When blade 2 is in the upwind or in {HEAD ~ the downwind sectors} of {TAIL ~ the cylindrical path} it creates mainly drag and drive component forces 
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When blade 2 is in the upwind or in { HEAD ~ the downwind sectors } of { TAIL ~ the cylindrical path } it creates mainly drag and drive component forces
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH