Which speed range is associated with the onset of translational lift?

Translational lift occurs when a helicopter moves from hovering to forward flight, allowing it to take advantage of increased airflow over the rotor blades. This phenomenon is crucial for understanding helicopter performance in various flight modes.

The speed range associated with the onset of translational lift typically begins around 16-24 knots. At these speeds, the helicopter blades begin to experience additional lift due to the increased relative wind that enhances the efficiency of the rotor system. The rotor blades are able to generate more lift because they are operating in an area of increased aerodynamic efficiency where the incoming airflow creates favorable conditions for lift production.

In contrast, speeds below this range generally don't provide enough forward motion for translational lift to occur effectively, as the helicopter remains primarily in a hover state. When operating at speeds below 16 knots, the aircraft is still relying predominantly on induced lift without the benefits of translational lift. Once speeds exceed 24 knots, the helicopter typically begins to fully utilize translational lift, but the onset is best recognized in the 16-24 knot range.