HOVER BOARD

[bluefox609]

help I need some designs for making a HOVER BOARD
please if you have any ideas please post cause I need
them

[agm]

Hi bluefox609,

Welcome to the forum. I found some websites that should help you by searching for hoverboard and how to make a hoverboard, so you could try plugging that into your favorite search engine to find even more.

Background info:
http://www.howstuffworks.com/hoverboard.htm

Instructions for building one:
http://gadgetshow.five.tv/jsp/5gsmain.j ... n=Features
http://amasci.com/amateur/hovercft.html

Photos/audio/video of experiences building one:
http://www.flickr.com/photos/13559856@N ... 152692147/
http://www.metacafe.com/watch/850861/bu ... overboard/
http://www.wonderhowto.com/how-to/video ... ch-192831/

Many if not all of these ideas involve using a leaf blower or other gas-powered engine, so you'll want to make sure you adult supervision while using the hoverboard and while constructing it with any potentially dangerous tools like saws.

Feel free to post your thoughts and ask questions if anything you read doesn't make sense.

Hope that helps,
Amanda

[bluefox609]

thanks a ton, i needed exactly what you gave me. once again thanks ..... alot.










with thanks,
blue fox 609

[agm]

Glad to help! I actually neglected to check our archive of project guides, and we have a related project about a hovercraft:

https://www.sciencebuddies.org/science- ... p036.shtml

This outlines some background info, supplies you'll need, and gives good safety info that you should check out. There are also lots of suggestions for variables that you can change to learn more about what you build. Good luck -- I'd be interested to hear how your project goes even if you have no more questions for us!

Amanda

[bluefox609]

I need to know........ if i should use wood or plastic for the platform? I want a light platform so that I can be lifted of the ground higher than normal.
if any ideas please post.










bluefox609

[agm]

It's nice that you're already thinking about how to improve the designs you've found! In fact, you could actually build it both ways and see if you are able to improve the lift.

It definitely might be possible to substitute plastic for wood in a design, but you need to make sure it can perform all of the functions that the wood does. Some considerations:

--It must be able to support enough weight without bending or breaking, such as a rider above and things hanging from below, depending on the exact design. To achieve the required strength, you might need to use a thicker piece, so the plastic might not turn out to be as light as you'd initially think.

--If the weight of the wood platform is only a small fraction of the weight of (hovercraft + rider), then reducing the platform's weight won't reduce the total weight of the system by a large percentage and thus won't increase the lift much. On the other hand, if the platform is a large percentage of the total weight (including rider), you're definitely onto something.

--It must be able to connect to the other parts properly and securely. For example, it might be harder to drill into some kinds of plastic without splitting them -- strong plastics are sometimes also brittle.

--Cost and ability to obtain the right kind of plastic are probably also considerations.

If you could tell us what hovercraft design you're planning to use and what kind of plastic you're thinking of substituting, that would help us to be more specific.

Amanda

[bluefox609]

yeah, but i'm wondering could i use a tough pexiglass, basicly what they use to make snowboards.

[yasinrahman]

Plexiglass could be a good alternative for strength, but it will be heavy. Unless you use some kind of thin sheet with low weight. Plexiglass is strong but it cracks if it falls or is under a lot of force. Again as agm said, cost will be a factor.



thanks,
Yasin

[bluefox609]

if I use a tough platform, i'm worried that it will be to heavy

[agm]

Hi bluefox609,

I think that's a valid concern. A good first step might be to find out how much the wood platform weighs and how much the entire hoverboard weighs (as suggested in whatever design you have chosen). Then, as I mentioned before, you will want to decide whether the platform constitutes a large enough fraction of the total weight to give you much room for improvement. This will likely involve investigating the plastics that you're thinking of using, including the thickness required to make them strong enough as well as the density (so that you can calculate the mass).

For example, if the wood platform weighs 15 lb and the entire hoverboard + rider weighs 150 lb, then the platform constitutes 10% of the total weight (I am only including numbers as a concrete example -- I don't know what design you have chosen!). Say you could find a piece of plastic with all the required properties (strength, size, ability to connect to other parts, etc) that weighs 5 lb. It's hard to figure out exactly how much higher you would go by decreasing the weight by a certain amount, but here's a good way to think about it: There are basically two forces acting on the hovercraft: gravity and the upward force provided by the air. To get off the ground, when the hovercraft is on the ground, the force of the air must be greater than the force of gravity so that there's a net upward force. However, if there was always a net upward force on the hovercraft, it would keep going up (force = mass * acceleration). So, that means that at the height where the hovercraft stabilizes, the force provided by air must equal the force of gravity on the hovercraft. The force provided by air decreases when the hovercraft is off the ground because some of the air escapes sideways instead of pushing off of the ground. (Since the air escapes equally in all sideways directions, those forces cancel each other out. If you lean to one side, more air escapes from the side that's higher off the ground, resulting a force that moves the hovercraft sideways.) If you decrease the mass of the hovercraft + rider, then not as much force from the air is required, so it can go higher, letting a little more air escape sideways, before it balances the force of gravity. I don't know enough about fluid dynamics (air and other gases are considered fluids along with liquids) to give you an equation with the exact relationship, but I suspect that the increase in lift would not be more than a factor of (original weight)/(decreased weight) -- 150/(150-10) = 1.07 in this case, or 7% higher.

Two more things to consider: (1) the hovercraft might become harder to steer (and even perhaps less safe) if it rides higher off the ground; (2) if you are looking at a design that's able to lift an adult and you're smaller, you will go higher without making any changes. If you wanted to investigate the effect of total weight on maximum height, as an alternate to building different platforms, you could use riders of different weights or step on carrying different objects to change the total weight.

(Side note: weight is actually a measure of force, and mass is mass. However, if you are always in the same gravitational field (e.g. on Earth), then weight = mass * 9.81 m/s^2 doesn't change, so it's proportional to mass and we can talk about increasing/decreasing them interchangeably. But you'll get into trouble with F = ma, etc, if you miss that point.)

Hope that helps,
Amanda

[Craig_Bridge]

If you make some gross assumptions and do some simple calculations you can get a reasonable understanding of what you are dealing with.

If the hovercraft and passenger weights 250 pounds and is 30 inches in diameter, then there is about 707 square inches of area on the bottom of the platform under the skirt. This means it will take about .35 psi of air pressure to lift the unit. The skirt perimeter is about 95 inches. If it floats on 1/8 inch of moving air, then there is about 12 square inches of moving air. To put this in perspective, a typical 1/2 hp forced air furnace squirel cage fan would not provide enough air flow through a 4 inch round duct to obtain enough pressure to accomplish this.

You don't need to experiment with this large a scale device to do a great science fair project. The principles hold at a much smaller scale which is a whole lot easier to experiment with.

As to your question about low weight high strength materials. Hollow core plywood designs are hard to beat with plastics. Things like plywood, fiberglass, woven cloth, and carbon fiber will outperform most plastics for this kind of an application.