Battery technology has increase 10 fold in the last few years. Model airplanes with electrics could barely wobble into the air a few years ago, now they can out perform the I/C engine planes.

Brushless motors are the only way to go especially when hooked up to a good digital speed controller. (brushed motors benifit from a good digital controller too)

Sometimes when you run like you are with just a switch, it uses up a lot of power fast. A controller allows you to feed the power in and use what you need, not just draw all the amps you can for short busts.

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If it ain't broke, and you mess with it long enough, it will be.