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A350XWB, the Plane Airbus Did Not Want To Build, Makes Maiden Flight
McGruber writes "The BBC reports that the Airbus A350XWB (extra wide body) has made its first flight. Like the Boeing 787, the A350 offers airlines the chance to combine long-range services with improved fuel efficiency. The A350's fuselage is made of carbon fibre reinforced plastic, while many other parts of the aircraft use titanium and advanced alloys to save weight. It also has state-of-the-art aerodynamics, and engine manufacturer Rolls Royce has produced a new custom-designed power unit. Airbus claims that all of this means the A350 will use 25% less fuel than the current generation of equivalent aircraft. It also points out that noise and emissions will be well below current limits."
I would hope so! Aircraft last a long time due to the careful maintenance.
It's hard to get excited about a plane that exists only in response to another, and was then a victim of design by committee.
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Does any manufacturer really want to design new planes? The engineers do, it's their job & mostly their passion but the shareholders won't want to if they don't have to. Every time you design a new aircraft you commit to billions of investment and lots of risk, both financial and technical.
The saying I was most often quoted in my aerospace degree "How do you make a small fortune? Start with a large fortune and invest in aerospace".
The best that you'll probably get is that once it becomes clear that a planned development needs to start that the shareholders decide to go all-out for it, and the rest of the company commit to it 100%.
Accidental airplane? What happened? Airbus couldn't find a plane sized condom?
Who wants to fly in a plane the manufacturer didn't want to build? Way to announce a new product!
This issue is a bit more complicated than you think.
- The A350 offers airlines the chance to combine long-range services with improved fuel efficiency.
- The A350's fuselage is made of carbon fibre reinforced plastic, while many other parts of the aircraft use titanium and advanced alloys to save weight.
- It also has state-of-the-art aerodynamics
- Engine manufacturer Rolls Royce has produced a new custom-designed power unit.
- The A350 will use 25% less fuel than the current generation of equivalent aircraft, and noise and emissions will be well below current limits.
Hmm... So, with all those benefits, why didn't Airbus want to build it?
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25% less fuel is sure to be passed on as a cost savings to the customer, amiright?
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First flight?
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Its great to see aircraft builders embrace composites. Although I am curious about how long lived these aircraft bodies will be compared to metal ones.
It would be cool is rocket builders were the next to use composites for bodies like the high powered rocketry hobby has with carbon fiber but that might be asking for too much since the stresses on large rockets are large.
Here's to hoping they picked a slightly less volatile set of batteries.
Why would they not want to build it? With the troubles Boeing is having, it may their best chance at making their name as THE provider of fully functional aircraft.
Don't blame me for redundant posts. I can't type very fast. Hence the user ID.
It's a technical term. See: http://en.wikipedia.org/wiki/Wide-body_aircraft
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Since these planes won't suffer from metal fatigue like planes made out of aluminum, that means that they'll last longer?
the plane airbus did not want to build at the time, as they were busy with the A380
Good people go to bed earlier.
Theoretically, yes. In practice, airliners can easily make into into their 20s before reaching their practical end of life, longer if they're not cycled a lot. Many don't survive that long in 1st tier airlines, though.
Yes, you're right. It's meant to differentiate it from the original A350 concept (A330 with new engines, basically), which would've been narrower.
Absolutely, however the thousands of lbs of jet fuel that fill the wings and body are much more flammable. Any fire that would risk burning the composite structure of the aircraft would already be equally deadly in an aluminum aircraft.
These planes will still be flying in the 2030s.
Since these planes won't suffer from metal fatigue like planes made out of aluminum, that means that they'll last longer?
Metal aircraft don't necessarily have to suffer so badly from metal fatigue that they have to be replaced inside of 15-20 years. Fatigue depends on usage patterns and there are 747 still flying after 30 years of regular use and with good maintenance should be able to last at least the better part of another decade. USAF engineering studies project that their B-52 fleet would not reach the fatigue limits of it's wing structure until the 2040s but keep in mind these B-52s do not get flow as hard as the 747. The B-52s that are now in service left the factory in the mid 1960s. An American airforce veteran I met a few years ago told me that there are actually cases of the third generation of soldiers from a military family flying B-52s. Dunno if that's true but theoretically it sure could be. Just about the only criticism you can throw at the B-52 is that it could do with an upgrade to more modern fuel efficient engines which Boeing estimated would increase it's already impressive loiter capability by 46%.
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If you are talking about the 787 the A350 is not really in the same weight category. The A350 airplane is a lot larger and competes with the 777.
Metal fatigue in airliners is driven by several factors: humidity of the air in which they are operated (for example planes the spend their lives in Hawaii suffer more than planes that operate mostly in the southwest of the US) the number of pressurization cycles (the fuselage acts like a balloon.... the structure inflates a bit when pressurized and relaxes when below approx 8000 ft... therefore planes that spend most of their hours on long flights last longer than those that have fewer flight hours but made many short flights) plus the usual mechanical (bending)stresses any plane would experience.
Composites are not immune to stress and failure... they are just different. Composites are less sensitive to moisture (which means dreamliners can have more comfortable moister cabin air without contributing to structural wear) they handle the pressurization cycles better (so planes like the dreamliner can pressurize their cabins more to make passengers more comfortable at altitude) and so on. Composites also have an interesting thermal reaction: they soften a bit in heat (making them slightly less-suited to hot weather ... a possible issue on the ground in hot places, but not at altitude where it's cold even over the equator) but they actually get stronger as they get colder (so composite planes are actually stronger and safer at high altitudes). Composites are made of various fibers embedded in various types of plastics (resins) and their strength comes from the fibers as long as the plastic holds those fibers together properly... but the resins are much more sensitive to heat and particularly sunlight than metal. How the resins will hold-up after 20+ years of high-altitude exposure to the sun (higher UV etc) is a bit of a question... materials science people can simulate this stuff, but nothing beats real-world exposure and real-world operating conditions. If those resins age poorly and become crumbly (and less sticky, therefore less able to hold the fibers in place) then these airframes will have shorter service lives.... but they will still probably win-out because of all the monetary savings that their increased efficiencies provide during those service lives
it was originally designed to fly very long flights at high altitudes (one pressurization/depressurization cycle per large number of flight hours) which would allow a long airframe life. They're not tactical aircraft.... they are intercontinental bombers. Even after Soviet anti-aircraft missiles improved in their ability vs high-fliers and B-52 plans were re-aligned for low-altitude strikes... they still involved very long flights and few pressure cycles. 20 years of B-52 operations probably inflate/deflate the fuselage as much as 3 or 4 years of airliner activity. Most machines that are lightly-used and well-maintained will last a long time. The B-52 is is a brilliant design for its day... but it's obsolete and while it would not fare well penetrating Russian defenses in 2013, it's still fine for bombing bronze-age targets into the stone-age; it's therefore still useful given the targets that are being bombed these days.
Theoretical life vs commercial life. There are plenty of A340-500/600s that have no remaining commercial value beyond parts, with less than 6-7 years of service.
And as for the /. summary, it is a carbon skin on Al-Li frame for the fuselage, not a carbon fuselage.
metal fatigue is not so much a function age, it's more a function of usage. if a plane has a design life of 20,000 takeoff cycles, it will last 30 years of being flown twice a day 300 days a year. if it's only being flown a couple of times a month, you can do the math. and with the b52 largely obsolete and usage therefore declining, lifetime limitation caused by metal fatigue becomes more and more remote as other factors like corrosion take precedence.
One other problem is our knowledge of Metal Fatigue has increased greatly since the B-52 as have alloy advancements but most importantly our ability to mathematically assess stress and its affects are beyond the imagination of the B-52 designers thanks to the computer age. Anyway, when people designed the B-52 they really didn't know how much aluminum would be needed in a certain stress/flex area to prevent metal fatigue failure which had hunted some previous airframe designs and even some later ones. Why is the extra knowledge bad for the life span of newer A/Cs? because they know when they need more metals to prevent fatigue to get the desired design life span but also when to use less metal while knowing that it will last 30,000 cycles but might not last 40,000 cycles. This knowledge leads to better fuel economy and performance trough sacrificing A/C life span. The fuel economy probably is probably a net financial gain for the operators and even this can be counted out. So today's designed are more likely to make their intended service life without any problems but not very likely to go well beyond it.
Fatigue still happens in these materials but it's not as bad as with Aluminium - needs higher stresses to start cracks and there's a few ways the materials halt crack growth. Finding cracks is a bit less trivial but there are still ways to find them and see if they are big enough to be a problem.
Great headline, mediocre summary. Typical Slashdot.
Follow the journalistic practice of the inverted pyramid. It's a widespread tradition among news reporters for a reason.
The headline should tell the whole story. If I wanted, I could read all the headlines in a newspaper and know all the stories. Just not the details.
The first sentence, the lead, should tell the story, a little bit more, perhaps, than the headline, or at least in fully grammatical instead of clipped English. If I wanted, I could read all the headlines and leads in a newspaper and know all the stories. Just not the details.
The first paragraph should tell the whole story, beginning, middle, and end. If I wanted, I could read all the first paragraphs in a newspaper and know all the stories. Just not every detail.
The following paragraphs should present details, the most important first, the smallest, least meaningful details in the last sentence of the last paragraph, so that at any moment I could stop reading and still have the complete story. Just not every tedious last detail.
Again, the poster did it beautifully in the headline, but the summary paragraph left out the juiciest part. Why did Airbus not want to build this plane? It didn't have to go into all the details. That's the job of the linked article. But one sentence, or even half a sentence, would suffice. For example:
The BBC reports that the Airbus A350XWB (extra wide body) has made its first flight. Like the Boeing 787, the A350 offers airlines the chance to combine long-range services with improved fuel efficiency. But at first Airbus did not want to build it, because it was already overbudget and late on another airplane, the A380. But Airbus needed an answer to Boeing's new Dreamliner. The A350's fuselage is made of carbon fibre reinforced plastic, while many other parts of the aircraft use titanium and advanced alloys to save weight. It also has state-of-the-art aerodynamics, and engine manufacturer Rolls Royce has produced a new custom-designed power unit.
Something like that.
On the other hand, carbon composites often suffer slow degradation and eventual delamination through simple sun exposure.
The Sonic Cruiser would not have been supersonic - it would only have flown at almost the speed of sound to avoid causing a sonic boom. The slightly shorter flight times on long-haul routes would not have made the necessary ticket premiums appealing enough for passengers (or so airlines presumed). And your missile theory is flat out ridiculous - do you think commercial airliners can get anywhere near their maximum speed at lower air pressures? At lower altitudes the Sonic Cruiser would not have been able to fly any faster than other airliners. Furthermore, all aircraft designed after 9/11 have better security features by default so any jihadists making a new hijacking attempt will be sure to choose an older model.
Simple UV exposure can be effectively eliminated with simple paint.
An extra dose of UV blockers/stabilizers in the top resin coat(s) can do most of the job too.
Indeed, they do paint them... for precisely this reason. Have you noticed the new American Airlines paint scheme? For many years they have had nice shiny unpainted aluminum bodies as part of their image, but with the 787 being all composites that would not be possible.... so their new corporate image includes an aircraft paint scheme that will work on composite aircraft; they are planning to paint gray where they used to have shiny metal.
No paint is a perfect UV reflector, however.... some sunlight will get through, particularly at high altitudes where there is much more intensity (less atmosphere above to block it). This is certainly not a show-stopper... it just puts some uncertainty into the lifespan of these products which is similar to the uncertainty we had when we started mass-producing aluminum airplanes; with the passage of years and lots of experience across many airline fleets in many parts of the world and in many conditions we will learn, both the limits of current composites, and ways to make them better
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I'm a stress engineer working on the forward fuselage (S13/14) for build standards MSN5 and MSN17 and the skin, stringers, and frames are all carbon fibre. It's a shame you've been moderated to 5 because you're wrong. You also seem to be confusing frame with frame*s*. There isn't a frame with a skin just wrapped around for aerodynamics; the stringers and frames are there to stop the skin buckling and the skin takes most of the loads.
It's more about propagation of delaminations rather than cracks.
That's nice, but I have no idea what plane you're talking about.
That is effectively the same thing (really just a specific type of cracking) so please don't bring it up to confuse readers that have no background in materials science.
Ha, I never though of delaminations as being cracks; but yeah, now I can see that it's a cleaving between plies. Good thing I'm a static stress guy rather than Fatigue and Damage Tolerance :)
Correct, I am not excited about Microsoft.
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While I'm aware of the size difference, the A350 is still a response to the technologies used in the Dreamliner. It's less a direct market competitor than a direct company-to-company statement of "yes, we can build big things from composites too."
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I wish you were wrong.
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