Is it possible for a helicopter rotor blade to stall?

A helicopter rotor blade can indeed stall, and this scenario is particularly relevant in the case of retreating blade stall. Unlike fixed-wing aircraft, where stall typically refers to a loss of lift due to insufficient angle of attack, helicopter rotors have a more complex aerodynamic behavior because they operate in a rotating frame of reference.

In the context of a helicopter, the rotor blades each experience different airflow conditions as they rotate. The advancing blade (the blade moving forward into the direction of flight) operates at higher relative airspeeds and typically maintains adequate lift. Conversely, the retreating blade (the blade moving backward) can experience a decrease in airspeed, and if the angle of attack increases beyond a certain point, it can lead to stall conditions. This phenomenon is known as retreating blade stall and can result in a significant loss of lift, which is critical for maintaining control and performance, especially during maneuvers such as steep climbs or high-speed flight.

The other options do not accurately describe the characteristics of rotor stall. Saying that rotor blades can never stall under any circumstances ignores the physics of flight dynamics. Limiting stall occurrences to specific conditions, like vertical takeoff or maximum speed, also misrepresents the various factors that contribute to stall across the operational