# Research and design a model hovercraft

as a project for my geometry and trigononometry class i have to research and design a model hovercraft, i have been researching but all i seem to find are the instructions for how to build a model without the use of any math or stuff that is just way too complicated. Can anyone suggest whereabouts to start looking for "simple" math involved in hovercrafts?

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Pengwuino
Gold Member
Theres a reason why the math isnt simple. Hovercraft are rather complicated things.

Why make a model? Wow them and make a rideable hovercraft I did one with some friends and the help of the physics teacher in grade 10. First of all, we made it circular, for stability. I think it was about 4 ft in diameter but it might have been a bit less. We made the skirt out of some strong material I forget what it was called though, lol, a lot of help I am. For the edges of the skirt we wrapped it onto the topside and then stapled it. However there is a trick, because with just staples it will tear through the skirt. So first, duct-tape the skirt to the hovercraft, and (well, we actually duct-taped the entire skirt to make it stronger) then staple it. The duct-tape will prevent the staples from tearing through. Make sure there are holes in the skirt placed specifically in the bottom. They allow for air to escap, but not too big of holes, remember, you can always make them bigger, making them smaller isn't as easy. Duct-tape the edges to these holes as well so they don't tear. We used 2 leaf-blower's for our air source and they were sufficient power to even hover my friend who is...well, he weighs more than the avg person his age.

I'm not sure about the math involved...we just used very basic math to figure out where the holes should be. Hope this gives u some ideas though.

-Jon

Danger
Gold Member
I don't have time to look for the formulae right now, but the simplest ones are actually mentioned earlier in PF (I can't remember which forum). You might be able to figure them out just by knowing what you need to find. Probably the least difficult is to get your cushion loading, which is the total weight of the craft divided by the surface area within the curtain. That will tell you how many psi of air you need to supply in order to float the load. You'll also need to know what flow-rate of fan you have to use in order to produce that pressure. You can always get away with using one that's too big, because curtain leakage will bleed off the excess. The fan characteristics will in turn determine how strong a motor you need to run it.
One thing that makes a big difference is just knowing what you mean by a 'model'. An upside-down pie pan with a PC cooling fan in it doesn't require any calculations at all; a perfect 1/4 scale model of an English Channel hoverferry would be horrendous.

thanks evry1

just wanted to say thanks, u've been heaps of help. i'm now looking at propellor equations to determine length of the fans and air pressure

:)

Hovercrafts are interesting vehicles, gently floating about a surface with minimal friction and only some interaction now and there.

*Just curious, are they sometimes "more difficult" to maneuver than other types of ships? Do they require more skill/experience to navigate/steer/maneuver?

Danger
Gold Member
bomba923 said:
*Just curious, are they sometimes "more difficult" to maneuver than other types of ships? Do they require more skill/experience to navigate/steer/maneuver?
They're definitely more difficult to control in the sense that you have to anticipate what you want to do long before it has to be done. Reactions are much slower than a ground vehicle or airplane, because there's no interaction with the ground or air for manoeuvrability. It's like sliding on ice. The skill required is no greater or less than for most vehicles, but experience is very important since the skills are different.

yes knowing what i need to find has definately helped

i am looking at the bernoulli equation right now but still seems rather complex more physicsy than mathsy surprising considering its a math assignment

You learn about bernoulli in high school over in WA?? What are you finding hard to understand about bernoulli?

bernoulli equation

uhm basically i am teaching myself the bernoulli equation because of its connection with the hovercraft...i think i kinda get it in relatio to hang gliders in such but am having trouble connecting it with the different aspects of the hovercraft