page_title: Helicopter rotor
section_title: Hub
hierarchical_section_title: Helicopter rotor / Design principles / Hub
caption_attribution_description: Sikorsky S-92: detail of rotor
context_page_description: A helicopter main rotor or rotor system is the combination of several rotary wings 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 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. The name is derived from the Greek words helix, helik-, meaning spiral; and pteron meaning wing.
context_section_description: The simple rotor of a Robinson R22 showing (from the top):
  The following are driven by the link rods from the rotating part of the swashplate.
  Pitch hinges, allowing the blades to twist about the axis extending from blade root to blade tip.
  Teeter hinge, allowing one blade to rise vertically while the other falls vertically. This motion occurs whenever translational relative wind is present, or in response to a cyclic control input.
  Scissor link and counterweight, carries the main shaft rotation down to the upper swashplate
  Rubber covers protect moving and stationary shafts
  Swashplates, transmitting cyclic and collective pitch to the blades (the top one rotates)
  Three non-rotating control rods transmit pitch information to the lower swashplate
  Main mast leading down to main gearbox
caption: The rotor head of a Sikorsky S-92
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