Lancair Live!

Hi All,

We recently had a problem with a bit of shimmy in the nose gear. It seems to have been caused by an air bubble trapped in the shimmy damper (went away after we ejected it and re-inflated the strut), but I don't understand how it got there? We had a bit of a seep through the front two bolts (I think they have some relation to the damper?), but it couldn't have caused it since the struct is under high pressure. I'd be interested in anyone has any theories or experience with this?

Also, does anyone have any diagrams of the inner workings of these struts? I'm kind of curious.

Best,
Konstantin

I have some photos and videos of when Bob Pastusek and I took apart one of the Ecco struts. He is very knowledgeable on them and has rebuilt his several times. I would be happy to send you my photos and video shortly.


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Konstantin,

Regarding nose strut service questions, I would suggest you contact Kevin Risse with Risse Racing in Redmond Oregon at ... 530-941-1821 or email: kevin@risseracing.com

... George

Konstantin,

Here are two pictures of the internals of the Esco nose strut. The internal vane is what controls the rotary shimmy damping. If your strut has lost oil, there could be air bubbles in this section and that will prevent the strut from controlling the shimmy. It is very important to check the rotary damping of the strut and make sure you feel the damping in both directions without any air pockets where there is no rotary damping. I hope this helps. I have lots more pictures if you are looking for any other details of the internal parts.

Kevin

Thanks everyone, appreciate the help!

We did test the damping action, and there seemed to be a dead zone in the damper. After we got rid of it, the shimmy is gone for now.

But how can an air pocket appear in the strut even if it seeps oil (it was through the two screws holding the damper vane)? The strut is under 300psi minimum, how does the air get there?

What was the fluid level? Normally the damper is always submerged. If fluid level gets low, it can pull in some air.

The fluid level seemed to be fine - it was still draining a bit at full compression.