Good question: like I said in the original post that’s an estimate; it’s where I’m doing guesswork. See the “nominal power draw” variable in the top left of the sheet? Change that and you’ll change the “power on duration”, or how long the batteries will last. I guessed the nominal power on duration based on Paul saying something like 8 multistar batteries will give you 40 minutes of flight time. That’s all, and it needs backed up by data. Intuitively the flight times look reasonable, and no matter how much data we collect it ultimately depends on variables out of our control; wind speed, wing size, pilot weight, pilot flying behavior, and more.