A
helicopter main rotor or
rotor system is the combination of several
rotary wings (
rotor blades) and a control system that generates the aerodynamic
lift force that supports the weight of the
helicopter, and the
thrust that counteracts
aerodynamic drag in forward flight. Each main rotor is mounted on a vertical mast over the top of the helicopter, as opposed to a helicopter
tail rotor, which connects through a combination of
drive shaft(s) and gearboxes along the tail boom. The
blade pitch is typically controlled by a
swashplate connected to the
helicopter flight controls. Helicopters are one example of rotary-wing aircraft (
rotorcraft).