I made a copy of one of my plastic pipe instruments to try the result, it works quite well so I share the result with you!
I made a video about this project :
The first version is a fully 3d printed 3 parts flute, you have to glue the parts together, you can lightly sand the holes, then it's ready to play.
The second version needs a piece of plastic pipe, 20mm outside 17mm inside, this kind of pipe is european electric conduit.
Here is the blueprint to drill the holes on the pipe :

I hope you will have some fun with project, can't wait to see what you'll do with that!
The author marked this model as their own original creation.