Angier,

 

If there is oil under the flange on the fork (after the fork is taken off for inspection), there is an internal leak and internal seals must be replaced.  It already sounds problematic if oil is leaking by the strut wiper seal.  If Lancair still can add the self-centering option, you should consider doing that.  However, that would have no bearing on the shimmy whilst taxiing.

 

Grayhawk

 

At the moment, my focus is intently riveted on my nose gear strut.
On the 10th landing back at KBVY yesterday, I felt (for the first time), a momentary vibration in my control stick. It was brief, maybe lasting 2 seconds. I have no idea what nose wheel shimmy feels like, perhaps one of you with experience in this area could elaborate.
So here's what I've got, my strut dates from 1995 and is not self centering. I've got 4ZQ up on jacks and and when turning the nose wheel from
side to side, there is no sound that might indicate air bubbles inside. I do notice that there is greater resistance when turning the wheel to the left as compared to turning to the right. There is some evidence of oil dampness on the strut. I have not yet removed the fork to see if there is any oil pooling up inside. At this point, I'm guessing that if this were the case, I would see it leaking down along the fork. I'm told by Ross at the factory, that the principle cause of nose wheel shimmy is a lack of fork oil, no oil....no dampening, etc.
So my plan is to release pressure from the strut, check the oil level and cycle the strut up/down until there is no sign of air bubbles. I got some 20 weight fork oil from the local Harley dealer. My plan with the strut extended and full of oil is to collapse the strut, close the valve, set the plane on its nose wheel and re-pressurise the strut, and go fly.

I'm all ears for nose strut advice/suggestions.

Angier Ames
N4ZQ



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