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Airbus A350/A350 XWB

carsinamerica

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fightingirish said:
Fanart... ::)
Not just fanart, stupid fanart. Apparently this A370 will have a third engine nacelle (front half only) strapped to the vertical stabilizer, but it can't be an actual engine, since there's no exhaust anywhere. That should work well.
 

mz

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Triton said:
Why are the 787 engines placed so wide apart? To reduce ground clearance? (Since there is dihedral, the higher the engines go the further you put them from the centerline). If the vertical tail and rudder sizing is dominated by engine out scenarios, that would explain why the 350 can do with a relatively smaller fin.
 

Grey Havoc

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In further woes, the planemaker was also forced to call off a ceremony planned for Saturday to deliver its new A350 jetliner to Qatar Airways after the Gulf airline said it was delaying the handover indefinitely.

Analysts said the rebuff from the airline, famously picky about accepting new aircraft and widely believed to use such tactics to obtain last-minute concessions, was overshadowed by concerns over the model it replaces, the A330.

Airbus, which has already announced plans to cut A330 production by 10 percent to nine aircraft a month, said it would have to cut production again in 2016 to an unspecified level.

That follows slow progress in finding buyers for the current model ahead of a mid-term upgrade called A330neo in 2017, as well as a sharp output ramp-up for the all-new A350.

"The most critical years are 2016 and 2017," Enders told analysts at an investor conference.

Airbus said core operating income would return to growth in 2017. Some analysts had expected double-digit improvements as early as 2016.

Airbus shares tumbled 10.4 percent, the biggest one-day percentage fall since July 2008, to close at 43.175 euros, their lowest close since mid-October.

Aerospace analyst Rob Stallard said the transition between current models and new ones, which also affects the smaller A320 family, was proving a bigger drag on profits than expected.

For now, analysts advised against reading too much into the postponed first A350 delivery, which Airbus has targeted by year-end and which it still predicts will happen "very soon".
https://uk.finance.yahoo.com/news/is-this-the-end-of-a380---the-world-s-largest-airplane-101418365.html
 

fredymac

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I've noticed in videos of the A350 flying that its' wings don't seem to flex nearly as much as the 787. I wonder if that is a design choice or if the construction technique is significantly different. For minimized weight and efficiency, I would think a carbon fiber wing would naturally tend to flex much more than conventional designs. I haven't seen noticeable flex in B2 bombers either so I would assume that was a design decision. Smaller, all carbon fiber air frames such as fighters also appear fairly rigid. I remember there was something called "aero-elastic" tailoring or some such that was supposed to allow predetermined flex to optimize lift/drag vs g loads. That was way back in the 80's and I don't know if anything came of it.
 

malipa

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Nope.. Flex is bad for you aerodynamic efficiency, because it decreases aspect ratio and therefore increases drag and decreases lift. The reason I guess is the age difference, because Airbus could use more advanced technology to make it stiffer and keep weight down... the whole reason the 787 flexes more is because the weight would increase more and would have a worse efficiency factor than the extra drag. Because of new technology Airbus can form its wing into a more preferred shape :p
 

fredymac

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malipa said:
Nope.. Flex is bad for you aerodynamic efficiency, because it decreases aspect ratio and therefore increases drag and decreases lift. The reason I guess is the age difference, because Airbus could use more advanced technology to make it stiffer and keep weight down... the whole reason the 787 flexes more is because the weight would increase more and would have a worse efficiency factor than the extra drag. Because of new technology Airbus can form its wing into a more preferred shape :p

I'm no aeronautical engineer (optics is my trade) so I just tend to observe general design behavior. I notice that gliders (especially high performance) have very flexy wings as did Burt Rutan's high aspect designs. The general principle of strong only where needed allowed you to play games with the physical properties (and save weight).
 

red admiral

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Perhaps greater usage of adaptive use of trailing edge devices to modify lift distribution on the A350?
 

malipa

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I'm a student Aerospace engineering :p The thing about high aspect designs is that they tend to be quite bendy, and if they aren't they will break under turbulence and flutter. These designs are actually quite fragile and hard to design. The use of CFRP make it some what easier (look at the aspect ratio of the 777X/A350/787 wings against the 747-8, 777-300er or A380 with aluminum wings). But in the end it is still a novel technique. (And they still need to find out where to use what material...)
 

hesham

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Hi,

here is the Airbus A.350 XWB family.

http://www.fzt.haw-hamburg.de/pers/Scholz/dglr/hh/text_2007_09_20_A350XWB.pdf
 

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