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.