A yaw motor is absent. The turbine passively yaws towards the prevailing wind direction. ECN has carried out a feasibility study from which the flexible rotor has been a promising spin off. Flexible rotor blades enable drastic alleviation of the fatigue loading. The location of the girders as load carrying members highly determines the dynamic behaviour of the blade.
Small modifications can significantly improve the aero-elastic damping of the rotor.
Elastic coupling between bending and torsion is researched using turbine simulations followed by experiments at Delft University of Technology to validate analytical predictions on aero-elastic tailoring. Elastic blade twist induced by bending can also be applied to improve the power curve of a constant speed rotor.