To: Dave Jackson. .. .It is you that is mixing apples and oranges.. .. .Here is the question I posed.. .. .Now here is a problem for you scientific types. Instrument a rotor blade so that at each given blade station from the root to the tip there was a strain gage to measure the forces and then bring the blade up to speed the forces would go from max to minimum from the root outward to the tip. Is this correct or not. Why?. .. .Here is your response, which is confusing as it deals with blade stations and centrifugal clutches. Is the formula you posted below your answer to why?. .. .The following is the answer to your 'Why'. . ._____________________ . .. .The shoe must have mass for the clutch to work.. .The drum does not need to have mass.. .. .The equation for centripetal force is:. .F = M * v^ / r. .i.e. Force = Mass time velocity squared divided by radius.. .. .Therefore, because the drum does not need to have any Mass it cannot impart a Force.