REFLECTOR: Nose Wheel Steering

[Brett Ferrell]

Looks like it was Sid Knox, about 29 June 2006, I'm away from home, so I don't have the pictures, but here's the discussion: http://www.velocityxl.com/phpBB2/viewtopic.php?t=3573&highlight=damper

"
quote]
Shimmy damper_3

One of the local knowledgeable mechanics reminded me that Cessna for years
had a hydraulic shimmy damper on their nosegear. I examined and took
photos
of an older 150 and 172 to see how they did it. The same guy gave me a
discarded damper that someone had tried to get apart and essentially
ruined
(by FAA standards). I took it apart, honed the bore, filed off the rough
edges on the piston, put in new o-rings and snap rings, and filled it with
automatic transmission fluid (ATF). Total cost less than $2.

I made up the mounting hardware initially from cereal box cardboard to get
a
general idea of fit and then from thin Al (quick and easy to modify) only
strong enough so that I could check geometry. Finally, I made up what you
see in the photos from 1/8 inch mild steel ( I do not have any chrome-moly
plate).

I took (angular) drag data for both the original Belview setup and for the
Cessna damper. It became immediately apparent that the ATF was too thin
so I replaced it with Shell 100 (50 wt) aircraft oil. This stiffened it
up
considerably and that what I am currently using.

It was during the initial fit-up process that I discovered that the fork
had
been bent bad. I noticed it when I was pulling (by hand (dump-valve
open))
the whole gear up into the nose of the plane to check for fit. One side
of
the wheel lightly dragged on one of the two alignment "posts" (I don't
know
the official name for these). I considered trying to straighten it but I
don't have a large enough press to do that sort of work so I ordered a new
fork assy. It has since arrived but I am still experimenting with the
original as it works. just looks a little strange. The new fork is
considerably stronger than my old original.

Ok, time for taxi testing. Big nut backed-off as before. Two high-speed
runs (fast enough to fly the canard and let it plop) and no shimmy. Time
to
go around the pattern. Take-off, no shimmy. Retracted the gear. lights
out. Extend the gear. both lights ok. Landed and let it roll for awhile
and still no shimmy. Taxied back, easily made both sharp turns into the
hanger.
This may be a keeper.

More photos to follow... I am pushing the bandwidth limit now.

Sid Knox
Oklahoma
Velocity N199RS
W7QJQ "
---------------------------
Somebody has also come up with a shimmy damper installation. I thought I
had a picture but couldn't find it.

Maybe the inventor could speak up?

Scott

Chuck Jensen wrote:
> Tom,
>
> The super-duper nose wheel lock by Ken Mishler is the answer to your problem.  Controlled with a push/pull cable in the cabin, a pin slips into a mating surface mounted on the nose gear that prevents the nose gear from swiveling.  The pin is disengaged for taxiing and reengaged on the takeoff roll.  Not having to worry about shimmy, the tension on the nose wheel can be backed WAY OFF.  Taxing is then a pleasure, instead of an annoyance.  Highly recommended.
>
> Chuck Jensen
>
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
> Behalf Of Tom
> Sent: Tuesday, May 06, 2008 6:08 AM
> To: reflector at tvbf.org
> Subject: REFLECTOR: Nose Wheel Steering
>
>
> My nose wheel steering is too stiff. Pretty much have to continually tap
> a brake while both taxiing and on take off. I realize the balance we
> have to play with nut torque to achieve reasonable directional control
> vs shimmying. Are there any alternatives out there such as shimmy
> dampeners, different lube type washers, etc??? thx Tom
> _______________________________________________
> To change your email address, visithttp://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives:http://www.tvbf.org/archives/velocity/maillist.html
>