Very interesting spreadsheet!

Is the model utilized an approximated one? If so, what is the accuracy?

I was thinking about a servo related issues. Imagine a servo whose arms are attached to ailerons (i.e., tipical trainer setup). What is the required torque now? We have two surfaces to move, instead of one... but I was thinking that perhaps in this case the required torque is LESSER than the required torque for a single servo attacched to one aileron. In fact, since ailerons move in opposite directions, when one pushes the servo arm in one direction, the other aileron will push the other arm in the other direction... so the servo in this case will not see any torque!

What do you think about that?