{HEAD ~ An elongate drive shaft} extends from {TAIL ~ an engine mounted fore} of the concavity to the impeller 
extends from
{ HEAD ~ An elongate drive shaft } extends from { TAIL ~ an engine mounted fore } of the concavity to the impeller
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH