The Hippo


Jan 20, 2020








Finished hovercraft. Courtesy photo.

 Here’s what you’ll need to break the bonds of gravity: 

1 sheet of ½-inch plywood (4 x 4 feet is all you need)
1 standard tarp (6 x 8 feet is fine)
1 leaf blower (gas or electric)
1 old chair 
Duct tape
13 feet of foam pipe insulation 
A few short screws, wire ties
Tools you‘ll use along the way: jig saw, drill, staple gun, screwdriver, scissors

Breaking Gravity
Build a real hoverboard

By Rick Ganley

No need to pretend to hover on an over-priced skateboard that could explode into flames at any moment; you can roll your own hovercraft in a couple of hours with a few common hardware finds and that old leaf blower in the shed. It’s a basic science project that physics teachers and science geek middle-schoolers have been doing for years. And yeah — it really works! 

Get ready
Start by cutting a 4-foot-diameter circle from the plywood. Use the scrap to cut out a circle of wood about 7 inches in diameter and set it aside. 
Place the leaf blower in the center of the 4-foot circle and note where the nozzle would come into contact with the wood. Cut a hole through the wood the same diameter the nozzle. This is where you need to be a little creative: depending on the blower, you may need to use some flexible piping to direct the airflow into the hole. Lighter electric blowers may work fine placed vertically with the nozzle stuck directly into the hole. Once you have the hole for the nozzle cut, set the blower aside.
The tarp will become the skirt; this is what directs the air and gives the hoverboard its lift. Spread the tarp out on a clean flat surface and place the board in the center. Fold the tarp up around the edge of the board. Leaving a gap of an inch or two, use a staple gun to staple around the entire perimeter. It’s OK (in fact desirable) for the tarp to be loose around the edges and underside of the board. It will inflate with air from the blower and form a cushion (or pillow) for the board to float on. Trim the excess portion of the tarp from the top of the board and use duct tape to completely seal the edges all around. The trick is to make the seal airtight. 
Now turn over the craft so the tarp side is face up. Take the 7-inch-diameter circle of wood and place it in the center on top of the skirt. Attach it using short wood screws (making sure not to poke through the top).You may want to place short strips of tape over the screw heads to keep any rough edges from scratching the flooring. 
Cut six 2-inch holes in the tarp in a ring formation about 2 inches from the 7-inch wood. To keep the tarp from tearing, you can use some tape on the edges of the holes. 
Turn the craft back upright. Mount the leaf blower. Again, you need to be creative depending on the model; you can use brackets or wire ties to avoid any damage so you can still use it to clean up the yard. However you mount it to the board, be sure to keep the blower’s air intake clear. Use duct tape to seal the nozzle into the opening on the board, taking care not to poke into the tarp below. Ensure the seal is airtight; any escaping air is lost lift power. 
Self-adhesive pipe insulation works well for edging and will prevent any damage to people, pets and things in the path of your hovercraft. Peel off the tape backing from the foam pieces and attach it to the perimeter of the board. 
Put your chair on the top of the craft; before you secure it in place, check to see that the center of gravity with the pilot in the seat (yes, you’re about to become a pilot!) is centered. 
Get set for the maiden voyage
A few notes before we begin the fun: First, this isn’t Back to the Future, and you aren’t Michael J. Fox in denim; don’t try this thing standing up. You will get hurt. Sitting down, the craft is quite stable and you’ll have no worries. 
Something else to keep in mind: Your new space age machine is truly capable of “flying” over smooth, flat flooring. It will not conquer grass, gravel, water or an incline of any sort. So start off in the workshop or kitchen. 
Ready to go? Sit down, start up the leaf blower and you should have liftoff. If all is functioning correctly, the skirt should be mere millimeters off the floor, but your hovercraft should be frictionless. Have a partner push you around the room. Note the ease with which you float around in free space, confident you have indeed mastered — no, conquered! — the force of gravity. You, yes you, have overcome an “absolute” force with nothing but some plywood, plastic and a yard fan. Quite impressive, you are. 
The kids will love taking rides. The cat will not. Earplugs may be a good idea for long sessions. Advanced users may want to experiment with a second leaf blower or fans to make thrust and actually self-power their craft. You may also want to try making different skirts with more or less “pillow” and alternate hole patterns and sizes to see the effect it has. The point is to learn a little science and have a lot of fun. 
Happy hovering! 

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