The power of water is sometimes understated, especially as a means of propulsion. This project uses the water and pressure from an ordinary garden hose to propel a 3D printed octo-copter into the skies.
This project only takes a couple hours, as all you need to do is print the file, screw it onto a hose, and turn on the tap. No other parts required.
Step 1: Print!
There are two options here. If you have access to a 3D printer, use the attached STL file to print out an octocopter. Use supports and solid infill to avoid leaks; less than 0.26mm layer height is recommended.
The second option is to use an external 3d printing service, specifically Shapeways. The model is at my Shapeways shop here, and is very inexpensive.
Step 2: De-support (for Home Printer-ers)
If you printed the octocopter at home, you'll need to remove the support structure. In Cura, my proffered software, there's a setting to only add support that touches the buildplate. Otherwise, there'll be support inside the tubes. This will probably not work, and you'll need some awesome Dremel skills to drill out all the support.
If you ordered it from Shapeways, you don't have to do this. Hooray!
Step 3: Fly!
Screw the octocopter into the end of a regular garden hose. Then, turn on the hose to full volume. Hold onto the hose a couple feet away, and use the inflexibility of the hose to guide the octocopter and keep it from falling over. Some hoses will work better than others-- look for the most flexible one in your house/garden.