Radial Flow Water Pump--How to calculate Watts required to power it Hi all, I'm currently working on an independent project where I'm building a radial flow water pump to be sent to a village in Senegal. I'm having trouble figuring out what motor to use to power this water pump and how much power is actually required. Project specifications: -Well is ~12 meters deep -Impeller blades are 5.08 cm long -Impeller blades are 1.27 cm in width -discharge pipe is 0.6cm inner diameter So far I have figured that the torque required for the impeller is τ = ρghAR/2, where A is the area of the impeller blade, and R is the distance from the axis to the far end of the impeller blade. ρ is 1000kg/m^2, g is gravity, and h is the height, 12 meters. Is this correct? IF so, I desperately need help trying to figure out what motor to use and how many Watts are needed to power it. I know that I can find Watts from torque and rpm, but I don't know how exactly to find the rpm either. If someone could point me in the right direction I would be EXTREMELY grateful.