Multicopter configurations and sizes
Multirotor UAVs are typically found with three, four, six or eight rotors, and aircraft with these configurations are typically known respectively as tricopters, quadcopters, hexacopters and octocopters. Quadcopters are the most common design, having a less complex stabilising mechanism than tricopters and fewer parts (and therefore less manufacturing cost) than hexacopters or octocopters.
The more rotors a multirotor drone has, the more thrust it can generate and thus the greater a payload it can lift. Heavy lift multirotor drones that lift very heavy industrial cameras or delivery payloads will often be hexacopters or octocopters. Drones with more than four rotors also have a degree of redundancy, allowing them to still make a gradual descent in the case of an individual rotor failure.
The tradeoff is that a greater number of rotors requires a higher current draw, and therefore hexacopters and octocopters will need to carry a greater weight in batteries to achieve the same flight endurance as a quadcopter of similar size. Larger multicopter drones may have the ability to carry hydrogen fuel cells, which can provide a greater energy output to mass ratio than conventional battery technology.