The aerodynamic twisting forces tend to turn the blades toward which angle?

The aerodynamic twisting forces tend to turn the blades toward which angle?

• A. low blade angle
• B. high blade angle
• C. mid blade angle
• D. variable angle

Answer: (B)

The twisting effect from aerodynamic loads on a rotating blade acts to increase the blade’s pitch, so it tends to turn toward a higher blade angle. As the blade spins, sections farther from the hub see higher relative wind speeds and produce more lift. That lift creates a twisting moment about the blade’s axis that tends to rotate the blade toward a larger angle of attack, i.e., a higher blade angle. The pitch control system must counter this tendency to maintain the commanded blade pitch.

The twisting effect from aerodynamic loads on a rotating blade acts to increase the blade’s pitch, so it tends to turn toward a higher blade angle. As the blade spins, sections farther from the hub see higher relative wind speeds and produce more lift. That lift creates a twisting moment about the blade’s axis that tends to rotate the blade toward a larger angle of attack, i.e., a higher blade angle. The pitch control system must counter this tendency to maintain the commanded blade pitch.