PPRuNe Forums - View Single Post - Helicopter Dynamics: Gyroscopic Precession
Old 19th Mar 2014, 13:30
  #142 (permalink)  
AnFI
 
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Crab: "so you accept that your statement above was complete tosh then(?Ed)" Er, no.

Me:"there are 2 things (i can think of) that control force is needed for: 1 to overcome the moment of CoP at Arm from Pitch Axis and 2 to rotate the blades about their Pitch Change Axis - which is bigger if there is a larger polar moment of inertia around the pitch change axis , as you might well find for a larger chord blade (H500 compared to Gazelle for instance). I never really bought the story about the CoP not moving for symmetrical aerofoils anyway ... you can certainly feel it move in the (non hydraulic) H500 when you 'pull a bit'." (modified to the CoP change may just be inboard blade section stalling a little)

"1 to overcome the moment of CoP at Arm from Pitch Axis" covers: "Servo transparency is all about the amount of hydraulic power available in the jacks to oppose the aerodynamic forces trying to return the blade to flat pitch."

and I agree on your call of 'bull****' on :"Aerospatiale claimed it was a design feature to prevent pilots overstressing the aircraft"

and I agree that the ripples in Space-Time are far more interesting


and while we are talking tosh i think one of the really interesting phenomena is the business of blade stall at full RRPM by pulling to hard (needing to) lots of accidents from that.
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