When the two sides already have wings, sandpaper comes the curve to reduce aliasing the strength of the wind. Gently rub both sides, gently place the same (watch out for broken wings).
When the two wings on either side, remove the sandpaper to outdo the arc to reduce the force of the wind. Gently, gently rub the two sides to do the same. (Beware defeated)
the whole wing 2 side to bring the sandpaper to outdo the curve to reduce tension side of the wind gently gently rub both 2 side to be the same. (be careful with broken wings)