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A quadcopter, also called quadrocopter, or quadrotor [1] is a type of helicopter or multicopter that has four rotors. [ 2 ] Although quadrotor helicopters and convertiplanes have long been flown experimentally, the configuration remained a curiosity until the arrival of the modern unmanned aerial vehicle or drone.
Four rotors. Also referred to as the quadcopter or quadrotor. Usually two rotors turn clockwise and two counter-clockwise. More than four rotors. Referred to generally as multirotors, or sometimes individually as hexacopters and octocopter, these configurations typically have matched sets of rotors turning in opposite directions.
Disk loading of a hovering helicopter is the ratio of its weight to the total main rotor disk area. It is determined by dividing the total helicopter weight by the rotor disk area, which is the area swept by the blades of a rotor.
Rotors to the left and right are in a transverse configuration while those in the front and to the rear are in a tandem configuration. An advantage of quad rotors on small aircraft such as drones is the opportunity for mechanical simplicity. A quadcopter using electric motors and fixed-pitch rotors has only four moving parts.
Cierva Air Horse - a British three-rotor "heavy lift" helicopter first flying in 1948. Three rotors were used to give a large lift without compromising rotor strength. [16] Volocopter designs - a series of German prototype electric multicopters with 18 rotors, the first electric multicopter in the world to achieve crewed flight.
In general, a rotor may spin about an axis which is aligned substantially either vertically or side-to-side (spanwise). All three classes have been studied for use as lifting rotors and several variations have been flown on full-size aircraft, although only the vertical-axis rotary wing has become widespread on rotorcraft such as the helicopter.
A coaxial-rotor aircraft is an aircraft whose rotors are mounted one above the other on concentric shafts, with the same axis of rotation, but turning in opposite directions (contra-rotating). This rotor configuration is a feature of helicopters produced by the Russian Kamov helicopter design bureau .
Since the tail rotor is driven by the main rotor transmission during autorotation, heading control is maintained as in normal flight. Several factors affect the rate of descent in autorotation: density altitude, gross weight, rotor rotational speed, and forward airspeed. The pilot's primary control of the rate of descent is airspeed.