1) Q: What is a brushless outrunner motor?
A: An 'outrunner' motor has a stationary central stator, while the outer housing
rotates. This design allows relatively low RPM with very high torque, eliminating
the need for a gearbox. Outrunners are also considered ‘brushless’ and has no
physical wear on electrical contacts. This type of design is ideal for the rough
hobby of FPV.
2) Q: What is KV?
A: The KV rating of a motor that stands for RPM per volt, and indicates the
motor's 'no load' speed per applied volt. For instance, a 900KV motor will spin at
approximately 1000 rpm per applied volt. If you connect a fully charged 4 cell
Lipo battery (16.8 volts) to a 1000KV motor it will spin at about 16,800 rpm (16.8
x 1000) with no propeller attached. The KV rating is determined by the number
and type of motor windings, and is a main factor in determining what size
propeller can be used on a motor.
3) Q: How do I choose the right battery for my motor?
A: The right battery depends on three factors: 1. Propeller size choice 2.Motor size and
kv 3.Overall weight. Bigger Propeller using lower KV with low voltage may require more
capacity. Smaller propeller using high kv with high voltage may require less capacity to
accommodate for weight. Correct battery really depends on the setup and is case by
4) Q: Why does my motor vibrate in specific throttle levels?
A: Every drone and power systems involving rotating mass has issues with vibrations.
Resonant frequency between the frame, motors, and propellers create a specific pocket
of frequency the gyro cannot simply tune out. Use of Gyro and Dterm Notch Filters in
flight controller firmwares may help alleviate the vibration issue, but soft-mounting
hardware will be best to solve this resonant frequency issue. Soft-mounting the motors
and/or flight control boards will help remove this vibrating issue.
5) Q: Why does my motor get excessively hot?
A1: Check to see if motor mounting screws are protruding into the wired coil. Having a
screw pinch wires can cause electrical short and may damage more than just the motor
(i.e. ESCs, PDB, Flight Controller).
A2: Check for magnet slippage. Slipping magnets may disrupt performance of motor and
cause unwanted desyncs and heat.
A3: Check for dirt or debris in between the stator and magnets.