Picture of Launch It: The Improved CD Hovercraft.
The CD hovercraft is a tried-and-tested Make, but technological improvements have tended to be in the method of connecting the balloon to the CD. I have attempted to apply some of Sir Christopher Cockerell's original developmental research to this old favourite.
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Step 1: Materials and Tools

Picture of Materials and Tools
In addition to the basic materials (an old CD, a balloon and a plastic bottle cap and hot glue), you will need a sheet of paper or light card, a thin sheet of expanded polystyrene, ordinary glue and a sharp knife.

The type of glue is not vitally important, since it will not be under any strain greater than the weight of the polystyrene and paper. If you use a water-based glue, though, try and be very sparing with it, as excess water will make the paper "cockle" and cut the vehicle's efficiency.

Step 2: What are the Improvements?

Hovercraft gain lift from pressure-drops. More rapid changes in pressure and downward air-velocity give rise to greater lift.

Early attempts at a hovercraft simply blew air down an open shaft towards the ground. However, when the bulk of the shaft was closed off, and the air-flow restricted to the edges of the craft, the increase in lift was startling.

In the traditional CD hovercraft, the drop in pressure is gradual, spread over the whole surface of the CD. We are going to use the polystyrene and paper to create channels that will restrict the airflow so that the pressure-drop occurs more rapidly near the edge of the disc.

Step 3: Restricting the Flow.

Picture of Restricting the Flow.
The air is restricted by using channels cut in a layer of polystyrene, capped by a layer of paper.

Using the attached templates, cut pieces from the polystyrene and the paper. If you are doing it by eye, remember that the CD has a diameter of 12cm.

It is easier to glue the polystyrene to the paper, and then both to the CD. Use the "normal" glue to do this, being careful not to clean off any "ooze" before it dries: blobs of glue on the bottom of the hovercraft will catch on the surface below the craft and slow it down or even stop it completely.
agishero2 years ago
Word File Can't Be Downloaded
Kiteman (author)  agishero2 years ago
(Thanks - I've submitted a bug report)
ilpug3 years ago
These are really fun to make. I recognize that set of craft knives, i bought mine for 99c at a discount store and most of them broke in a week. How did yours hold up?
Kiteman (author)  ilpug3 years ago
Fine, I'm still (ab)using them.
ilpug Kiteman3 years ago
Wow. Maybe i am just more prone to breaking things.
kiteguy3 years ago

Quote: "being careful not to clean off any "ooze" before it dries: "

Perhaps this is one reason it would not "fly" as wanted.
Wyle_E7 years ago
If you have a source of dry ice, a small plastic bottle of dry ice chips would last longer than the air in a balloon. The original version of this gadget is the "dry-ice puck" that's been used in physics classes for almost a century. It has a thick, polished steel puck instead of the CD, and a copper ball (remember copper toilet-tank floats?) to hold the dry ice. With that much mass, it would glide *slowly* for several yards without visibly slowing. One of these days I may dust off my old Unimat lathe and make one.
Kiteman (author)  Wyle_E7 years ago
That is true, of course, but most readers won't have access to lumps of dry ice.
hintss Kiteman4 years ago
buy them at Ralphs?
a918bmxr5 years ago
this is the latest in self propelled balloon hovercraft technology
(klik linc)
Kryptonite6 years ago
I've tried this the "Original" way, and I think it worked better than yours, any ideas why? I thought that yours would go better, oh well, better luck next time.
astro boy6 years ago
replace the cd with another piazza base more power or smaller hole longer run
Kaiven7 years ago
do you kkow where polysterine can be found in a house? where i live, we don't have that kind of pizza stuff. Alos, is there anything else i can use? thanks
isnt styrofoam polystyrene?
Yes. It's clear that you want polystyrene foam, aka styrofoam, and not solid polystyrene. Open-cell foam (the original Styrofoam) won't work here, because it won't hold air. Closed-cell foam, used in disposable cups and plates, is what works.
Kiteman (author)  Kaiven7 years ago
Ceiling tiles? DIY stores sometimes sell thin sheets of expanded polystyrene as insulation (maybe to go behind radiators), craft / modelling stores will sell it as a modelling material, or be able to advise on other alternatives.
Kaiven Kiteman7 years ago
oh! i found something! maybe a styrofoam meat tray. Mine had chicken :)
Kiteman (author)  Kaiven7 years ago
That's fine - as long as it'a big enough to cover the CD.
Kaiven Kiteman7 years ago
ok, i might try something i can find
pyrotecnix7 years ago
dude no way i have the same blade kit thing as you soz i am a bit lame...
zachninme7 years ago
This seems... too complicated... it seems your air channels actually allow too much air coming out too easily, decreasing run time. I'm not sure, but maybe...
Kiteman (author)  zachninme7 years ago
The excess air-flow seems to be through the central hole, which is why I restricted it there.

However, v2 will involve few/narrower channels from the centre to the edge, a change of glue and possibly plastic to cover the bottom instead of paper.
Hot glue dries a matter of minutes, if not seconds...
But its not low-friction. You need something that will be smooth.
It says you need ordinary glue, it can be used the same way as normal glue.
Kiteman (author)  Weissensteinburg7 years ago
I couldn't use hot-glue on the base because the gun melted the 'styrene and it cooled too quickly, before I got it completely smooth.
Ah, gotcha.
Wow! Five projects for one contest, and all fantastic!
Kiteman (author)  ProfessorZ427 years ago
I seem to have had a rush of blood to my 'ibles, don't I? It could have been six, but the local plumbing supplies stores all close on Sundays. That will have to wait, now - I have costumes to make!
bobbyk8817 years ago
fuji film rules !!!!!!!!!!! and its not badly printed
Kiteman (author)  bobbyk8817 years ago
The balloon is badly printed.
Then why is there a big bubble of "FUJIFILM" missing?
awoodcarver7 years ago
Kite you must want that prize , I started a tater launcher-gold bearing gravel sucker for this contest but cant get to my tools to cut/round off some parts (garage is full of someones couches and such)good luck and do a new vid when it is done , I will have some of the kids at school make a few of these
I believe this instructable calls for liberal use of the ubiquitous double-sided sticky tape! Excellent instructable, I like the design mods to the classic cd-hovercraft. Pity you had to rush it at the end there, though. Waiting anxiously for an update, lol