Mailing List lml@lancaironline.net Message #2550
From: Marvin Kaye <marvkaye@olsusa.com>
Subject: A LNC2 Aileron Trim System - Spring Biased and Servo Operated
Date: Wed, 09 Jun 1999 18:57:44 -0400
To: <lancair.list@olsusa.com>
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Posted for Scott Krueger <Sky2high@aol.com>:

Several people have expressed interest in my Aileron trim system.  I have
drawn (I am not a draftsman nor artist and left-handed to boot) the system
components and their relationship and have included them as jpg attachments
to this e-mail.

The system was setup to be jam free and is easily overridden should the
servo "run away".  2 1.25 inch "hardware store" springs were used (per
side) to protect against dramatic force changes if one should break or
become disconnected.  Sensitivity can be adjusted by changing the length of
the arm between the "T" cable connection and the servo attach point.  

Note that the cable that passes thru the phenolic fairleads only moves when
you adjust the trim.  All other stick movement is taken up by the springs.
The cable length is determined such that there is very slight tension in
the cables with hands off the stick.  This provides a light self-centering
function and keeps the control surfaces from being battered around when the
aircraft is parked.  The springs are adjustable by the usual cut and bend
process.

The aluminum arms are constructed from 1/8 inch thick material.  All
pivoting connections are made with castle nuts except for the servo
connection which is made with small rod ends so that the required degrees
of freedom are available.

I mounted the Mac rocker switch on the console forward and to the right of
the elevator trim wheel.  Left side depressed, left wing goes down, right
side, right wing.  This could be controlled by a stick mounted sw.

The trim indicator is mounted on the panel within my scan (close to
attitude ind) and pre-takeoff ck list item is to center the trim.

Scott Krueger
N92EX

[Please note... the JPGs referenced in this article will be uploaded to the
LML homepage as soon as I receive a fresh copy of the zipfile which
contained them.  I'll announce their availability as soon as they are
posted.     <Marv>    ]


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