SIFT Army Aviation Information Practice Test 2025 – All-in-One Study Guide for Exam Success!

At high speeds on the retreating side of a rotor blade, lift decreases significantly due to the changes in relative airflow. As the helicopter gains speed, the rotor blades experience different airspeeds along their length. On the retreating side, the rotor blades are moving opposite to the direction of flight, which results in a relatively lower speed of airflow over these blades. This leads to a decrease in the angle of attack and, subsequently, a reduction in lift production.

The aerodynamic phenomenon is influenced by the differences in velocity between the advancing and retreating blades, contributing to what is known as "blade stall" on the retreating section. By understanding this behavior, pilots can better manage rotor performance during flight, particularly in high-speed maneuvers where the effects of airflow play a significant role in rotor efficiency and handling characteristics.