What produces rotational relative wind?

The correct answer relates to how rotor blades generate thrust and create airflow around the helicopter. The rotation of the rotor blades as they turn about the mast is responsible for the production of rotational relative wind. As the blades spin, they produce lift by changing the angle of attack, and this movement generates a specific airflow known as rotational relative wind. This wind is crucial for the performance of the rotor system, as it interacts with the lift generated by the blades and helps to keep the helicopter stable during flight.

In contrast, the other options address different aspects of airflow: wind generated by forward motion refers to the translational lift that occurs when a helicopter moves forward, while airflow caused by descent pertains to the vertical movements of the helicopter. Finally, updrafts encountered during flight are related to external atmospheric conditions and not directly to the rotor's rotation. Each of these factors impacts flight dynamics but does not specifically relate to the concept of rotational relative wind produced by the spinning rotor blades.