Chapter 9.6 and 9.7 have been added to report KD 622. Chapter 9.6 gives the calculation of the aerodynamic moment if the blade axis is shifted more to the nose. This has as advantages that the aerodynamic moment becomes larger and so the influence of the friction moment of the bearings becomes relatively smaller. It has also as advantage that the system reacts more sensible to wind gusts. Chapter 9.7 gives the geometry calculation of the compression spring.