An artificial bird is introduced which was developed using two new
features in biologically-inspired flight, active torsion and partially linear
kinematics. Active torsion rests on well established theoretical
predictions in unsteady aerodynamics. The concept of partially linear
kinematics is inspired by zoological observations on flying locusts.
When the wings flap upwards, the servomotor for the active torsion
turns the outer wing from a positive angle of incidence within
a short fraction of the flapping period into a negative angle of incidence.
Between the turning points the angle of torsion remains
constant. Numerical calculations confirm the expected benefits
compared to passive torsion.