Guides
Sizing a BLDC motor for a UAV
The parameters that decide whether a brushless motor fits a UAV mission – and why the motor belongs inside the complete drive, not picked in isolation.
Start with the mission
Motor sizing begins with the mission profile: take-off weight, required thrust, cruise vs. hover time, and operating voltage. These define how much power and torque the drive must deliver and for how long – the foundation for every other decision.
KV rating and propeller matching
The KV rating (rpm per volt) describes how fast a motor turns per applied volt at no load. A high KV means high speed and is suited to smaller, faster propellers; a low KV means more torque for larger propellers. Choosing KV is really about matching the motor to the propeller and the available battery voltage.
Power-to-weight
In aviation, power-to-weight (specific power, kW/kg) is decisive – every gram of drive mass costs payload or endurance. Custom BLDC motors are wound and built to maximise power density for the specific application rather than relying on an off-the-shelf compromise.
Why integrated design beats component selection
Selecting a motor in isolation often leads to a mismatch with the inverter and battery. SMOTO designs the motor together with the inverter, battery and embedded software as one complete system from a single source – so the BLDC motor is optimised within the whole drive, with one accountable partner and fewer external interfaces, from the first feasibility study to series production.