A380 wing fence??

[rwong2005]

Hi everyone,

I have read through articles about winglet and wing fence in this forum and I couldn't find what are the differences between them. If someone could explain a little bit more, I would really really appreciate it.

1) what is the difference between winglet and wing fence? except the shape is different, I know they both are used to reduce induce drag and wingtip vortex, any other difference?

2) A380 uses wing fences is because it's wingspan is 80m long which reaches the maximum limitation for the gate. Is there any other reasons other than this?

3) It's an interview question and I have no idea how to explain better other than telling them that A380's wingspan is 80m long already, if it uses winglets, it won't fit at the gate?

Please help...

desperated.....

[TyroPicard]

A wing fence is designed to stop spanwise flow (out towards the wingtip) on the upper wing surface. By reducing the strength of this flow the strength of the wingtip vortex is reduced.

A320 style winglets are like endplates and presumably do the same thing.

Winglets like a 747-400 ..... don't know much about those so I'll keep quiet.

Hope this helps .. and don't panic!

Cheers, TP

[rwong2005]

Thanks, TyroPicard

i really apprecicate your input, and I do understand better than before about the wing fence.

I still don't know any other reasons why 380 use wing fences though...

Thanks again, tyroPicard and i really appreciate your input

Rwong2005

[hekokimushi]

hi guys.

i also do not understand why the A388 does not use winglets. any one know?

how does winglet differ from wingtip fence?

[XPMorten]

Winglet topic (http://www.pprune.org/forums/showthread.php?s=&threadid=178621&highlight=winglet)

Cheers,

M

[Charles Darwin]

A wing fence is put around the wings upper surface if the airline wants to carry more than 800 passengers. Without the fence they would just fall off :E

[Posh boy]

A wing fence , as T P mentioned reduces spanwise flow therefore reducing the strength of wing tip vortices. It overall increases wing efficiency as the vortices are the main source of induced drag.
Winglets increase the aspect ratio of the wing without increasing its span. As you probably know wings with higher aspect ratio tend to have lower induced drag.

It is not always necessary or benefitial to employ winglets as other considerations must be taken into account such as weight and costs.
Sometimes you get very little benefit in performance, depending on profile of the wing etc. This is probably the case with airbus.

Also in some cases it is possible to getforward force component aiding your flight.

[get a bigger hammer]

As mentioned before wing fences do prevent side slip.

However winglets do as follows. The vortex derived at the wing tip by high pressure air escaping from below the wing tip to lower pressure above the wing is much reduced consequently reducing drag. However the vortex that is generated at the tip of the winglet now lies above the wing. This vortex being of greater velocity than the air around it produces additional lift. Winglets also prevent aileron reversal again buy preventing high pressure air escaping to the upper surface of the wing reducing aileron reversal at high speeds and the necessity for inboard mounted high speed ailerons.

[MMEMatty]

A Wing fence also (if i can remember my Aviation Technology Lectures) prevents "Ram's Horn" vortives from forming on the wing. These spanwise vortices destroy lift and increase drag. A wing fence stops them from growing past where the fence is.

As for a winglet, all i know is that they control the wing end vortex (the one caused from air spilling over the wing end) and increase lift and reduce drag.


Matty

[rwong2005]

Thank You So Very Much for everyone's input. They are very helpful. I really appreciate it.

sincerely

Rwong