The drone motor is the core component of the entire power system,responsible for converting the electrical energy stored in the battery into mechanical energy,which ultimately generates thrust through the propellers.Whether it's a consumer-grade aerial photography drone,an FPV racing drone,or an industrial-grade long-endurance drone,all rely on the efficient operation of motors.The performance of the motor directly determines the drone's flight time,speed,payload capacity,and control stability.
However,"drone motor"is not a singular concept(If you want to learn more about drone motors,you can first read our FPV Motor Guide.).There are several drone motor types, which can be classified based on different criteria:some are based on their working principle(drive method),others on their structural design(rotor type),and still others on the drone's overall flight architecture(multirotor,fixed-wing,VTOL,etc.).Understanding these classifications not only helps enthusiasts quickly differentiate between common motor types but also provides a reference for pilots when selecting motors.
This article will introduce the types of drone motors from three main perspectives: drive method(brushed/brushless),rotor structure(outrunner/inrunner),and drone architecture(multirotor/fixed-wing/VTOL/coaxial system).
I.Classification by Drive Method
The most fundamental way to classify drone motors is by their drive method(commutation principle),which refers to how the electric current switches direction inside the motor to keep the rotor in continuous rotation.Based on this,motors can be divided into Brushed Motors and Brushless Motors.Although the principles of these two drone motor types are similar, they have significant differences in performance and application.
1. Brushed Motor
Working Principle:
A brushed motor relies on the mechanical contact between brushes and a commutator to achieve current commutation.When current flows through the brushes into the coil,electromagnetic force pushes the rotor to rotate.As the rotor turns,the commutator continuously switches the direction of the current,creating continuous rotation.
Advantages:
Low Cost:The manufacturing process is simple,making it suitable for large-scale,low-cost production.
Simple Control:It can be driven by a simple DC power source without the need for a complex Electronic Speed Controller(ESC).
Beginner-Friendly:Easy to understand and debug,often used in toy-grade drones.
Disadvantages:
Short Lifespan:The constant friction between the brushes and the commutator causes wear and tear,requiring regular maintenance or replacement.
Lower Efficiency:Friction and sparks lead to energy loss,resulting in lower electrical energy utilization.
Noisy and Prone to Overheating:High-speed operation creates significant friction,making it unsuitable for long,stable flights.
Application Scenarios:
Commonly found in low-cost toy drones and some ultra-small training models.
Still used in educational or entertainment products where extremely low cost is a priority.
However,with the popularization of brushless motors,brushed motors have largely been phased out in the aerial photography and racing sectors.
2. Brushless Motor
Working Principle:
A drone brushless motor eliminates the brushes and mechanical commutator,instead using an Electronic Speed Controller(ESC)for electronic commutation.The ESC rapidly switches the current's direction based on signals from the flight controller,driving the rotor's magnetic field to rotate continuously,thereby achieving efficient and stable power output.
Advantages:
High Efficiency:High electrical-to-mechanical energy conversion rate,reducing energy waste.
Long Lifespan:No mechanical friction parts,giving it a theoretical lifespan far exceeding that of brushed motors.
Powerful Performance:Capable of driving large propellers and delivering high thrust,adaptable to various flight demands.
Stable Operation:Low noise and minimal vibration contribute to smoother flights.
Disadvantages:
Higher Cost:Requires precision manufacturing,making it generally more expensive than brushed motors.
Reliant on an ESC:Must be paired with an Electronic Speed Controller,which increases system complexity.
Higher Debugging Requirements:Parameter settings(PWM,protocols,current limiting,etc.)require experience.
Application Scenarios:
The standard motor for almost all mid-to high-end drones today.
Aerial photography drones(e.g.,DJI Air/Phantom series).
FPV and racing drones(high-KV models for strong bursts of power).
Industrial drones(e.g.,logistics,agricultural spraying,inspections),which use large-size,low-KV brushless motors.
II.Classification by Rotor Structure
In addition to the drive method, another important way to distinguish drone motor types is by their rotor structure.The rotor layout directly determines the motor's torque output characteristics,speed range,and the size of propellers it can accommodate.The two main rotor structures for drones are Outrunner and Inrunner motors.
1. Outrunner Motor
Working Principle and Structure:
In an outrunner motor,the rotor is on the outside,and the stator is on the inside.The rotor casing is connected to the motor's outer shell and rotates,driving the propeller.Because the magnets are distributed on the outer ring,the turning radius is larger,allowing it to produce greater torque at lower speeds.
Performance Characteristics:
High Torque Output:Capable of directly driving large-sized propellers.
Moderate RPM:The rotational speed is relatively low,providing smoother power delivery.
Good Heat Dissipation:The rotating outer shell creates airflow,helping to dissipate heat more easily.
Slightly Heavier:The external rotor adds a certain amount of inertia.
Application Scenarios:
The mainstream choice for multirotor drones.
Aerial photography drones(emphasizing stable thrust and low vibration).
Long-endurance and industrial drones(driving large propellers to enhance efficiency).
2. Inrunner Motor
Working Principle and Structure:
In an inrunner motor,the rotor is located inside the motor,while the stator is on the inner wall of the casing.The rotor has a smaller mass and a shorter turning radius,allowing the motor to rotate rapidly at a higher frequency.
Performance Characteristics:
High RPM:Can easily reach tens of thousands of revolutions per minute.
Fast Response:Ideal for scenarios requiring rapid acceleration or frequent speed changes.
Relatively Low Torque:Typically needs to be paired with small propellers or a gearbox to amplify torque.
Compact and Lightweight:However,it is more susceptible to overheating.
Application Scenarios:
FPV racing drones(pursuing high RPM and quick response).
Fixed-wing drones(requiring high-speed motors for long-duration cruising).
Some small,high-speed drone platforms.
III.Classification by Drone Architecture
In addition to the motor's drive method and rotor structure,we can also classify types of drone motors based on the drone's overall flight architecture.Different aircraft designs determine the number and layout of motors,as well as the requirements for thrust and efficiency,leading to several representative motor application scenarios:multirotor motors,fixed-wing motors,VTOL motors,and coaxial motor systems.
1. Multirotor Motors
Working Logic:
A multirotor drone relies on multiple motors working simultaneously to achieve lift and attitude control.The flight controller adjusts the speed differential between the motors to perform hovering,ascending,descending,and turning maneuvers.
Performance Characteristics:
Multiple Motors:Typically 4,6,or 8,which distributes the load and provides redundancy.
Often Use Brushless Outrunners:To provide stable,high torque.
Requires Fast Motor Response:And high precision in speed adjustment.
Application Scenarios:
Consumer-grade aerial photography drones(e.g.,DJI Mavic,Phantom series).
Industrial applications(surveying,inspection,agricultural spraying).
FPV quadcopter racing drones(small-size,high-KV motors).
2. Fixed-Wing Motors
Working Logic:
A fixed-wing drone relies on its wings to generate lift;the motor only needs to provide forward thrust.The motor can be in a"pusher"configuration(mounted at the tail)or a"tractor"configuration(mounted at the nose).
Performance Characteristics:
High Efficiency is Crucial:For long-duration,stable cruising.
Often Use Efficient Outrunners:Though some small to medium fixed-wing drones may use lightweight inrunners.
Must Balance Light Weight with Reliable Heat Dissipation.
Application Scenarios:
Mapping and reconnaissance drones.
Long-endurance logistics drones.
Industrial fixed-wing platforms(e.g.,pipeline inspection,border surveillance).
3. VTOL Motors(Vertical Take-Off and Landing)
Working Logic:
VTOL drones combine the advantages of multirotors and fixed-wing aircraft.The motors must provide both vertical lift and forward thrust for cruising,which often requires complex tilting mechanisms or multiple motor systems.
Performance Characteristics:
Multi-Mode Operation:Requires motors with both durability and fast response.
Common Configurations:Tilt-rotor,tilt-wing,and composite wing(lift-plus-cruise).
Motors Often Need to Switch Power Output between different flight modes.
Application Scenarios:
Industrial long-endurance inspection drones.
Logistics and transport platforms(urban/mountain routes).
Military tactical reconnaissance drones.
4. Coaxial Motor System
Working Logic:
A coaxial motor system uses two counter-rotating propellers stacked vertically on the same axis.This design doubles the thrust within the limited space of a single arm or airframe.Common designs include"two propellers on one shaft"or"two motors stacked coaxially."
Performance Characteristics:
Increases Lift and Thrust Density within a limited footprint.
Symmetrical Counter-Rotation can cancel out some of the reactive torque,improving flight stability.
Higher System Complexity and slightly lower efficiency than a single-motor setup,with increased maintenance and debugging difficulty.
Application Scenarios:
Heavy-lift transport drones(logistics,firefighting,rescue).
Military drones(to enhance redundancy and safety).
Specialized VTOL architecture drones.
Drone Motor Types Comparison Table:
Classification | Types | Working Principle | Key Features | Advantages | Disadvantages | Typical Applications |
By Drive Method | Brushed Motor | Uses brushes + commutator for current switching | Simple structure, direct DC drive | Low cost, easy to control, beginner-friendly | Short lifespan, low efficiency, noisy, prone to overheating | Toy drones, educational/training models |
Brushless Motor | Uses ESC for electronic commutation | High efficiency, stable output | Long lifespan, powerful, low noise, supports large propellers | Higher cost, requires ESC, tuning experience needed | Consumer drones (DJI, FPV), industrial drones (logistics, spraying, inspection) | |
By Rotor Structure | Outrunner Motor | Rotor outside, stator inside | Large torque at low RPM | High torque, stable thrust, good cooling | Slightly heavier, more inertia | Multirotor drones, aerial photography, industrial platforms |
Inrunner Motor | Rotor inside, stator on casing | High RPM, fast response | High speed, compact, lightweight | Lower torque, prone to overheating, needs gearbox for large props | FPV racing, small high-speed drones, fixed-wing drones | |
By Drone Architecture | Multirotor Motors | Multiple motors balance thrust & attitude | Requires precise response | Redundancy, stable hover, strong control | Higher power demand, multiple motors add weight | Quadcopters, FPV drones, aerial photography |
Fixed-Wing Motors | Provides forward thrust, wings generate lift | Tractor or pusher configuration | High efficiency, long endurance | Limited hovering ability | Mapping, reconnaissance, logistics drones | |
VTOL Motors | Supports both vertical lift & forward thrust | Tilt-rotor/tilt-wing/compound | Flexible, multi-mode operation | Complex design, higher maintenance | Inspection, transport, tactical drones | |
Coaxial Motor System | Two counter-rotating props on one axis | Higher thrust density | Compact lift, cancels torque, redundancy | Lower efficiency, complex maintenance | Heavy-lift drones, military & rescue drones |
IV.Conclusion
Drone motors are not a single component but can be classified from various perspectives.Understanding these common types of drone motors helps us make more reasonable choices based on the application scenario.Whether pursuing stable aerial photography,extreme racing,or industrial heavy-lift and long-endurance flights,the choice of motor type will directly impact the drone's performance and reliability.In the future,as drone applications continue to expand,motor technology will also continue to evolve,bringing more efficient,durable,and intelligent power solutions.