For information about Medieval Postal Service see the Team Urban Siege Website
Medieval Postal Service is a Floating Arm King Arthur (FAKA) style trebuchet which uses no secondary trigger. The counterweight is actually cocked leaning slightly backwards, which keeps the carriages against the rear end stops. A hinged bar in between the arm and hanger holds the hanger in position, and to trigger, the tip of the arm is pushed backwards until the counterweight begins to fall. The arm then follows the hanger on its own without any sort of secondary trigger, and the hinged bar (called the AntiTipover Bar, or ATB) swings out of the way. This machine shot a 9 pound pumpkin 1074 feet at the 2008 World Championships of Punkin Chunkin with a mere 700 pound counterweight.