Windage

In aerodynamics, firearms ballistics, and automobiles, windage is the effects of some fluid, usually air (e.g., wind) and sometimes liquids, such as oil.

Windage is a force created on an object by friction when there is relative movement between air and the object. Windage loss is the reduction in efficiency due to windage forces.

For example, electric motors are affected by friction between the rotor and air. Large alternators have significant losses due to windage. To reduce losses, hydrogen gas may be used, since it is less dense.

Causes of windage are:

The term can refer to:

Aerodynamic streamlining can be used to reduce windage.

Hydrodynamic drag is a hydrodynamic effect similar to windage.

In firearms parlance, windage is the sight adjustment used to compensate for the horizontal deviation of the projectile trajectory from the intended point of impact due to wind drift or Coriolis effect. By contrast, the adjustment for the vertical deviation is the elevation.