Look Mom! I built a Hovercraft in the Living Room
- Plywood, 3ft. or 4ft. Square 3/8" or 1/2" Thick
- Plastic Sheet, 1' larger than the above Wood
- Leaf Blower
- Small Plastic Disk
- Coffee Can Lid or 6" Lexan Disk 1/8"
- Bolt, 2", 1/4-20
- Nut, 1/4-20
- Fender Washers
- Smooth Floor
- Electric Saber Saw
- Razor Knife
- Duct Tape
Make a plywood disk, either 3' or 4' in diameter. Drill a 5/16" hole in the exact center, and make sure the 2" bolt easily passes through it. Make a hole which exactly fits the end of your leaf blower. This hole must be placed half way between the center of the disk and the edge. Placing the mouth of the leaf blower on the wood and tracing is a good idea. Later you can seal any leaks with duct tape. The hose should be flush with the bottom surface. Next, place your plywood disk on the center of your large plastic sheet. Fold the edges of the sheet up over the plywood, then use the staplegun to staple it to the top of the plywood disk. Put a staple about every 4". The plastic should be tight against the wood, but don't pull it too tight or the plastic will tear loose when inflated. Cut off the excess plastic and use duct tape to make it look nice. To add the "skirt lifter" poke a hole in the center of the coffee can lid and attach it to the bottom of the hovercraft. From the bottom it should go as follows...bolt, fender washer, plastic disk, plywood disk, fender washer, and nut. The coffee can lid forms the donut hole when the leaf blower slightly inflates the plastic into a donut shape. Time to cut center holes. Use your razor knife to cut six vent holes in the plastic. They should be about 2" in diameter. They must be placed within a few inches of the coffee can lid. Space them out so that there is plenty of plastic between each of them. If they are too far away from the center they will become plugged when the plastic sheet lays flat against the floor. If the plastic between the holes is too narrow, it will tear. You can reinforce the thin necks of plastic between the holes with duct tape. Flip your Hovercraft over so the plastic is on the bottom. Place it on a smooth floor, stick the leaf blower in its' hole and turn it on. The plastic on the bottom should inflate. If it does not, lift the plywood up a bit to let the air get in and inflate the skirt. The Hovercraft will lift up slightly and start gliding around. Make sure you are on a very smooth floor.
What's going on?
The air inflates the plastic which pushes upon the floor and provides a ground hugging skirt. This lifts the entire Hovercraft. The coffee can lid provides relief fro the plastic sheet, so that the inflated plastic doesn't tear loose from the center. The coffee can lid also lifts up the plastic so ari can escape through the vent holes and pressurize the center donut hole. The air leaks along the floor and out from the edges of the Hovercraft. This creates an air film bearing which has very low friction. The plastic isn't touching the floor, the Hovercraft is riding on a thin layer or film of air. Try climbing aboard. Adult supervision is required when boarding. Pictures for this project can be found at http://amasci.com/amateur/hovercft.html