User avatar
Stitch
Topic Author
Posts: 22920
Joined: Wed Jul 06, 2005 4:26 am

Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 2:22 am

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
 
n710ps
Posts: 1117
Joined: Tue Oct 10, 2006 7:09 am

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 2:27 am

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!
 
ShyFlyer
Posts: 4698
Joined: Fri Jun 19, 2009 11:38 pm

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 2:30 am

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

 checkmark 

Besides, wouldn't it be destroyed/scrapped after certification anyway?
I lift things up and put them down.
 
norcal
Posts: 1507
Joined: Sun Mar 20, 2005 1:44 am

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 3:40 am

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?
 
OldAeroGuy
Posts: 3183
Joined: Sun Dec 05, 2004 6:50 am

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 4:26 am

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
 
redflyer
Posts: 3881
Joined: Thu Feb 24, 2005 3:30 am

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 5:57 am

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
 
N231YE
Posts: 2620
Joined: Tue Jul 25, 2006 9:24 am

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 6:11 am

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...
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 6:17 am



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
 
KELPkid
Posts: 5247
Joined: Wed Nov 02, 2005 5:33 am

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 6:58 am

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 :-)
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 7:15 am



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
 
Boeing7E7
Posts: 5512
Joined: Sat Jul 31, 2004 9:35 pm

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 8:52 am

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.
 
Boston92
Posts: 2553
Joined: Wed Aug 09, 2006 6:56 am

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 12:31 pm

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 avatar
HAWK21M
Posts: 29867
Joined: Fri Jan 05, 2001 10:05 pm

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 6:34 pm

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
I may not win often, but I damn well never lose!!! ;)
 
Sinlock
Posts: 1631
Joined: Fri Dec 22, 2000 12:55 am

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 9:43 pm

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.
 
OldAeroGuy
Posts: 3183
Joined: Sun Dec 05, 2004 6:50 am

RE: Boeing May Not Test 787 Wing To Destruction

Wed May 30, 2007 11:49 pm

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
 
Starglider
Posts: 657
Joined: Sun Oct 01, 2006 12:19 am

RE: Boeing May Not Test 787 Wing To Destruction

Thu May 31, 2007 5:12 am

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
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Boeing May Not Test 787 Wing To Destruction

Thu May 31, 2007 5:26 am




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
 
Fly2HMO
Posts: 7207
Joined: Sat Jan 24, 2004 12:14 pm

RE: Boeing May Not Test 787 Wing To Destruction

Thu May 31, 2007 6:06 am

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 
 
2H4
Posts: 7960
Joined: Tue Oct 19, 2004 11:11 pm

RE: Boeing May Not Test 787 Wing To Destruction

Thu May 31, 2007 6:31 am




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
 
iwok
Posts: 979
Joined: Wed Jan 26, 2005 2:35 pm

RE: Boeing May Not Test 787 Wing To Destruction

Thu May 31, 2007 2:43 pm

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
 
Sinlock
Posts: 1631
Joined: Fri Dec 22, 2000 12:55 am

RE: Boeing May Not Test 787 Wing To Destruction

Thu May 31, 2007 10:02 pm

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?
 
OldAeroGuy
Posts: 3183
Joined: Sun Dec 05, 2004 6:50 am

RE: Boeing May Not Test 787 Wing To Destruction

Thu May 31, 2007 11:38 pm

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
 
redflyer
Posts: 3881
Joined: Thu Feb 24, 2005 3:30 am

RE: Boeing May Not Test 787 Wing To Destruction

Tue Jun 05, 2007 8:10 am

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
 
Starglider
Posts: 657
Joined: Sun Oct 01, 2006 12:19 am

RE: Boeing May Not Test 787 Wing To Destruction

Tue Jun 05, 2007 8:05 pm

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
 
SEPilot
Posts: 4913
Joined: Sat Dec 30, 2006 10:21 pm

RE: Boeing May Not Test 787 Wing To Destruction

Tue Jun 05, 2007 8:33 pm

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

Who is online

Users browsing this forum: bohica, Kickert and 21 guests