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Homemade Engine-powered and Human-powered Hovercrafts

Building a Type I Hovercraft

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TYPE I:

Simple Circular Hovercraft

Costs around $30, not including motor/shopvac

Holds: 1 Person


This is the easiest of all the hovercrafts to build, requiring maybe a day of work at most if you have the right materials. You need a circular piece of wood with a bag skirt (see "skirt types" on the nav bar to the left) and some caulk/staples to hold it in place. (There is also an explanation for how to buld the skirt below) The way it works is through a hole in the top you can plug in any sort of air-blowing mechanism (if you're looking for something simple, find a ShopVac that you have laying around...it works great for this kind of thing) and the bag will inflate lifting you either around and inch or two in the air or an amount where you wont even be able to tell the bag is inflated (depends on how tight the skirt it and other factors). These can lift up to around four inches but ours can't do that and we've only seen pictures of other peoples'. Don't get me wrong, it's fun; you pretty much have to sit cross legged in the middle (unless its a quite big model) and you can have tons of fun pushing yourself around of having someone else push you. Make sure your ShopVac has extension cords!

The Plywood works best if it's from a 4 by 4 sheet of plywood, about a half inch thick. *Find the center of the circle and tie a string around a nail. tie the other end two feet away from the nail to the tip of a pencil. set the nail in the middle and stretch the string while drawing a big circle that is inscribed in your 4 by 4 sheet of plywood. (It's like a giant compass) Then cut the circle with a jigsaw. (or other cutting device). Obtain a two inch bolt with a nut. drill a whole for this bolt in the center of your plywood. Then make a hole about half way between the center and the edge of your hovercraft for the air blowing device.

For the skirt here is some basic info (go to skirt page for more information on various skirt types): You need a strong plastic, nylon or canvas to hang from the circle and it needs to be sealed air-tight around the edge of the circular wood (a shower curtain works good). lay this piece flat on the ground. Take the plywood which you have already cut and place it top up in the center of the skirt material. Take the sides and fold them onto the top of the plywood, making it overlap itself about every six inches. Make sure that the skirt is not too tight or too loose. Then staple this very firmly to the top (don't staple the bottom). You'll then want to duct tape this to the plywood to where the air won't escape. Make sure that if you covered up the hole for feeding air under the craft with the skirt, you should cut a hole in the skirt so it still works.

The next part is quite necessary, so don't skip it. You will want to find a coffee can lid or other large, strong, and thin disk. (we used paint can lid). drill a hole in the center of it that is the size of the one you drilled in the center of your plywood. drill or cut that same size hole in the center of the skirt where it covers up the hole in the plywood. Put your two inch bolt in (facing up so it lays flatter on the ground) and put the nut on.



The air coming in has to come out, so cut six holes about one inch in diameter about 4 inches away from the outside of the coffee can lid. (see picture at right).

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The air goes into the bag, inflating the bag and lifting the hovercraft up. The air then goes beneath the craft and into a chamber of air (plenum chamber) and when that air gets to a high amount of pressure it glides out from underneath the bag.


There also needs to be some way for air to escape so your hovercraft doesn't decide to explode on you. Also, air escaping (from underneath preferably, but if you've done a really bad glueing job with the skirt around the top, I guess that'll work) from the bottom will create some friction on the ground. Cut one (small) hole at a time on the bottom and test each time until you think sufficient air is escaping. It should be enough so that it stays consistently inflated the same amount. If there are too many holes, it won't inflate much, and then will start to inflate more when the holes get blocked up. If there are too few holes, the whole mechanism will overinflate. DONT SIT ON IT IF ITS OVERINFLATED!

Put the holes in a circle around the middle piece of wood on the bottom, keeping them consistently sized and spaced. The usual amount of holes for a standard 4-ft diameter hovercraft is six, at about an inch and a half to two inches each.

You might want to tape or mount the source of your air into it's hole (with tape if you want it to be temporary) so it doesnt spew out.

TYPE I HOVERCRAFT
hovercraft1.jpg
Simple circle with a bag skirt

shopvac.jpg
A ShopVac...see if you have one laying around

circletopside.jpg
Make sure to wrap the skirt material around to the top to mount it.

underside.jpg
The air holes on the bottom of the craft

hov3.gif
Diagram

MORE INFO ON HOW TO BUILD A CIRCLE HOVERCRAFT:
http://www.amasci.com/amateur/hovercft.html http://www.vast.org/vip/HOVERCFT/instrctn/index.htm

Have a question? E-Mail Mr. Hovercraft at mrhovercraft@gmail.com ! If you haven't noticed, we're all "Mr. Hovercraft".