Most of the software I use is from other sources. Richard Nakka prime among them.
But I have developed a few bits and pieces that work OK and serve their purposes pretty well.
KnCalc: A
little VB utility I wrote while taking a programming class. Not
real user-friendly at first, but great for getting quick calcs of
prospective motors. I still use it a fair amount. Click Here to download software (.zip file) Click Here for instructions on installing and using it.
BATESCalc: Excel* spreadsheet to calculate the progression of Kn ratios for BATES grains of ideal and not-ideal length.
UninhibCalc: Variation of BATEScalc for uninhibited grains.
Coneburner: Calculates Kn ratios for motors using a deep cone configuration.
Endburner: Calculates Kn ratios for end-burning motors.
Being spreadsheets, these can be easily modified, or incorporated into more sophisticated spreadsheets.
* Don't have Excel? These also run under Open Office Calc, part of a FREE office suite from Sun Microsystems.