Hovercraft

Hovercraft
This is a full size(4ftx8ft) one person hovercraft built over one summer for less than $200. It was built with no prior experience or knowledge of hovercrafts but with sheer determination to build something different. So check this project out, hope you like it.
 
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Step 1The Skirt and Base

The Skirt and Base
Lets start out with a little history, I built the hover craft during the summer between my sophomore and junior years of high school. It was built by a good friend, Brain, and myself Doug. Like I said I built the entire craft for less $200 including the engines and the fans. I will explain how I did it soon but lets start out some of the main things you will need to get started.

3hp Horizontal Shaft Engine $50 at a local lawnmower repair shop
4hp Vertical Shaft engine took it off one of my lawnmowers
5.2 moisture resistant Lauan Plywood 4ftx8ft
Styrofoam 4ftx8ft
1/2in Plywood 2ftx4ft
A couple 2x4 8ft
A couple 1x2 8ft
1/4in bolts and nuts 1in- 3in
Wood Screws 1/2in - 1in
Plastic sheeting Painters Sheet (this is the skirt material)
Brass Grommets with punch You can get this as a kit

This is about what I started out with but in no way is this everything youll need. Also keep in mind that this is how I did it, if you plan on taking on a project like this do it how you want to and with what is available to you. Use this as a guide so that you do not make the same mistakes I did.

Lets start out from the ground up. On a hovercraft the only thing that touches the ground is the skirt. The skirt is the part of the hovercraft that holds air to lift the craft. Like in the second picture my hovercraft has two engines, one for lift and one for thrust. The lift engine pushes air under the craft and the skirt holds the air in. As more air is pushed under the craft pressure builds up and lifts the hovercraft off the ground. This is how a hovercraft hovers, the only thing in between the base of the craft and the ground is air.

But before I designed the skirt I designed the base of the craft. It has to be light(this is the most important) and it has to be strong enough to hold the weight of a person and the engines and everything else. Keep in mind though that when hovering the craft is actually more stable than when its not. The air pressure helps to hold the weight evenly over the entire craft.

This said here is how I made the base. I got two sheets of 4ftx8ft lauan and a piece of 2in thick Styrofoam. The lauan was the cheapest and the lightest sheet of plywood I could find at home depot. One note, I got almost everything for this hovercraft at home depot. Lows or any hardware store will probably have the same items I got.

The base is just the two sheets of plywood with the Styrofoam sandwiched in between. Holes are drilled all the way through this sandwich and bolts are used to hold all of the components on the base.

Back to the skirt which is one of the more trickier parts of a hovercraft. It has to hold its shape under pressure and it has to be the right size. To big and it will drag on the ground which will slow the craft down or not let it move at all and to small and it will not hold enough air to sustain lift.

To overcome this I designed my skirt to have 8 different pieces that I sewed all together with nylon string. For each of the four sides of the craft there are two skirt pieces. A upper half and a lower half, which are same shape. The picture shows what each part looked like. Basically the same design for all four sides just different lengths. The skirt is actually smaller than 4ftx8ft by 2in on all sides. This is done so that the skirt can sandwich between the Styrofoam and the top piece of plywood. So you will need four longer skirt pieces and four shorter ones.
Each piece first needs its flap folded over and sewn. To sew the skirt I used a standard sewing machine and sewed along the seam lines which are 1/2in from the edge. Now take two pieces one short and one long and sew them together at the angled end. Now do this again for all the other pieces to form a two rectangles. Now put one rectangle on top of the other and sew along the outside perimeter. This forms the whole skirt but its not done yet.

Now duck tape along the seam for added strength then flip the skirt inside out so the seams are in the inside. Punch holes on the inside of the skirt in the middle of the flap on the top and the bottom of the skirt with the grommet kit. Put holes on all corners and every foot along the length of each side. Drill holes through the base that line up with the grommets. Sandwich the top of the skirt between the Styrofoam and the top piece of plywood and then use 1/4in bolts to hold it all together.

This completes the skirt and the base. This is the most general part of the build. The rest of the craft is built specific to the engines, fans and components I used, you will have to adapt these plans to fit your components.

Sorry about the pictures I could not get them to show up very well. I included the DWG file though. The last picture is the overall skirt put together showing the flap folded over with the dashed line and where holes should be put with the circles.
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290 comments
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Apr 9, 2009. 8:15 AMPickPacket says:
That looks safe..
Apr 9, 2009. 8:10 PMpufferboytbh says:
THIS IS IN NO WAY SAFE. For our cadet's "Pioneer's" platoon (building stuff), we built 3 full sized hovercrafts for use. The prototype on it's first run tore itself apart, srapel flying everywhere, nearly killing myself and many other cadets. In building these hovercrafts, ensure that there is a metal mesh over the air intake (and outakes) and that the propellers are insulated in metal. Depending on your propller speed. Have fire equipment ready. Being 14, I don't want me or my cadets to die.
Nov 22, 2011. 7:50 PMJaredicus says:
What branch JROTC are you? I am army JROTC.
Apr 9, 2009. 8:15 PMpufferboytbh says:
By the way... The same thing happened about a month later. With the metal, the propeller stayed in the engine housing, causing only damage to the engine, housing and propeller. The hovercraft remained floating, while we remove the two year seven cadets from the craft, set up a perimeter, and killed the engine. The craft didn't even sink! MUCH SAFER.
Oct 9, 2011. 1:44 PMszulli-randall says:
Does anyone think it's possible to make it hover a few FEET off the ground?
Nov 5, 2011. 3:04 PMjbowman7 says:
they're called hoverwings, google it
Nov 8, 2011. 8:51 PMszulli-randall says:
I ment without wings.
Nov 9, 2011. 2:24 PMjbowman7 says:
Then no, it's not possible, the skirt has to be touching the ground to maintain the air cushion. but you can still hit jumps with a sturdy hovercraft. Look up hoverwings though, they're cool.
Nov 22, 2011. 3:19 PMiminthebathroom says:
Not sure if even they hover that high actually, maybe periodically though
Nov 22, 2011. 9:32 AMgeckomage says:
will this hold a 260 lb person like myself? :P i normally go muddin in my truck when i wana have fun driving something. but this'd be fun :D
Nov 22, 2011. 7:08 AMthreewingwonder says:
You could build your own fans from wood, all you would have to do is check out Universal Hovercraft with a search. I have built a hovercraft from plans that I got from them. turned out to be a very versital craft.Mine was 6ft x 12 ft and had a 5 hp lift motor and a 30inch home made lift fan and 2-5 hp thrust motors with 48inch homemade thrust fans. I now have plans for a little bigger craft for exploring. You should really check out :Universal Hovercraft, they are based in Cordova Illinois. A very good place to start a hovercraft adventure.They have plans,supplies and advice/tutorails for hovercraft builders.Great ible though
Apr 19, 2011. 12:25 AMgopalrr says:
hi,

can you share details of how you did the 70%/30% distribution of air thrust to lifting and propulsion ?

gopalrr
Aug 19, 2011. 8:52 AMrocketman20 says:
Where did you get the fan you used for trust.
Nov 22, 2011. 4:46 AMelina0 says:
OMG! This seems me too heavy..
Aug 2, 2011. 3:33 PMrbland says:
you probably want to put some sort of cage around the vents too: http://www.stuff.co.nz/national/5380361/Auckland-man-decapitated-testing-hovercraft
May 3, 2011. 9:24 AMrocketman20 says:
Are the Brass Grommets just for attaching the skirt to the base? Also does the skirt have holes in it? I am trying to build a hovercraft myself but am having a hard time understanding how the skirt works.
Jul 28, 2011. 8:05 PMjdhover says:
so is your base piece hollow or is it ducted?
Jul 20, 2010. 5:52 PMnibbler125 says:
you need a real fan that metal one has no airfoil and you could easy double youre lift with a good wood one it will cost allot more tho up to 200$
Apr 15, 2011. 10:35 PMss2pheonix says:
or just make one yourself, assuming of course you have basic air foil knowledge and the ability to carve
Apr 15, 2011. 10:32 PMss2pheonix says:
i think i would have used one 12hp engine or bigger from a lawn tractor and rigged the mowing deck to feed the air for the lift and controlled the drive fan with the drive train from said lawn tractor.
Feb 9, 2011. 10:02 AMilpug says:
nice. i think you need a much tougher more rigid skirt. i would also use a more powerful motor, or maybe two really powerful leaf blowers used together, feeding air in from two separate points, instead of one point.
Sep 9, 2010. 6:21 AMWesley666 says:
This would work, what you need to do is get a 30in or larger diameter fan and maybe a 5hp motor for it, then it should hold the weight.
Sep 7, 2010. 8:33 PMcronama says:
id like to see a vidio of that pimp wagon
Jul 28, 2008. 9:55 AMpindalanderz says:
for the skirt why not use an inner tube for a tractor tire?
Sep 7, 2010. 9:21 AMcronama says:
ive always wonderd that my self, you would think that the thick rubber would make it more dourable. my guss is that if you use one dont inflate it completly leave some slack, but then agin i have no idea
Jun 9, 2009. 3:18 PMweasel999 says:
the thrust fan..... u shud have ma it blow the other way and attached a sail
Jul 25, 2009. 1:38 PMhippopotamusofdoom says:
it wouldn't go any where because it would be pushing the sail one way and the engine would be going in the opposite
Aug 22, 2010. 11:14 PMthe_doctor says:
well not exactly, if you were to make the intake vents point forward then it would pull and push in the same direction.
Jun 6, 2010. 7:18 PMnaruto the ninja13 says:
can you put the back fan on a swivle for steering?
May 20, 2010. 9:03 AMdracoaliamin says:
 Ok now that fan is a great idea but there are much more safer cheaper and more efficient mays to make that fan that puts air into the skirt. There are two main problems with your design. The first is safety. Did you consider what would happen if someone got there foot in there? The second problem is air escaping. It would be a good investment to put a skirt around the fan so that air could not escape. However the best way if you are building another one then it would be good to stick a leaf blower in a hole and seal the edges.
May 16, 2010. 5:59 AMjeroen says:
yooh i dont understand how you make the ropes of undersite of the skirt to the undersite of the hovercraft
Apr 24, 2010. 3:33 PMpyroboy08 says:
I would bet a contributing factor to your inability to hover with the propulsion engine on is that you put your lifting engine to far forward. try putting it right in front of the propulsion engine and you sit in front of that. that may not cut it, but it would definitely help. you should seek a larger fan for lifting and a larger motor if nessisary
Sep 16, 2009. 1:39 PMBIGHAIRYDUDE says:
just wondered if that specific hovercraft can go on grass and water?
how high does it hover?
Feb 25, 2010. 5:08 AMRahdzhillaxxx says:
Just curiouse of the notion that a squirrel cage blower might produce a more sufficient amount of  lift  per HP. I dont know if it does or not just thinking  it might. 
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Author:dbc1218
I enjoy building things more than actually using them.