What is the term for the difference in lift between the forward-going and aft-going blades in a helicopter during forward flight?

The difference in lift between the forward-going and aft-going blades in a helicopter during forward flight is referred to as "asymmetrical lift." This phenomenon occurs because the rotor blades experience varying angles of attack as they rotate. The forward-going blade encounters more airflow due to the helicopter's forward motion, which increases lift. In contrast, the aft-going blade operates at a reduced angle of attack, leading to less lift.

Understanding this concept is crucial for pilot proficiency and helicopter aerodynamics, as it impacts stability and control during flight. Asymmetrical lift can also influence the helicopter's tendency to roll or yaw, which pilots need to account for in their flight maneuvers. The term highlights the non-uniform distribution of lift across the rotor system, which is a fundamental consideration in helicopter design and operation.