Anstellwinkels

Anstellwinkels is the plural form of the German term Anstellwinkel, commonly translated as angle of attack. In aerodynamics, the Anstellwinkel describes the angle between the chord line of an airfoil or wing section and the oncoming relative airflow. The Anstellwinkel can vary along a wing, across different flight conditions, or between aircraft and configurations, yielding multiple Anstellwinkels for analysis.

Measuring and interpreting Anstellwinkels involves either direct sensors or calculations. In flight, angle of attack is measured with dedicated sensors (AoA vanes or probes) or inferred from the aircraft’s pitch, flight path angle, and attitude. The Anstellwinkel is a primary parameter governing lift production: as the angle increases, the lift coefficient generally rises until a critical angle, after which flow separation causes a rapid lift drop known as stall.

Key factors influencing Anstellwinkels and their effects include airfoil shape, surface roughness, Reynolds number, Mach number, and wing configuration. For many subsonic wings, the stall commonly occurs in the mid-teens of degrees, but exact values vary widely. At higher speeds or compressible flows, the relationship between Anstellwinkel and lift changes due to aerodynamic and structural considerations.

Practical use of Anstellwinkels spans aircraft design, testing, and operation. During design, engineers map lift and drag as functions of Anstellwinkel to define safe operating envelopes. In flight testing, AoA data help assess stall margins, handling qualities, and performance. Pilots monitor angles of attack indirectly through airspeed and attitude to maintain controlled flight and avoid stall.

See also: angle of attack, airfoil theory, stall, lift coefficient.