This is the plan for a set of pan pipes. The other models found did not take into account that a tube less than 7 times the width of the opening will not make any sound.

A 2mm thickness of the pipe will prevent any "leaks". The parametric version allows you to change the notes used. I cheated a little using numbers in inches converted to 10 milimeters each (where a C pipe should be 6 inches long, it's 60mm on this model)

Load up the stl to print out a 62mm high pan pipe. The scale (major) is good but I still need to listen to find the actual frequency it belches out.

If you want to print a bigger or smaller one, load up the .scad and modify to taste.

Source of the length used is here: http://www.panflutejedi.com/tube-lengths.html

The ratio of each tube opening versus length is 1:10. You can usually go between 1:7 and 1:14, but 1:10 provides a sweetspot.