I'm building a quadcopter as my bachelor's degree thesis. I'm having trouble finding a reliable equation for calculating the static thrust for a quadcopter. The equations I have found give me ridiculous results. I know that it's difficult to derive such an equation and I know that there are online calculators (like this). But how do these calculators calculate static thrust? There has to be an approximate equation somewhere. This is what I'm asking. I don't mind the equation(s) that lead me to there, I would just like to know them.
Edit: More information
The following snapshot is taken from Mathcad software. It's various equations i have gathered from supposed trustworthy websites. These equations lead me to the calculation of static thrust. I think the equations are pretty self explanatory. Thank you.