Which term describes an upward sweep of rotor blades caused by lift and centrifugal force?

• A. Coriolis Effect
• B. Coning
• C. Deviation
• D. Density Altitude

Answer: (B)

Coning is the upward sweep of rotor blades caused by lift and centrifugal force as the rotor spins. When each blade generates lift, it tends to rise along the blade’s span, and the centrifugal force acts outward on the blade mass, pulling the blade tips away from the hub. The combination makes the blades bend upward, so the tips ride higher than the roots and the whole rotor disk forms a cone shape. This effect increases with higher rotor speed or greater blade loading (more lift from collective). Other terms describe different ideas—Coriolis Effect is about motion deflection in a rotating frame, Deviation refers to path changes for the aircraft, and Density Altitude is about air density with altitude—none of these describe the blade’s upward sweep due to lift and centrifugal force.