Yesterday I "fixed" a Skywagon with an habitual heavy wing. That is,
this airplane had a ground loop somewhere in its past and the wing tip
was repaired in the field. It apparently never looked or flew correct
after that and the current owner removed the wing and had it properly
repaired in a jig and painted. There is no evidence of any damage by
looking at the wing and with the wing repaired the air plane flew
straight, ball in the middle, feet on the floor and did not drop off on
a wing regardless of airspeed. The owner next had the ailerons and flaps
reskinned and this is when the heavy wing began to appear.

The shop doing the reskinning had tried various things to eliminate the
heavy wing to include; adjusting the eccentrics out to the max with one
wing all the way up and the other all the way down. They next tried
lowering a flap several degrees by adjusting the actuator rod. These
corrections did not fix the heavy wing problem.
The shop next put a fixed trim tab on one of the ailerons and sent the
owner home. The owner continued to complain to the shop that even with
the trim tab the wing was still heavy and would fall off in cruise
airspeed flight requiring constant right aileron correction in this
case. The shop was suspect of the ailerons they had reskinned as the
airplane flew straight before they reskinning these controls surfaces.
They switched one of the ailerons out from a different airplane and test
flew it. The switched aileron solved the problem and the airplane flew
straight again without the heavy wing! The problem was narrowed down to
the reskinned ailerons. So what was the difference in the ailerons
before and after the reskin or for that matter the switched one? From
simple inspection it was not obvious. I then looked closely at the skins
on the reskinned aileron and the difference became clear.

With a straight edge laid from the leading edge to the trailing edge
along each "V" of the corrugated skin of both the top and the bottom of
the ailerons the difference is seen. Some of the V's were depressed or
bowed in at the middle (con caved) up to 1/2", some were straight and
some were bowed out in the middle (con vexed). The aileron, as we know,
is an airfoil in shape and the characteristic of this airfoil is changed
by the bending of the skins, in, straight or out, along the V's. During
the reskinning process heavy bars and tools get placed on these skins.
It is very normal to have some deflection alone these V's both top and
bottom sides. What I observed from inspection of these ailerons was con
caved deflection on one one side and con vexed deflection on the other
side (same aileron). This caused the ailerons to deflect in flight and
produced a heavy wing.

The correction for bent V's is to carefully rub with a rag on the palm
of you hand on V's deflected out or con vexed until it is straight or
bent it the other way (con caved) as needed. With a 1/4" long square or
round bar instead through the diamond opening in the trailing edge of
the aileron, V's that are deflected inward or con caved, they can be
straighten or bend outward (con vexed) as needed.

If adjusting the eccentrics does not eliminate a heavy wing and you have
checked to see that the aileron's V's are not deflected, then you may
want to try this "fix". Go to the aileron on the wing that is heavy and
slightly defect downward (con cave) the V's on the top of this aileron.
If this does not give you the results needed go to the opposite wing and
deflect (con cave) the V's upward on the bottom of this aileron. You may
need to deflect the opposite side of the ailerons in the con vex manner
with the bar/tool until you get the desired results.

I removed the trim tab the repair shop had installed and when I finished
"tweaking" the aileron yesterday the airplane flew between 130 to 160
kts IAS with my feet off the rudders, ball in the center, control wheel
centered and no tendency to fall off on a wing, straight or in a turn.

Al Hewitt