What does RBS stand for?

What does RBS stand for?

• A. Rapid Blade Stall
• B. Retreating Blade Stall
• C. Rotor Blade Stall
• D. Reduced Blade Stall

Answer: (B)

In forward flight, the rotor experiences dissymmetry of lift: the blade moving opposite the flight direction (the retreating blade) encounters less relative wind and, to keep the rotor producing the necessary lift, the blade must pitch up more. If the retreating blade’s angle of attack reaches or exceeds the stall limit, that blade stalls, reducing lift on the retreating side and causing a potentially dangerous roll toward that side. This specific phenomenon is what RBS refers to: Retreating Blade Stall. That’s why the correct expansion is Retreating Blade Stall. The other phrasing describes generic stall or uses terms that aren’t the standard name for this rotorcraft-specific condition.

In forward flight, the rotor experiences dissymmetry of lift: the blade moving opposite the flight direction (the retreating blade) encounters less relative wind and, to keep the rotor producing the necessary lift, the blade must pitch up more. If the retreating blade’s angle of attack reaches or exceeds the stall limit, that blade stalls, reducing lift on the retreating side and causing a potentially dangerous roll toward that side. This specific phenomenon is what RBS refers to: Retreating Blade Stall.

That’s why the correct expansion is Retreating Blade Stall. The other phrasing describes generic stall or uses terms that aren’t the standard name for this rotorcraft-specific condition.