the rotational plane the amplitude of the auxiliary pitch control signal 4 a is directly related to the amount by which the corresponding actuator is caused to travel and therefore also to the pitch angle of the corresponding rotor blade i e the greater the amplitude of the auxiliary pitch control signal 4 a the more u201c positive u201d the pitch angle for example the maximum amplitude of the auxiliary pitch control signals 4 a might correspond to a pitch angle adjustment of about 1 u00b0 to 4 u00b0 for rotor blade 3 a this auxiliary pitch control signal 4 a is overlaid on the main pitch control signal as explained in fig2 above and the combined pitch control signal is applied to the corresponding actuator as described with fig3 above the same applies to the other two blades for which auxiliary pitch control signals 4 b 4 c are added to the main pitch control signal and applied while those blades are in the upper half of the rotational plane p as the graphs indicate a time interval corresponding to almost one additional rotation of the hub separates consecutive auxiliary pitch control signals 4 a 4 b 4 c in this and in the following diagrams the maximum pitch correction a max is shown to be the same for all three blades but it is to be understood that the pitch angles of the.