The blades are fabricated with a root portion having {HEAD ~ a cavity} adapted to mate with {TAIL ~ the disk protrusions} 
adapted to mate with
The blades are fabricated with a root portion having { HEAD ~ a cavity } adapted to mate with { TAIL ~ the disk protrusions }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL