A quadrotor is an aircraft that is lifted and propelled by four rotors. Quadrotors are classified as rotorcraft, as opposed to fixed-wing aircraft, because their lift is derived from four rotors. They can also be classified as helicopters, though unlike standard helicopters, quadrotors use fixed-pitch blades, whose rotor pitch does not vary as the blades rotate. Control of vehicle motion can be achieved by varying the relative speed of each rotor to change the thrust and torque produced by each.
Local Government Applications
In the not-too-distant future small automated quadrotors could conceivably be used to obtain condition information about hard-to-reach assets such as building roofs. Judging by the maneuverability displayed in the youtube videos below it might even be possible to send a quadrotor zipping down a side entry pit, to see what is going on in the stormwater drainage system.
It could also find application in dam pipeline inspections. Many pipelines cross very rugged country making it difficult to inspect them on-foot. A quadrotor with a high resolution camera attached could fly around and take a video of the pipeline.