Hovercrafts

Other Chit-Chat
1

Me and some friends are trying to get together this summer to build either a hovercraft or go kart. So far, it’s leaning much more torwards hovercrafts, cause they’re slightly more legal (and one of us lives by a beach, with plenty of open space).

So, i was wondering, does anyone know any good sites about building hovercrafts? we have some basic plans, but nothing specific yet. One of our ideas used a vaccum cleaner motor, and the other a gas engine (leaf blower) to lift the hovercraft up, but none of us are sure how the whole skirt system works, so we’re wondering how to make it work, but we couldn’t find anything online :/.

So far, as a prototype, i think we’ve decided to get a circular plywood board, a big battery, and a vaccumm cleaner motor. but we have no idea how to make the skirt. if we get that design done, we’re going to convert it slightly, and you’ll all know if that works ;).

our other design calls for a gas engine, so we can use it on the beach and in the water. we have some basic plans, but once again, nothing on how to make the skirt. this design is more complicated than a circle, but i think a rectangular skirt would work, so making it won’t be too hard.

so, if anyone knows of any good sites on building hovercrafts, or more specifically, anything on how the skirt works, and how to make your own skirt, i’d be grateful, and we just might have a very unique thing to show off next year :p.

2

hi lets see the dream of everyone to build a hovercraft. Hmm first of all I recomend watching the junkyard wars hovercraft episode. It may be on july 4. hovercraft plans
http://www.howstuffworks.com/hoverboard.htm

3

Thats some pretty intresting stuff yea I tried to bulid a tiny hovercraft using CD (Compact Disc) motors, a paper plate and small pieces of rubber. The concept and design was sound and It kinda sorta work a little bit but It did’nt:D

4

hmm, the only problem i have is still the skirt. we have plans, basically a rectangle with a rounded nose (more areodynamic ;)). for forward propulsion, i believe we’re using a propeller (mostly cause it’s easier for us). we had this crazy idea to have the prop mounted on a ‘turntable’, so by turning the steering wheel, you pull a wire, which turns the prop, which in effect turns the hovercraft. technically, it works. a rudder may be better though, but we have yet to test all of this. to fill up our hovercraft we want a leaf blower i think, because they’re easily avalible. otherwise, we’ll need to somehow find a lawn mower, and a nice big fan :p. this once again brings me to the skirt, for which we have no idea how to work. any ideas on how to build one?

5

Ian,
I don’t know how big your vacuum motor is but of all the vacuums that i have come accross, i don’t think that i have seen one suitable for the task at hand. having an electrical vacuum motor under that kind of stress is bound to bring up some problems. even if the motor is going to be strong enough in theory, it is definitly going to overheat rapidly. I definitly reccomend a blower for this. a gas motor is much better under pressure and less likely to overheat. it is also better becauseit doesn’t need a vacuum chamber. i don’t know what type of vacuum u would use, but if it is a shop vac than you would have to strap that whole vac to the deck. the gas is ideal if you are going to be riding on it.
If you are looking for a material for the skirt itself, it is best to use a tightly woven tarp (a few layers thick) and a rubber tubing on the bottom to be in contact with the ground on the edges.
P.S- Any vehicle that is ride on and self propelled is illegal in NY state (even if it has anexcellent driver:D )

6

It had to be a hovercraft it:). It couldn’t be something that I could find free plans for off the internet. http://groups.yahoo.com/group/rchovercraft/ free hovercraft plans lifts 60 pounds probably get a skirt idea hear

7

steve, that doesn’t make any sense, cause then my bike, my parent’s cars, my friend’s boat, hell, even the robot (meg did ride on it twice) would be illegal :p. i think you can get a permit though, and treat it like a boat (cause we plan to use it in the water).

also, you can take about a shop vac, and take out the motor, and use that. for that hovercraft, you’ll probably see it if we decide to build it. the other one, i’m not so sure what we’ll do, but it’s more of a fun thing. the electrical one does have a purpose. and, the shop vac should be able to hold at least 200 lbs, more than enough for what we want.

also, aside from the skirt material, i just need some basic plans on how to assemble it.

8

Lol!

Nearing the end of the build our student teacher got bored and built one of those Hovercrafts during one of our FIRST sessions. He mainly built it for his tech seminar class… but it was fun riding it… it was a good break from troubleshooting the robot code…

His was a round piece of plywood about 3-4’ in diameter with plastic sheeting wrapped around one side of it, attached to the edges, and one nut through the middle that held the sheeting in place there (be sure to tape up this spot very well… and probabaly use a washer that will act as some type of o-ring)… then he put a hole on one side of it and that’s where the shop vac/leaf blower went…

The plast sheeting had 1" diameter holes in it, spread out approximately 6" apart, soccer ball style (alternating). I’m not sure if he bought the sheet that way, or he put the holes in himself…

9

we’re trying to make a slightly bigger one :stuck_out_tongue:

10

hi im orie and i’ve been working with ian on our hovercraft idea. My most current hovercraft design is modeled after the star wars x-34 land speed that luke used in episode four. I have a few problems with that design. first, the whole design is made of wood and im not sure if it will be strong enough to handle the vibration of the gas engines. does anyone have any ideas for an engine mount that could keep my craft from falling apart? Second, the hovercraft needs two propellers, one for lift and one for thrust, i am worried about making them mmyself because if they are not perfectly symmetrical, they could cause the whole craft to vibrate and consequently fall apart. does any one know where i can buy pre-made propellers that would be able to fit the crankshaft of a lawnmower engine?

i also have some other questions that i hope someone will be able to answer:

what is the best material for the skirt? i was planning on using heavy duty tarp, because its very durable, but most hoverraft plans call for rubber.

what is the best way to mount a lawnmower engine or a leaf blower engine using only wooden parts?

11

does anyone know the mathematical equations to calculate the forward thrust of any propeller?

12

hey ian, it think we could get more help if we moved these questions to technical discussion.

13

One of the students on our team (next years captain) built a hovercraft for a science fair project. I am not familiar with the details, other then it has lifted 98lbs. (Little John).
Gas powered, IIRC.

I will direct his attention to this post, and he can correct me.

Wetzel

I think thats what I was told by this guy....
14

The reason they use rudders instead of turning the propeller - the propeller holds a lot of rotary inertia when it is spinning. To turn a spinning propeller puts a lot of stress on the bearings, and might cause your hovercraft to tilt.

Try redirecting some of the lift air flow backwards to create your propulsive force.

I seem to remember some guys from my high school doing that when they built their hovercraft. If you’re using a large enough gas motor, you should have power to spare.

I have very few ideas for the skirt. Look at Jackie Chan’s Rumble in the Bronx for inspiration, and be sure to wear life jackets.

Good luck!

15

I too am planing on making a Hovercraft this summer. I have already made some prototypes with electric motors. The basic concept is pretty easy. If you look in McMaster Carr they have some propellors that are suited to handle some air movement but only a few Hp. For Skirt material we are getting the stuff they make parafoils out of and the frame will be EMT pipe with foam to fill it in. We are still looking for a source to find the correct propellors. If you look online you can find calculators for hovercraft design. I would Really reccomend watching the junkyard wars of hovercraft building they explain the concepts very well including the skirt.

Andrew

16

i missed that episode :(. is there anywhere that i can download it online, or is it supposed to air again anytime soon?

as for propellers, i’ve heard if you look in the right hobby shops, you can find propellers made for model airplanes. not the tiny electrical ones, but the huge gas powered ones. i’ve seen one site with a 24" prop from a hobby shop (i think). it’s www.xinventions.com. not a bad site, some pretty cool stuff :D.

for skirt material, me and orie were thinking tarp type material. there is an army surplus store nearby, but i’m not sure what they have.

17

In HS my tech class built a couple of Hover Crafts. All were electric powered. We used the old ELECTROLUX vacuum cleaner motors. We mounted two motors piggy back on a plywood board that was glued (calked maybe) to an inner tube, from a HUGE tire.

It could hold 2-3 people and with a couple of extension cords you could glide down the entire hallway.

From what I’ve read in the past few years and scene while teaching I would model a hovercraft after the commercial models.

One motor in the back with a bug prop. From what I read it seems like the more blades on the prop the more air that is pushed, and the less air that can leak back through the prop, actually they are more like fan blades to a turbine engine.

As for a skirt, I agree with those that suggest using a heavy duty tarp. The ideas is to create a cushion of air beneath the vehicle, and that when the air leaks out under the skirt it does so in an even and balanced fashion. Balancing the hovercraft is critical, and building a skirt that only allows minimal air “leakage” is the main goal.

I saw a Web site a few years ago about a kid, probably 15, who built a hover craft with 2 engines. One was a leaf blower that provided lift, the other was a 5 HP Briggs and Stratton Engine attached to a 2 blade prop. HE said he could lift about 120 lbs and move at about 20 MPH.

It looked just like a junkyard war project :slight_smile:

Please make sure some Adults are around. You guys aren’t building a toy, remember it is a vehicle, whether it is legal or not, it is still dangerous.

Good Luck and have fun. Just be careful, remember SAFTEY FIRST.

18

yeah, that kid who built the hovercraft is the one who has www.xinventions.com, and there’s a bunch of pics on the site. i think we want to build something like that, only a little bigger and more powerful. we’re not exactly sure though.

also, is it possible to power a shop vac with say, a car battery and a volt converter? i have a really cool idea, but it wouldn’t work with extension cords.

19

ive been to xinventions.com and its one of my favorite sites but they fail to explain the technical aspects of building a hovercraft. although i dont mind experimenting with different ideas, i would feel a lot more confortable knowing that my plans actually have a chance of working. and as for the junkyard wars episode, i cant remember who won, but it was pretty close untill one of the driver leaned to far to the side while turning and crashed the side of the hovercraft into the ground. since the hovercraft was fairly light, it stopped on impact bu the driver was a little less fortunate, being thrown into the mud. but one of the team’s hovercraft was basicall a jet engine mounted on a foam platform. they used only on propeller that was mounted inside a stripped down turbine engine and diverted half the air to lift the craft. the idea may be similar but i am hoping that our craft will be a little more than a floating platform.

20

Just simply visit www.hovercraft.com for plans