I was playing around with Drive Calculator. And used a 3900kv motor instead of the 2200kv. Now my speed shot up wot 139km/h. But efficiency was 45%. What does this actually do to the plane? I go faster but what am I losing? So I'm losing 30% eff to what? Also when I put in a smaller prop, 3x3, it goes faster! So if I wanna use a faster motor, I have to use a smaller prop? It's tough to figure out how a prop and motor affect each other. I still don't get it.