Ground effect (aerodynamics)

=== Fixed-wing aircraft ===

=== Fixed-wing aircraft ===

When an aircraft flies at or below approximately half the length of the aircraft's [[wingspan]] above the ground, ground effect is often-noticeable. This is caused primarily by the ground obstructing the creation of [[wingtip vortices]], reducing [[downwash]] behind the wing as well as upwash in front of the wing.''Aerodynamics for Naval Aviators.'' RAMESH TAAL, HOSUR, VIC. Australia: Aviation Theory Centre, 2005.''Pilot's Encyclopedia of Aeronautical Knowledge'' 2007, pp. 3-7, 3-8. The nearer the wing is to the ground, the more pronounced the effect. In ground effect, the wing requires a lower [[angle of attack]] to produce the same amount of lift. In [[wind tunnel]] tests, in which the angle of attack and airspeed remain constant, an increase in the [[lift coefficient]] ensues,{{sfn|Dole|1981|pp=3–8}} which combined with the reduced drag accounts for the "floating" effect.{{Cite book |last=Hurt |first=Hugh H. |url={{google books|plainurl=y|id=Yyl257bX2rwC}}|title=Aerodynamics for Naval Aviators |date=1965 |publisher=Office of the Chief of Naval Operations, Aviation Training Division |isbn=978-0-89100-370-0 |language=en|pp=379-383 }}

When an aircraft flies at or below approximately half the length of the aircraft's [[wingspan]] above the ground, ground effect is often-noticeable. This is caused primarily by the ground obstructing the creation of [[wingtip vortices]], reducing [[downwash]] behind the wing as well as upwash in front of the wing.''Aerodynamics for Naval Aviators.'' RAMESH TAAL, HOSUR, VIC. Australia: Aviation Theory Centre, 2005.''Pilot's Encyclopedia of Aeronautical Knowledge'' 2007, pp. 3-7, 3-8. The nearer the wing is to the ground, the more pronounced the effect. In ground effect, the wing requires a lower [[angle of attack]] to produce the same amount of lift. In [[wind tunnel]] tests, in which the angle of attack and airspeed remain constant, an increase in the [[lift coefficient]] ensues,{{sfn|Dole|1981|pp=3–8}} which combined with the reduced drag accounts for the "floating" effect.{{Cite book |last=Hurt |first=Hugh H. |url={{google books|plainurl=y|id=Yyl257bX2rwC}}|title=Aerodynamics for Naval Aviators |date=1965 |publisher=Office of the Chief of Naval Operations, Aviation Training Division |isbn=978-0-89100-370-0 |language=en|pp=379-383 }}

[[Low wing|Low winged aircraft]] are more affected by ground effect than [[high wing]] aircraft.Flight theory and aerodynamics, p. 70 Due to the change in up-wash, down-wash, and wingtip vortices, the airspeed system may make errors due to changes in local pressure at the [[Pitot–static system#Static pressure|static source]].{{sfn|Dole|1981|pp=3–8}}

[[Low wing|Low winged aircraft]] are more affected by ground effect than [[high wing]] aircraft.Flight theory and aerodynamics, p. 70 Due to the change in up-wash, down-wash, and wingtip vortices, the airspeed system may make errors due to changes in local pressure at the [[Pitot–static system#Static pressure|static source]].{{sfn|Dole|1981|pp=3–8}}