a cylinder and piston forming {HEAD ~ a chamber} mounted on {TAIL ~ a drop vehicle}; and 
mounted on
a cylinder and piston forming { HEAD ~ a chamber } mounted on { TAIL ~ a drop vehicle } ; and
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH