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.

Comments

I hope they test it!

[chris098]

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?

Re:I hope they test it!

[trolltalk.com]

They might as well - its not like they can then just stick it on a production model and sell it, since its already been over-stressed. Any failure post-production would bring HUGE lawsuits.

Re:I hope they test it!

[morgan_greywolf]

It's potentially more dangerous than an alumnium wing, 150+% of design load has to be a substantial amount of energy stored in the wing, and while aluminum will deform in failure (converting most of the energy to heat) carbon fiber seems more likely to shatter

What difference does it make if your wings shatter or merely deform? Either way, you're dead!

Re:I hope they test it!

[timeOday]

Typically, fatigue cracking has been the limiting factor in aircraft structures, and has caused numerous crashes.

That is the issue. It doesn't really matter whether the wings can bend until they touch when they are brand new. What matters is whether they will hold up after billions of tiny deflections, especially if there is a defect deep inside or as they get chipped, etc.

Re:I hope they test it!

[Firethorn]

Yes, but from my reading, it's likely that the carbon fiber wing will still be intact after suffering forces that would have reduced the metal wing to a twisted, useless mess.

So, while some failure modes might be worse than traditional aluminum wings, it's also likely to be better in others.

Then it becomes a matter of risk assessment and minimization. A good example would be seatbelts - there is the occasional accident where you'd be better off without the belt, but in the vast majority of accidents you're far better off with it on.

Re:I hope they test it!

[kryten_nl]

Have you looked at comparisons between bonded and riveted aluminum yet? I bet there's a fair bit of literature comparing the two construction methods.

I'm deducing your knowledge level from your comment, forgive me if I've miscalculated.

Who cares if they bend

[Titoxd]

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.

While its great they are so flexible

[N3WBI3]

Does it really matter if, because of how they are bent, you lose lift?

Re:While its great they are so flexible

[Hoi Polloi]

If they are so flexible does this mean they could ditch ailerons and go back to the ancient days of flying and bring back wing warping?

Don't break it

[Broken scope]

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.

Re:Design accommodations?

[__aawkdb2598]

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.