What principle explains how lift is generated by rotor blades?

Lift generation by rotor blades in rotary-wing aircraft, such as helicopters, can be primarily explained by Bernoulli's Principle. This principle refers to the relationship between the velocity of a fluid and its pressure. As air flows over the rotor blades, the shape and angle of the blades cause the air to move faster above the blades than below them.

According to Bernoulli's Principle, higher speed airflow results in lower pressure. Therefore, when the rotor blades create a difference in airflow speed between the upper and lower surfaces, the pressure above the blades decreases compared to the pressure beneath them. This pressure difference generates lift, allowing the aircraft to ascend or maintain altitude. Understanding this principle is fundamental to the physics of flight for helicopters and other rotorcraft, as it directly relates to how rotor blades manipulate air to produce the necessary lift.