Rotorspeling

Rotorspeling, often translated as rotor wash or downwash, refers to the mass of air that is blown downwards by the rotating blades of a helicopter rotor. This downward-moving air is crucial for generating lift, enabling the helicopter to fly. As the rotor blades spin, they push air towards the ground, creating a region of high pressure beneath the rotor disc and low pressure above it. This pressure differential results in an upward force, counteracting gravity.

The intensity and characteristics of rotorspeling are influenced by several factors, including rotor diameter, blade speed, blade pitch angle, and the helicopter's forward speed. In a hover, rotorspeling is most concentrated directly beneath the rotor disc. As the helicopter moves forward, the downwash tends to tilt backward. This phenomenon has practical implications for helicopter operations. For instance, the strong downdraft can kick up dust and debris, affecting visibility and potentially damaging equipment or personnel on the ground, a phenomenon known as brownout or whiteout depending on the surface.

Pilots must manage rotorspeling during takeoff, landing, and hovering. Understanding and anticipating the effects of rotorspeling is essential for safe maneuvering, especially in confined areas or when operating near other aircraft or structures. The interaction of rotorspeling with the ground can also create complex aerodynamic effects, such as ground effect, which can alter lift characteristics.