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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.
In SOVIET RUSSIA... erm...NSA AMERICA, the Internet logs onto YOU!
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%.
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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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.
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.
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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Eventually I guess but the airlines need to pay off the airplanes first.
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.
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.
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.