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

[davedent at comcast.net]

I don't know if you ever owned an EZ or Cozy but I have over 1500 hours in them.  I fist changed out the nose wheel tensioner in 1983 and it was never used again.  After the bevel washer idea was used the major problem of shimmy went away.  If there was a problem with shimmy it was not the design it was the user.  Once a year I checked the tension on mine and they never changed.  The only problem that I ever found to cause shimmy after this was too low of tire pressure. I kept between 50 and 60 psi in my nose tire.  In most cases it would cause the tire and complete casting to leave the plane and most times through the prop.  So let's not blame it on the design but the lack of care on the operator that causes most of the problems with a good design.  

I kept my tension at 12lbs and this was enough.  All it needed was a little drag and this would do it. The original was to high of a maintenance issue so Mike and Burt did away with it in the design. 

Believe me there was a lot of changes in the EZ''s during the time that I owned them.  I made a great deal of them, changes that is.  I'm sure as more Velo's fly a number of changes will come out to improve them.  I am so thankful for the people like Bob in the experimental aircraft community for their innovations to improve on planes.  Without it we wouldn't be having planes like the Long EZ, RV's and others.  It took the builders to improve on them to make them great planes they are today. 
Dave 

-------------- Original message -------------- 
From: Richard Riley <richard at riley.net> 

> 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. 
> 
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