What is the fore (lead) and aft (lag) movement of the rotor blade in the plane of rotation called?

What is the fore (lead) and aft (lag) movement of the rotor blade in the plane of rotation called?

• A. Lead and Lag
• B. Married Needles
• C. NAVAID
• D. Mast

Answer: (A)

Lead and lag motion describes the blade’s fore-and-aft movement in the plane of rotation. The rotor blade is mounted to the hub with a lead-lag hinge (also called the drag hinge), which lets the blade move forward (lead) or backward (lag) as it spins. This motion arises from aerodynamic drag and the blade’s inertia as cyclic pitch is applied and the blade passes through the plane of rotation, helping to absorb loads and prevent binding. So the correct term for this in-plane blade movement is lead and lag. Other options don’t relate to rotor blade motion in the plane of rotation.

Lead and lag motion describes the blade’s fore-and-aft movement in the plane of rotation. The rotor blade is mounted to the hub with a lead-lag hinge (also called the drag hinge), which lets the blade move forward (lead) or backward (lag) as it spins. This motion arises from aerodynamic drag and the blade’s inertia as cyclic pitch is applied and the blade passes through the plane of rotation, helping to absorb loads and prevent binding. So the correct term for this in-plane blade movement is lead and lag. Other options don’t relate to rotor blade motion in the plane of rotation.