alpha hinge

alpha hinge (plural alpha hinges)

1. (aeronautics) On rotorcraft, a hinge perpendicular to the plane of rotor rotation about which the blades trail or lag.
   • 1953, Daniel Otto Dommasch, Elements of Propeller and Helicopter Aerodynamics, page 129:

     Similarly, as a blade with an alpha hinge lags through an angle §, ...

   • 1958, Aviation Week and Space Technology - Volume 69, page 226:

     When rotor goes to autorotation, an inclined alpha hinge provides automatic change of blade pitch to three degrees as the shaft stops rotating.

   • 2013, Wayne Johnson, Rotorcraft Aeromechanics, →ISBN, page 218:

     When flap and lag hinge inclination was introduced on the autogyro rotors, the inboard (flap) hinge was designated the “delta hinge,” and the outboard (lag) hinge designated the “alpha hinge.”