If anybody is familiar with the program called TWCalc, could you please tell me specifically what the terms “Air Length” and “Cork to End Length” mean? Thanks!
It’s Daniel Bingamon’s program. You can send him a PM or an email and get the straight facts from him.
Happy whistle building!
Judy
I primarily pay attention to air length, as that is the length of the whistle body from fipple top to bell bottom. Nice program too! 
/The hole placements given on http://profs.sci.univr.it/~gonzato/whistle/ measure from the edge of the blade. I found them to be very accurate for an alto G whistle, can’t vouch for the others. But they’re very unambiguous.
Mikey,
Hi. Things like bore diameter and wall thickness effect were the holes go. The calculator lets you plug in the exact stats.