There is {HEAD ~ one radial opening} in {TAIL ~ drum} 5 for each crank arm 6 
in
There is { HEAD ~ one radial opening } in { TAIL ~ drum } 5 for each crank arm 6
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH