When I was a lad (sometime between the invention of electricity and the introduction of personal computers) my friend Mark and I wanted to build a hovercraft. With the help of his dad (well, at least we got to watch most of the construction) we built a small, simple, cheap machine to play with on the driveway.

A simple sheet of plywood (probably 3/4", if I remember correctly) cut into a 4-foot disk, a skirt made out of garden edging, and a blower motor from a gas furnace, combined with a long heavy-gauge extension cord had us playing in one weekend. (You are right, the garden edging would collapse and get crushed when the machine stopped. Mark's dad put a few wooden blocks around the inside edge of the skirt to absorb the weight of the machine when it was idle.) While not suited to racing like our friends the Brothers Long and the Scrap Daddies did, it was a very kid-friendly project that demonstrated most of the key science behind a hover craft.

Another advantage (to the parents) is that it couldn't go farther than the extension cord could reach. They didn't have to worry where we were.

-- Rick Tyler (rick@raf.com), January 19, 2001

Answers

I helped one of my sons build one for a science fair project, using a small vacuum cleaner for the air supply, and a big tin can lid with a rolled edge. It would elevate with the vacuum cleaner and about six lbs of canned goods on it and it moved easily on a smooth surface, like an air puck. We didn't know that you had to have a skirt, but the rolled edge served the purpose on a smooth surface.

-- Waddy Thompson (cthomp3851@aol.com), January 19, 2001.

I made a little r/c hovercraft as a project in Highschool. I used styrofoam insulation to make a circular base (2' diam.). Around the edge as a skirt I used a really large rubber band sort of material. This rubber I found at my physiotherapy place, they use it to give to patients to excercise at home. I put two small motors facing downward (with hand carved propellors, like the team on JYW). It had two more motors on the top on opposite ends. To go straight, both motors would be on.. to turn, you'd just put one motor on.

Mike http://mikebeauchamp.com

-- mikebeauchampDOTcom (mikebeauchamp@home.com), January 20, 2001.

My son and I built a round 4 foot hoover craft that we saw on tv. We used a 3.5 hp Shop vac blower and used clear plastic visquene across the bottom with 4 - 4 inch holes cut in the bottom to vent the air under the disk.. It would scream down the cement driveway until it ran out of extention cord and the extention cord came out of the wall. It would lift a large adult sitting in a lawn chair balanced in the middle and could be pushed around by my 35 pound daughter easily. It only cost $12 for a sheet of OSB and I had everything else around the house.. the kids played on it till I needed my Vacuum back a few weeks later.

-- Gary Mills (gary.mills@corp.cccomm.net), January 20, 2001.