What is the maximum rotor speed for use of the rotor brake?

What is the maximum rotor speed for use of the rotor brake?

• A. 150 RPM
• B. 180 RPM
• C. 200 RPM
• D. 170 RPM

Answer: (D)

The rotor brake is intended for use only when the main rotor is turning slowly, so that braking torque can arrest motion without imposing excessive loads on the drivetrain. The specified maximum for engaging the rotor brake is 170 RPM. At or below this speed, the brake can stop the rotor smoothly without overstressing the transmission, mast, or blades. Applying the brake at a higher rotor speed risks large decelerating forces that can cause mechanical damage or unsafe loads in the rotor system. In practice, you let the rotor slow to about 170 RPM and then apply the rotor brake to finish stopping.

The rotor brake is intended for use only when the main rotor is turning slowly, so that braking torque can arrest motion without imposing excessive loads on the drivetrain. The specified maximum for engaging the rotor brake is 170 RPM. At or below this speed, the brake can stop the rotor smoothly without overstressing the transmission, mast, or blades. Applying the brake at a higher rotor speed risks large decelerating forces that can cause mechanical damage or unsafe loads in the rotor system. In practice, you let the rotor slow to about 170 RPM and then apply the rotor brake to finish stopping.