{HEAD ~ The rotor spindle} and controls pass through {TAIL ~ a central hole} between the spar caps 
pass through
{ HEAD ~ The rotor spindle } and controls pass through { TAIL ~ a central hole } between the spar caps
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH