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Boeing's New 787 Wings — Amazingly Flexible
An anonymous reader writes "Boeing is making the wings of its new 787 out of carbon fiber instead of metal. That means the wings are so strong and flexible that they could bend upward and touch above the fuselage — or come close. The company is expected to deliver the first 787 to All Nippon Airlines in May 2008. 'Boeing has completed static testing of a three-quarter wingbox, but engineers are still considering whether to limit testing of the full wing to a 150% load limit held for 3 sec. or to continue bending it to see when it breaks. 'There's a raging debate within the engineering team to see if we should break it or not,' says [787 General Manager Mike] Bair.'" They have come a long way in wing flexibility.
Breaking it isn't necessary for certification, but Bair says the wing is so strong and flexible that there's been talk that maybe it could be bend far enough for the wingtips to touch above the fuselage--or come quite close.
From the article:
No one's ever really tried that before, so testing is critical.
Since this seems like such a new concept (please correct me if I'm wrong; I don't follow plane technology too much), it would just seem prudent to try bending the wings until they break... how can they make accurate judgments and calculations without knowing exactly how much stress the wings can take before snapping?
You could, instead of downright trying to see how much it will take, try to get it up to 200% (or something, I'm not an aerospace engineer) and see for how long it can hold up to extremes like that. Might be more valuable data. Maybe someone more in the know can elaborate.
The 787 will be the envy of "tuner" kidz everywhere with it's carbon fiber wings.
If only one could find a 4ft diameter chrome exhaust tip...
Pull them back, let them go, and... BOEINNNNG!
Of course, having the wings be flexible is a good thing, but the real important part here is that they are made of carbon fiber. Carbon fiber is much less dense than metal, which reduces the weight of the plane. If the surface area of the wings is held constant, then fuel consumption can be reduced significantly, as the downward pull of gravity is shrunk as well.
If any article screams out for a Slashdot poll, this one is it.
1. Chicken out and don't break 'em
2. See how far they go and post it to YouTube
3. Orinthop mode! Pull 'em back and let 'em flap!
4. Cowboy Neal
Learning HOW to think is more important than learning WHAT to think.
Airbus: Care for some metal wings?
Boeing Client: No, thank you, I take them flexible, like my women.
No, you are wrong. Boeing use good old US carbon fiber, while the Europeans use that low rent carbon fibre stuff. No comparison at all. Carbon fibre comes in litres and the fibre length is in metres, while carbon fiber comes in gallons (or perhaps liters) and fibers are measured in feet, (or perhaps meters). See how easy they are to distinguish?
Pining for the fjords
Does it really matter if, because of how they are bent, you lose lift?
You are joking, right? Assembly of the first A350 won't even begin for about 5 years. It's not at design freeze. The 787 is about to roll out, and first flight is in a few months.
...as long as they post a video of it on their website!
Insisting on "correct" English is like saying that there is only one, definitive recipe for chili.
Am I going to be the first person here to think these engineers sound like they're just having way too much fun with this?
Also I wonder what would break first, the wing, or the connection to the plane. I'm expecting the video to hit the internet in about a week.
Both companies have been using carbon fiber. The 787 uses an unprecedented amount of it. You can't say it's nothing new by citing an Airbus project that doesn't have a scheduled delivery until 2013. http://en.wikipedia.org/wiki/Airbus_A350
"They have come a long way from even just a year ago."
The linked video may have been uploded about a year ago, but it cites as its source a PBS production from 1995. (Which, incidentally, is discussing an entirely different airplane, the 777.)
With reasonable men I will reason; with humane men I will plead; but to tyrants I will give no quarter. -- William Lloyd
Anyone notice that the "year ago" was a video of "Boeing 777 Wing Ultimate Load Test"
Anyone notice that the date on the file is 1/14/1995?
The implication that this was a 787 wing in test a year ago - is in error....
The point of the 787 is to fly further, more cheaply. So while costing less to fly, it is also supposed to do to the Pacific what the Boeing 767 did to the Atlantic market. That is, the 767 brought in a revolution of being able to connect mid-sized cities on both continents, rather than forcing people to go through hubs on larger aircraft such as the 747 or DC-10.
Thin flexible wings date back to the Boeing B-47. Up until this plane appeared in 1947, planes tended to have thick rigid wing structures. Advances in aeronautics, fluid dynamics, and structure design enabled engineers to create thin flexible swept wings that offered lower drag at high speed without flutter or breakage. The wings of B-47 (and B-52) were so floppy, they needed outrigger wheels to keep the wings from dragging on the ground during landings and take-offs.
Two wrongs don't make a right, but three lefts do.
A bit of wisdom from a Retired Boeing exec who I forgot the name of.
The story was about one of the earlier Boeing's, they had stressed the wing to like 10 times any theoretical force that could be possibly placed on it during a rather publicized testing of its strength. They test folks were all about trying to break it.
During the process of doing this an exec asked them what they were doing. "Breaking the wing" they replied.
The exec said No, stop the testing.
Why? the testers asked.
Because the headline won't read ,
"Boeing wing breaks at 40 times the stress encountered during possible flight conditions",
Instead it will read
"New wing of new Boeing Jet Breaks".
Please note Its been awhile since I heard that story, but I think the point is pretty clear.
You mad
This would make one heck of a good video for Youtube would if it's done right. I would be very interested to watch the test accompanied by the 1812 overture with the wings snapping in a spectacular fashion just as the drums hit! Oh, and add two squirrels and a cat fighting to the video. And while you're at it add lightsabers and two chicks kissing. Now that would make a good video!
load "$",8,1
Airplane wings flex quite a bit more than you'd expect. Airliners.net has a great head-on shot of a 747 taking off that shows the wingtips flexed up higher than the fuselage. Kinda freaky looking.
When you have nothing left to burn you must set yourself on fire
The actual requirement from Title 14, Code of Federal Regulations, Part 25, Subpart C, paragraph 303 is where ultimate load definition comes from:
Unless otherwise specified, a factor of safety of 1.5 must be applied to the prescribed limit load which are considered external loads on the structure. When a loading condition is prescribed in terms of ultimate loads, a factor of safety need not be applied unless otherwise specified
The three second requirement comes out of paragraph 305(b):
(b) The structure must be able to support ultimate loads without failure for at least 3 seconds. However, when proof of strength is shown by dynamic tests simulating actual load conditions, the 3-second limit does not apply. Static tests conducted to ultimate load must include the ultimate deflections and ultimate deformation induced by the loading. When analytical methods are used to show compliance with the ultimate load strength requirements, it must be shown that--
(1) The effects of deformation are not significant;
(2) The deformations involved are fully accounted for in the analysis; or
(3) The methods and assumptions used are sufficient to cover the effects of these deformations.
If our intrepid engineers manage to test to 200% for 3 second, then somebody is going to come along and say, "let's see if we can make the wings lighter"
Good thing or bad thing?....depends upon your point of view I guess.
As it turns out, validating airframe structures with respect to FAA airworthiness requirements is kinda what I do for a living.
A goal is a dream with a deadline
No, not really. The A350 is currently under development, well behind the development of the 787, which will be released first.
It's true that the A350 will use composites, but to imply that Boeing is trailing Airbus on this ("Nothing new") when Airbus is actually trailing Boeing is just inaccurate.
>Or you could, you know, give up a disgusting habit that is poisoning you.
What? Give up slashdot? Never. I'll die first.
Open Source Drum Kit, LPLC deve board - mjhdesigns.com
I want to see the 787 do the Y-M-C-A :)
You are joking, right? Assembly of the first A350 won't even begin for about 5 years. It's not at design freeze. The 787 is about to roll out, and first flight is in a few months.
Yeah, it kind of reminds me of when Airbus called Boeing's composite barrel design "old fashioned"!
Bearing in mind that nobody has produced such a design yet, including Airbus. Until Boeing did it a couple of weeks ago, that is.
The A350 was designed in direct response to the 787, which surprised Airbus in the amount of interest it received (they had at the time placed their bets on the now-troubled A380 program, which may never break even). Saying the 787 copied any of the A350's design or construction methods is getting it completely backwards.
The engineers at Boeing are smart enough to design the wing for optimal performance under normal conditions. That includes whatever wing bending occurs under nominal conditions.
If the aircraft is experiencing extreme conditions which are bending the wing excessively, then you _want_ to lose lift, rather than stress the wing and airframe more. Kind of like how sailors change to smaller sails during storms.
"National Security is the chief cause of national insecurity." - Celine's First Law
Ladies and Gentlemen, this is your captain speaking... If you take a look out the windows on the left side of the plane, you will notice our right wing....
The above comments are not guaranteed to make sense to anyone other than the author...
The fact that the 787 is a "plastic airplane" will get a lot of play, and having wings that bend, potentially to the point that they will tough, is just the most obvious and mediagenic manifestation of that. But it is just the tip of the iceberg of the innovations.
1) Yes, it's almost completely carbon fiber. This means that the plane can (and is) lighter, so it will be more fuel efficient. Also, it's easy to make complex curved shapes, so the wings and fuselage are slightly more aerodynamic. Because carbon fiber structures are so strong, the windows can be larger, and the plane can be pressurized to a lower altitude (it will be pressurized to 6000' instead of the typical 8000' of today's fleet). There is no corrosion, and little worry about fatigue in composites.
2) The plane is not built in Seattle, although that's where the final assembly takes place. All of the building takes place in multiple facilities around the globe, each producing parts to Boeing's plans. These parts will "snap together" in the Everett plant. The first 787 is being assembled right now, and will roll out on 7/8/7 (just over a week from now.) Apparently the left wing was off by 2 thousands of an inch or so, the right wing was absolutely perfect. Boeing converted three 747's to be gigantic cargo transporters to move all the parts from around the world to Everett.
3) The plane has almost completely electric, without the high-pressure pneumatic systems that older planes had. In particular, the AC systems are electric. This will be somewhat more efficient, and safer.
4) The plan for certification of the plane is borderline insane. The final assembly started a couple of weeks ago, and the plane will be rolled out in a week, the first flight will be in a couple of months, and the first delivery will be in Q2 2008. This is a tiny fraction of the time this process required on previous airplanes -- maybe 1/4 the time of the 777 and even less than that of the latest Airbus. This would be remarkable, even if the plane wasn't revolutionary in every other way, too!
5) Aviation Week and Space Technology visited the final assembly line recently, and were surprised to find that it was almost an empty building. That's not because they weren't ready -- that's because there are almost no tools needed to assemble the plane. They snap together the pieces, install the landing gear, and roll it down the building on its gear installing the various subassemblies. Boeing intends to assemble a plane every three days once they get going, a remarkable and unprecedented schedule.
Anyway -- there are so many revolutions in this airplane that I would have thought it was a scam if it was any other company than Boeing. It remains to be seen if they can meet their goals, but so far things are going remarkably according to the plan they laid out a few years ago.
Thad
I love Mondays. On a Monday, anything is possible.
I am an aerospace engineer, however i am a propulsion engineer and not a structures guy. Ill try to add some light on the subject.
First off the requirement is a 1.5 saftey factor, ie 1.5 times greater load on the wings then they would encounter during operations. In the past, wings were always broken on new planes. Not only is this fun (engineers do like breaking things, its true), but it provides very useful data to validate your computer models and test methodology. Not often does an engineer get to shatter such an expensive and large article! Predicting before hand when a wing will snap can be very useful on future airplane designs to optimize the structural layout. Remember, any load past the 1.5 saftey factor just means you made the wing too strong, and thus it has extra weight!
Now a days, the structural FEMs (finite element models) and load definitions from CFD (Computational Fluid Dynamics) have become so good, that its not necessary to validate the tools. They have been validated before, and there is a high level of confidence. Someone mentioned above me that these wings were different since they are composite, but in fact commercial airplanes have had composites in the wings for a long time. The military has been making nearly all composite airplanes for even longer.
The A380 from Airbus ran into trouble a few years ago, as they designed the wing for 1.5 load factor, but on testing it only made it to 1.48. Hence they had to add extra weight and strengthen it. But being that they aimed for 1.5 and got to 1.48 shows you how accurate the tools have become.
There might also be a cost element in this decision. I believe Boeing could potentially use that model for some other purpose, whether it be passenger escape tests, wing fuel fire tests, wing fatigue tests, or maybe even just for a model to sit in a hanger somewhere and generate PR. Personally, im hoping to see a great video on YouTube of those wings splintering into pieces!
...a perfectly engineered wing would break at 150.000001% Anything stronger is over-engineered and represents an unnecessary weight penalty. (Other versions of the 777 video make this same point; the engineers were sweating the fact that the wing did NOT break at 151, 152 or 153) The reason for breaking the 787 wing is to prove that it is not over-engineered. The problem is the geometry of the carbon fiber wing flexion may allow the tips to flex and touch without representing meaningful aerodynamic loading. Once you've pulled the tips past vertical you've entered he realm of the hoop wing and exited the realm of meaningful testing and data.
"carbon brake discs are about to be banned from Formula-1 car races because many drivers are already ill."
Neither of the points addressed in that sentence are true. Since the guy who responded on a fucking blog is now a proven liar, why do you think anything else he says is reliable?
Take a look here. There was a 1.5 inch difference in the diameter of the Section 41 (nose and cockpit) and the Section 43 (forward fuselage, where the forward entry door is). The parts are made in Wichita and Charleston, SC. They have managed to join them now, but the job was "challenging".
Now I am an engineer at an aircraft MRO. Once these things hit more than 15 years old, there are going to be a million problems with this fuselage. Carbon fibre is a very different beast to aluminium, or even fibreglass. For one, the carbon is a conductor of electricity, which can lead to galvanic corrosion (the circumferential frames are still aluminium, there are still metallic fasteners going through the skin to attach them). Also, repairs are going to be an absolute bitch.
Twice in the last month, we have had to fix large holes in the side of aircraft due to trucks driving into the side of them. These incidents happened at outstations (where there were no major repair facilities) and we had to send out a small team to assess and repair the damage. In both instances these were done by a repair engineer, inspector and a couple of sheet metal workers in a couple of days. They took a sheet of metal, an air compressor and a bucket of rivets.
Currently, composites are used on a number of components on almost all aircraft. Invariably they are removable components, like flight control surfaces, or fairings. In order to repair them, they are usually removed from the aircraft and repaired in a composites shop, where temperature and humidity can be controlled - preferably in an autoclave.
Now, how the hell is anyone going to remove a fuselage section to drag it into a shop?
In fact, there is a seperate "limit load" test that is performed at 100% and must show no detrimental permanent deformation. It is not unheard of that a structure will pass the ultimate load test yet fail the limit load test because of this criterion even though the limit load is smaller.
A goal is a dream with a deadline
The first time this was really driven home to me was in undergraduate school in '88. A classmate was working on a portable carbon-fiber bridge project for the Army. It had to support the weight of a main battle tank crossing it. In the full-scale test demo, the general overseeing the project commented that you'd get one and only one tank crew to cross the bridge. He felt that after the other tank crews saw how much the bridge flexed, there was no way they'd want to drive on it.
Actually, there was not a different in diameter. It's just that one of the cylinders hadn't been supported properly for a couple days and became oblate. It was still the right size, just not the right shape. So they jacked it back into shape and connected it. It wasn't difficult.
Your comments about holes in planes ("ramp rash") are also off base. Boeing has two patch kits, one which can be applied in a very short time, the other which takes something like 36 hours to cure. Boeing has shown to the airlines that fixing small holes from collisions with trucks won't be a problem.
http://lkml.org/lkml/2005/8/20/95
It's a BAD THING to have wings flexing. You lose aileron control effectiveness. You lose lift. The engines get off axis and lose intake efficiency. The flight envelope warps. The wings might be able to flex, but all the contained torque tubes, wiring ducts, landing gear, tanks, pipes, motors and valves have to be specially designed to tolerate the flexing.
What the heck are you talking about?
Nothing about the wing flexing causes a loss of lift, aileron effectiveness, or engine intake efficiency unless the wing flexes in such a direction to it.
You can also flex in such a way as to increase lift, aileron effectiveness, or engine intake efficiency.
Wing flex is actually a good thing from a turbulence and sudden control input perspective. But you're right in saying the infrastructure in the wing would have to tolerate the flexing as well.
All opinions presented here aren't mine.
Man, the first half of your comment is cool but the second half pulled me out of lurker mode to comment.
Why can't you develop a means of not smoking in public places? I personally could care less if you want to feed your nicotine addiction by smoking tobacco or shooting it, or whether you'd like to chew fiberglass or smoke arsenic in your spare time. But for the rest of us who find the smell and smog offensive and the thought of even more lethal second-hand smoke less than attractive, please abstain. Especially in crowded areas like airports.
Have you ever been to Frankfurt? After my last couple visits I'll be routing flights around it if for no other reasons than that it smells like a truck stop. Wait, I'll take that back as it's unfair to the last couple of truck stops I've been to.
I've seen smoking booths and umbrella/fume hood lounge arrangements in airports, and as a non-smoker I've got to say that it just doesn't work.
In 1969 I went to work for Boeing at their 747 plant in Everett. A monumentally huge plant, each of its two assembly lines could roll out a 747 every 7 days. All wings were fabricated on-site using the latest technologies: laser-aligned jigs and robotic rivet machines. They had such stiffness and strength that the wingtips in the static test facility could reportedly be pushed & pulled upwards by hydraulic rams & cables more than 30 feet above their nominal resting levels before the first components started to fail (spars deforming, rivets shearing, ...). I don't know how many G's would be required to produce that much deflection, but I'm sure the number would be more common to modern fighter aircraft than airliners. I've never felt safer than when flying in a 747. If the 787 carbon fiber wing really outperforms a 747's aluminum "slab", I'm going to enjoy flying on the new bird.
The Mythbusters school of aeronautical engineering?
Here are new photos of the first 787 before paint.
787 Photos
30% off web hosting. Coupon code "SLASHDOT".
What is the point of having all that cool test equipment and cameras if you can't break stuff ?!?
;)
hehe, 30 years later i still remember a trip to the local power station that had the test equipment for powerlines and stuff. They crushed a large ceramic insulator til it blew up. Took some insane amount of pressure like 20000 psi. Quite spectacular. They had a rig for pulling apart a powerline too, we would have killed for that test
I was under the impression that carbon fiber was actually renowned for being inflexible and tending to shatter, rather than deform (at least from my experience with motorcycle fairings and carbon fiber rims). Is there a less-rigid mix of CF? If so, why is it not used in racing products?
hers a linky to the rollout of the dreamliner in the middle of the nightb ID=2642&page=1>itle=First%20787%20Dreamliner%20& css=gtitle.css&pubdate=06/26/2007
http://seattlepi.nwsource.com/photos/popup.asp?Su