I made a pan flute with copper tubing (3/4 in diameter) to correspond to the following notes/lengths:

C - 15.4cm
D - 13.6cm
E - 12.0cm
G - 9.8cm
A - 8.7cm
The original instructions called for PVC pipe at 1/2in diameter, so the notes are off.

How do I change the measurements of the pipes with those notes to fit the copper volume and 3/4in diameter of the tubing?

Extra note: I'm planning to cut up some more copper to build other notes to play a C major scale, so if I know how to do this, I can probably cut more to make a bigger pan flute.

Thank you!