From: "Bill George" <bgeorge@innercite.com>
To: "Lancair List" <lancair.list@olsusa.com>
Subject: Control Surface Balancing
Date: Mon, 14 Jun 1999 12:05:11 -0700
Message-ID: <000001beb698$d55d5360$8d20de9e@bill-george>
Importance: Normal
Mime-Version: 1.0

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Date:	Sat, 12 Jun 1999 23:16:22 -0700
From:	Matt TestElectronics <matt@testelectronics.com>
To:	"'lancair.list@olsusa.com'" <lancair.list@olsusa.com>
Ian Crowe. Asks:
Can any of our more technical brethren in the aerodynamic field give us some
pointers as to what we are trying to achieve by balancing and to what degree
of balance we should aspire to?

Ed from Watsonville replied:

>>>
The elevator control surface balancing is done to keep control pressures on
the stick constant when the aircraft is experiencing G forces. The main
thing to avoid is having the front of the elevators heavy. If the front of
the elevators are heavy the plane will over react to control inputs. When
you pull back on the stick, the G forces will pull the rudder up even more
and tend to push the stick back. This is control reversal you then have to
maintain forward pressure on the stick to keep the plane from rising
uncontrollably. The same reversal applies to pushing forward on the stick.
You can probably imagine, this situation is non intuitive, and makes it very
difficult to control the airplane. The best thing to do is get it exact, or
make the rudders a little heavy on the trailing edges.  Another way to think
about it is the heavier the trailing edges are the more sluggish your plane
is going to be you will need muscle to pull aerobatics maneuvers. The closer
you get to the balance point the easier your plane is going to respond to
your control inputs. When you get beyond the balance point, your plane
starts to dangerously add to your control inputs, so never go here.
<<<

I find this explanation to be very confusing as well as misleading, with the
interchange of elevator and rudder seeming indiscriminately. Also there is
NO mention of flutter prevention, which I have understood to be the primary
reason for careful balancing of the control surfaces, especially elevators &
ailerons. Am I completely misinformed or what?  No smart remarks please!

Bill George - 530-642-8063
bgeorge@innercite.com
Fly-In Chairman
2nd Annual Golden West EAA Regional Fly-In
Castle Airport, September 10-12, 1999
Golden West Aviation Association
http://www.gwfly-in.org/


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