said pitch angle and {HEAD ~ a position} of the blades gather wind energy in the upwind and downwind sectors of the cylindrical path and generate {TAIL ~ lift} in the upper and lower sectors of the cylindrical path, 
said pitch angle and { HEAD ~ a position } of the blades gather wind energy in the upwind and downwind sectors of the cylindrical path and generate { TAIL ~ lift } in the upper and lower sectors of the cylindrical path ,
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH