the fourth component rotates at a first ratio with respect to the rotor during {HEAD ~ the first mode} of {TAIL ~ operation} 
of
the fourth component rotates at a first ratio with respect to the rotor during { HEAD ~ the first mode } of { TAIL ~ operation }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL