Pete,

 

One other place that should be checked is the bearing blocks at the top of the nose gear strut.  There are two bearings that are pressed into the bearing blocks.  When they're fully inserted into the bearing blocks they hold the strut posts securely with no play.  But after time, they can slip outboard and allow the top of the strut to move laterally.  I made two "donuts" from aluminum tubing that keep the bearings fully inserted into the blocks.  Drew Dickinson down in Texas originally discovered this one.

 

Mike Easley

Colorado Springs

 

Paul,

 

Thanks for the feedback.  I do have the Lancair casting for jacking the plane, which is great for changing tires and brakes, but it does not help for checking whether the gear leg is loose in the upper socket.  I borrowed a wing jack and a carpeted 12” square pad from my local mechanic and was able to get the gear off of the ground.  The legs seemed as tight as they were when first installed.

 

Note that I have had absolutely no shimmy for the first 250 hours I have flown the plane.  It just showed up a month or so ago.   Maybe a brake issue?  I don’t feel it on initial roll-out, just as I slow between 40 to 20 knots.

 

I’ll do a search on the other forum.  Again, thanks for the assistance.

 

Pete

 

From: Paul Bricker [mailto:pbricker@att.net]
Sent: Thursday, January 05, 2012 10:59 AM
To: lml@lancaironline.net
Subject: Re: [LML] Gear shimmy

 

Pete,

First with the easy question. There is a casting you can buy from Lancair parts that "clips" around the lower end of the gear leg and provides a jack point for a floor jack. You'll also want this during condition inspections when you remove the wheels to repack the bearings. If you can't get one from Redmond let me know off list. I may know where an 'extra" is.

 

The shimmy question has been explored, investigated, experimented on, photographed, argued over, and generally beaten by many on this list. Main gear leg movement is one of what, by my count, appears to be 3 possible causes. The others are loss of damping in the strut, and movement in the mount between the strut and the motor mount. I'm sure other people will soon jump in with all the other causes I've forgotten. 

 

I recommend joining the [Lancair_ES] list. Their archives should have more details on this ES issue. There are many who have worked this problem diligently who monitor this list, so standby for more advise.

 

Paul Bricker

pbricker@att.net

 

From: "pete@leapfrogventures.com" <pete@leapfrogventures.com>
Reply-To: Lancair Mailing List <lml@lancaironline.net>
Date: Wed, 04 Jan 2012 16:38:21 -0500
To: <lml@lancaironline.net>
Subject: [LML] Gear shimmy

 

After 250 shimmy free hours, I am now getting gear shimmy when my ES-P slows down through about 30 knots.  I think I recall folks saying this is due to looseness in the upper main gear leg sockets.  Is this correct, or is there another cause?  My strut (new version) looks fine.

 

If it is loose main gear, how do you suggest that I get the main gear off of the ground?  There are no obvious jack points.

 

Thanks for the advice!

 

Pete

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