Aspect ratio (wing)

The stretching is a dimensionless parameter for the slenderness of an airfoil. It is defined as the ratio of the square of the wing span to the wing surface, or alternatively the ratio of the range to the mean depth of the wing ( aspect ratio):

With

• Wingspan
• : Wing area
• : Middle wing depth

A high aspect ratio of the wing reduces the induced drag caused by end vertebra. However, ultra-thin wings cause problems with the mechanical stability of the wing and in the maneuverability of the aircraft. Winglets have a stretch - widening influence and thus cause a reduction in induced drag.

The stretching of a wing is important in the subsonic range and for aircraft that are operated with a high lift coefficient. In supersonic, this is no longer true, so no need for a high aspect ratio and the aerodynamic characteristics of a wing can be almost completely decoupled from the Mach number. An example is the delta wing.

Slender wings with high aspect ratio can be found in all flight sailors, such as sailplanes, albatrosses, gulls, etc. birds, which move more by flapping wings, have a lower aspect ratio, eg Crow.

Leaving the span of a wing - and thus its extension - go to "infinity", so vanish the effects of the finite wing and it is a pure two-dimensional Profilumströmung ago.