Report KD 409 describes the ecliptic safety system with a torsion spring. The spring stiffness has been reduced such that the spring moment for 100 degrees rotation of the vane arm is now a factor 1.5 higher and not a factor 2 higher than at the beginning position. The rated wind speed is increased from 7 m/s up to 8 m/s. These modifications make that the delta-V curve is lying closer to the ideal curve.