{HEAD ~ Noise reduction} in counter rotating fan propulsion is accomplished by providing an engine core, driving an outer blade row from the engine core and driving {TAIL ~ an inner blade row} from the engine core 
{ HEAD ~ Noise reduction } in counter rotating fan propulsion is accomplished by providing an engine core , driving an outer blade row from the engine core and driving { TAIL ~ an inner blade row } from the engine core
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH