This instructable coves how to build a hovercraft out of a foam tray, cardboard, and some other household items.
Step 1: Materials
For this project you need:
A foam meat tray (smaller is better)
Some non-corrugated cardboard (I used the kind in Kudos bar boxes)
A small 1.5 volt DC motor
A propeller that can attatch to the motor (I used one from an old RadioShack kit)
A nine volt battery
A nine volt battery snap
A glue gun
A craft knife
Step 2: Make the Intake
The intake should be as short as possible to allow very little air to escape. Measure the length from the bottom of the motor to the end of the propeller blade, then add a half a centimeter or so. The top should be just wide enough to fit the motor on it without too much overhang. The angle of the back isn't crucial, but I have found 45˚ works the best. Once you have figured out the measurements and cut it out of cardboard, glue it all together with liberal amounts of hot glue.
Step 3: Make the Base
The base is just a foam meat tray with a hole in it. Trace the outline of your intake in the center of the meat tray, then cut it out with the craft knife. Be careful not to dent the bottom edge of the tray, as it could cause it to go off balance and touch the ground.
Step 4: Attatch the Intake to the Base
Now hot glue the intake to the foam tray, directly over the hole, with the meat tray facing down.
Step 5: Attatch Motor and Battery
Use the tape to attatch the motor to the top of the intake, and more tape to attatch the battery to the back, just past the intake. Make sure to leave enough room for the fan blade to move. Then attatch the battery snap to the battery.
Step 6: Finished!
To start, place the hovercraft on a hard, smooth surface. Put one of the wires from the battery snap through one of the holes in one of the contacts on the back of the motor and bend it so it doesn't come loose. Then, put the other wire through the other hole, so that it just barely stays there. That way, it's easier to remove when you chase it down. If the propeller blows the air forwards, reverse the wires. Also, this is a 1.5 volt motor, so hooking it up to a nine-volt is not good for it. Don't let it run for long periods of time or it will burn out the motor. It works by creating a high pressure zone inside the meat tray. The escaping air travels under the rim of the meat tray, causing the tray to lift off the ground very slightly. The top part of the propeller provides lateral thrust, causing the whole thing to move forward.