Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Sun, 25 May 2003 22:04:30 -0400
Message-ID: <redirect-2363150@logan.com>
From: "Gerry Leinweber" <gerry@doctorseyecare.ab.ca>
References: <list-2358035@logan.com>
Subject: Re: [LML] Re: Stiff controls at higher speeds in IV-P
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Problem of stiff controls in our IV-P (particularly over 160 KIAS) is
resolved!!!

Mark at the factory suggested we adjust our aileron neutral position to be
just slightly negative.  The trailing edge thickness of both ailerons is
slightly more than 1/4" (thanks for reminder to check that) and we made our
first adjustment so the top edge was 1/4" up from flush.  Did our usual
double check on all bolts, nuts, etc and went for a test flight.  Difference
was amazing.

We tested the controls at different speeds, and certainly, as the speed
increases, the controls stiffen, but now they do at a consistent, steady
amount, even at 220 TAS (200 KIAS) and 6000 ft, the control force to turn
the aircraft is smooth and makes the bird a pleasure to fly.

How much less force? Without an objective method of measuring stick force
(but my partner Jerry Mulder has our digital scale apart and is trying to
design just such a device) and recognizing the physics and the lack of
leverage in moving the ailerons with wrist only, I would hazard a guess that
the force or pressure to initiate a rate 1 turn has been reduced to at least
1/2, and likely 1/3 of the previous force.  The A/P works much better now,
but still needs final adjustments as authority is not the same in both
directions, but much improved.

Thanks to all who provided input, and ideas. In the spirit of this forum and
the old Japanese saying that "None of us are as smart as all of us" Jerry
Mulder and I will continue to develop a little tool any builder might want
to use to measure stick force while flying (it would fit over the bare metal
stick on the co-pilot side) as each plane built is slightly different, and
yet ultimately we all need to fly them safely and comfortably.

Discussion.  One might speculate what does the solution teach us.  It could
be that the exact angle of incidence of our wings (we used a smart level to
be as exact as we could be) on this IV-P is different from the others, yet
as builders, we are not experts in aerodynamics, particularly laminar flow,
but we are interested in practical solutions.  What requires no speculation
is that for us, this particular solution worked for our plane, and we want
to share that information with the LML builders community.  The other lesson
learned is that a project such as this involves many different skills,
systems, financial factors, safety issues and ultimately matches the man
made machine against the forces of nature (gravity, wind pressure, drag,
turbulance, etc).  Our thanks to all the input from various builders, staff
at the factory, and other home builders in our local area who have all help
out at various times in various ways.  Happy building and flying to all

Gerry Leinweber  IV-P  C-GLFP