Therefore, with the lateral articulated joints of blade 2 following a circular path, and its rear section articulated joint following an elliptical path, {HEAD ~ the desired effect} is obtained in {TAIL ~ the form} of cyclical changes in the blades pitch angle as it travels in the closed cylindrical path 
Therefore , with the lateral articulated joints of blade 2 following a circular path , and its rear section articulated joint following an elliptical path , { HEAD ~ the desired effect } is obtained in { TAIL ~ the form } of cyclical changes in the blades pitch angle as it travels in the closed cylindrical path
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH