quadcopter

A quadcopter, also called quadrocopter, or quadrotor is a type of helicopter that has four rotors.Although quadrotor helicopters and convertiplanes have long been flown experimentally, the configuration remained a curiosity until the arrival of the modern UAV or drone. The small size and low inertia of drones allows use of a particularly simple flight control system, which has greatly increased the practicality of the small quadrotor in this application.

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