all motors will do this. i noticed this even in the beginning of my DF adventure, but my thrust to weight ratio was so low and i was drawing so much out of a tiny battery that i attributed it to my cheap setup. brushed may do it more becuase of the amount of energy lost in heat in the carbon brush, although i do not know. mine may actually be more severe than your guys's becuase my motor is much smaller than the gearbox it sits in, so almost all cooling wind is blocked by the gear box mounting plate. Put a heat sink on and see what happens. what i fear is that i have damaged my $40 motors. a single $40 replacement motor is bad enough, but to think i was doing this to all four of them, ($160) i hope to god i am not too late...

best case scenario is my motor has lost some performance due to the heat accelerating the wear and tear.

Cheers guys,
-Clam