the motor is not the problem. Need more prop. Do you have something to check temperature with?,..like the raytac infra-red "gun"? I use the B50 9S with 6.7 gearbox, 3S3P lipoly (equivalent to 10 old roundcells), and 16X10 APC "E" prop. The temperature thing really means nothing at all unless you have something to actually check it with and have real numbers. I personally can't hold my fingers on a motor thats 135 degrees,.. so that could be percieved as "really hot",..when it's not. No need to be concerned untill you hit 200+ on the motor at the end of a flight. As an aside, someone at SEFF last weekend was concerned that their motor was getting "extremely hot", and they were limiting flights to 3~4 minutes and allowing it to cool. I checked their temps with my raytac device and read 126 and 129 on two flights. I call that "cold" in brushless motor terms