Castle Holdings LLC -- our motor production facility

[BrianG]

You have to remember the resistive losses come from I^2*R. True, resistance is higher in a higher turn motor because of the added turns and thinner wire, but less current makes a bigger difference because that is the squared part of the equation. So, as long as the top speed is the same (load), a higher voltage on a lower kv will result in the same amount of work and same overall power as a lower kv/voltage setup.

[nuz69]

Briang, you forgot that the resistance depends of the length AND the surface of the wire ;) For the same volume of matter (or same weight for both motor), a wire twice more more long have a resistance four times higher.
R = R0 * length/surface and you have to keep length*surface equal for both motor (volume or weight).
So the multiplication R*I² would be exactly the same.
For example, I am sure that the 1515/2Y motor resistance is average 4 time higher than the 1515/1Y one.