|We used to
straighten our build up wings in Formula One. The methods we used
were much more difficult than we have a need to do today. Diagonal
cut wings epoxied together was one way to do it for a very bad wing.
We used to also cut the aileron line from where the ailerons ended
to the tip. Then we would bend it and glue it in a new position to
compensate for the twisted wing. We only did this with the worst of
the warped wings. This was just prior to throwing them away and building
a new one. Building a new one was common also.
Now, with the composite wings, there is no excuse for not having
a straight wing, no matter how much of a twist there is in a wing.
I had one wing that had so much of a twist in it that full aileron
trim would not make it fly level. By doing what I am explaining,
the wing was straightened to the point that there was no aileron
deflection for level flight. In order for an airplane to be properly
trimmed, there should not be any aileron deflection at all at neutral.
The first step is to fly the airplane and leave the aileron trim
where the airplane needed it to fly with the wings level. Note which
aileron is up. That is the wing tip to moved. By experience, I have
found that if you move that wing tip to where the aileron and the
fixed part of the wing tip on the outside portion of the wing is
in line, it is very close to where you want to be. Moving it is
Bolt the wing on the fuse and leave the radio on with the aileron
trim in the position that it was in for level flight. Get someone
to hold the airplane solid on a table with the wing we are going
to repair off the edge of the table. I have found that the easiest
place to heat and move the wing is at the aileron cut at the outside
end of the aileron. Using a monocote heat gun, I heat about a 6"
area from the trailing edge to the leading edge on both the top
and bottom of the wing. If the temperature is correct, it should
be hot to your touch, but not hot enough to bubble the paint. Heat
it in several passes over the area instead of trying to do it in
one pass. You must heat the top and bottom before you twist it to
the proper angle. The heat must go deep in the wing skin, not just
the surface to be able to move the wing.
Once the wing is heated, take the tip in your hand and hold it
at where you want it plus a little. Now, while holding it in position,
rub the heated area of the wing with a wet towel to take the heat
out of the skin and to set the new shape of the wing. Remember the
goal is to align the outboard aileron with the new wing shape with
the aileron in the new flying position. You may have to repeat the
process several times to get it where you want it after it has cooled.
When it is where you want it, it is time for the next step.
Now you will have a wing that the aileron center and tip does not
match the wing. We use the same method to straighten the ailerons.
With the radio holding the center of the aileron at the neutral
position, heat and bend the aileron to match the new position of
the straightened wing. Now remove the wing and mechanically center
the other aileron to match the wing. Next time you fly the airplane,
the ailerons will be perfectly aligned with the wing and in neutral
flying position. If not, you may have to repeat the process. Once
I have completed this, the wings have kept their shape. The heat
of the sun does not seem to affect the changes you have made.
This process is simple, and it has taken me longer to explain it
than do it
Do not be afraid to try it, it works well.