Editing Flight (section)

==== Lift ====
{{Main|Lift (force)}}
[[File:Airfoil lift and drag.svg|thumb|right|300px|Lift is defined as the component of the [[aerodynamic force]] that is perpendicular to the flow direction, and drag is the component that is parallel to the flow direction]]

In the context of an [[fluid flow|air flow]] relative to a flying body, the '''lift''' force is the [[Vector (geometric)#Vector components|component]] of the [[aerodynamic force]] that is [[perpendicular]] to the flow direction.<ref>[http://www.lerc.nasa.gov/WWW/K-12/aerosim/Manual/fsim0020.htm "Definition of lift."] {{webarchive|url=https://web.archive.org/web/20090203074439/http://www.lerc.nasa.gov/WWW/K-12/aerosim/Manual/fsim0020.htm |date=2009-02-03 }} ''NASA.'' Retrieved: May 6, 2012.</ref> Aerodynamic lift results when the wing causes the surrounding air to be deflected - the air then causes a force on the wing in the opposite direction, in accordance with [[Newton's third law of motion]].

Lift is commonly associated with the [[wing]] of an [[Fixed-wing aircraft|aircraft]], although lift is also generated by [[Helicopter rotor|rotors]] on [[rotorcraft]] (which are effectively rotating wings, performing the same function without requiring that the aircraft move forward through the air). While common meanings of the word "[[wikt:lift#English|lift]]" suggest that lift opposes gravity, aerodynamic lift can be in any direction. When an aircraft is [[cruise (flight)|cruising]] for example, lift does oppose gravity, but lift occurs at an angle when climbing, descending or banking. On high-speed cars, the lift force is directed downwards (called "down-force") to keep the car stable on the road.