Message-ID: <19981223040005.23336.qmail@www02.netaddress.usa.net>
Date: Wed, 23 Dec 1998 03:58:23
From: Dan Schaefer <dfschaefer@usa.net>
To: lancair.list@olsusa.com
Subject: Main gear shim
Mime-Version: 1.0

          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>>
          <<  Lancair Builders' Mail List  >>
          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> 
>>
Ed Sikora asked about what to use for the shim between the main gear 
rear bearing plate (GM ??) - aluminum ar phenolic.

First let me say that having 1/4 inch clearance back there at first 
glance sounds like too much. I don't believe it is, and here's the 
reason. When you're diddling that sucker into place to drill the bolt 
holes where you want them, the extra wiggle room the 1/4" affords is 
welcome. Of course, juggling an extra piece could be tough, but my 
experience says it's nice to have some room to help get things adjusted.

As to the material to use, I'd use 1/4 in. phenolic simply because it's 
easier to fabricate and I think it's lighter (by how much, don't ask!). 
The shim is only in compression - something phenolic is suited to - 
and you can bond it in once everything is lined up and drilled. Also 
since it's only in compression, I wouldn't even bother to put any BID 
over it. It ain't goin' anywhere once you pull up on those bolts.

No matter how careful you are in getting the distance between the 
pivot bearings set up, when all is said and done, if you are a normal 
human being, you almost certainly end up with around a gap of 1/8 inch 
or so, i.e., fore-and-aft slop. Not so bad, really, but it makes for an 
un-nerving noise every now and then as the horizontal shaft moves - 
well, for and aft. Just cut a washer from the required thickness of 
plastic like some of the stuff available from Aircraft Spruce - cut 
out a little bit of the ring and snap it over the pin on the horiz. shaft. 
Works for me.

Merry Christmas,

Santa flies a Lancair!

Dan Schaefer
N235SP