bladeletts 34 to rotate around their center mounting holes 38 fig3 a depicts two actuators 44 which provide redundancy the bladeletts 34 are biased into their retracted positions using any suitable biasing mechanism such as springs the operating cam 6 may be rotated in several different ways a screw jack system may be employed a hydraulic actuator could be another choice a servo motor a rack and pinion assembly a worm gear assembly crossed helical gears pneumatic or hydraulic or any other means to impart force to the operating cam to cause rotation fig8 depicts one version of a rotation mechanism which includes a hydraulic cylinder 52 attached to rotor head 3 it is connected to the operating cam 6 by a rotation mechanism arm 54 attached to the operating cam 6 by a pin or rotation mechanism bolt 56 sufficient clearance is provided to allow the rotation mechanism bolt 56 to rotate relative to operating cam 6 hydraulic fluid is introduced into the hydraulic cylinder 52 through first and second feed lines 58 and 60 respectively pressurizing the cylinder to move the rotation mechanism arm 54 either inward or outward relative to hydraulic cylinder 52 thereby rotating the operating cam 6 either clockwise or counterclockwise thereby causing the cam grooves 8 to move the blade spars 10 and blades 12 either inwardly or outwardly of the operating cam.