torsion flexural flutter

The tendency toward aileron control reversal in flexible wings. The deflection of control surfaces produces a large amount of camber at the rear of the section. This causes the resultant lift force to move rearward, thus tending to twist the section nose-down. If the structure is insufficiently stiff in the torsion, the resultant decrease in the angle of attack can cause a loss of lift, and the reversal of control is effected.