DIY Leaf Blower Hovercraft (#Making)

So my daughter wanted a hovercraft. A lot of bad stories start that way, but this one has a happy ending.

DIY Hovercraft are easy to build–we made ours in a couple hours from materials lying around our garage, repurposed from gathering wood dust, cobwebs, cat pee, etc.

Many sites provide instructions; we followed some from Make Magazine. Here’s a more detailed set of instructions, which we should have followed instead.

What you need is:

  • A working leaf blower or shop vac
  • A piece of plywood (at least 4 x 4 ft.)
  • A tarp or shower curtain
  • A plastic disc (bucket lid, coffee can lid, etc.)

Tools required, or at least really nice to have:

  • Jig saw
  • Staple gun
  • Box cutter or scissors
  • Lots of duct tape

We had an old leaf blower that had been dead for years, which my husband had failed to fix. My daughter’s solution was to buy a new one–unfortunately, my husband had already replaced the broken one with a much larger model that seemed overly heavy for this project. Plus, you know, he was still using it to blow leaves and stuff.

“Why don’t you fix the old one?” suggested my husband.

“Why not?” I asked my daughter. I’ve never taken apart anything with an engine before, and she’s nine, but we had two things going for us: naivety and the Internet. We downloaded the instruction manual and watched one video on YouTube. With a lot of virtual hand holding, my daughter and I took everything apart, cleaned the air filter, checked the carburetor (after finding out what a carburetor was), checked the spark plug (this one I didn’t have to look up), and removed the spark arrestor (I still don’t really know how this works, but it’s apparently very important). It looked like this:

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Spark Arrestor Before

On the YouTube video, the guy took a wire brush, plugged it into his drill press, and used that to clean the spark arrestor. I didn’t have a wire brush attachment, so I took the spark arrestor, plugged that into the drill press, and held up a wire brush. This is what it looked like after:

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Spark Arrestor After

So we put everything back together…

And it didn’t work.

Until I read the instruction manual, and found an algorithm for
How to Start Your Leaf Blower When It Doesn’t Start, or something to that effect. It involved flipping the choke to the other position. I wish I could say it was more complicated, but it wasn’t, and I’ll never know what would have happened if I’d tried that first.

I do know that when that thing started up for the first time in five years, my husband literally danced for joy.

After that, the rest of the hovercraft was easy:

  1. Cut the plywood into a 4×4 ft circle (we only had a large enough piece for a 4×3 ellipse)
  2. Halfway between the center and the edge, cut a hole just big enough for the leaf blower nozzle. (We used some extra flexible tubing here, which allowed us to keep the leaf blower as close to the center as possible.)
  3. Cut the tarp about four inches bigger than the board.
  4. Nail a “bucket lid” to the center. You can use a coffee can lid or other plastic circle. We used a square lid out of necessity. It probably screwed up the air flow, but not more than our other mistakes.
  5. Staple the tarp in place, leaving it “loose enough.” It turns out it probably doesn’t need to be as loose as we made it–you need just enough to create a thin cushion of air.
  6. Cut six slots around the bucket lid, for air to escape. These should be about 2 in. holes fairly close to the bucket lid, because you want the air to come out not on the bottom of the tarp (like we did), but towards the center.
  7. Tape down the tarp really well, tape the nozzle in place, and turn it on!

As you can tell by these instructions, our first attempt was not perfect. We did some more research and filled in the gaps after the fact. But this is what we got!

 

 

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