The use of drones has become widespread not only for military purposes but also for civilian tasks. They are used for aerial reconnaissance, fire adjustment, as well as for photo/video shooting, mapping, agriculture, search and rescue operations, and more. The effectiveness of a drone's operation largely depends on its technical components, among which the motor plays a key role.
The motor is the basis of a drone's power system, its "heart," which directly determines flight characteristics. Lift, climb rate, maneuverability, and stability in the air depend on the motor's efficiency.
This material was prepared by the Flash Army team for everyone who uses drones in various fields of activity. In this article, we will examine the role motors play in drone design, their main characteristics, types, and features.
What is a drone motor
A drone motor is an electric motor that converts electrical energy from the battery into mechanical energy and drives the propellers. It is thanks to the operation of the motors that altitude is maintained, movement in different directions occurs, and maneuvers are performed.
Properly selected drone motors ensure their proper operation. If the motor's characteristics are not consistent with the frame size, propeller type, or power supply voltage, this can lead to overheating, increased power consumption, reduced thrust, and faster wear of parts. In critical cases, speed controllers may overload or the motor may fail.
Main motor characteristics
The technical parameters of the motor directly affect its compatibility with different types of drones. Among the main characteristics, it is worth highlighting power, motor type, operating voltage, and dimensions. Let's consider each parameter in more detail.
Power and thrust
Power is determined by the size (stator), KV value (RPM/volt), and battery voltage. The higher the KV, the faster the motor spins, but the smaller the propeller it can turn. A high KV value (e.g., 2500KV+) is suitable for fast and light drones, while a low KV value (900–1300KV) is for freestyle. It is worth noting that more maneuverable drones can more easily bypass drone detectors.
Drone motors are chosen based on the thrust-to-weight ratio, where the total thrust of the motors must exceed the drone's weight by at least two times (for racing, 8–10:1). It is important to ensure that one motor produces thrust that is at least 50–60% of the drone's total weight.
Let's consider how the "thrust-to-weight" rule works using an FPV motor as an example:
- 2:1 — drone barely flies (for filming);
- 4:1 — comfortable flight, good control (standard);
- 10:1 — high speed.
Motor type (brushless, brushed)
Drone motors are divided into two types: brushed and brushless.
Brushed motors have a simple design that includes brushes and a commutator. In such a motor, electric current is transmitted to the rotor windings through special brushes (graphite or metal) that contact the commutator. This element is responsible for changing the direction of the current and ensuring the rotation of the rotor.
The operating principle is quite simple, but they have a limited lifespan. Due to constant friction, the brushes wear out over time, leading to the need for motor replacement. Brushed motors are mostly installed in compact drones, training models, and budget devices.
Brushless motors are a more modern and common option. They are used for FPV drones, aerial photography, and industrial UAVs. The design lacks brushes and a mechanical commutator. Instead, phase switching occurs electronically using an electronic speed controller (ESC), which provides more precise control and higher operating efficiency.
In such motors, permanent magnets are located on the rotor, and the windings are on the stator. The speed controller sequentially supplies current to the windings, forming a rotating magnetic field that drives the rotor. This reduces mechanical losses, heating, and wear, which positively affects the motor's lifespan.
Operating voltage and current
Voltage is usually measured in the number of lithium-polymer batteries (S). Most often, this value is 4S–6S. For small drones, 2S–4S are used, and for large ones, 6S–8S. Thus, the higher the voltage, the greater the power the motor can develop, but at the same time, the requirements for compatibility with the ESC and other drone components increase.
Weight and dimensions
Motor dimensions (usually indicated in the format 2207, etc.) indicate the stator diameter and height. The larger the motor, the more windings and magnets it can have, which affects its power. For 5-inch FPV drones, options 2207–2306 weighing 30–34 g are chosen, and for heavy ones, powerful 2807–3115 weighing 70–120+ g.
Types of motors
Drone motors are divided into categories that correspond to the types of drones themselves. Let's consider some of them.
For racing drones
High-speed motors with a high KV rating and stator are used in racing and freestyle. They provide quality acceleration, instant response to control, and high maneuverability. However, such options consume more energy and have a shorter operating time.
For quadcopters and multirotors
Universal motors for quadcopters belong to the middle class and are used for most multirotors. They are easy to control, efficient for reconnaissance and filming.
For cargo and professional drones
For heavy UAVs, powerful motors with a low KV value are used, as they are capable of working with large propellers and lifting loads.
Selection criteria
An incorrectly selected power unit often leads to accelerated wear of components. Therefore, before purchasing, we recommend checking compatibility with the drone, flight style, and possible maintenance options.
Compatibility with the drone
The motor must match the parameters of the drone's frame, propellers, battery, and speed controller. Manufacturers often provide a table with characteristics that helps check the motor's compatibility with the drone against all necessary criteria.
Purpose and flight style
One of the main selection criteria is considering the type of drone, as different types of UAVs require appropriate motor characteristics.
Reliability and maintenance
It is worth paying attention to the quality of materials, the level of protection against dust and moisture, and the motor's lifespan. Screws that attach the motor to the frame can loosen due to vibration, so this needs to be regularly monitored. You can also periodically check the wire insulation for damage. Such simple maintenance steps significantly extend the motors' lifespan.
Conclusion
Motors are one of the central elements of a drone, on which its flight characteristics, operational stability, and effectiveness in various conditions directly depend. They generate thrust, determine speed, maneuverability, and load-lifting capacity, and also affect power consumption and flight duration.
In this article, we examined the main technical parameters of drone motors: power, thrust, motor types, voltage, weight, and dimensions. Considering these features will help drone operators better navigate the capabilities of their devices.
You can familiarize yourself with the available drone motor options in the Flash Army online store. The catalog presents various types of power units that are suitable for both military and civilian tasks.
