brushed motors... AC or DC... try late 1800's...

the basic motor rotated by battery power.. late 1700's.

I know you are talking R/C motors..
even tether cars.. 1940's
before that tether cars were fuel powered ...

even look at electric trains for children... pre WWII.... * 1940's *

I started RC racing in 1991... I remember seeing RC stuff in the 1970's...
but radio's were Box radios with sticks.. like aircraft radios.