What is the term for the ability of the rotor blade to move in a vertical direction, with blades flapping independently or in unison?

What is the term for the ability of the rotor blade to move in a vertical direction, with blades flapping independently or in unison?

• A. Blade Flap
• B. Blade Track
• C. Blade Grip
• D. Blade Stall

Answer: (A)

Blade flap is the vertical movement of a rotor blade about its hinge, letting the blade rise and fall relative to the hub. This motion can occur independently for each blade or be coupled so all blades flap together, depending on the rotor head design. Flapping helps balance lift as the rotor turns and allows the blade to absorb gusts and changes in lift without tilting the rotor plane. It’s different from blade track, which involves the blade’s path in the plane of rotation, blade grip, which is the hub attachment, and blade stall, which is a aerodynamic condition where the blade reaches its critical angle of attack.

Blade flap is the vertical movement of a rotor blade about its hinge, letting the blade rise and fall relative to the hub. This motion can occur independently for each blade or be coupled so all blades flap together, depending on the rotor head design. Flapping helps balance lift as the rotor turns and allows the blade to absorb gusts and changes in lift without tilting the rotor plane. It’s different from blade track, which involves the blade’s path in the plane of rotation, blade grip, which is the hub attachment, and blade stall, which is a aerodynamic condition where the blade reaches its critical angle of attack.