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MBSDALHOU
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A350 "winglet"

Mon Oct 24, 2016 8:42 pm

Hi everyone! First time posting so here goes!
Maybe it's just me but do the winglets (or whatever Airbus has named them) do they see to almost curl up when the plane is on the ground and when in air it looks as if they unfold some.
I'm aware that to some degree wing flex gives way to the illusion, however any insight is greatly appreciated!
Thank you everyone!
 
32andBelow
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Re: A350 "winglet"

Mon Oct 24, 2016 8:58 pm

Isn't it more of a raked wingtip than a winglet?
 
a380787
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Re: A350 "winglet"

Mon Oct 24, 2016 9:15 pm

the A350 wingtips are fixed, not foldable like the 777-9. If you wanna force a term on it, I'd say "raked sharklet" ?
 
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scbriml
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Re: A350 "winglet"

Mon Oct 24, 2016 9:47 pm

32andBelow wrote:
Isn't it more of a raked wingtip than a winglet?


It's definitely a winglet (or more corectly sharklet), not a raked wingtip:
Image

Although, from some angles, the upsweep looks less defined:
Image

But it most certainly does curve upwards:
Image
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32andBelow
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Re: A350 "winglet"

Mon Oct 24, 2016 9:57 pm

scbriml wrote:
32andBelow wrote:
Isn't it more of a raked wingtip than a winglet?


It's definitely a winglet (or more corectly sharklet), not a raked wingtip:
Image

Although, from some angles, the upsweep looks less defined:
Image

But it most certainly does curve upwards:
Image

But it's part of the wing right? Cannot be removed?
 
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ikolkyo
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Re: A350 "winglet"

Mon Oct 24, 2016 9:59 pm

32andBelow wrote:
scbriml wrote:
32andBelow wrote:
Isn't it more of a raked wingtip than a winglet?


It's definitely a winglet (or more corectly sharklet), not a raked wingtip:
Image

Although, from some angles, the upsweep looks less defined:
Image

But it most certainly does curve upwards:
Image

But it's part of the wing right? Cannot be removed?


It can be removed.
 
32andBelow
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Re: A350 "winglet"

Mon Oct 24, 2016 10:09 pm

ikolkyo wrote:
32andBelow wrote:
scbriml wrote:

It's definitely a winglet (or more corectly sharklet), not a raked wingtip:
Image

Although, from some angles, the upsweep looks less defined:
Image

But it most certainly does curve upwards:
Image

But it's part of the wing right? Cannot be removed?


It can be removed.

Huh, looks like a single piece in that photo.
 
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ikolkyo
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Re: A350 "winglet"

Mon Oct 24, 2016 10:13 pm

32andBelow wrote:
ikolkyo wrote:
32andBelow wrote:
But it's part of the wing right? Cannot be removed?


It can be removed.

Huh, looks like a single piece in that photo.


Here is a photo of a QR A350 missing its left winglet

Image
 
iahcsr
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Re: A350 "winglet"

Mon Oct 24, 2016 10:19 pm

How about we call it 'Curvelet'?
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Erebus
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Re: A350 "winglet"

Mon Oct 24, 2016 11:17 pm

scbriml wrote:
Image


Unbelievable picture. Not only is the winglet supersized from that angle, but just look at how much of the wing section the aileron appears to occupy. Mind tricks...
 
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JannEejit
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Re: A350 "winglet"

Mon Oct 24, 2016 11:39 pm

Jaysus ! It's a blended winglet concept, same as Boeing, but named 'Sharklet' in Airbus terms, presumably for copyright reasons. I'm not sure if the marketing term 'Sharklet' actually applies to the A350 model but a blended winglet it is. It is not a naturally lenghened wing in term of overall span, but an added on structural piece that's blended in using outer skin laminates, that give the appearance and presumably airflow characteristics of a single wing from root to tip. But yes, hit it hard enough and it will fall off.
 
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Polot
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Re: A350 "winglet"

Tue Oct 25, 2016 12:16 am

Is the A350 allowed to fly with only one winglet, like the A330, or no (like I believe the 737 with blended winglets?)?
 
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ikolkyo
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Re: A350 "winglet"

Tue Oct 25, 2016 1:53 am

Polot wrote:
Is the A350 allowed to fly with only one winglet, like the A330, or no (like I believe the 737 with blended winglets?)?


Not sure about the A350 but the 737 is unable to fly with one winglet missing. That is set to change with the 737 MAX planned to be certified for that.
 
SteinarN
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Re: A350 "winglet"

Tue Oct 25, 2016 2:26 am

Polot wrote:
Is the A350 allowed to fly with only one winglet, like the A330, or no (like I believe the 737 with blended winglets?)?


It is most certainly allowed to fly long enough so that it can land. But I doubt it is allowed to take off with one missing, altough i am sure the aircraft would have no problem becoming airborne with one missing.
 
SCAT15F
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Re: A350 "winglet"

Tue Oct 25, 2016 3:09 am

By far my favorite wingtip device design. Wish the 747-8 had these...
 
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A330freak
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Re: A350 "winglet"

Tue Oct 25, 2016 4:41 am

After the aircraft was certified, Airbus did a few test flights on MSN3 with one winglet removed.
ImageAirbus A350XWB - MSN 003 by Rami Khanna-Prade, on Flickr
ImageA350-900 MSN003 F-WZGG VOL TEST SANS LE WINGLET DROIT by Jérémy Le roch, on Flickr
ImageAirbus A350XWB - MSN 003 by Rami Khanna-Prade, on Flickr
ImageAIB250GG 20/1/2015 by A380_TLS_A350, on Flickr
One the subject of other aircraft operating without winglets, I've seen a 744 operate commercially with one winglet missing and I know Airbus has flown the A380 without both winglets.
 
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MoKa777
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Re: A350 "winglet"

Tue Oct 25, 2016 6:57 am

iahcsr wrote:
How about we call it 'Curvelet'?


I like "Curvelet"!
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scbriml
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Re: A350 "winglet"

Tue Oct 25, 2016 7:54 am

JannEejit wrote:
Jaysus ! It's a blended winglet concept, same as Boeing, but named 'Sharklet' in Airbus terms, presumably for copyright reasons.


MoKa777 wrote:
I like "Curvelet"!


Nah, it's Sharklet because that's way more awesomer than winglet! ;)
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There are 10 types of people in the World - those that understand binary and those that don't.
 
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MoKa777
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Re: A350 "winglet"

Tue Oct 25, 2016 7:59 am

scbriml wrote:
JannEejit wrote:
Jaysus ! It's a blended winglet concept, same as Boeing, but named 'Sharklet' in Airbus terms, presumably for copyright reasons.


MoKa777 wrote:
I like "Curvelet"!


Nah, it's Sharklet because that's way more awesomer than winglet! ;)


Can't argue with that!
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Flightsimboy
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Re: A350 "winglet"

Tue Oct 25, 2016 12:26 pm

scbriml wrote:
32andBelow wrote:
Isn't it more of a raked wingtip than a winglet?


It's definitely a winglet (or more corectly sharklet), not a raked wingtip:
Image

Although, from some angles, the upsweep looks less defined:
Image

But it most certainly does curve upwards:
Image


Look at the first and third picture and then look at the middle one. That definitely does not look like the same "sharklet". Almost like an optical illusion. The two pics clearly seem to bend upwards while the middle one sems to bend outwards. Beautiful.
LAX772LR - "Answer to goofy question:" in response to my question about the B737-MAX8 being grounded. 48 hours later all B737-MAX8 grounded worldwide. Go figure!!
 
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scbriml
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Re: A350 "winglet"

Tue Oct 25, 2016 5:58 pm

Flightsimboy wrote:
Look at the first and third picture and then look at the middle one. That definitely does not look like the same "sharklet". Almost like an optical illusion. The two pics clearly seem to bend upwards while the middle one sems to bend outwards. Beautiful.


It is a thing of beauty and does look amazingly different depending on your viewing angle. The sharklets can even look different in the same pic!
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DocLightning
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Re: A350 "winglet"

Wed Oct 26, 2016 9:02 pm

A few things.
*Planar wing extensions work by increasing the wingspan and thus decreasing the overall pressure differential between upper and lower surfaces as integrated along the wingspan. They also increase the span at the gate and increase the bending moment on the wing root by moving the center of lift outboard.
*Nonplanar extensions work by altering the lateral flowfield in the vicinity of the wingtip and reducing the magnitude of the lift-induced vorticity while moving the axis of that vorticity upward and outboard. Almost all of these devices involve some span increase but not as much as a coplanar tip extension. They also increase the lift on the outboard wing, increasing bending moment, but not as far outboard as a coplanar tip extension. They provide less drag reduction/lift improvement per unit of length, but require less wing strengthening.
*A sharp curve will cause an interference vortex to form at the join between the winglet and the main wing. I can't find a good visual depiction of this, but someone who knows more aerodynamics than I do might be able to find one. Anyway, sharp curves=bad.

Boeing's solution to the problem is to use a folding coplanar wing extension. This provides the most aerodynamic benefit with the smallest increase in total wetted area, but comes at the cost of the mechanical complexity of the folding mechanism (which is much less complex than a flap, aileron, or landing gear) and the added bending moment at the tip. However, it negates the problem with increased span at the gate.

Airbus chose to go with a hybrid solution with no moving parts. However, to negate the issues with a sharply curved winglet (like those on the original A330/A340) they chose to blend the tip extension into a vertical device. It's a compromise solution combining the trade-offs and benefits of both designs into one.
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crimsonchin
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Re: A350 "winglet"

Thu Oct 27, 2016 8:51 pm

scbriml wrote:
JannEejit wrote:
Jaysus ! It's a blended winglet concept, same as Boeing, but named 'Sharklet' in Airbus terms, presumably for copyright reasons.


MoKa777 wrote:
I like "Curvelet"!


Nah, it's Sharklet because that's way more awesomer than winglet! ;)


Still surprised that Airbus named the winglets on the A320 "Sharklets" but not the ones on the A350. The A350 winglets are much closer to the shark look than the A320.
 
voiceofgoa
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Re: A350 "winglet"

Fri Oct 28, 2016 2:56 am

Erebus wrote:
scbriml wrote:
Image


Unbelievable picture. Not only is the winglet supersized from that angle, but just look at how much of the wing section the aileron appears to occupy. Mind tricks...


A wide-angle lens used was used in that picture and it was placed close to the winglet to exaggerate its size and perspective relative to the more distant objects & fuselage.
 
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Erebus
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Re: A350 "winglet"

Fri Oct 28, 2016 3:11 am

crimsonchin wrote:
scbriml wrote:
JannEejit wrote:
Jaysus ! It's a blended winglet concept, same as Boeing, but named 'Sharklet' in Airbus terms, presumably for copyright reasons.


MoKa777 wrote:
I like "Curvelet"!


Nah, it's Sharklet because that's way more awesomer than winglet! ;)


Still surprised that Airbus named the winglets on the A320 "Sharklets" but not the ones on the A350. The A350 winglets are much closer to the shark look than the A320.


Well, they call the A330neo winglets "Sharklets" too even though it resembles a bit more like the A350 ones than the A320 ones. I wonder if the term "Sharklet" is more a supplier/manufacturer term than coming from Airbus themselves. Korean Air Aerospace makes the A320neo and A330neo winglets and I think the A350 winglets are made by FACC.
 
WIederling
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Re: A350 "winglet"

Fri Oct 28, 2016 5:03 pm

32andBelow wrote:
Huh, looks like a single piece in that photo.


Good Workmanship :-)

The wingtip devices show common mode curve up and increase of sweep back from wing to final tip
while reducing the profile depth to zero.
( i.e. they look like any good piece of well done impedance match device.)
Murphy is an optimist
 
WIederling
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Re: A350 "winglet"

Fri Oct 28, 2016 5:08 pm

Are there any "condensing fog chamber" photos around to show the flow around the wingtips?
( similar to this one for the A330^HA340: http://41.media.tumblr.com/451fe1e9e452 ... 1_1280.jpg )

( 4 engines obviously is no A330. careless me.)
Last edited by WIederling on Fri Oct 28, 2016 5:20 pm, edited 1 time in total.
Murphy is an optimist
 
WIederling
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Re: A350 "winglet"

Fri Oct 28, 2016 5:13 pm

DocLightning wrote:
It's a compromise solution combining the trade-offs and benefits of both designs into one.


IMU it is a synergistic combination of both ( actually 3 effects: curve up, curve back and taper.
If you think it is a compromise to get away from folding wingtips you underestimate the designers. )
Murphy is an optimist
 
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DocLightning
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Re: A350 "winglet"

Fri Oct 28, 2016 6:02 pm

WIederling wrote:
DocLightning wrote:
It's a compromise solution combining the trade-offs and benefits of both designs into one.


IMU it is a synergistic combination of both ( actually 3 effects: curve up, curve back and taper.
If you think it is a compromise to get away from folding wingtips you underestimate the designers. )


No underestimation here. The span increase wasn't enough to cross a span class, so that wasn't a huge drawback. The upward curve cuts the span increase. The backward aspect will provide some wing unloading in gust scenarios and will also assist with separation issues at high AOA and shock formation at high speeds.
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DocLightning
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Re: A350 "winglet"

Mon Oct 31, 2016 2:54 am

Let me expound on the different kind of wingtip devices and how they work, as well as their advantages and disadvantages.

All aircraft generate a trailing field of vorticity (well, two such fields) rotating inwards towards the wing. This field of vorticity is a natural continuation of the field of vorticity that is generated as a result of the process of lift production. Thus, an airplane flies through a downwash of its own making:Image.

The trailing vortices have no tensile strength and no effect on the aircraft, but the field of vorticity forms on the aft section of the wing. So any wingtip device is going to attempt to weaken the overall field of vorticity and move the region in which it forms away from the main wing.

Up until recently, a non-planar device was most common on airliners that had such devices. These nonplanar devices range from the simple tip fences on the Airbus A320
to the winglets on the 744
or the A330/A340.
Even the blended winglets on the 737 and A320 families.
Some devices feature downward wing-like elements that rotate outward when the wing flexes and extend the span. (https://www.google.com/patents/US9193445) The bottom line is these nonplanar devices straighten the flow near the wingtip and reduce the magnitude of the vorticity and downwash there. Instead, the vorticity is shed at reduced magnitude from the tip of the wingtip device, above and behind the main wing, reducing the downdraft. In this arrangement, the increased lift is mostly added to the outboard section of the main wing, so some spar strengthening is necessary.

A 3-foot nonplanar device will do the job of a 2-foot wingtip extension but it will only put the bending moment on the wing root of a 1-foot wingtip extension.

The planar extension used by Boeing is also known as the raked wingtip. The idea is that the longer wingspan leads to less pressure differential integrated along the wing span. However, there are some issues. A leading edge needs a high-lift device. If not, there might be flow separation at high angles of attack (Takeoff) and the wingtip might stall until it fell down into a lifting attitude again. It would start to flap like a bird and in the worse case scenario, this could cause loss of control of the aircraft. But way out there, the wing becomes too thin to install a leading edge device. Boeing found that by increasing the sweep on the outboard planar extension, a stable vortex tended to form in that region at high AOA and this reduced the risk of separation. But not enough. It turns out that the use of a blunt leading edge will also reduce separation as seen here:Image

Blunt LEs aren't normally a solution in an airliner because they make a lot of shock at high sonic speeds. But when they are highly swept this is not an issue. But to make the high-sweep extension long enough, the trailing edge had to be swept back, too. You can see in this image that if the trailing edge line is not swept back, the increased sweep of the leading edge causes the two edges to intersect sooner. By increasing the trailing edge sweep, the extension can be made longer. An alternative shown is less sweep, but with this decreased sweep a leading edge device (labeled "28") is necessary, and that quickly negates the benefits offered by the device. Image

This has the additional advantage of moving the center of lift aftward on the raked tip. If that wing hits a gust, the raked tip will "weathervane" the leading edge into a more downward AOA and thus dump lift, reducing stress on the inboard spar. But the wingtip extension necessarily moved the center of life outboard and so there is more strengthening for the spar. Planar extensions can also interfere at the gate. But overall, when designed into a wing, they provide the best aerodynamic performance for the least wetted area and additional structure.

Boeing overcame this with the folding tip. But the folding tip comes at the expense of the weight, mechanical complexity, and hit to dispatch reliability inherent in any moving part. Now, I will point out that flaps are much heavier, more complex, and are absolutely critical to the flight and we don't wring our hands over their reliability or complexity. Still, it's not a negligible effect.

The upshot of this is that there is no single one best solution for all cases. I'd also be willing to bet that Boeing would have designed the A350 wing with a raked tip. The devices are obviously worth the trouble or they wouldn't be there, but I'm not sure that a Boeing-style raked tip vs. an Airbus style curved tip would really make much of a difference overall.
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