This is funny:
I want to use the 220A of course.
Just a minute, 0.0895 Ohms - oh no, that makes 220A * 220A * 0.0895 = 4331 Watt of ohmic powerlosses. That will not work for more than 10 seconds.
So i have to go back to 50V 80A. 80 * 80 * 0.0895 = 572W
So i can put in 4000W, getting 3438W (or less) out.
An outrunner has half the resistance and thereby half of the ohmic powerloss, 40% less area for induced drag and wheighs less than the half. And it can be cooled much better. It also has less than half of the length.