Which term is the axis about which the rotor assembly rotates?

• A. Chord Line
• B. Induced flow
• C. TAF
• D. Axis of rotation

Answer: (D)

The main idea is knowing the specific term for the line around which a rotor turns. In a rotor system, the rotor assembly spins about a central line—the axis of rotation—through the rotor mast. This axis is the reference for all angular motion: every point on the rotor describes a circle around it, and the angular velocity is defined with respect to that axis. The chord line is simply the line from the leading edge to the trailing edge of an airfoil, not related to where the rotor rotates. Induced flow refers to the downward air velocity produced by the rotor’s thrust, an aerodynamic effect rather than a rotational reference. TAF isn’t describing the rotation axis either; it’s a different concept or acronym. So, the term that names the axis about which the rotor assembly rotates is axis of rotation.