Build Notes / 10th Apr 2021

Mini Hovercraft

The "complete" mini hovercraft

This mini hovercraft was my first build in my Can We Build series, which is essentially a justification to build a whole load of weird things and film it.

It took 3 evenings to build, and a fourth wrap-up day to get some B-roll footage and film the closing remarks, so it fitted quite well into my proposed schedule of "a few days" that I used in the intro. If I ever run longer there, my excuse will be that I meant "the equivalent of a few full days", which given I fit this around work, is more like 5 - 6 days of evenings!

Most of the time slowdown was waiting for 3D printing - I love resin printers, and they produce some lovely results, but my goodness are they slow, even with the new monochrome screens. If I wanted to truly rapidly build this, I think using the laser and the CNC router only would have been the way to go.

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Materials

This, like most of these builds, used a lot of random parts I have lying around the workshop (this is one of the advantages of having grown one over the years in my basement and eventually out to its own location), but here's the main materials I used:

The 3D prints are made using an Anycubic Photon Mono X, using Elegoo Grey Resin. I like the grey as it has very decent layer times, but any 3D printer with a big enough print bed and any resin will likely work here.

Tool Thoughts

I made significant use of CNC machines here in the Shapeoko and the laser cutter, which is mostly because I'm terrible at cutting out perfect circles, but you could do most of this with a jigsaw and some scissors if you needed to.

I quite like the use of medium-duty staples to secure the skirt - this is often what's done with fabric on chairs anyway, after all. What's not shown in the video is that when I stapled the second skirt, I put the staples much closer together, and that seemed to help with making it pretty airtight (well, as much as a hovercraft skirt needs to be).

Safety Notes

Brushless motors with props attached are dangerous - make sure you are careful around them when they are connected to power and especially if they are not enclosed yet. I had one mis-programmed ESC/motor spin up when I powered off the RC controller and it made a lovely set of cuts on my finger (you can sort of see it healing over in some of these clips).

I wear eye protection at all times when doing anything I perceive as even slightly hazardous, like this, but I added work gloves after that just to make sure, as well as always unplugging the battery before I powered off the transmitter just in case.

Added onto that, be aware of the normal precautions about storing, charging and discharging lithium-polymer (LiPo) batteries, and making sure that the ones you choose can support the current draw.