Originally Posted by ivanc
Brushed motors use capacitors to reduce the arcing in the commutator. Without these capacitors the arcing creates a lot of radio interference which screws up the receiver.
The brushless motors we use are also DC motors but they do not have mechanical commutators. The commutation (change of polarity) is done electronically in the ESC.
Technically, they are three phase AC motors, we just run them on DC, hence the speed controller. It's easy to confuse the two, and not knowing it won't make a difference anyway.
Now, I'm thinking of a crash I had with my first RC plane ever. About a decade ago I had a motor-glider with a Graupner 400 in it. When building it, I never soldered those capacitors on, one day it dove nose first into dirt, that's probably why. I miss that thing.