For this purpose, the bases of {HEAD ~ the outer trailing edges} of the second row blades have {TAIL ~ a negative propulsion angle} 
For this purpose , the bases of { HEAD ~ the outer trailing edges } of the second row blades have { TAIL ~ a negative propulsion angle }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL