Rotor head shake during pre rotation

[LARRYEBOYER]

I am experiencing severe rotor head and control parts shaking violently during pre-rotation. Any suggestions on cause and how to eliminate on my RAF?

 

[gyrojake]

If it never happened before, make sure nothing is getting ready to fall off.

 

[tomhall]

Larry, Check the pre-rotator clutch pads and friction disc. I saw this happen on an RAF some years ago. It may be caused by the clutch intermittently catching and releasing then catching again. Check the gap between the clutch plates; it may be too wide. I bought some Cessna brake pads to have on reserve to replace the clutch pads. Tom T. Hall in MN

 

[Kolibri]

Wow, that'd get my attention! If Tom is correct, please do nonetheless afterward tear down your gimbal head and inspect it for any damage/loose parts/etc. Having my SC rotor head to compare against the OEM RAF head, I am very leery of the Kindersley design.

Regards, Kolibri

 

[birdy]

Your clutch is glazed.
Ruff up the disc and pads.

 

[gyro]

I know mine did this when the engagement wheel got out of round. but that is on a wunderlich....I'm not sure what a RAF has??

 

[eddie]

I believe I had to do what birdy said to mine 5 or six years ago,it had a vibration at about

70 and the it would go away at about 90 RRPM.




Best regards,

 

[LARRYEBOYER]

Thank you all for your input. Good ideas to pay attention to.

 

[eddie]

hey Larry: did you find the vibration source during the prerotation.




Best regards,