Temporary disclaimer for why this is in the “Flying Contest”.  Instead of designing a plastic object that flies through the air, I designed a STEM kit that will create a Vortex of air that flies through the air!

Watch it knock over targets and blast smoke below:

What's included:

STEM Kit includes the main body, three different twist-on labelled orifice plates (50mm, 38mm, and 25mm), and two optional cone inserts (5 and 10 degrees).

I used PETG with a 0.4mm nozzle and a 0.3mm layer height for a quick and functional print.

You can add a colour change on the orifice plates to get a contrast for the lettering (letter side faces the build plate).

The cones print with the smaller diameter on the build plate in “Vase mode”.

The main body prints with the solid ring facing the build plate and the twist-lock tabs facing upwards.  The outside of the solid ring helps hold the balloon in place (see below) and the internal solid ring acts as a stop for the cone inserts.

To assemble:

Cut the bottom end of a balloon off.

Stretch the balloon over the back end (solid ring) portion of the main body.

It is recommended that the balloon is further secured by a strip of electrical tape to make sure it doesn't pop off when you pull it back.

When using a tapered cone, the larger diameter slides in first and is secured in place with the orifice plate.

Now you are good to experiment or just shoot targets with a vortex of air.

STEM can investigate questions:

• What effect does the orifice size have on the vortex of air?
• Does the taper help or hinder the vortex?  (note the 10° taper is pretty much line to line with the 50mm orifice so it effectively functions as just a conical nozzle, what effect does that have if there is no “lip”)?
• How far does the vortex travel (spoiler, it's quite noticeable at least 20 feet away, could it be further???).

Fun Tips

• You can blow smoke rings by placing the orifice over an incense cone and filling the body with smoke.
• Set up targets to knock them over with a blast of air.  The vortex is surprisingly powerful.  

If you would like to print the cardstock target base that I used in the demo video, you can download it here:

[https://www.printables.com/model/180922-1-inch-game-base-for-cardstock-or-photo](https://www.printables.com/model/180922-1-inch-game-base-for-cardstock-or-photo)