Centrifugal twisting moment

The force moment, acting about the longitudinal axis of a propeller blade, which tries to rotate the blade toward a low-pitch angle. As the engine rotates the propeller, centrifugal force tries to flatten the blade so all of its mass rotates in the same plane. Centrifugal twisting moment (CTM) opposes aerodynamic twisting moment (ATM), but normally CTM is the greater. The resultant of these two twisting moments is a force on a rotating propeller that tries to move the blades toward a low-pitch angle.