How It Works: Creationism
Of course, this setup can only hover, not move.
A system was thus devised by which a signal sent to a Lego motor would turn a series of gears and worm gears to which blades were mounted. These blades sat in front of the floor fan's output side. Redirecting the airflow also redirected the hovercraft's motion. Another Lego motor was attached to the switch of the fan, and a third was detailed to turn the ShopVac on and off. All three are connected to potentiometers, whose function is described in the circuit section.
Both the ShopVac and the fan came whole and were modified
to suit the requirements of the hovercraft. The ShopVac's canister, filter, and ventilation plate were all removed, a plastic tube was taped to its output, and it was screwed upside down to the plate. The Vornado fan's switch mechanism was opened and the wires were extended for easier access, and the pipe holding it to the stand was removed. It was set on two contoured plywood slats to hold it perpendicular to the plate, and the gears for the fan were taped to the fan on the bottom and suspended from the top with twine. A Lego man was attached to one of the gears for balance. A housing was built for each of the remaining motors and a device to turn the switch it was connected to. The 23.5" diameter base was water-jet cut from a 24x28x1/8" sheet of aluminum. Holes were drilled in it for the ShopVac's ventilation plate, for the zip ties holding the motor housings and plywood fan supports, and for the hose attached to the ShopVac's output. The plastic tarp skirt was pleated and attached around the bottom of the plate. It was then duct taped along the top rim for security. A string was strung through the bottom, allowing us to gather the skirt.
Hovercrafts are simple creatures. Left to their own devices, they would spend their days grazing on the kelp berries in the North Pacific Ocean. They rarely reach diameters of more than 5 inches in the wild. Their natural predators include the sea otter, the pelican, and the human. The first two often mistake them for mobile floating oysters, while the latter harvests them for their chewy underbelly. In the common form, an air intake above the top plate takes in air. This air is expelled below the plate through a clever series of holes and hoses. A pseudopodic skirt skirting the edge of the plate holds the air under the plate until there is sufficient air pressure to lift the plate enough that the skirt no longer touches the ground and the air is able to escape. The hovercraft is one of the most recently domesticated animals - the first ranches were founded by English entrepeneurs in the 1850's. They hoped to breed them for diameter and lift, but were unable to find more than a niche market for their new transports.