a. Passiv wing twisting

Normally, the twisting can only change between two mechanically given final positions of the angle of incidence. The transition easily takes place through aerodynamically forces (for example simple membrane flapping wings).

There is no automatic alignment of the magnitude of twisting to variable angles of incidence during the wing beat.

b. Active wing twisting

The twisting is mechanically controlled by the drive of the flapping wing (EV1 to EV5) or an additionally servo drive. Thereby, cyclically, a temporal mostly sinusoidal variation of the wing twisting during a flapping cycle takes places .

There is an automatic alignment of the magnitude of twisting to varying, but not to anticipated angles of incidence during the wing beat.

c. Aeroelastically wing twisting

The wing is constructed elastically to twisting. Size and direction of the twisting are determined by the springiness of torsion of the wing and by the torque of the aerodynamically forces.

There is an automatic alignment of the magnitude of twisting to varying and also to anticipated angles of incidence during the wing beat.

d. Aeroelastically controlled wing twisting

Arm and hand wing are connected elastically and by a hinge. As a result of changing lift and acceleration forces an up- or down bending of the hand wing towards the arm wing takes place (aeroelastically). This motion will be used to control the twisting of single wing sections or of the whole wing (please look at articulated flapping wing of EV6 to EV8).

There is an automatic alignment of the magnitude of twisting to varying and also to anticipated angles of incidence during the wing beat.

e. Radio-controllable wing twisting

The twisting is - in addition to the aforementioned methods - controllable by a radio-controlled servo drive.