Brushed vs. Brushless
If you’re new to RC and wondering what all this “brushless” stuff is about, here’s the deal. RC motors, for a looong time, all used brushes, as illustrated below. The brushes transfer electricity to the commutator, which makes the motor spin because of magnets and science and stuff (we’re keeping it real simple here, guys). The commutator spins too, which means it’s constantly wearing against the stationary brushes and creating friction. Motor performance eventually deteriorates, until you have to replace it.
A brushless motor, as you may have guessed, has no brushes or commutator. Instead, a “stator” is energized to create a magnetic field that makes the magnetic “rotor” spin without touching it. No touching means no friction or wear, so you get more power and efficiency, with much longer motor life.