# Relative Wind

In aeronautics, the relative wind is the direction of movement of the atmosphere relative to an aircraft or an airfoil. It is opposite to the direction of movement of the aircraft or airfoil relative to the atmosphere. Close to any point on the surface of an aircraft or airfoil, the air is moving parallel to the surface; but at a great distance from the aircraft or airfoil the movement of the air can be represented by a single vector. This vector is the relative wind or the free stream velocity vector.

The angle between the chord line of an airfoil and the relative wind defines the angle of attack. The relative wind is of great importance to pilots because exceeding the critical angle of attack will result in a stall, regardless of airspeed.

### Other articles related to "wind, relative wind, relative":

Wind Turbine Aerodynamics - General Aerodynamic Considerations
... vector, and U is the speed of the moving wind turbine part ... The force F is generated by the wind interacting with the blade ... The primary focus of wind turbine aerodynamics is the magnitude and distribution of this force ...
P-factor - Causes
... straight and level flight at cruise speed, the propeller disc is perpendicular to the relative wind ... blades moving down and forward will have a greater relative wind velocity and therefore increased thrust, while propeller blades moving up and back will have a decreased relative wind ...
Angle Of Attack - A Simple, Non-technical Explanation
... The angle of attack can be simply described as "the angle at which relative wind meets an airfoil ... by the chord of the airfoil and the direction of the relative wind or between the chord line and the flight path." While a wing's angle of attack is less than its critical angle (wh ... is called the ‘slow stall speed.’ When the wing is moving into the relative wind at that speed or less, it does not generate sufficient lift, resulting in the critical angle of attack being exceeded because of ...
Relative Wind in Freefall
... Relative wind is also used to describe the airflow relative to an object in freefall through an atmosphere, such as that of a person's body during the freefall ... In a normal skydive the vertical descent of the skydiver creates an upward relative wind ... The relative wind strength increases with increased descent rate ...

### Famous quotes containing the words wind and/or relative:

The way leads to freedom, to freedom it goes. The old world must crumble. Awake, wind of dawn!
Alfred Döblin (1878–1957)

Man may have his opinion as to the relative importance of feeding his body and nourishing his soul, but he is allowed by Nature to have no opinion whatever as to the need for feeding the body before the soul can think of anything but the body’s hunger.
George Bernard Shaw (1856–1950)