Most powerful 550 size motor

[gpetilli]

JVN has done a great job tabulating the motors in his JVN-DesignCalc.20130105 spreadsheet. He shows the RS-550 as 245W however the 550 uses an internal fan and you must keep the input and output vents clear and it does not last long at stall (peak power, slowest fan). The CIM, Mini-CIM and Bag motors are sealed with no fan (last year some teams reported bearing issues with the Bag motor that is reportedly resolved).

The 775s are also air cooled, but have significantly more surface area and I believe they are more rugged. The 775-18 is 266W. Note that all motors over 120W must be on a dedicated speed controller - so the best option might be 2x RS-545-12 (2 x 73W), but you still have the fan problem.