hovercraft
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12/13/15, 7:52 PMHovercraft
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This is a full size(4ftx8ft) one person hovercraft built over one summer for lessthan $200. It was built with no prior experience or knowledge of hovercrafts butwith sheer determination to build something different. So check this project out,hope you like it.
Disclaimer (March 2013): I have not made any changes to this Instructablesince the early days of this website, 2006. Take this Instructable as anexample of how not to build a Hovercraft. The homemade thrust fan andunshielded rotating parts make this homemade craft pretty dangerous. Ifyour building a hovercraft of your own please consider the safety aspectslarge rotating parts and apply this understanding in your design. For agreat example of how to build a working and safe hovercraft see thisInstrucable 10-HP-Hovercraft (http://www.instructables.com/id/10-HP-Hovercraft/)
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Posted:Mar 30, 2006
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Doug Costlow(/member/Doug+Costlow/)
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Hovercraft by Doug Costlow (/member/Doug+Costlow/)
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12/13/15, 7:52 PMHovercraft
Page 2 of 12http://www.instructables.com/id/Hovercraft/
Step 1: The Skirt and Base
Lets start out with a little history, I built the hover craft during the summerbetween my sophomore and junior years of high school. It was built by a goodfriend, Brain, and myself Doug. Like I said I built the entire craft for less $200including the engines and the fans. I will explain how I did it soon but lets startout some of the main things you will need to get started.
3hp Horizontal Shaft Engine $50 at a local lawnmower repair shop4hp Vertical Shaft engine took it off one of my lawnmowers 5.2 moisture resistant Lauan Plywood 4ftx8ft Styrofoam 4ftx8ft1/2in Plywood 2ftx4ftA couple 2x4 8ftA couple 1x2 8ft1/4in bolts and nuts 1in- 3inWood Screws 1/2in - 1inPlastic 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 likethis do it how you want to and with what is available to you. Use this as a guideso that you do not make the same mistakes I did.
Lets start out from the ground up. On a hovercraft the only thing that touchesthe ground is the skirt. The skirt is the part of the hovercraft that holds air to liftthe craft. Like in the second picture my hovercraft has two engines, one for liftand one for thrust. The lift engine pushes air under the craft and the skirt holds
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Bio: I enjoy building things more thanactually using them.
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12/13/15, 7:52 PMHovercraft
Page 3 of 12http://www.instructables.com/id/Hovercraft/
and one for thrust. The lift engine pushes air under the craft and the skirt holdsthe air in. As more air is pushed under the craft pressure builds up and lifts thehovercraft off the ground. This is how a hovercraft hovers, the only thing inbetween 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 belight(this is the most important) and it has to be strong enough to hold theweight of a person and the engines and everything else. Keep in mind thoughthat when hovering the craft is actually more stable than when its not. The airpressure 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 apiece of 2in thick Styrofoam. The lauan was the cheapest and the lightest sheetof plywood I could find at home depot. One note, I got almost everything forthis hovercraft at home depot. Lows or any hardware store will probably havethe same items I got.
The base is just the two sheets of plywood with the Styrofoam sandwiched inbetween. Holes are drilled all the way through this sandwich and bolts are usedto 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 tohold its shape under pressure and it has to be the right size. To big and it willdrag on the ground which will slow the craft down or not let it move at all and tosmall 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 alltogether with nylon string. For each of the four sides of the craft there are twoskirt pieces. A upper half and a lower half, which are same shape. The pictureshows what each part looked like. Basically the same design for all four sidesjust 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 toppiece of plywood. So you will need four longer skirt pieces and four shorterones.Each piece first needs its flap folded over and sewn. To sew the skirt I used astandard sewing machine and sewed along the seam lines which are 1/2in fromthe edge. Now take two pieces one short and one long and sew them togetherat the angled end. Now do this again for all the other pieces to form a tworectangles. Now put one rectangle on top of the other and sew along theoutside 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 outso the seams are in the inside. Punch holes on the inside of the skirt in themiddle 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 holesthrough the base that line up with the grommets. Sandwich the top of the skirtbetween the Styrofoam and the top piece of plywood and then use 1/4in boltsto 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 Iused, 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 includedthe DWG file though. The last picture is the overall skirt put together showingthe flap folded over with the dashed line and where holes should be put withthe circles.
skirt1.dwg (/files/orig/FZH/N8A2/0MDEP27VUJ9/FZHN8A20MDEP27VUJ9.dwg)
skirt2.dwg (/files/orig/FQ9/TP5J/15KEP27VUJQ/FQ9TP5J15KEP27VUJQ.dwg)
12/13/15, 7:52 PMHovercraft
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skirt2.dwg (/files/orig/FQ9/TP5J/15KEP27VUJQ/FQ9TP5J15KEP27VUJQ.dwg)
skirt3.dwg (/files/orig/FCZ/L483/OS2EP27VV0J/FCZL483OS2EP27VV0J.dwg)
GregQ (/member/GregQ)
I don't get how you were so concerned about the weightof the base using light weight wood, etc. when you end upsitting on it. If it can't lift a heavy base, there's no chanceof it lifting a person.
SpencerT2 (/member/SpencerT2)
Excuse me, when you said "hovercrafts," you were notusing a real word. Hovercraft does not have a plural form.The plural form, is, in fact, hovercraft.
hovercraftorg (/member/hovercraftorg)
Lawn mower blades are very dangerous, we use the samefan blades as used in air conditioners pitched at about 37.5degrees. It is important to add proper fan guards front andrear - hovercraft racers don't like doing this as it slows airthru the duct, but there was a fatality in NZ, someone lost afew fingers in Australia last year - if you want your kids toplay guitar or piano, make sure you fit proper guards.
weargle (/member/weargle)
i couldnt get a fan so i made one using the lawn mowerblades by bending them
KrystianEly (/member/KrystianEly)
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12/13/15, 7:52 PMHovercraft
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i have a prodject in college where we have to use theinformation over the 2 years to build something, everyonechose a go-cart but i chose a hover craft im building this onmy own, do you think it will be worse if i was to add slightlybigger engins? thanks.
pavilion89 (/member/pavilion89)
My craft is about 8 icnh height, 8feet length, 4 feet wide andcapacity for a person only. is 2.8hp enough ?
Doug Costlow (/member/Doug Costlow) (author) % pavilion89
(/member/pavilion89)
I don't think that will be enough unless the craft is verylight. check out thishttp://www.instructables.com/id/10-HP-Hovercraft/same size but uses a 10hp engine
pavilion89 (/member/pavilion89)
what is the suitable material to built a fan for engine of2.8hp?
Doug Costlow (/member/Doug Costlow) (author) % pavilion89
(/member/pavilion89)
I would not recommend building your own fan,especially not like the steel fan I built for this craft.Most fans/props I've seen are made from wood orhave plastic baldes connected to a center metal hub.Also, if your building a craft similar in size to mine,2.8hp won't be enough power.
assaultpioneer (/member/assaultpioneer)
Wonder if you could make two smaller almost hoverboardsconnect them to make a hover "pontoon boat" or catmeran
Dovim (/member/Dovim)
hey, awesome guide. i have a couple questions though. howfast can it go? can you make it have more surface areawhile using the same skirt and engine setup? and i thoughtof a way in which the forwards thrust fan might be replacedby a spinning wheel which could be lowered andmaneuvered like that of a motorboat (i don't know very wellhow to explain it). thanks
Doug Costlow (/member/Doug Costlow) (author) % Dovim (/member/Dovim)
It didn't really go anywhere, read the last step. Whywould you want to make it bigger? If you did make it
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12/13/15, 7:52 PMHovercraft
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would you want to make it bigger? If you did make itbigger with engines similar to mine, it would be wayunderpowered and probably not hover. An outboardwheel could work but I think it would defeat thepurpose of a "Hover"craft
Dovim (/member/Dovim) % Doug Costlow (/member/Doug Costlow)
Ah, i see. so it was too heavy for the fan to actually accelerateit, right? well, an outboard wheel would solve that problem, ithink. also, i see the purpose of a hovercraft as a vehicle thatcan go on land and water, so if the outboard wheel could alsobe used as a fan in the water, then the purpose would becomplete. also, an addition of an outboard wheel would lead tothe only speed limit being air resistance, since it doesn't touchthe ground (as different to all other vehicles), whereas thewheel could be lifted so it didn't touch the ground. the result isit could just keep accelerating and accelerating. The resultscould be interesting. The thing about making it bigger wasmerely curiosity, though. i can see that it would have nopractical purpose, and if i could make it smaller without losingstability, then it contributes to making it lighter, thus faster. As isaid, the results could be interesting. i'll have to do a lot ofthinking on it, but the hovering mechanism of your hovercraftseems like a great way to start.
double_g (/member/double_g) % Dovim (/member/Dovim)
I'm not sure if this is true as I'm rather new to the hovercraft scene, butfrom what I've read it seems that increasing the area actually increasesthe lift generated. I'm not sure where the page was that said this but ifyou crunch some numbers on the following website you'll find that thisseems to be true. http://www.olshove.com/HoverHome/hovcalc.html(http://www.olshove.com/HoverHome/hovcalc.html)If someone can explain this it would be much appreciated, since I haven'tyet figured it out (I'll ponder on it a bit more in the meantime and see if Ican come up with a logical explanation).
Of course weight to lift gain must be considered.
-hope this helps future builders
Double_G
Doug Costlow (/member/Doug Costlow) (author) % double_g (/member/double_g)
If you increase the size of the craft and therefore thearea the pressure needed to maintain lift will decreasebut the amount of air needed to be forced under thecraft will increase. This usually means you have to usea different fan or a more powerful lift engine. Duringthe design of the craft you have to decide what youwant. If you want a bigger hovercraft you need tomatch that with the right size engine and lift fan, but ifyou already have the engine size set then you need todecide on the right size craft. The guy that createdthat site from your link says he used Hovercrafting AsA Hobby to create the calculator so I would start there.
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12/13/15, 7:52 PMHovercraft
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double_g (/member/double_g) % Doug Costlow (/member/Doug Costlow)
Thanks I built my hovercraft for my high school senior project.I've planned on making a bigger better version so I'll definitelytake your advice for that if I ever get back around to it. Alasplans for the new version are in a long list of projects not thesmallest of which being my senior project for my undergrad inelectrical engineering.
Pfarmkid (/member/Pfarmkid)
how did you make the steering controls?
threewingwonder (/member/threewingwonder)
You could build your own fans from wood, all you wouldhave to do is check out Universal Hovercraft with a search. Ihave built a hovercraft from plans that I got from them.turned out to be a very versital craft.Mine was 6ft x 12 ft andhad a 5 hp lift motor and a 30inch home made lift fan and 2-5 hp thrust motors with 48inch homemade thrust fans. Inow have plans for a little bigger craft for exploring. Youshould really check out :Universal Hovercraft, they arebased in Cordova Illinois. A very good place to start ahovercraft adventure.They have plans,supplies andadvice/tutorails for hovercraft builders.Great ible though
Pfarmkid (/member/Pfarmkid) % threewingwonder (/member/threewingwonder)
How much did it cost?
PickPacket (/member/PickPacket)
That looks safe..
pufferboytbh (/member/pufferboytbh) % PickPacket (/member/PickPacket)
THIS IS IN NO WAY SAFE. For our cadet's "Pioneer's"platoon (building stuff), we built 3 full sized hovercraftsfor use. The prototype on it's first run tore itself apart,srapel flying everywhere, nearly killing myself andmany 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 inmetal. Depending on your propller speed. Have fireequipment ready. Being 14, I don't want me or mycadets to die.
Jaredicus (/member/Jaredicus) % pufferboytbh (/member/pufferboytbh)
What branch JROTC are you? I am army JROTC.
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12/13/15, 7:52 PMHovercraft
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pufferboytbh (/member/pufferboytbh) % pufferboytbh (/member/pufferboytbh)
By the way... The same thing happened about a monthlater. With the metal, the propeller stayed in the enginehousing, causing only damage to the engine, housingand propeller. The hovercraft remained floating, whilewe remove the two year seven cadets from the craft,set up a perimeter, and killed the engine. The craftdidn't even sink! MUCH SAFER.
szulli-randall (/member/szulli-randall)
Does anyone think it's possible to make it hover a few FEEToff the ground?
jbowman7 (/member/jbowman7) % szulli-randall (/member/szulli-randall)
they're called hoverwings, google it
szulli-randall (/member/szulli-randall) % jbowman7 (/member/jbowman7)
I ment without wings.
jbowman7 (/member/jbowman7) % szulli-randall (/member/szulli-randall)
Then no, it's not possible, the skirt has to be touching theground to maintain the air cushion. but you can still hit jumpswith a sturdy hovercraft. Look up hoverwings though, they'recool.
Doug Costlow (/member/Doug Costlow) (author) % jbowman7
(/member/jbowman7)
Large hovercraft, like the ones the military use, hover afew feet off the ground but that height is sort ofproportional to the their size. A small hover craft thathovered that high would most likely by unstable,remember your sitting on air, so nothing but yourbalance will keep you upright.
iminthebathroom (/member/iminthebathroom) % Doug Costlow (/member/Doug
Costlow)
Not sure if even they hover that high actually, maybeperiodically though
geckomage (/member/geckomage)
will this hold a 260 lb person like myself? :P i normally gomuddin in my truck when i wana have fun drivingsomething. but this'd be fun :D
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12/13/15, 7:52 PMHovercraft
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gopalrr (/member/gopalrr)
hi,
can you share details of how you did the 70%/30%distribution of air thrust to lifting and propulsion ?
gopalrr
Doug Costlow (/member/Doug Costlow) (author) % gopalrr (/member/gopalrr)
that distribution is typical of a hover craft that uses asingle engine to turn one ducted prop. the duct is splitto divert 30% of the air underneath the craft for lift andthe rest for thrust. My hover creaft used two enginesand fans so that distribution is different
rocketman20 (/member/rocketman20)
Where did you get the fan you used for trust.
Doug Costlow (/member/Doug Costlow) (author) % rocketman20
(/member/rocketman20)
I made it from sheet metal and angle iron, but I wouldnot recommend doing this at all. Get a purpose madeprop thats been properly balanced.
elina0 (/member/elina0)
OMG! This seems me too heavy..
rbland (/member/rbland)
you probably want to put some sort of cage around thevents too:http://www.stuff.co.nz/national/5380361/Auckland-man-decapitated-testing-hovercraft
rocketman20 (/member/rocketman20)
Are the Brass Grommets just for attaching the skirt to thebase? Also does the skirt have holes in it? I am trying tobuild a hovercraft myself but am having a hard timeunderstanding how the skirt works.
Doug Costlow (/member/Doug Costlow) (author) % rocketman20
(/member/rocketman20)
they are just for attaching the bottom edge of the skirtto the base with small rope
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12/13/15, 7:52 PMHovercraft
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jdhover (/member/jdhover)
so is your base piece hollow or is it ducted?
Doug Costlow (/member/Doug Costlow) (author) % jdhover (/member/jdhover)
its a sandwich of t pieces of 1/4" plywood with 2" ofStyrofoam in between.
nibbler125 (/member/nibbler125)
you need a real fan that metal one has no airfoil and youcould easy double youre lift with a good wood one it willcost allot more tho up to 200$
ss2pheonix (/member/ss2pheonix) % nibbler125 (/member/nibbler125)
or just make one yourself, assuming of course you have basicair foil knowledge and the ability to carve
ss2pheonix (/member/ss2pheonix)
i think i would have used one 12hp engine or bigger from alawn tractor and rigged the mowing deck to feed the air forthe lift and controlled the drive fan with the drive train fromsaid lawn tractor.
tgo (/member/tgo)
would a water bed matress work for the skirt or would it betoo heavey
Doug Costlow (/member/Doug Costlow) (author) % tgo (/member/tgo)
I think it would be to heavy.
ilpug (/member/ilpug) % Doug Costlow (/member/Doug Costlow)
it works fine. canvas tarp coated with polyurethane sealer isperfect.
vhayden (/member/vhayden) % tgo (/member/tgo)
There are ready made plans for using a water bed mattress for the skirt. Ifyou are interested, let me know.
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12/13/15, 7:52 PMHovercraft
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geoslim13 (/member/geoslim13) % vhayden (/member/vhayden)
i am!!!! i know you aren't replying to me but i have a friend, wellmy grandmas friend that has become a family friend, that has awater bed and is thinking of getting rid of it along with histreadmill (different project) that could work. it is a king orqueen (whichever is bigger)!!!!
Thelonelysandwitch (/member/Thelonelysandwitch) % tgo (/member/tgo)
use a thick tarp and duct tape
ilpug (/member/ilpug)
nice. i think you need a much tougher more rigid skirt. iwould also use a more powerful motor, or maybe two reallypowerful leaf blowers used together, feeding air in from twoseparate points, instead of one point.
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