Which factor directly leads to the dissymmetry of lift between the advancing and retreating blades?

Which factor directly leads to the dissymmetry of lift between the advancing and retreating blades?

• A. Rotor RPM
• B. Air Temperature
• C. Forward Airspeed
• D. Difference in Relative Wind Between Advancing and Retreating Blades

Answer: (D)

In forward flight, the rotor experiences different airflows across its disk. The blade moving with the flight direction (advancing side) meets air that is moving faster relative to it, while the blade moving opposite (retreating side) encounters slower relative wind. This difference in relative wind between the two blades changes the lift they generate, creating the dissymmetry of lift. The root cause is this unequal relative wind across the disk, not the overall rotor speed or the ambient temperature. Forward airspeed sets up the situation, but the direct factor producing the unequal lift is the difference in relative wind between the advancing and retreating blades.

In forward flight, the rotor experiences different airflows across its disk. The blade moving with the flight direction (advancing side) meets air that is moving faster relative to it, while the blade moving opposite (retreating side) encounters slower relative wind. This difference in relative wind between the two blades changes the lift they generate, creating the dissymmetry of lift. The root cause is this unequal relative wind across the disk, not the overall rotor speed or the ambient temperature. Forward airspeed sets up the situation, but the direct factor producing the unequal lift is the difference in relative wind between the advancing and retreating blades.