During an autorotation with a turn, which action prevents rotor RPM from exceeding limits?

During an autorotation with a turn, which action prevents rotor RPM from exceeding limits?

• A. Push forward cyclic
• B. Raise the collective
• C. Increase throttle to maintain rotor RPM
• D. Apply left pedal to counter yaw

Answer: (B)

In an autorotation, rotor speed is controlled mainly by blade pitch, which you change with the collective. Raising the collective increases blade pitch and thus rotor drag. That extra drag dissipates energy in the rotor system, slowing it down if it’s approaching an overspeed. Lowering collective would reduce drag and let the rotor speed up toward the limit, which you don’t want. The other controls don’t directly limit rotor RPM in this situation: pushing forward cyclic mainly affects descent and rotor disk angle, not a reliable brake on speed; increasing throttle isn’t applicable since the engine isn’t driving the rotor in autorotation; and applying left pedal changes yaw/heading, not rotor RPM.

In an autorotation, rotor speed is controlled mainly by blade pitch, which you change with the collective. Raising the collective increases blade pitch and thus rotor drag. That extra drag dissipates energy in the rotor system, slowing it down if it’s approaching an overspeed. Lowering collective would reduce drag and let the rotor speed up toward the limit, which you don’t want.

The other controls don’t directly limit rotor RPM in this situation: pushing forward cyclic mainly affects descent and rotor disk angle, not a reliable brake on speed; increasing throttle isn’t applicable since the engine isn’t driving the rotor in autorotation; and applying left pedal changes yaw/heading, not rotor RPM.