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