REFLECTOR: Shimmy on landing...Some clarifications please THANX!

[Richard Riley]

At 06:15 PM 4/9/2006, you wrote:
>On the retract gear  I would check all the above.  On the fix gear I 
>would still keep a watch on the pivot point.  With the trailing type 
>you will have less tendency for shimmy but still check the tension 
>on the washers.  The Long EZ and Cozy's don't seem to have this 
>problem.  To the point that the nut is even a castle type.  Of 
>course they use a fiberglass gear and most of the vibrations is lost 
>in the gear itself and not transfered up into the airframe.
>Dave

Believe me, EZ's and Cozys (and Berkuts) are all subject to NG 
shimmy.  The Long originally came without the belville washer setup - 
there was a boss with a threaded hole, you were supposed to put a 
little chunk of phenolic in it and tighten a bolt down on top of it 
to make friction.  It didn't work well at all.  Bob Davenport came up 
with the belville mod.

It's a balancing act in those airplanes, you want the nut tight 
enough to avoid shimmy, loose enough that you can still turn with brakes.