How is hunting corrected for in an articulated/rigid rotor system?

How is hunting corrected for in an articulated/rigid rotor system?

• A. Articulated: drag dampers; Rigid: blade bending
• B. Articulated: autopilot; Rigid: feedback control
• C. Articulated: hydraulic dampers; Rigid: wing flaps
• D. Articulated: blade bending; Rigid: drag dampers

Answer: (A)

Hunting is a slow oscillation of the rotor system in response to disturbances that must be damped to keep the rotor stable. In an articulated rotor, the hub allows flapping and lead-lag motion, and drag dampers attached at the hub resist the velocity of these motions. That viscous resistance dissipates energy from the oscillation, reducing its amplitude and stopping the hunting effectively. In a rigid rotor, there are no flapping hinges to provide that damping, so the blade itself must absorb and dissipate the energy. The blades bend under aerodynamic and inertial loads, and this elastic deformation introduces energy dissipation and a phase shift that damp the oscillation, smoothing out hunting. So, articulated systems use drag dampers to curb hunting, while rigid systems rely on blade bending for damping.

Hunting is a slow oscillation of the rotor system in response to disturbances that must be damped to keep the rotor stable. In an articulated rotor, the hub allows flapping and lead-lag motion, and drag dampers attached at the hub resist the velocity of these motions. That viscous resistance dissipates energy from the oscillation, reducing its amplitude and stopping the hunting effectively.

In a rigid rotor, there are no flapping hinges to provide that damping, so the blade itself must absorb and dissipate the energy. The blades bend under aerodynamic and inertial loads, and this elastic deformation introduces energy dissipation and a phase shift that damp the oscillation, smoothing out hunting.

So, articulated systems use drag dampers to curb hunting, while rigid systems rely on blade bending for damping.