Our team started working on the same idea(manually integrate the drag + projectile formulas to calculate the projectile path)(
http://ideone.com/aoChY, but we haven't quite gotten it to the level of completeness you did.
This is going to require a lot of testing to get the constants right though(and to see if it is accurate at all).
(Also, no offense, but I would heavily suggest for you to refactor your code. All of those functions with repeated code and the whole "god" class is going to make things hard to modify and debug later on)