#main_rotor  rotor consisting of large rotating airfoils on a single-rotor helicopter that produce the lift to support the helicopter in the air
  supertype:  #rotor  rotating mechanism consisting of an assembly of rotating airfoils; horizontal rotors on a helicopter or compressor rotors of a jet engine
  part:  #rotor_blade__rotorblade__rotary_wing  the long airfoil that rotates to provide the lift that supports a helicopter in the air
  part:  #rotor_head__rotorhead__rotor_shaft__rotorshaft  the axis around which the major rotor of a helicopter turns

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