Anyone built a hovercraft?

my3cents · 23-06-2014 12:27PM #1

So I've taken a notion to build a hovercraft and wondered if anyone here has any experience in the area?

Currently I'm in the research phase. After a week or so of reading up on the subject online my inclination is to build something like a UH 14P Super Sportsman (I'd post a link if this stupid website ever gets around to letting me post links so if your interested google the name and you'll find it). However I'm tending to think along the lines of making something smaller and cheaper or going for a 2 engine design because where I want to use it would benefit from the extra control that 2 engines seem to provide. On the smaller and cheaper I have the plans for the UH10P similar to UH10F at hovercraft.com and there's a usable 2 engine design at calvin.edu with a step by step pictures of their design. The construction method for all the designs I've looked at so far are some type of foam and fiberglass resin or foam, thin ply and fiberglass resin.

I've worked with fiberglass and epoxy resin before making canoes (years ago), I've a decent workshop (this might be a good excuse to buy some more tools

) large space in a barn and worked a lot with small engines so I think I have skills necessary but apart from the size of the project there are a couple of key features that have me worried. The fan(s) and the thrust duct(s) look a bit tricky and are top of my worry list.

Before I go any further I'm going to price up the main materials and spend some time hunting for a suitable engine or engines because I think whatever design I choose will revolve around what I can get/afford for the engine(s).

Then again .......... I've seen a fairly simple single engine hovercraft wheel barrow (vintageprojects.com) which might be a better first project?

fergal.b · 23-06-2014 11:28PM

I have thought about it but not built one yet:) I hope you keep us posted on you build and if I can I will help out along the way.

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my3cents · 24-06-2014 09:17AM

I've started to price materials and now I'm looking for a bit more information on exactly how you workout the best air flow for the skirt and the best way to attach it.

I keep coming back to the wheelbarrow hovercraft idea as a test bed. The plans that are online and available from ebay sellers for the wheelbarrow hovercraft are all the same ones found at vintage projects which has a wooden deck and framework but I was thinking I could make the deck out of EPS foam and fiberglass keeping it all very simple. Once I'd made a simple foam and fiberglass deck I'd be happier with the construction methods and it would give me some insight as to how much lift is available from home made fan blades. Another thought is that loading up a wheelbarrow prototype would give me some idea as the lifting power of various hp's of old lawnmower engines.

One way or another its going to be a long project if for no other reason than that way I can spread the cost.

fergal.b · 27-06-2014 07:23PM

This might save you a bit of work http://www.donedeal.ie/boats-for-sale/hovercraft/6821617

When you say home made fan blades do these not have to be very finely balanced ? As for the engine I would look out for a rotax engine maybe one from a jet ski it would have much more power to weight than a lawnmower engine.

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my3cents · 28-06-2014 08:22AM

Thanks for the link, very nice but more than I can afford, my plans run to €1500 (hopefully a lot less) and I'm pricing this particular design http://yalestation.yale.edu/hovercraft/files/PDF/UH10P%20Simplified.pdf. I can get a brand new 4 Stroke 12.5 hp engine for €495 (its probably cheap and rubbish) but hope to pick up something second hand for a bit less, an ideal would be a s/h 15hp Honda engine and I'd even use electric start if available. Power to weight ratio isn't too much of a problem and the design takes into account the lawn mowers engine weight and there is a max suggested weight for each of the plans I've looked at and while I don't think its quoted for other UH10's is max 65lbs.

All the thrust and lift blades I've seen on build blogs and on plans have been hand carved so thats what I'll have to have a go at. A mate has a CNC routing table so I might see if there is a way of doing some of the work on that?

If I had a suitable small test pilot (child) I'd definitely give this a try http://www.hovercraft.com/content/index.php?main_page=index&cPath=39 but as I'm the only one likely to be using it I'll have to start with something bigger without starting something so big I'll never finish it.

gctest50 · 30-06-2014 11:43PM

little bit more

the fan looks like one from a large generator / air compressor

engine is like one from a snowmobile

https://www.youtube.com/watch?v=FR1cF-XXX7c

my3cents · 01-07-2014 08:46AM

If I could buy one (multi-bladed) like that I probably would but then I couldn't use direct drive and have to introduce the additional work/cost of gears/belts/pulleys.

With a directly connected system you have to get (make) the blades so that they produces maximum thrust when your engine is at maximum speed. If the blades aren't matched to the engine then either the engine won't reach its max speed and max thust or go too fast and burn out (over simplified). It seems that it makes little difference to the thrust produced through a thrust duct whether its a 2 bladed fan or a 20 bladed fan but the 20 bladed fan can be run at lower speed and is far less noisy the pay off is that to get the lower speed you need a gearing system which is to complicated for cheap home made hovercraft.

In comparison to the Discovery Channel Hovercraft lets just say mine will look somewhat "agricultural".

fergal.b · 01-07-2014 09:39AM

Another homemade one http://news.bbc.co.uk/2/hi/uk_news/england/7946634.stm

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my3cents · 01-07-2014 02:10PM

Plenty of info on the one I intend to build here http://www.instructables.com/id/10-HP-Hovercraft/?ALLSTEPS lots missed but still a nice documentation of the essential steps. Impressive that it would still work with a 300lb (20 stone) pilot.

my3cents · 01-07-2014 03:24PM

I want to try and avoid this particular scenario http://www.salient-news.com/2011/08/hovercraft-propeller-shears-off-killing-the-driver/

gctest50 · 01-07-2014 03:58PM

http://www.athboyhovercraft.ie/

http://www.odd.ie/hovercraft-grand-prix-experience-cavan.php

http://www.extremesports.ie/hovercrafting

https://www.youtube.com/watch?v=-77A7LsOLZk

https://www.youtube.com/watch?v=Qle2JSfHYfE

Stovepipe · 03-07-2014 08:11PM

Hi there,
If you want to see direct drive or geared engines driving pusher propellors, I suggest you take yourself to Limetree Airfield, a microlight aircraft centre, near Portarlington and look at pusher microlights with many engine combinations, including Rotax, Fuji Robin and even BMW motorbike engines. Lots to see from a very friendly bunch of guys, especially with info regarding propellors.

regards
Stovepipe

Anyone built a hovercraft?

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