From: Fredmoreno@aol.com
Message-ID: <b5e6d3f0.250de9c0@aol.com>
Date: Mon, 13 Sep 1999 01:46:40 EDT
Subject: IV Hydraulic lines + a safety feature
To: lancair.list@olsusa.com
Mime-Version: 1.0

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I did it the way Brent described (after I saw his installation) and it can be 
done.  I made two changes from the factory plans.  First, I made the tunnel 
under the spar wider than called for in the book.  I would make it wider yet 
which may not be possible in the IV-P because of the pressurization loads on 
the floor.  Second, I ran the brake lines (rigid aluminum -- forget the 
nyla-flo) and the hydraulic lines for my home brew speed brakes through the 
tunnel as well.  This made things a bit cramped (hence the desire for a 
bigger tunnel) but with patience, a couple of beers for enhanced attitude 
adjustment, and tube bending followed by restraightening, I got a total of 13 
lines through a tunnel 6.5 inches wide.  The tunnel is plenty big enough for 
the lines.  The extra space is needed to wiggle the last few lines through.  
Twenty-four inches wide by four inches high would have been real nice, but 
perhaps a bit excessive given the allowable space.

    Suggested safety feature: When one of our unnamed colleagues did a belly 
slide in his IVP, the asphalt ground through the floor beneath the spar.  At 
the end of the slide, dust was rising from the cockpit floor, and some the 
lines were grazed enough to ooze some hydraulic fluid.  Now imagine fuel 
lines sliding along the asphalt... 

After letting my imagination consider the consequences, I cut a piece of 1/4 
inch thick high density polyethylene sheet (same stuff I used on the landing 
gear door cams which need 1/4 inch stuff, not the 1/8 stuff from the factory) 
into the shape of a T.  The cross bar of the T is almost as wide as the 
core-free area on the floor in front of the spar.  The column of the T runs 
down the tunnel full width under the tubing.  (You can put this in easily 
after installing the lines.)  

Now if I do a belly slide (who, me??), the asphalt can chew its way through 
the floor under the spar, and as it continues to nibble away at carbon, it 
will meet the polyethylene sheet which will move up (lifting the tubes) as 
the airplane grinds itself and your checkbook down to a nub.  (Figure about 
$1000/second.)  Not pretty to contemplate.  But better than contemplating a 
belly slide on a concrete runway with lots of anti-hydroplaning saw cuts 
which has been specially tailored to abrasively remove epoxy-carbon and 
aluminum until striking oil..... 

While we're at it: how to best prevent the hydraulic lines on the floor from 
abrading one another?  I have wrapped spiral nylon around the lines, but they 
can still wiggle.  A friend suggested potting them in place with mix-and-pour 
foam (or maybe the foam that comes in pressurized cans).  Push them down, add 
a transverse swath of foam a couple of inches wide, let harden, sand off 
excess foam. The foam is soft enough that lines could be easily dug out if 
necessary in the future, and potential vibration/abrasion of lines could be 
reduced or eliminated.  Any comments or thoughts about this potential problem 
and solution?

Fred
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