The Indian flute is unique in that it has two chambers, the sound chamber and a Slow Air Chamber.
Other methods of locating holes include picking a number between 3/8 and 1-1/8 inches and spacing them evenly beginning about 4" from the back end of the sound chamber. Or, you can give it to the person who will be playing it and have them hold it comfortably. Neighbor's grandson show. Note the dowel.
For those who want more info on this:
Lew Paxton Price wrote several booklets giving the tuning of Indian flutes in detail.
His formulae consider wavelength, size and shape of the various openings.
How to figure the location of finger holes based on diameter and length of the bore, etc.
Charles W. (Charlie) Brown said: