Message-ID: <37F1A060.808C17AD@nii.net>
Date: Wed, 29 Sep 1999 01:15:12 -0400
From: "Angier M. Ames" <alphadog@nii.net>
Organization: Alpha Delta Research
To: lancair.list@olsusa.com
Subject: Re: LNC2 hydraulic hoses
References: <19990928044135.AAA12816@truman.olsusa.com>
Mime-Version: 1.0

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Not being familiar with the main gear actuation cylinders on a IV, I cannot
speculate on whether rigid line is appropriate. But in any application where
rigid line is forced to flex, it will ultimately fail.

Substituting Aeroquip 'super gem' stainless fittings for those which come with
the kit results in a weight saving of 12 grams per fitting. Plus, these
fittings are rated at 12000 psi MINIMUM burst.

Substituting Aeroquip stainless teflon 2807-4 hose for Imperial Eastman which
came with the kit is a wash with both weighing in at 28 grams per foot.
However 2807-4 hose has a much smaller OD of .19 and has a minimum radius bend
of 2 inches and MINIMUM burst pressure of 12000 psi. Yes, -4 aluminum line
weighs less than 28 grams per foot but not that much less.

Admittedly, our hydraulic system normally sees relatively low pressures, but
what might happen if the high pressure cut off switch failed? The system might
see higher pressures.
How about all those perfect flairs on your -4 aluminum lines, would you trust
that line and your flairs to 12000 psi?

Ease of initial installation and future field removal, insignificant
additional weight, significant additional cost, and more than one way to do it right.

Angier Ames
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