Sparrow Hawk 1 Pre-rotator

[Colin Gibson]

Help.
Can anyone supply data an the efficiency of their Sparrow Hawk 1 pre-rotators.
Mine has the three small clutch pads and has essentially been a poor performer right from the beginning.
Have these clutches been improved and if so, what and how were they improved.
I have learned to fly it as originally built but its time to improve the efficiency of this component. It would certainly improve my take offs to have it working better.
Colin