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jokubas - n/a
5-Feb-07, 11:11 AM
hey, im looking forward to building a cheap hovercraft. It would be 8x4ft, for lift i am going to use a leafblower, and for thurst lawnmower engine or something similar. Also, im going to try riding it on water. Here's a picture of a "design" im thinking about: index.php?t=getfile&id=552&private=0

Would this work? What do you think about it? Would like to hear all suggestions and would be grateful if you posted your own cheap hovercraft pics.

Happy Snapper - n/a
5-Feb-07, 01:20 PM
not sure about cheep.

but for a wide range of hovercraft pic's

goto



www.hovercraftvideo.co.uk



there are load's.

jokubas - n/a
5-Feb-07, 02:30 PM
thanks http://hovercraft.org.uk/images/icons/smiley_icons/icon_wink.gif however didn't find anything made from simple materials like plywood. what about my skirt design, do i correctly understand how does bag skirt work?

sixpackpert - n/a
5-Feb-07, 03:14 PM
Your picture is not showing. Try posting it up again.

Don83000 - n/a
5-Feb-07, 03:33 PM
if you want some cheap plans to give you a idea down to even a 6ftx3ft craft try here.



http://www.universalhovercraft.com/

jokubas - n/a
5-Feb-07, 05:07 PM
@sixpack, thanks, fixed

@don, yeah, ive seen them, but they're made out of expensive materials, like fiberglass or something of that kind. basically, i have an idea, which is in picture, just want to know what you think about it

Don83000 - n/a
5-Feb-07, 05:29 PM
What you have drawn is basically the small UH craft they construct some of their craft like you want to do but their small craft just uses a small B&S engine instead of a leaf blower which also gives them forward thrust but you have the right idea for a very simple craft but be warned the performance is going to be pretty grim but get get what you pay for if you increased the size by 25% it would help quite a bit stability wise and fit a larger engine / fan or prop if using separate lift.

Ian Brooks - n/a
5-Feb-07, 07:34 PM
It'll probably work OK on very short grass, but is unlikley to work on water as the 'footprint' is quite small leading to a high cushion pressure.



Make the plywood the thinnest you can find, otherwise it will be too heavy.



Ian

jokubas - n/a
6-Feb-07, 12:00 PM
<table border="0" align="center" width="90%" cellpadding="3" cellspacing="1"><tr><td class="SmallText">Quote:</td></tr><tr><td class="quote">
..but is unlikley to work on water as the 'footprint' is quite small leading to a high cushion pressure.
</td></tr></table> could you explain please? http://hovercraft.org.uk/images/icons/smiley_icons/icon_smile.gif

Russ Pullen - n/a
6-Feb-07, 12:58 PM
<table border="0" align="center" width="90%" cellpadding="3" cellspacing="1"><tr><td class="SmallText">Quote&#58;</td></tr><tr><td class="quote">
..but is unlikley to work on water as the 'footprint' is quite small leading to a high cushion pressure.
could you explain please? http://hovercraft.org.uk/images/icons/smiley_icons/icon_smile.gif
</td></tr></table>





In all hinesty, if yu have so little knowledge of hovercraft principles you're on a road to nowhere in terms of contructing a functioning craft.



My suggestion is to buy a old banger, which works or needs work and learn th eprinciples first.



Not trying to kill your enthusiasm but building a working craft without any knowledge is a non-starter.



Russ

jokubas - n/a
6-Feb-07, 01:22 PM
i believe, why im asking to explain - is English

<table border="0" align="center" width="90%" cellpadding="3" cellspacing="1"><tr><td class="SmallText">Quote:</td></tr><tr><td class="quote">
My suggestion is to buy a old banger, which works or needs work and learn th eprinciples first.
</td></tr></table> well, here, in lithuania i havent seen a hovercraft, i doubt if somebody has one http://hovercraft.org.uk/images/icons/smiley_icons/icon_smile.gif

Russ Pullen - n/a
6-Feb-07, 05:35 PM
Then travel! Seriously, before you start work on something you've never even set eyes on, i strongly suggest that you make the effort to undertake some research, visit some folks and look at their craft. Buy the constructors guide (available from the hoverclub) and gain the knowledge you need before embarking on any thought sof building a craft.



Otherwise, your project will end up like 75% of the first-time builds. Unfinished, run out of money and enthusiasm and advertised on ebay for no money.



If you don't even undertsand such basic principles as skirt design or the neccessary calculations of weight and size, then i would be astounded if you built something that worked at all well, let alone something which was safe.



Come to the UK, preferably on a race meeting weekend, and you'll see 60 craft in action, no two the same! You'll learn more in one weekend than you believe possible.You're more than welcome to visit the Flying Fish factory, and speak to our engineers too.



Russ

jokubas - n/a
7-Feb-07, 01:04 PM
<table border="0" align="center" width="90%" cellpadding="3" cellspacing="1"><tr><td class="SmallText">Quote:</td></tr><tr><td class="quote">
Then travel! Seriously, before you start work on something you've never even set eyes on, i strongly suggest that you make the effort to undertake some research, visit some folks and look at their craft. Buy the constructors guide (available from the hoverclub) and gain the knowledge you need before embarking on any thought sof building a craft.
</td></tr></table>I've spent a lot of time searching and reading information on the internet

<table border="0" align="center" width="90%" cellpadding="3" cellspacing="1"><tr><td class="SmallText">Quote:</td></tr><tr><td class="quote">
If you don't even undertsand such basic principles as skirt design or the neccessary calculations of weight and size, then i would be astounded if you built something that worked at all well, let alone something which was safe.
</td></tr></table> Who said that i absolutely dont understand principles of hovercrafts? Yes, im no pro, so thats why im asking for suggestions and thoughts

<table border="0" align="center" width="90%" cellpadding="3" cellspacing="1"><tr><td class="SmallText">Quote:</td></tr><tr><td class="quote">
Come to the UK, preferably on a race meeting weekend, and you'll see 60 craft in action, no two the same! You'll learn more in one weekend than you believe possible.You're more than welcome to visit the Flying Fish factory, and speak to our engineers too.
</td></tr></table> i want to remind you that im not going to build some kind of super duper hovercraft, but only a simple hovercraft using no expensive composites and i dont think its worth time and money just for going to the UK and seeing few hovercrafts

Keith Oakley - n/a
7-Feb-07, 02:28 PM
To return to your original question 'Would this work?'. The answer is yes but the real questions are 'how well?' and 'what do want to do with it?'



It will work fine as a simple hovering platform demonstrating basic principles on a flat smooth surface like tarmac or grass up to say 3cm high. How much it will carry depends on the power of the particular leaf blower you use but it will probably lift a person.



If you take it on water it will hover but because its small area will cause a higher cushion pressure than we normally use it will create a deep depression in the water with lots of spray, which may well stop the engine. The deep depression will mean it takes more thrust power to climb out of it and get 'over hump speed'. It's unlikely that a lawn mower engine will develop enough thrust to achieve this.



The structure is identical to the flat platform chassis I used on my first craft Hoveranne1 in 1967. My experience with that was that it was not structurely rigid enough and the craft would warp if you set it down on uneven ground. In my case that led to the fan hitting the duct but in your case with a fan securely mounted within the leaf blower that wouldn't be a problem. I also found that a 5cm high slab of foam within the 'chassis' wasn't enough to provide flotation so the craft would sink, so you need to calculate how much foam you need. The other problem with a very flat hull is that there is no scope for a planing surface (angled power boat shape at the sides of the hull) so if you ever did get any speed up over water when you drop back on the water the craft will probably flip over.



All these problems have been solved in later hull designs by building a monocoque box shape higher than a flat platform which gives structural stiffness, inherently floats, and has planing surfaces at the side. If you design it properly a simple rectangular box design probably using 3-4mm thick plywood jointed using 5cm wide strips of GRP resin takes very little more work and materials than your flat platform. Making it at least 10 feet by 6 feet (and preferably bigger) will double the lift area and halve the cushion pressure. Your understanding of a simple bag skirt is fine. The size and number of the holes on the inner wall of the bag will adjust the relative pressure in the bag versus the cushion underneath and thus the stability. Start with a few holes and cut more until you've got the right compromise between stability and air under the craft.



In conclusion - fine as a basic hovering platform on flat smooth land but I wouldn't take it over water.

Russ Pullen - n/a
7-Feb-07, 05:52 PM
<table border="0" align="center" width="90%" cellpadding="3" cellspacing="1"><tr><td class="SmallText">Quote&#58;</td></tr><tr><td class="quote">
Then travel! Seriously, before you start work on something you've never even set eyes on, i strongly suggest that you make the effort to undertake some research, visit some folks and look at their craft. Buy the constructors guide (available from the hoverclub) and gain the knowledge you need before embarking on any thought sof building a craft.
I've spent a lot of time searching and reading information on the internet

<table border="0" align="center" width="90%" cellpadding="3" cellspacing="1"><tr><td class="SmallText">Quote&#58;</td></tr><tr><td class="quote">
If you don't even undertsand such basic principles as skirt design or the neccessary calculations of weight and size, then i would be astounded if you built something that worked at all well, let alone something which was safe.
</td></tr></table> Who said that i absolutely dont understand principles of hovercrafts? Yes, im no pro, so thats why im asking for suggestions and thoughts

<table border="0" align="center" width="90%" cellpadding="3" cellspacing="1"><tr><td class="SmallText">Quote&#58;</td></tr><tr><td class="quote">
Come to the UK, preferably on a race meeting weekend, and you'll see 60 craft in action, no two the same! You'll learn more in one weekend than you believe possible.You're more than welcome to visit the Flying Fish factory, and speak to our engineers too.
</td></tr></table> i want to remind you that im not going to build some kind of super duper hovercraft, but only a simple hovercraft using no expensive composites and i dont think its worth time and money just for going to the UK and seeing few hovercrafts
</td></tr></table>



Suit yourself.



Good luck with the project. I'll buy you a beer when i see it fly. http://hovercraft.org.uk/images/icons/smiley_icons/icon_smile.gif

jokubas - n/a
7-Feb-07, 06:30 PM
Keith, thanks for a VERY informative post, however i didn't understand what you meant here: <table border="0" align="center" width="90%" cellpadding="3" cellspacing="1"><tr><td class="SmallText">Quote&#58;</td></tr><tr><td class="quote">
The other problem with a very flat hull is that there is no scope for a planing surface (angled power boat shape at the sides of the hull) so if you ever did get any speed up over water when you drop back on the water the craft will probably flip over.
</td></tr></table>

After reading your description of the hull, i guess it should look similar to this one: http://www.hovercraft.com/builders/6f_projects/brianjoly/ima (www.hovercraft.com/builders/6f_projects/brianjoly/images/photos/hull12.jpg) ges/photos/hull12.jpg right?



Russ, thanks, ill remember that http://hovercraft.org.uk/images/icons/smiley_icons/icon_razz.gif

Keith Oakley - n/a
7-Feb-07, 07:42 PM
Yes similar but normally the angled surface would be continuous from the bottom of the hull to the outer side at around 30 degrees to the horizontal. This one appears to rise at an angle then extend out horizontally. If you consider the craft tipping in, the planing surface should meet the water first and provide a restoring force to push the hull back up. I suspect with this one theres a good chance this horizontal outer edge will hit first and not provide enough uplift.

Along with the use of a planing surface the front bag skirt is normally angled back so it doesn't 'stick it's chin out' into a wave. For stability the nominal ground contact point on the bag is normally 3-5cm (distance C-E)in from the outer edge of the hull at the sides and back. At the front it could be 15-30 cm (A-E) back from the front hull edge.

Hopefully the attached pic from the now long out of print 1974 Hovercraft Handbook will help

index.php?t=getfile&id=558&private=0

Superwedge - n/a
8-Feb-07, 06:32 AM
Why not join the Discover Hovercraft program if you are a student. or Have access to a shool. Good plans including Hull design Skirt , prop Duct single engine 10Hp-13Hp



http://www.discoverhover.org/ (www.discoverhover.org/)

Horus - n/a
8-Feb-07, 12:20 PM
Hello,



do a search on google or yahoo for homemade hovercraft or include leafblower all the sites you need are listed there.



You have a very simple design in your original post, but are asking complicated questions when the answer is simply to build from plans that are already available all the questions have that wat already been answered and learn from that experience, afterwards build another to your own design using the knowledge you have gained.



Good luck,



Richard.

tonybroad - n/a
8-Feb-07, 02:00 PM
Look no further - i saw this one being made on the Gadget Show some time last year and they wrote up how to build it



http://gadgetshow.five.tv/jsp/5gsmain.jsp?lnk=401&featur (http://gadgetshow.five.tv/jsp/5gsmain.jsp?lnk=401&featureid=72&pageid=141&show=s4e4&section=Features) eid=72&pageid=141&show=s4e4&section=Features



it did work best in a school gymnasium, anyhting other than a smooth surface and it will struggle



good luck