Wingtip vortices
Thread Starter
Wingtip vortices
Reviewing ATPL theory 'again' and found conflicting ideas as to when wing tip vortices are at their strongest. Would it be at the point of max lift ie at the point of stall or during rotation on takeoff.
Ideas would be appreciated
Cheers
Ideas would be appreciated
Cheers
At the point of a full flap stall, I would suggest.
Vortices really only develop above 'ground effect' height (if I recall correctly) of 0.8 b where b is the aircraft wingspan.
Vortices really only develop above 'ground effect' height (if I recall correctly) of 0.8 b where b is the aircraft wingspan.
Would it not be under the most loading? i.e. greater at 3 g than at 1 g.
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My notes state and I quote
"The intensity or strength of the vortex is primarily a function of aircraft weight and configuration (flap setting etc.). The strongest vortices are produced by heavy aircraft, flying slowly, in a clean configuration. For example, a large or heavy aircraft that must reduce its speed to 250 knots below 10,000 feet and is flying in a clean configuration while descending, produces very strong wake."
So CLEAN config and HEAVY during take off and landing seen to be the phases that produce max wing tip vortices.
"The intensity or strength of the vortex is primarily a function of aircraft weight and configuration (flap setting etc.). The strongest vortices are produced by heavy aircraft, flying slowly, in a clean configuration. For example, a large or heavy aircraft that must reduce its speed to 250 knots below 10,000 feet and is flying in a clean configuration while descending, produces very strong wake."
So CLEAN config and HEAVY during take off and landing seen to be the phases that produce max wing tip vortices.
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Why unaccelerated flight?
Vortices forming in the vicinity of a wing are not dependent on aircraft weight, but they are dependent on lift generated. I would not have thought load factor was relevant.
Vortices forming in the vicinity of a wing are not dependent on aircraft weight, but they are dependent on lift generated. I would not have thought load factor was relevant.
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The most important factor is the Coefficient of Lift (Cl) for the wing. As Cl increases (at lower speeds), the differential between lower wing and upper wing pressures increase, these being the origin of the wing-tip vortices. AoA, Load factor etc, all have a part to play, but put these 2 together to find the Cl that the pilot is calling for.
Wing tip vortices are reduced with flap set, unless the wing has full span equally deflected flaps. The outer sections of each flap assembly produce their own vortices, thus, there may be several sets of vortices, the total of which would be the same as for the clean wing, but are instead distributed between the various vortex generating lift surfaces, making each individual vortex of less energy than the wing-tip vortices standing alone.
Wing tip vortices are reduced with flap set, unless the wing has full span equally deflected flaps. The outer sections of each flap assembly produce their own vortices, thus, there may be several sets of vortices, the total of which would be the same as for the clean wing, but are instead distributed between the various vortex generating lift surfaces, making each individual vortex of less energy than the wing-tip vortices standing alone.
