Engineering Expedition Everest, complete with a yeti

Walt Disney Imagineers faced a monster of a challenge when they planned Walt Disney World's latest park attraction, Expedition Everest. The yeti is supported by a structural beam connected to its back. The beam attaches to a vertically mounted actuator that gives the creature 2 ft of vertical motion. The vertical actuator, in turn, connects to a sled that moves 5 ft horizontally on metal ways to give the yeti back and forth motion. At just under 20-stories high, the man-made mountain in Disney's Expedition Everest is the tallest peak in Florida. It took three years and more than 38 miles of rebar, 5,000 tons of structural steel, and 10,000 tons of concrete to build the mountain. They chose to build the largest mountain in Florida, lay track through that mountain, and populate it with one of the largest, fastest-moving robotic creatures in history — a 25-ft tall, 20,000-lb yeti, the Abominable Snowman. Riders see the simian yeti only as a quickly darting silhouette or hear it as a lonesome howl before they get up close and personal with it. "As the ride goes along and guests get closer to the yeti, the more real he becomes, building excitement and bringing the ride to a climax when they meet faceto-face," says John Van Oort, principal mechanical engineer for the Show Mechanical Group, Disney Imagineering, The yeti relies on Disney's Audio-Animatronics technology, which was first developed in the 1960s to animate 3D robots of characters from Disney movies. And although Disney won't say what that technology consists of, or even whether it's analog or digital, the results are "awesome," according to those who have ridden the Expedition Everest. We also know that hydraulics power much of the yeti's movements. "It has 19 axes of motion, but it's a bit different than past