REFLECTOR: nose wheel shimmy

[Sid Knox]

----- Original Message ----- 
From: "Scott Derrick" <scott at tnstaafl.net>

> Thats on a retract isn't it.

Yes.

> Whats the turning radius with the damper connected?

Don't know the aircraft turning radius but the measured swing of the wheel 
is about 45 deg  left, 30 deg right.  Obviously, I don't have the geometry 
correct but it does what I need.  Between my hanger and the taxiway is a 90 
deg turn followed immediately by a 120 deg turn in the opposite direction. 
Before (using the Belview washers), it was a major pain-in-the-butt 
negoiating these turns... often going off into the grass.   Now, with the 
free-turning nosewheel, it is simple.   And, no shimmy, no worrying about 
adjustments.

> When turning in tight quarters do you bottom out or top out on the damper 
> often?
> No worries the damper would break from over extending?

For the above mentioned turns, I feel no indication that I have hit the 
ends.

> How big is that damper?  It looks big in the picture,  got a part number?

It is a damper off of some older model Cessna that a friend had in the scrap 
pile because someone had "ruined" it (by certified standards) trying to get 
it apart and damaged the piston and bore.  I cleaned it up, got some o-rings 
from AutoZone and it feels good as new.   I am using Shell 100 for a working 
fluid.  I tried hudraulic oil (John Deere) but because of the scoring in the 
bore, it did not damp as much as I wanted...it had essentially two 
orfices... the proper one and the score.  So, the heavier oil compensates 
for the higher internal bypass.  There is *no* leakage to the outside.

This is probably not a good mod if one must buy a good damper as they are 
*very* expensive! (typical Certified B.S. pricing).

Sid


Sid