Brian and Pat Tarmar wrote:
> The current high winds in the UK remind me of the
> problem which has occurred to me twice this year after
> a crosswind departure from home base (Old Sarum - a
> fairly bumpy grass airfield) with a subsequent landing
> on a hard runway without significant crosswind. Having
> taken-off with a 15-25 knot crosswind (from the right
> in both cases - the "best" side), severe nosewheel
> shimmy was encountered on landing, which continued
> until the aircraft was brought to rest. Not pleasant
> waiting for something to break, and unable to do
> anything about it. Fortunately no damage on either
> occasion. Has anyone else encountered this problem, and
> is there a remedy? The friction on the (so called)
> shimmy damper was checked as between 8-9 Kgs on both
> occasions. Ian Rickard has suggested that I reduce
> friction to around 5-6 Kgs in the hope that slipstream
> will straighten the nosewheel in flight from any
> inadvertant sidethrust imparted during rotation.
> Brian Tarmar G-OBJT 055 Classic Trigear,
> 912S/Warpdrive and XS front/mods 65 hours and still
> smiling when it ain't shimmying!
I would say the opposite ! The shimmy is the nosewheel
moving from side to side on the ground when landing. Any
deflection from central on take-off may make the first
shimmy movement but once the oscillation starts looseness
of the damper will actually make it worse.
I would suggest tightening up the "big nut" one flat and
trying it again. Maybe two flats. If it is too tight it
will not want to steer on the ground (but it won't shimmy !)
I took mine apart on my annual and found that there were a
lot of grooves in the plastic (damping) disc and there was
some cr*p in there as well. I cleaned it all up, including
the metal surfaces and then I turned the plastic disc over
to give me a new smooth surface. I had it tight before and
the movement was in jerks. Now it is very smooth, and no
shimmy. And it steers on the ground (most of the time !)
G-OWWW is exactly the same as yours - Classic Tri-Gear, XS
FWF, 912S but I have an Airmaster.
Richard
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