A new chapter 6 has been added to report KD 439 about the pendulum safety system with a torsion spring. In this chapter the use of the VIRYA-10 rotor is described. I expect that this pendulum safety system can be used up to a rotor diameter of about 20 m but for such a large rotor diameter it might be better to keep the rotor in the wind by a wind servo in stead of by a double vane.