Further, the method includes enlarging {HEAD ~ the hole} until the sensed parameter represents a preselected air flow rate through {TAIL ~ the hole} 
Further , the method includes enlarging { HEAD ~ the hole } until the sensed parameter represents a preselected air flow rate through { TAIL ~ the hole }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL