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