I think this might be the oldest published 3d printed boomerang. I uploaded it to another 3d sharing platform in 2011.

A simple tri-blade boomerang.

Look anywhere on the web for throwing instructions, e.g.: http://www.rediboom.com - this is an actual returning boomerang!

Edit: Videos of this design in flight have been posted on Youtube. Thanks guys!

I'll add more once I find them.

https://youtu.be/38K8bOXgk2M

Print instructions

The first of these I had printed in ABS; size should fit into a 20x20 cm bounding box, thickness should be 3.5 mm. Making it a little larger won't hurt, but the 3D printing company I used only has a 20x20 printing area.

Meanwhile, I have printed plenty of these in PLA, too. Also, different sizes work well, anything between 150 mm and 300 mm squared should be fine.