conversations, but my feelings always revert to the pivot axis with relation to the ground. With this in mind, have you any sag in the tailwheel spring. If it sags it can cause a forward leaning pivot that can result in shimmy - in my experience.
dynomike
05-15-2015, 07:06 PM
tighten up the pivot bolt a quarter turn. use has probably loosened up the joint and the dampening it provides.
Av8r3400
05-15-2015, 07:46 PM
Dick,
Controversial in many conversations, but my feelings always revert to the pivot axis with relation to the ground. With this in mind, have you any sag in the tailwheel spring. If it sags it can cause a forward leaning pivot that can result in shimmy - in my experience.


+2 on checking for sag in the spring. A likely cause.
Meyertheflyer
05-16-2015, 07:00 AM
I had the same Matco problem that would shimmy on a three point landing when the tail is weighted during roll out. It would disappear by a little forward stick. I took a little more slack out of the springs and tightened the pivot nut which had loosened slightly during the first 50 hours. I used marker paint to watch if it loosens any more.
So far I haven't had any more shimmy. The one issue I still have is the amount of breakout force that's required to unlock the tail wheel. I need a little speed and stomp on a brake to swivel the aircraft. Possibly because the tail is so light or it'll just take time to wear in. Not sure yet.
n85ae
05-16-2015, 11:02 PM
Not controversial with me, it's all about the angle. Fix that and you can run
loose chains. I agree with Lowell on this.

Jeff


Dick,
Controversial in many conversations, but my feelings always revert to the pivot axis with relation to the ground. With this in mind, have you any sag in the tailwheel spring. If it sags it can cause a forward leaning pivot that can result in shimmy - in my experience.