To keep the rotor in balance during blade blending, what do some manufacturers require?

• A. Making a lighter blade
• B. Making an identical blend on the blade 90 degrees opposite
• C. Making a different blend on another blade
• D. Making an identical blend on the blade 180 degrees opposite to maintain rotor balance

Answer: (D)

Mass removal during blade blending changes a blade’s weight and can upset the rotor’s balance. To keep the rotor balanced, the same blending is applied to the blade opposite it in the disk, at 180 degrees, so the weight change is symmetric around the axis. If you blended a blade without matching the opposite blade, or did it at a different angular position, the centrifugal forces would become uneven as the rotor spins, causing vibration and potential damage. Using an identical blend on the opposite blade maintains both static and dynamic balance during operation.