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