Frans,
You give me the impression that you are using a digital level to set the
deflection. Get a protractor that measures inside and outside angles or
make cardboard templates for your travel and measure the deflection at
the hinge. The bottom of the wing at the hinge should be close to flat.
Measure your deflections from that. If you do nothing more than make
cardboard templates with 24 degrees up and 22 degree down angles for
measurement of the deflection, it should work.
Normally, if your starboard aileron goes down too far the port up stop
is not set correctly. Remember the rule, the bell crank stop sets the
up limit, and by default, the down throw on the opposite aileron. As
you know, the geometry of the flight controls gives more up aileron than
down for adverse yaw affects.
With both up stops set at 24 degrees at the hinge, and no slop in the
system, the down throw should be very close to 22 degrees. Please
measure with a protractor verses the chord line as you may be setting
the up stop too far up which yields too much down on the opposite side.
If the up is set too high, due to rod length differences and bell crank
throw, this makes the left and right throw different due to the angle
deflections of the bell cranks (when the aileron up point is approaching
30 degrees (Cosin of .866) you get a noticeable difference in linear rod
throw) which means you won't get the same amount of throw on each wing.
Only a couple of degrees, but frustrating to say the least.
Just to bloviate, as far as digital levels and aileron measurement goes,
there can be 2-3 degrees of error by trying to hold a level and take a
measurement from an assumed known datum with the linkage moving under
weight of the level. Assumed datums such as a wing tip chord line are
suspect because the aileron angle has to be measured on its chord line
also, and it is very hard to get a pure wing tip chord line...
Especially if you don't make a shim to lay your digital level on to set
it to the chord line. This makes the aileron deflection measurement
inaccurate. Measure the deflection at the hinge.
To all builders: All rudder and aileron deflections on the Europa are
to be measured from the hinge lines. In all my aero books, these
deflections are made at the hinge line. Note that the stab hinge point
is at the center of the stab. In this case we use the flat of the top
of the stab trailing edge and set the digital to zero to measure
deflection of the stab. However, the trim tabs on the stab is measured
by protractor at the hinge...
When rigging any airplane, step back, sit down and look from about 10
feet behind the tail across the rear of the wings. The shadow of the
bottom of the wing surface should be the same on each wing. As you move
your head up, the shadow will disappear at the same spot equally on the
left and right as your head nears the level of the trailing edge. Using
a point such as the flap to aileron joint, which is very close to the
mean aerodynamic chord (where the roll trim really counts) as the point
where the wing shadows are equal is best. It is like trimming a model
airplane. If it looks straight it will fly straight. I have yet to
test fly a Europa, RV. Zenith or Kitfox type aircraft that flew bad when
I rigged them with this method. Your eyeball will detect as little as
.1 degrees between wing incidence using this basic method. Many times I
have gone back and corrected my digitally leveled and measured aircraft
because my Mark I eyeball said it doesn't look straight. Should the
aircraft have a slight roll during flight, I will shim or adjust a flap
by a small amount (1/32 inch at a time) to get the roll trim right due
to a slight building error. When I checked using the eyeball method, I
could usually see the problem and kick myself for not catching it. Of
course that will probably all change when I have eye surgery next week.
Anyone know a good seeing eye dog or eye patch company just in case?
Happy building
Bud
Custom Flight Creations
(813) 653-4989
----- Original Message -----
From: Frans Veldman<mailto:frans@paardnatuurlijk.nl>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Tuesday, October 14, 2008 2:19 AM
Subject: Re: Europa-List: Aileron setup
<frans@paardnatuurlijk.nl<mailto:frans@paardnatuurlijk.nl>>
Thanks for all the advice. I will try again, but the desciptions look
like what I have been doing so far. The points is, if I start with the
QD's vertical, the link rods adjusted to the upper limit, I somehow end
up with about 26 degrees down travel for the starboard aileron. As soon
as I start correcting this by adjusting the link rod, it messes up all
the other parameters, such as upper aileron limit, neutral setting etc
and whatever I try, I can't get it right anymore.
The weather doesn't look promising today, so I can't get the airplane
outside to try again.
BTW, I use the Europa factory sold digital level, and measure compared
against the wing tip, i.e. neutral is the aileron parallel to the wing
tip.
Frans
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