What is the purpose of blade twisting in rotor blades?

What is the purpose of blade twisting in rotor blades?

• A. To distribute the lifting force more evenly along the blade
• B. To increase rotor speed
• C. To reduce engine load
• D. To strengthen the blade root

Answer: (A)

Blade twist is used to achieve a more even lift distribution along the blade span by compensating for the fact that rotational speed (and the resulting relative wind speed) increases with radius. If pitch were the same everywhere, the tip would produce much more lift than the root, creating large bending moments and inefficiency. By twisting the blade—generally reducing the pitch toward the tip and increasing it nearer the hub—the angle of attack is balanced along the span, so each section contributes a similar amount of lift. This lowers peak loads, reduces vibrations and flapping, and improves overall rotor efficiency. The other options aren’t the purpose of twist: twist does not set rotor speed, directly reduce engine load, or strengthen the blade root.

Blade twist is used to achieve a more even lift distribution along the blade span by compensating for the fact that rotational speed (and the resulting relative wind speed) increases with radius. If pitch were the same everywhere, the tip would produce much more lift than the root, creating large bending moments and inefficiency. By twisting the blade—generally reducing the pitch toward the tip and increasing it nearer the hub—the angle of attack is balanced along the span, so each section contributes a similar amount of lift. This lowers peak loads, reduces vibrations and flapping, and improves overall rotor efficiency. The other options aren’t the purpose of twist: twist does not set rotor speed, directly reduce engine load, or strengthen the blade root.