We know that most of the lift is produced by air flowing in two dimensions across the upper and lower surfaces of an airfoil. To make it even more confusing, a third dimension has an aerodynamic effect.
The third dimension of the airfoil is the wing tip. As air flows from the bottom (high pressure) around the wing tip to the top (low pressure), this creates a rotating air flow called a tip vortex.
Tip vortex create a downwash resulting in a reduction of lift.
For an example the heavier, slower and in a clean configuration the aircraft is, the greater the angle of attack (AOA) it is during flight, the stronger the vortices. When an aircraft is in the takeoff, climb or even in the landing phase it produces stronger vortices, which leads to dangerous wake turbulence.
Wake turbulence can be dangers to small aircraft when taking off or even landing behind larger aircraft.
Rotate prior to the point at which the preceding aircraft rotated when taking off behind another aircraft.
Approach the runway above a preceding aircraft’s path when landing behind another aircraft. Touch down after the point at which the other aircraft wheels contacted the runway.
Note: If there is 10kt wind across the runway, the wake will drift about 1,000 feet a minute in the direction of the wind.
Caution must be taken when the wind is clam or in a light, quartering tailwind. This causes the wake turbulence or vortices to remain on the runway longer, even drift forward into the touchdown area.
If unsure where the other aircrafts touchdown point was, about 3 minutes provides a safe time for the wake to dissipate.
To help reduce the tip vortex winglets can be added to the top or bottom of an airfoil tip. Winglets act like a dam to prevent the vortex from forming.
Remember:
Wing tip vortices as viewed from the aft of the airplane, the left vortice rotates clockwise, whereas the right vortice rotates counterclockwise.
Small aircraft, when taking off or even landing behind larger aircraft.
Rotate prior to the point at which the preceding aircraft rotated when taking off behind another aircraft.
Approach the runway above a preceding aircraft’s path when landing behind another aircraft. Touch down after the point at which the other aircraft wheels contacted the runway.
If there is 10kt wind across the runway, the wake will drift about 1,000 feet a minute in the direction of the wind.
Caution must be taken when the wind is clam or in a light, quartering tailwind. This causes the wake turbulence or vortices to remain on the runway longer, even drift forward into the touchdown area.
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