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Boeing May Not Test 787 Wing To Destruction  
User currently offlineStitch From United States of America, joined Jul 2005, 31243 posts, RR: 85
Posted (7 years 6 months 20 hours ago) and read 5120 times:
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Quote:
...Boeing may decide not to stress the Dreamliner's plastic wings until they break.

"A decision has not yet been made to fully break the wing," said Scott Strode, vice president of 787 production. "We are still working on that."

There is no requirement that the wing actually be broken as part of the stress testing, Strode pointed out.

...Boeing and its 787 partners -- including Mitsubishi Heavy Industries, which manufacturers the 787 wing in Nagoya, Japan -- have been doing structural testing of a 787 wing for more than a year...Strode disclosed that Boeing already has stressed that wing to the required 1.5 times the limit load -- and it did not break.

http://seattlepi.nwsource.com/business/317186_wingbreak25.html

24 replies: All unread, jump to last
 
User currently offlineN710PS From United States of America, joined Oct 2006, 1166 posts, RR: 3
Reply 1, posted (7 years 6 months 20 hours ago) and read 5119 times:

I would do it if I were them. Granted they can use other numbers to get the critical stresss point numbers but why not be certain? I say break the thing. Besides I want to see it in video lol.


There is plenty of room for Gods animals, right next to the mashed potatoes!
User currently offlineShyFlyer From , joined Dec 1969, posts, RR:
Reply 2, posted (7 years 6 months 20 hours ago) and read 5109 times:

Quoting N710PS (Reply 1):
I say break the thing.

 checkmark 

Besides, wouldn't it be destroyed/scrapped after certification anyway?


User currently offlineNorCal From United States of America, joined Mar 2005, 2459 posts, RR: 5
Reply 3, posted (7 years 6 months 19 hours ago) and read 5069 times:

Let's say they do break it, but it breaks at 1.6 or 1.7 or something. Does that mean they can increase the MTOW (assuming the other parts of the aircraft like the gear can handle it) with out an increase in OEW?

User currently offlineOldAeroGuy From United States of America, joined Dec 2004, 3574 posts, RR: 67
Reply 4, posted (7 years 6 months 18 hours ago) and read 5030 times:

Quoting NorCal (Reply 3):
Let's say they do break it, but it breaks at 1.6 or 1.7 or something. Does that mean they can increase the MTOW (assuming the other parts of the aircraft like the gear can handle it) with out an increase in OEW?

Yes, depending, as you say, on the loads capability of the rest of the airplane.



Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
User currently offlineRedFlyer From United States of America, joined Feb 2005, 4376 posts, RR: 28
Reply 5, posted (7 years 6 months 16 hours ago) and read 4983 times:

I see a couple of issues with this development. The first and most obvious is, as long as the wing reaches the required 150% load without breaking, who cares if it ultimately breaks or not? We're talking certification here so if it meets the certification requirement then why break the wing, especially if it could be used for other testing purposes in the future? I'm assuming these wings, even sections of them, are not cheap and to be able to use the wing for other future (and occasionally unrelated) tests saves Boeing a lot of money.

The flip side of that argument could also be the reason that Boeing broke wings in the past. And my understanding there is that they did so to validate their engineering models. That is, they wanted to see at what point and where precisely on the wing the wing actually ruptured to prove that their engineering models were spot-on accurate. So is Boeing confident that they have their engineering model down pat, even if it is a new material they're working with?



My other home is a Piper Cherokee 180C
User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 6, posted (7 years 6 months 16 hours ago) and read 4973 times:

This is probably a side effect due to me putting 777 Wing Ultimate Load test from the 21st Century Jet documentary on the internet  smile 

Don't believe me? Check my profile and the "uploader" of the original YouTube video, also found in the article which was provided above...


User currently offline2H4 From United States of America, joined Oct 2004, 8956 posts, RR: 60
Reply 7, posted (7 years 6 months 16 hours ago) and read 4965 times:
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I wonder how the composite wing would fail....whether it would shatter and splinter, launching deadly shards of carbon into the air, or whether it would simply rupture in a contained manner....


2H4





Intentionally Left Blank
User currently offlineKELPkid From United States of America, joined Nov 2005, 6428 posts, RR: 3
Reply 8, posted (7 years 6 months 15 hours ago) and read 4942 times:

Quoting 2H4 (Reply 7):
I wonder how the composite wing would fail....whether it would shatter and splinter, launching deadly shards of carbon into the air, or whether it would simply rupture in a contained manner....


2H4


I would hazard a guess that, given the kind of "stretchy" nature of composites, it would merely remain deformed due to being stretched beyond it's elasticity point  Smile You might end up with a little more dihedral than you started the flight with Big grin



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offline2H4 From United States of America, joined Oct 2004, 8956 posts, RR: 60
Reply 9, posted (7 years 6 months 15 hours ago) and read 4927 times:
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Are airframe manufacturers required to perform similar tests downward....ie: proving that the wing can withstand 150% of the negative load limit?

Quoting KELPkid (Reply 8):
I would hazard a guess that, given the kind of "stretchy" nature of composites, it would merely remain deformed due to being stretched beyond it's elasticity point

It would certainly be interesting to see....


2H4




Intentionally Left Blank
User currently offlineBoeing7E7 From , joined Dec 1969, posts, RR:
Reply 10, posted (7 years 6 months 13 hours ago) and read 4882 times:

Quoting RedFlyer (Reply 5):
The flip side of that argument could also be the reason that Boeing broke wings in the past. And my understanding there is that they did so to validate their engineering models. That is, they wanted to see at what point and where precisely on the wing the wing actually ruptured to prove that their engineering models were spot-on accurate. So is Boeing confident that they have their engineering model down pat, even if it is a new material they're working with?

Just a hunch, maybe they don't do it before certification, but they do it afterward to validate the engineering.


User currently offlineBoston92 From United States of America, joined Aug 2006, 3390 posts, RR: 7
Reply 11, posted (7 years 6 months 10 hours ago) and read 4792 times:

Did anyone else watch Boeing show how they "test" the wings a couple weeks back on the "Today" show? I found it pretty interesting.


"Why does a slight tax increase cost you $200 and a substantial tax cut save you 30 cents?"
User currently offlineHAWK21M From India, joined Jan 2001, 31702 posts, RR: 56
Reply 12, posted (7 years 6 months 4 hours ago) and read 4715 times:

Quoting Boston92 (Reply 11):
Did anyone else watch Boeing show how they "test" the wings a couple weeks back on the "Today" show? I found it pretty interesting.

Is there a Youtube video on this,like the B777 one.
regds
MEL



Think of the brighter side!
User currently offlineSinlock From United States of America, joined Dec 2000, 1650 posts, RR: 2
Reply 13, posted (7 years 6 months 1 hour ago) and read 4675 times:

Quoting NorCal (Reply 3):
Let's say they do break it, but it breaks at 1.6 or 1.7 or something. Does that mean they can increase the MTOW (assuming the other parts of the aircraft like the gear can handle it) with out an increase in OEW?

Not really, MTOW is more directly related to the wings ability to generate lift efficiently during takeoff. As the weight go's up, higher takeoff speeds are needed to provide the needed lift due to the new higher MTOW.

In order to make use of a wing that could handle massive 7%-14% extra load you hint at 1.6 or 1.7 or something the only thing to really be done is change the flap/slat deployment layout to add more wing area, like whats been done with the 737-700ER, -900ER and 777-300ER

But if the wing was to make it to 1.6 or 1.7 it could open the possibility for Boeing to reduce the number of plys in the buildup of the wing and get a slight reduction of weight.



My Country can beat up your Country....
User currently offlineOldAeroGuy From United States of America, joined Dec 2004, 3574 posts, RR: 67
Reply 14, posted (7 years 5 months 4 weeks 1 day 23 hours ago) and read 4631 times:

Quoting Sinlock (Reply 13):
Not really, MTOW is more directly related to the wings ability to generate lift efficiently during takeoff. As the weight go's up, higher takeoff speeds are needed to provide the needed lift due to the new higher MTOW.

This is not correct. MTOW is rarely controlled by takeoff speeds. A 7% to 14% increase in takeoff weight only requires a 3.5% to 7% increase in takeoff speed. These increases in speed are normally handled by thrust increases to maintain takeoff field length or letting the takeoff field length increase. Changing wing area or revising the high lift system is rarely done to accommodate this level of weight increase.

As a case in point, consider the 772A vs the 772ER. MTOW went from 247.2t to 297.6t, an increase of 20% with no increase in wing area and no high lift system revision. There are many other examples of this type on other airplanes.

[Edited 2007-05-30 16:52:01]


Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
User currently offlineStarglider From Netherlands, joined Sep 2006, 679 posts, RR: 44
Reply 15, posted (7 years 5 months 4 weeks 1 day 17 hours ago) and read 4523 times:

Quoting 2H4 (Reply 7):
I wonder how the composite wing would fail....whether it would shatter and splinter, launching deadly shards of carbon into the air, or whether it would simply rupture in a contained manner....

If the wing would fail in that manner, i wonder how much carbon dust would be released from such a failure. Carbon fibers are good conductors of electricity. Carbon fiber dust can cause arcing and shorts in electrical equipment. Perhaps one of the less obvious reasons they may not want to test the wing to destruction?



Starglider


User currently offline2H4 From United States of America, joined Oct 2004, 8956 posts, RR: 60
Reply 16, posted (7 years 5 months 4 weeks 1 day 17 hours ago) and read 4513 times:
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DATABASE EDITOR




Quoting Starglider (Reply 15):

I would think a primary concern...as the original article suggests...would be the likelihood of an abrupt, violent, catastrophic failure damaging expensive test equipment.


2H4




Intentionally Left Blank
User currently offlineFLY2HMO From , joined Dec 1969, posts, RR:
Reply 17, posted (7 years 5 months 4 weeks 1 day 16 hours ago) and read 4480 times:

Quoting Stitch (Thread starter):
There is no requirement that the wing actually be broken as part of the stress testing, Strode pointed out

Where's the fun in that?

Quoting 2H4 (Reply 16):
...would be the likelihood of an abrupt, violent, catastrophic failure

Aren't they all very catastrophic anyways?  eyebrow 


User currently offline2H4 From United States of America, joined Oct 2004, 8956 posts, RR: 60
Reply 18, posted (7 years 5 months 4 weeks 1 day 16 hours ago) and read 4464 times:
AIRLINERS.NET CREW
DATABASE EDITOR




Quoting FLY2HMO (Reply 17):
Aren't they all very catastrophic anyways?

Heh heh...poor choice of words on my part. I was thinking more along the lines of a totally uncontained failure that would send large sections of the structure flying through the air and into equipment.


2H4




Intentionally Left Blank
User currently offlineIwok From Sweden, joined Jan 2005, 1108 posts, RR: 0
Reply 19, posted (7 years 5 months 4 weeks 1 day 8 hours ago) and read 4332 times:

Quoting 2H4 (Reply 7):
I wonder how the composite wing would fail....whether it would shatter and splinter, launching deadly shards of carbon into the air, or whether it would simply rupture in a contained manner....

I believe it basically turns into a fine mist of carbon & epoxy dust which essentially acts like "soot." It kind of gets everywhere.

-iwok


User currently offlineSinlock From United States of America, joined Dec 2000, 1650 posts, RR: 2
Reply 20, posted (7 years 5 months 4 weeks 1 day ago) and read 4216 times:

Quoting OldAeroGuy (Reply 14):
A 7% to 14% increase in takeoff weight only requires a 3.5% to 7% increase in takeoff speed.

My post did not state anything about a 7% to 14% increase in take off weight.

Quoting OldAeroGuy (Reply 14):
As a case in point, consider the 772A vs the 772ER. MTOW went from 247.2t to 297.6t, an increase of 20% with no increase in wing area and no high lift system revision.

Any chance thats because Boeing designed the -200A, -200B(ER) and future -300A on a common wing?



My Country can beat up your Country....
User currently offlineOldAeroGuy From United States of America, joined Dec 2004, 3574 posts, RR: 67
Reply 21, posted (7 years 5 months 4 weeks 23 hours ago) and read 4185 times:

Quoting Sinlock (Reply 20):
Quoting OldAeroGuy (Reply 14):
A 7% to 14% increase in takeoff weight only requires a 3.5% to 7% increase in takeoff speed.

My post did not state anything about a 7% to 14% increase in take off weight.

Aren't these your words below? If you weren't referring to takeoff weight, what did you mean?

Quoting Sinlock (Reply 13):
In order to make use of a wing that could handle massive 7%-14% extra load you hint at 1.6 or 1.7 or something the only thing to really be done is change the flap/slat deployment layout to add more wing area, like whats been done with the 737-700ER, -900ER and 777-300ER



Quoting Sinlock (Reply 20):
Quoting OldAeroGuy (Reply 14):
As a case in point, consider the 772A vs the 772ER. MTOW went from 247.2t to 297.6t, an increase of 20% with no increase in wing area and no high lift system revision.

Any chance thats because Boeing designed the -200A, -200B(ER) and future -300A on a common wing?

Any reason why you think the same won't apply to variants of the 787?



Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
User currently offlineRedFlyer From United States of America, joined Feb 2005, 4376 posts, RR: 28
Reply 22, posted (7 years 5 months 3 weeks 3 days 14 hours ago) and read 3822 times:

Quoting Boeing7E7 (Reply 10):
Just a hunch, maybe they don't do it before certification, but they do it afterward to validate the engineering.

Good hunch, and probably accurate.

Quoting Starglider (Reply 15):
If the wing would fail in that manner, i wonder how much carbon dust would be released from such a failure. Carbon fibers are good conductors of electricity. Carbon fiber dust can cause arcing and shorts in electrical equipment. Perhaps one of the less obvious reasons they may not want to test the wing to destruction?

I found this link to FI from another thread on the Civil forum. It seems the carbon fiber dust is the main reason why Boeing is hestant about breaking the wing:

"We're asking what will we gain, if anything, by taking the wing all the way to breaking point," he says, adding that one consideration is the large cost associated with cleaning up the fibrous contaminents that will result. [emphasis added]

http://www.flightglobal.com/articles...-as-first-test-airframe-comes.html



My other home is a Piper Cherokee 180C
User currently offlineStarglider From Netherlands, joined Sep 2006, 679 posts, RR: 44
Reply 23, posted (7 years 5 months 3 weeks 3 days 2 hours ago) and read 3767 times:

Quoting RedFlyer (Reply 22):
I found this link to FI from another thread on the Civil forum. It seems the carbon fiber dust is the main reason why Boeing is hestant about breaking the wing:

Thanks for the link, i had not read that particular article yet.  thumbsup 


Regards,
Starglider


User currently offlineSEPilot From United States of America, joined Dec 2006, 7019 posts, RR: 46
Reply 24, posted (7 years 5 months 3 weeks 3 days 2 hours ago) and read 3758 times:

Quoting KELPkid (Reply 8):
I would hazard a guess that, given the kind of "stretchy" nature of composites, it would merely remain deformed due to being stretched beyond it's elasticity point Smile You might end up with a little more dihedral than you started the flight with

Actually, I don't believe composites are "stretchy" at all. I have never done much with carbon fiber, but I have worked quite a bit with fiberglass. My experience is that it will bend but always come back to its original shape unless it breaks, which it usually does fairly violently, with the plastic matrix basically disintegrating into powder. I have never seen it take a permanent bend from externally applied load. This is probably related to the different fatigue characteristics of composites to metals; as unhardened steel and aluminum will plastically deform under sufficient applied load, and under repeated load less than the deformation point but above the non-fatigue point will fatigue.



The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
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