Steve Petermann – Seven-Hole Flute Design Software
This method of flute design developed by Steve Petermann adds a thumb-hole to the common six-hole flute design. This has a number of advantages in tuning and allowing some second-register notes to be played in the first register (with better resonance).
Steve has developed a spreadsheet for placing the finger holes that provides precise control of the tuning of cross-fingered notes. The spreadsheet does draw on the work of others, who are acknowledged in the spreadsheet. Steve is generously sharing this software and has allowed me to share it here. Steve also has no problem if flute makers offer flutes for sale with this design.
The spreadsheet (available below) is described by this YouTube video done by Steve:
Here is a link to the latest version of Steve's spreadsheet. Note that the target of the link is an XLSM file (an Excel spreadsheet with VBA macros) which you will need to save to on your system to use: