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