From: RWolf99@aol.com
Message-ID: <ed2b7daf.24a8e82e@aol.com>
Date: Mon, 28 Jun 1999 11:01:02 EDT
Subject: Jacking Points
To: lancair.list@olsusa.com
Mime-Version: 1.0

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In a message dated 6/27/99 9:58:25 PM, you wrote:

<<Instead of using the 1/4" holes I made at the cockpit closeout rib location,
I'm planning to use the holes at the wing tiedown points for jacking the plane
off its gear. Have any of you tried this with success? Is there a reason why
this should not be done?>>

Two possible problems, neither of which may be harmful:

1)  You would have to make sure that the wing root bending moment is not too 
high.  The wing design limit load in flight (6 G's times the gross weight) is 
distributed along the wing.  The concentrated load out at the wingtip would 
result in a higher bending moment per pound of load, but with a smaller load, 
of course.  I gotta think that it would be less than a 6 G flight load -- but 
I have not run the numbers.

2)  If you're building the plane, and the wings are off, you'd need another 
way to lift the plane.

Having said that, I agree that the per-plans jacking points are rather close 
inboard.  I once stood on the wing spar out near the BL-50 rib (climbing into 
my project) and caused the plane to lift off it's jack point on the other 
side.  (No damage was done -- the pin dropped back into the hole.)  My 
fuselage is very light now (there's almost nothing in it yet) so that won't 
be a problem too much longer.  Now I have a small stepladder near the wing 
root so I don't have to climb on the spar.  I use the A-frame jackstand that 
was in the LNN newsletter about four years ago -- It works great!

- Rob Wolf
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