REFLECTOR: Another shimmy story...

[Pat Shea]

I had 140 hrs on my XLRG without a hint of shimmy -
until last weekend. I was landing at an airport with a
relatively high density alt (6,500'), my mind was in
the Bahama's, and I just botched the landing. I hit
hard and the nose wheel bounced. I set the nose down
real nice and easy the second time but it started to
shimmy. Since a truly botched landing must also have a
drift component, I suspect mine did and that caused my
nose wheel was cocked off a little after the first
hit. I immediately raised the nose and tried lowering
it again - more shimmy. I pull the nose off again,
adding power by now to go around, but the nose fell as
the canard stopped flying - more shimmy. While
accelerating at full power with aft stick, the shimmy
stopped. Whew! Full stop. 

Each of the three shimmy events lasted about 2
seconds. Up until this point, my landings have all
been average or better, and The Big Nut on my nose
wheel is always tight (over 15lbs of break out force).

Post-mortem: There are significant rubber marks on the
inside walls of my nose gear fork where the tire was
rubbing during the shimmy (I have about 30 psi in my
nose tire). There's a hairline crack around one of my
knurled bushings. With the nose lifted into the air, I
can grab the nose wheel and wiggle it side to side at
least 1/4" (free play). The play is coming from the
nose gear pivot bolt and the sleeve (on the strut) the
bolt goes through. The tire, wheel, keel, and
captivator are fine. 

I've ordered a new strut, pivot bolt, newer style
bushings, and newer style bellville washers. In the
aviation world, $300 is a small amount to pay for a
botched anything. If this was a production plane,
you'd have to add another zero to that number...

Oh, and I ordered Ken's nose wheel locking system too.

FWIW, Pat        



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