The positions of {HEAD ~ the tracers} is determined by differential transformers having cores fixed for radial movement with {TAIL ~ respective tracers} 
The positions of { HEAD ~ the tracers } is determined by differential transformers having cores fixed for radial movement with { TAIL ~ respective tracers }
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL