ferret said:As I wrote before, running 2 identical motors at identical RPM at identical road speed will give nearly identical efficiency regardless of where they are installed.
According to the 0 degree slope example, this motor's peak efficiency is at 320 RPM. The rear motor setup will only operate at peak efficiency at 30 kmh. The mid motor's peak efficiency at 320 RPM can be used at several different speeds, Therefore the amount of time spent riding at peak efficiency is potentially greater with a mid motor.
That's in his graphs. The simulated crank drive is more efficient, since it's operating at 320rpm the whole time. It just doesn't make a really big difference.
Actually, I'm not real sure what he's up to there. The "remains constant at all travel speeds" would require the simulated gearing to approach an infinity ratio at the beginning, which seems a little silly - and doesn't match the graph, as I interpret it anyway. The simulation apparently does use some gearing advantage, because the outcome is different from the hub motor.