{HEAD ~ The ratio} between {TAIL ~ the fixed intake aperture}, and the configurable exhaust aperture creates a volume and thus a velocity differential in the air mass on either side of the relatively centrally located in the duct turbine type fan, 3 
between
{ HEAD ~ The ratio } between { TAIL ~ the fixed intake aperture } , and the configurable exhaust aperture creates a volume and thus a velocity differential in the air mass on either side of the relatively centrally located in the duct turbine type fan , 3
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH