Brushed Motors on RC Airplanes:
A Complete Wrong Choice for Radio-Controlled Flying Models.
Thrust to weight ratio of a brushed motor is way less than a brushless motor for same rated setup.
Brushed motors are highly inefficient because of its contacts between brushes and slip rings, increasing the overall friction and heat losses, thus reducing the overall flight time of your flying machine.
In order to get larger torques from brushed motors, the overall diameter of the rotor has to be increased, thus increasing the overall weight of the motor.
So in a nut shell, brushless motors are way more effective and efficient than any available brushed motor in the market.