How to choose a FPV drone motor

            Brushless motors eliminate brushes. The most direct change is the absence of electric sparks generated during the operation of brushed motors, which greatly reduces the interference of sparks on radio equipment. Without brushes, friction during operation is significantly reduced, resulting in smoother running and lower noise. With no mechanical contact, the internal resistance is also much lower. Furthermore, modern brushless motors commonly use neodymium-iron-boron magnets instead of ferrite magnets, which provide much stronger magnetic force. Therefore, the efficiency of brushless motors reaches 80%~90%, while it is difficult for brushed motors to exceed 40%.                          



Motor Specifications and Data Display***
                            Here’s the accurate, natural English translation for your FPV motor tech text:We often see designations like 2207 motor, 3115 motor, etc., on the casing or in the specifications of outrunner motors. These four numbers indicate the motor size.Regardless of the brand, specific motor models basically correspond to four digits:the first two digits represent the diameter of the motor’s stator coil, and the last two digits represent the height of the stator coil, in millimeters.Note: this refers to the stator, not the rotor can.Simply put:the larger the first two digits, the larger and thicker the motor’s radial size;the larger the last two digits, the larger and longer the motor’s axial size.Some manufacturers label motors based on the outrunner can, which is not standardized.For example, a motor labeled 4006 this way may actually be a 3506.

Motor KV rating
              KV rating: revolutions per volt, meaning that for every 1V increase in input voltage, the no-load (without propeller) speed of the brushless motor increases by this value. For example, a 1000KV motor rotates at 1000 RPM under 1V input voltage and 2000 RPM under 2V when idling. For motors of similar size, the lower the KV rating, the lower the speed at the same voltage, the higher the torque, and the larger propeller it can drive; the higher the KV rating, the higher the speed at the same voltage, the lower the torque, and only small propellers can be used. Relatively speaking, the lower the KV rating, the higher the efficiency. Aerial photography requires low-KV motors with large propellers, featuring low speed, high efficiency, and low vibration from low-speed motors, all of which are highly beneficial for aerial photography.






















Motor coil turns
              Some motors are also marked with the number of coil turns, such as 9T, 13T. Many motors have identical casings once the label is removed. In this case, motors with a lower KV rating, such as 500KV, have fewer turns but thicker enameled copper wire, making them suitable for driving large, slow propellers. Motors with a higher KV rating, such as 1200KV, have more turns but thinner enameled copper wire, making them suitable for driving small, high-speed propellers.
       
Propeller and Motor Matching
                     

•                1、Matching motors with propellers, and matching motors, propellers with the entire multi-rotor aircraft, are very complex issues. Therefore, it is recommended to use proven configurations. Here are several principles for discussion: choose the frame layout → select propellers → choose motors → select ESCs → choose batteries (use as large a propeller as possible, and keep the RPM as low as possible).

•               2、Use low-KV motors with large propellers, and high-KV motors with small propellers (because higher RPM is needed to compensate for insufficient lift). If a high-KV motor drives a large propeller, the torque will be insufficient, the motor cannot spin properly or reach sufficient speed, and the motor and ESC can easily burn out. If a low-KV motor drives a small propeller, there is no functional problem, but the lift will still be insufficient even at full speed, making it unable to take off.