Unequal rotor lift distribution

[1] A helicopter rotor blade is an airfoil, which is driven through the air to create lift.

If not mitigated, this effect would cause large bending stresses in the blade.

In addition, the tip would have to be made stronger to handle the increased load.

The high twisting necessary for good hover performance unfortunately causes vibrations at high forward speeds, because the angle of attack of the blade tips may become negative,[6] so a compromise is typically made.

[5][7] Tiltrotor aircraft such as the Bell Boeing V-22 Osprey are able to use more blade twist.

Overhead view of helicopter rotors. The rotor tips travel much faster than the inner sections, so produce more lift. (For the purposes of this article, the demarcated circular regions are irrelevant and should be ignored.)