1. The total pitch of the rotor is fixed and the structure is simple. If the motor, electronic governor, battery, paddle and frame are damaged, it is easy to replace them.

2. The blades of each rotor are short, and the linear velocity at the end of the blades is slow, so the impact force is small when a collision occurs, and it is not easy to be damaged, which is safer for people. Some small quadcopters have outer frames on their rotors, which can effectively avoid collision damage.

3. Environmental protection, low noise, small volume, light weight, low cost, convenient carrying, and suitable for multi-platform and multi-space use.

4. It can take off and land vertically, hover, fly sideways and fly backwards without catapults and launchers.