I stumbled on this by accident. You can 3D print the parts to make a giant bottle water rocket.
http://www.uswaterrockets.com/research_&_development/3D_Gardena_Nozzle/report.htm
I stumbled on this by accident. You can 3D print the parts to make a giant bottle water rocket.
http://www.uswaterrockets.com/research_&_development/3D_Gardena_Nozzle/report.htm