{TAIL ~ The collective control} for pitch change employs a coil spring mounted between a pitch horn and {HEAD ~ a hub} 
{ TAIL ~ The collective control } for pitch change employs a coil spring mounted between a pitch horn and { HEAD ~ a hub }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD