Which stall occurs at or near the rotor tip due to high angles of attack required to compensate for dissymmetry of lift?

Which stall occurs at or near the rotor tip due to high angles of attack required to compensate for dissymmetry of lift?

• A. Retreating Blade Stall
• B. Advance Stall
• C. Tip Stall
• D. Descent Stall

Answer: (A)

In forward flight, the rotor experiences dissymmetry of lift because the advancing blade moves through the air faster than the retreating blade. To balance this, the rotor system increases the angle of attack on the retreating blade. As forward speed climbs, that added angle of attack can become excessive near the outer portion of the retreating blade, causing it to stall. Since stalls tend to start where the local conditions reach the critical angle first, the stall occurs at or near the rotor tip on the retreating blade. This is the scenario described by retreating blade stall, the best answer. The other terms don’t fit the situation as precisely: the advancing blade is less prone to stall under these balance conditions, “tip stall” isn’t the standard label for this specific phenomenon, and a descent stall refers to a stall caused by low airspeed during descent, not dissymmetry of lift.

In forward flight, the rotor experiences dissymmetry of lift because the advancing blade moves through the air faster than the retreating blade. To balance this, the rotor system increases the angle of attack on the retreating blade. As forward speed climbs, that added angle of attack can become excessive near the outer portion of the retreating blade, causing it to stall. Since stalls tend to start where the local conditions reach the critical angle first, the stall occurs at or near the rotor tip on the retreating blade. This is the scenario described by retreating blade stall, the best answer. The other terms don’t fit the situation as precisely: the advancing blade is less prone to stall under these balance conditions, “tip stall” isn’t the standard label for this specific phenomenon, and a descent stall refers to a stall caused by low airspeed during descent, not dissymmetry of lift.