REFLECTOR: Nosewheel shimmy_1

[Andy Millin]

Sid,
 
Could you resend your picture?  For some reason I didn't receive the email.
 
Thanks for doing the research.

One of the builders had made a Nylon washer to replace the belville
arrangement.  I would like to see a picture of the Nylon solution.

Sid, I like your style.  Asking this group to come up with possible modes of
failure is like asking who wants free pie and chips.  :)

I haven't seen the picture yet...

-- You have a hard landing, maybe a few over time and it separates and goes
through the prop

	From Rich Guerra's videos you can watch the nose gear touch down.
When it comes down "plop" it appears it would shake the dampener rather
violently.

-- It bends the fork over time

-- It gets caught in the door upon retraction or extension

-- It costs more, weights more and adds complexity

-- Possible balance issue combined with a looser nut lets it flip around 180
-- gear is backwards when you try to retract or extend ... Possibly on touch
down

-- Attach point creates a stress riser in the main gear fork.  Over time the
fork cracks

Truth can be stranger than fiction.

We will never know what the problems are if it isn't tried and the real
information gathered.  Thanks again for giving it your time and letting us
know what you find.

On a related note:

I had spoken with my brother, also a pilot as well as president of a
machining company.  Alex had mentioned a type of hydraulic dampener that
could be a solution.  My brother agreed this could be a solution and pointed
me to a few websites to see "like" examples.

He immediately had concerns about the cost, size, weight and durability over
time.  His opinion was we could try it, but it would be expensive and had a
high probability of being a less than perfect solution.  Not to mention you
will be testing it on your $200K aircraft.

This has been a longstanding issue for aircraft with castering nose wheels.
Trying to find an elegant solution must not be easy.