Due to the sloping of the truncated cones sidewall, the gap 70 gets bigger through {HEAD ~ the length} of {TAIL ~ the air horn} 50 
Due to the sloping of the truncated cones sidewall , the gap 70 gets bigger through { HEAD ~ the length } of { TAIL ~ the air horn } 50
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH