Customizable rocket to be fired using compressed air - I use a cheap garden pressure sprayer with the spray tip removed. Great fun with kids!

Accurate enough for target shooting, or go for maximum range, perhaps with giant fins :)

1. Measure the outer diameter of whatever you're using to launch the rockets, add a small amount of tolerance (e.g. 0.5mm) and adjust the Inner Diameter setting to this value.
2. Adjust the size of the body, nose cone and fins
3. Ensure the perimeter width setting (Extruder tab) is set to something suitable for your printer (e.g. 130% of your nozzle diameter)
4. Generate STL and print
5. Slide onto launch tube, pressurise and fire!