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Post by FabienA380 on Nov 20, 2013 6:44:35 GMT 1
Could ever Airbus try to apply the new "folding-wing-ends" proposed by Boeing for its forthcoming 777X?... This would have to be developped first but could we ever imagine this??... Fabien
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philidor
in service - 6 years
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Post by philidor on Nov 20, 2013 23:39:48 GMT 1
I still can't believe the numbers of the winglets.. The A380s are used for very long haul. This is probably a major reason a wingtip improvement would yield excellent results. I also suppose that aerodynamic test equipments have been improved in the last few years, now allowing better designs.
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Taliesin
Final Assembly Line stage 1
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Post by Taliesin on Nov 20, 2013 23:58:51 GMT 1
The A380 was developed with ultra long haul in mind. And the technological standard for wingtips has certainly improved, but by that much? 3% is A LOT. In engine design and development, an improvement of 0,1% in fuel burn is considered a lot, improvements of 0,01% are still considered well worth chasing. A 3% improvement of fuel burn from a single modification is nothing short of gigantic.
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Post by Flying Dutchman on Nov 21, 2013 20:12:24 GMT 1
They will be able to use the experience from the A350 winglets
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mjoelnir
in service - 2 years
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Post by mjoelnir on Nov 22, 2013 3:19:50 GMT 1
I would not exclude folding from a new wingtip design from Airbus for the A380. they have been playing around with such ideas. The current wingtip design is very similar to the A320 old wingtip from around 1988. The A380 design is from before 2005 and optical no different to the one from the A320. Since than Airbus had played a lot with wingtip fences. IMO 3% lower fuel burn should be the low estimate, I would rather believe 4,5 to 5.
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Taliesin
Final Assembly Line stage 1
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Post by Taliesin on Nov 22, 2013 9:13:11 GMT 1
The current wingtip design is very similar to the A320 old wingtip from around 1988. The A380 design is from before 2005 and optical no different to the one from the A320. Since than Airbus had played a lot with wingtip fences. IMO 3% lower fuel burn should be the low estimate, I would rather believe 4,5 to 5. I realise that raked wingtips are all the rage in the aviation world and given their success, I'm sure they have advantages over the more conventional wingtip fences. I believe these advantages are mostly on the structural and weight side. It's important to note that technically, anything a raked wingtip can do, a wingtip fence can, too. It's not about the form, it's about how you alter the aerodynamics of the wingtip in a way that makes the outer part of the wing more efficient and reduces the wingtip vortex. Raked wingtips aren't new either, the 77W, 77L and 77F have had them for well over 10 years. It absolutely defies logic to suggest that Airbus didn't know about this and didn't test a raked wingtip on the A380, at least in a numeric simulation. Something else must be going on here.
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mjoelnir
in service - 2 years
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Post by mjoelnir on Nov 22, 2013 11:04:54 GMT 1
The current wingtip design is very similar to the A320 old wingtip from around 1988. The A380 design is from before 2005 and optical no different to the one from the A320. Since than Airbus had played a lot with wingtip fences. IMO 3% lower fuel burn should be the low estimate, I would rather believe 4,5 to 5. I realise that raked wingtips are all the rage in the aviation world and given their success, I'm sure they have advantages over the more conventional wingtip fences. I believe these advantages are mostly on the structural and weight side. It's important to note that technically, anything a raked wingtip can do, a wingtip fence can, too. It's not about the form, it's about how you alter the aerodynamics of the wingtip in a way that makes the outer part of the wing more efficient and reduces the wingtip vortex. Raked wingtips aren't new either, the 77W, 77L and 77F have had them for well over 10 years. It absolutely defies logic to suggest that Airbus didn't know about this and didn't test a raked wingtip on the A380, at least in a numeric simulation. Something else must be going on here. When did I mention a raked wingtip? I do not see any reason you would not be able to fold some kind of blended winglet if it would extend past the 80m. Having said above I am sure Airbus will also check a raked wing tip as well as a split wingtip fence.
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XWB
in service - 11 years
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Post by XWB on Nov 22, 2013 11:11:25 GMT 1
The Trent XWB however is significant heavier than the Trent 900 and will add a lot of weight to the airframe. And will EA upgrade its engine too? The german Wikipedia lists the TrentXWB as 200kg or 3% heavier than the Trent 900. Even multiplied by 4, this adds up to under 1 ton and in my opinion is well offset by a lower fuel burn on pretty much every mission. The TrentXWB is not an upgrade as such, but a new engine, I don't think "upgrading" the GP7000 would do the trick but GE might offer the GE90X for the A380NG. The dry engine weight is as follows: > Trent 900: 6,271 kg > Trent XWB: 7,277 kg This would add around 4 tonnes weight to the airframe, not a small figure IMO. I also understood the larger Trent XWB engine cannot be attached to the outer pods due to its size.
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Taliesin
Final Assembly Line stage 1
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Post by Taliesin on Nov 22, 2013 11:53:21 GMT 1
When did I mention a raked wingtip? I do not see any reason you would not be able to fold some kind of blended winglet if it would extend past the 80m. That's a good point, but as with all developments, plugging something new onto something old never yields the same gains as having everything developed together. I would be surprised if a folding wing extension with a new wingtip could yield that kind of gain in efficiency, but I'm prepared to stand corrected. I'm still not entirely sold on this folding wing extension, Boeing offered a folding wing extension for the 77W and 77L and as I'm sure everyone is aware, not a single customer bought it. A folding wing extension increases complexity and weight and it needs to be done in a way that even when the extension fails to fold back in for landing or even breaks off entirely, the plane can still fly. I'm pretty sure it would be an absolute nightmare to develop and certify, which brings me back to my original point.. I'm not entirely sold on the whole thing. The dry engine weight is as follows: > Trent 900: 6,271 kg > Trent XWB: 7,277 kg This would add around 4 tonnes weight to the airframe, not a small figure IMO. I also understood the larger Trent XWB engine cannot be attached to the outer pods due to its size. I only have the numbers off of Wikipedia to go by, where are yours from? It would surprise me if the difference actually were that high, the biggest difference between the 2 engines is a higher pressure ratio, the outer dimensions and even the thrust range are remarkably similar. It would surprise me if a few more compressor stages and other minor differences meant a difference in weight of 1 ton. I don't see why the engine couldn't be attached to the outer pods, it's only a few inches more in diameter. Even if that were a problem, you could probably fit it differently with a different pylon. You need a new pylon for a new engine anyway from what I understand.
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XWB
in service - 11 years
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Post by XWB on Nov 22, 2013 12:09:55 GMT 1
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