So I'm a newbie here... fascinating discussion in this thread. I have a question. I've got a design for a water wheel and have done the math up to knowing that, in the right configuration, I will have 10,000 ft-lbs of torque trying to turn it. What do I have to do to determine what the actual hp output will be? Do I have to identify all the friction and other resistance that will be acting upon it while trying to turn? And along with that, will I have to try to determine its speed (rpm)? Thanks in advance.