/hacks/hovercraft.html 29 May 2005

The DIY Hovercraft
-or-
"Is this all it does?"
Backstory:
The "alternate" title sums it up pretty well. My 7 year-old son had been on my case for a while about building him a contraption (his words). With the vagueness only a youngster can muster as my guiding force I lay about scratching my head for the better part of the winter. Then one evening I was taking apart our vacuum cleaner to keep it limping along for the umpteenth time when I chanced upon a startling discovery. Namely, that by smashing the vacuum to bits against the floor I could rid myself of that hunk of crap, feel better, and have raw contraption materials. A plan was born...
Materials:
All of the materials I list have a certain amount of latitude in exact choices. For example, if you use a vacuum like mine as inspiration, namely a Fantom POS2k, stop reading now, drive directly to the nearest thrift store and try again. What a pile of turd that thing was.
Anyhow, the list:
  • vacuum/blower
  • plywood or other sheet goods, about 3ft2 and 3/8" thick
  • plastic sheeting
  • scrap wood
  • staple gun
  • various fasteners and hand tools
  • ~8" diameter disc of thick but flexible plastic

The Build:
The boy on finished 'craft, about 3-4ft off of the ground

 It was a fairly straightforward project. At left is the aforementioned, anti-climactic (to the boy, I thought it was awesome), finished product. We'll then go step-by-step with the construction.
Step One:
Fantom brand donor vac Disassemble your vacuum down to the motor, fan, any necessary housings. Skip this section (obviously) if you are choosing to dual-purpose a leaf blower. Hmm, a gas-powered backpack blower with a stand up hover platform might push the excitement level into the visible smile range for my stoic child. I damn sure wouldn't ride it.
At left is my donor vacuum.

As seen in these shots of partial disassembly the vacuum pathing is/was woefully inefficient; up and down, up and down with hard plastic flap-type seals and generally unimpressive construction:
Vacuum cleaner or lab rat maze? A better view of the maze of suckage

The finished blower is shown below with the hose attached to a modified section of the outflow filter housing. The housing was quite irregular shaped so I removed all unnecessary material with a rotary cutter and then made a duct using a thick poly bag I had laying about.
Finished blower assembly
Step 2:
Prepping the platform. I went with a rectangular platform due to no other reason than that it was that shape when I dug it out of my lumber pile. Hindsight tells me that a round platform would likely be better for airflow than my rectangle was.

Somewhere in the general vicinity of the center of the platform a hole must be drilled to accept the hose of the blower. It's more than a little necessary to do this step BEFORE stapling the plastic liner to the underside.
The platform with corners rounded, inlet drilled, and skirt ready for attatchment A shot of my platform. The corners have been rounded off to help prevent tearing the skirt. The roll of material seen on the platform is some leftover weather stripping I used to seal up the skirt/staple/platform joint. Definite overkill, just use duct tape or something similar.

The finished platform with a decent view of the inlet port and the stapled and sealed skirt which, incidentally, is an old shower curtain:
The finished platform
Step 3:
In the previous picture you can just make out a bolt in the center of the platform. That is a critical piece I would be remiss in failing to mention. The skirt must be fastened to the platform to prevent it inflating like a balloon and bulging in the center. I passed a bolt through the platform, skirt, and that plastic disc I mentioned in the materials list. The disk shape allows it to act as a strain-relief since the skirt would certainly pull free from the bolt without it.

I choose to use the lid from an old plastic food storage container with the rim cut off. Well, it wasn't really an old container until my wife couldn't find the darn lid for it anywhere later that week.

I cut outlet holes in the skirt in a precise yet haphazard pattern. I knew that the holes must be large enough to allow for enough flow to create the air bearing the hovercraft rides on, yet small enough to maintain skirt inflation. After much hemming and hawing I reached the conclusion that six approximately 2.5" diameter holes placed in a hexagonal pattern would do the trick. I leave the distance between these holes as your aesthetic choice, because they were surely not engineered by me.

Will post a pic of the underside of the hovercraft as soon as I remember to take one.
Step 4:
Attach blower, electric cord, platform and kid together and turn it on. Sounds far more exciting than the little rat let on. Maybe I can get him to try it out on water next time. My plan is to permanently mount the blower and route power through a light switch box and normal household switch.
Another completed view:
Wrap:
I had a great time building it and I think my son will come back to it eventually. At the very least it gave us a chance to hang out and talk. The total cost was $0, everything used was leftover and/or scrap.
Questions? Send them to webmonkey(a)twofoos.com
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Updated: 9 October 2005 - Learned some damn html and unbroke it
Updated: 4 October 2005 - Made images smaller instead of constraining originals, changed layout
Published: 29 May 2005