The propellers of multi-rotor drones are similar to the wheels and tires of a car. The size of the propeller's pitch and diameter determines the torque it can provide. A smaller propeller rotates at a higher speed but provides less torque, while a larger propeller rotates at a lower speed but provides more torque. Of course, it is necessary to use the corresponding motor to achieve reasonable power.

Propeller classification based on material

Propellers can be roughly classified based on their materials into plastic propellers, resin composite propellers, carbon fiber propellers, and wooden propellers (which are relatively rare and will not be discussed further here). Plastic propellers are commonly used in toy planes, usually with hollow cup motors. Resin composite propellers are commonly used in consumer-grade drones, while carbon fiber propellers are more common in industrial-grade drones. However, some industrial-grade drones also use resin composite propellers.

Advantages and disadvantages of the three types of propellers

Plastic propellers have the following advantages: lightweight, low damage potential, low price, durability, and good flexibility. Their main disadvantage is their good flexibility, which also makes them susceptible to deformation and poor temperature resistance.

Resin composite propellers have the following advantages: relatively affordable price, moderate flexibility, better dynamic balance compared to carbon fiber propellers, and quiet operation. Their main disadvantage is that they are quite average and do not have any particularly noticeable advantages or disadvantages.

Carbon fiber propellers have the following advantages: high efficiency and good aesthetics. Their main disadvantages are their high price, vulnerability to damage, and high strength, which can lead to significant damage potential.

Classification by installation method Based on the installation method, propellers can be roughly divided into quick-release propellers, self-locking propellers, and regular propellers. Quick-release propellers have a propeller base installed on top of the motor, and the propeller is locked in place with a snap-on buckle (e.g. DJI's Mavic and Spark both use quick-release propellers). Self-locking propellers have a propeller nut attached to the propeller, and the wind resistance generated when the propeller rotates automatically locks it in place. Regular propellers are more commonly found on DIY drones, where the propeller passes through the motor shaft and is secured with a bullet-shaped nut.

Advantages and disadvantages: Quick-release propellers: easy to install, but the spring in the propeller base may wear out over time, resulting in the propeller not locking tightly and needing to be manually secured. Self-locking propellers: easy to install, with relatively low cost, but there is a possibility of the propeller flying off when braking at high speeds. Regular propellers: low cost and available in various models, but installation can be more complicated.

Classification by structure Based on the structure, propellers can be divided into folding and non-folding propellers. Folding propellers have lower thrust efficiency compared to non-folding propellers of the same model, but their smaller size allows for more compact storage. The biggest challenge of folding propellers is balancing the weight of the two blades, which needs to be extremely precise.

Classification by number of blades Based on the number of blades, propellers can be divided into two-blade, three-blade, four-blade, five-blade, and six-blade propellers. Propellers with two or more blades are mostly used in racing drones and have a relatively small diameter.