Joined: Mar 29, 2006 Posts: 289 Location: Scotland
Posted: Sun Feb 15, 2009 9:27 pm Post subject:
AB, please note we are refering to VnO not VnE that the CAA has imposed. Vne is set by the manufacturer. _________________ Generally wrapped in rubber, be it in the air or on the water.
Joined: Feb 14, 2008 Posts: 888 Location: Stavanger, Norway
Posted: Tue Feb 24, 2009 3:52 pm Post subject:
I think I have found out why the CAA may have brought Vno into place. This was a recommendation made by the NTSB to the FAA to reduce Vne on the R22 series to reduce the possibillity of loosing control of the main rotor.
"Issue an immediate airworthiness directive to reduce the Robinson R22 helicopter "never exceed airspeed" (V.3 to an airspeed that would provide an adequate margin of operating safety below the airspeeds at which loss of main rotor control accidents have occurred, until the reason for in-flight main rotor blade divergent behavior is established and design changes are approved and implemented, as necessary. (A-94-143)"
...and design changes were never made were they. As far as I am aware the FAA did not follow this recommendation after consultation with RHC, however it would appear the CAA did, and as per the supplement in the POH it was for control sensitivity, or rotor sensitivity as it should have been called.
Joined: Aug 23, 2005 Posts: 266 Location: On a course.... golf course
Posted: Wed Feb 25, 2009 9:56 am Post subject:
Vne isn't the speed for onset of retreating blade stall.
It is a combination of a lot of factors including stress on the head and mast and transmission. Otherwise, how would you explain a Vne on a B47 of 83 kt or so, when almost the same rotor on a 206 can go to 122kt?
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