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texfly101
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A380 Wing Test

Tue May 02, 2006 8:01 am

Pardon me if this has been discussed in a prior post, but I searched and didn't see it in a Topic line. But this has been of so much interest to a lot of people on this site, I thought I would add it. In AvWeek, 5/01/2006, the following statement appeared in an article about the A350 redesign. I'm not making any challenges or conclusions, only passing along info.

"Meanwhile, Humbert says the company has determined that wing design changes will not have to be made on the A380, after a test specimen narrowly failed to meet the ultimate loads limit. An in-depth analysis has shown that the wing in question had been subject to loads in excess of the ultimate load targets ahead of the official test. Airbus found the structure was damaged in the earlier test so that it could not hold up a second time to the specified breaking point. Airbus also does not need to repeat the test, Humbert adds, because the manufacturer can demonstrate the premature rupture was caused by the earlier damage."
 
airfrnt
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RE: A380 Wing Test

Tue May 02, 2006 8:10 am

Quoting Texfly101 (Thread starter):

"Meanwhile, Humbert says the company has determined that wing design changes will not have to be made on the A380, after a test specimen narrowly failed to meet the ultimate loads limit. An in-depth analysis has shown that the wing in question had been subject to loads in excess of the ultimate load targets ahead of the official test. Airbus found the structure was damaged in the earlier test so that it could not hold up a second time to the specified breaking point. Airbus also does not need to repeat the test, Humbert adds, because the manufacturer can demonstrate the premature rupture was caused by the earlier damage."

We will see what the EU and the FAA think of that. Last I heard the FAA wasn't buying that answer.
 
ikramerica
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RE: A380 Wing Test

Tue May 02, 2006 8:18 am

That's good news as to why it failed. It is very reasonable too. But I don't know that the regulating agencies will accept it without another test. While it isn't cheap, sacrificing one more wing to prove it's fine is better than having to make modifications to all the wings and future wings in the pipeline, right?

Hopefully the agencies will accept the calculations since it was very close.
Of all the things to worry about... the Wookie has no pants.
 
antiuser
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RE: A380 Wing Test

Tue May 02, 2006 8:43 am

Maybe they'll be able to certify it by analysis, didn't GE do that with the GE90 after it failed a blade-out test?
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B777LR
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RE: A380 Wing Test

Tue May 02, 2006 9:08 am

If Airbus is pleased with the wing and it meets their requirements that is great. Though I do have to point out that this may have some after effects for the futuer growth of the aircraft. The 900 model may need some more extensive refinements done to the wing down the road when they increase the MTOW. I just hope they are not rushing to get the airplane into service.
 
magyar
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RE: A380 Wing Test

Tue May 02, 2006 1:45 pm

This sounds a bit of talking the problem away. Just repeat
that test, if nothing to fear of!
 
WingedMigrator
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RE: A380 Wing Test

Tue May 02, 2006 2:19 pm

Quoting Magyar (Reply 5):
Just repeat that test, if nothing to fear of!

If they had 50 million Euro just lying around, I'm sure they'd consider it.  Smile
 
zvezda
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RE: A380 Wing Test

Tue May 02, 2006 2:24 pm

Why on earth would Airbus overstress a wing that they knew would later be used for certification testing? It makes no sense.
 
artsyman
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RE: A380 Wing Test

Tue May 02, 2006 2:33 pm

In the day of the lawsuit hungry human, the FAA cannot just accept the word of Airbus that the wing, despite failing the test is actually fine. All it will take a wing to fail inflight, killing everyone onboard and the FAA being sued for allowing Airbus to skip the certification process...
 
dazeflight
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RE: A380 Wing Test

Tue May 02, 2006 8:22 pm

Quoting WingedMigrator (Reply 6):
If they had 50 million Euro just lying around, I'm sure they'd consider it. Smile

They surely have 50 Mio. Euro just lying around. It's more a question of the time that would be needed to conduct such a second test.

ciao
Daniel
 
MD88Captain
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RE: A380 Wing Test

Tue May 02, 2006 9:05 pm

Sorry. Your mistake. Repeat the test. Eat the cost of your mistake. Comply with the requirements that you knew were in existance before you designed the thing.
 
OldAeroGuy
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RE: A380 Wing Test

Tue May 02, 2006 10:30 pm

Quoting Antiuser (Reply 3):
Maybe they'll be able to certify it by analysis, didn't GE do that with the GE90 after it failed a blade-out test?

No, they re-ran the test.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
RichardPrice
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RE: A380 Wing Test

Tue May 02, 2006 10:51 pm

Quoting B777LR (Reply 4):
Though I do have to point out that this may have some after effects for the futuer growth of the aircraft. The 900 model may need some more extensive refinements done to the wing down the road when they increase the MTOW. I just hope they are not rushing to get the airplane into service.

The A380-900 will use the A380F wing, which has been altered for a higher MTOW iirc.
 
dazeflight
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RE: A380 Wing Test

Tue May 02, 2006 11:04 pm

Quoting MD88Captain (Reply 10):
Sorry. Your mistake. Repeat the test. Eat the cost of your mistake. Comply with the requirements that you knew were in existance before you designed the thing.

They are surely lucky that you got nothing to say when it comes to certification  Smile
 
B777LR
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RE: A380 Wing Test

Tue May 02, 2006 11:25 pm

Quoting RichardPrice (Reply 12):
The A380-900 will use the A380F wing, which has been altered for a higher MTOW iirc

Ah ok. Thank you for the correction.
 
halls120
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RE: A380 Wing Test

Wed May 03, 2006 12:14 am

Quoting Zvezda (Reply 7):
Why on earth would Airbus overstress a wing that they knew would later be used for certification testing? It makes no sense.

More importantly, why did they use a wing section they knew had been damaged for this all-important test?
"Suppose you were an idiot. And suppose you were a member of Congress. But I repeat myself." Mark Twain, a Biography
 
RichardPrice
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RE: A380 Wing Test

Wed May 03, 2006 12:17 am

Quoting Halls120 (Reply 15):
More importantly, why did they use a wing section they knew had been damaged for this all-important test?

It may have not been apparent until after all the data had been collected and analysed from the entire testing regime that the wing had exceeded the limits earlier on, it may have occured in a test where that load wasnt the primary resultset and thus wasnt looked at in much depth until after the wings failure later on.
 
Poitin
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RE: A380 Wing Test

Wed May 03, 2006 12:30 am

Quoting Artsyman (Reply 8):
In the day of the lawsuit hungry human, the FAA cannot just accept the word of Airbus that the wing, despite failing the test is actually fine. All it will take a wing to fail inflight, killing everyone onboard and the FAA being sued for allowing Airbus to skip the certification process...

While the FAA can't be sued (they are part of the government), the airline that bought the plane can. As can Airbus. And, of course, the FAA would have to answer to Congress. So, basically, the FAA will cover their butts and say "break it!"

Quoting Halls120 (Reply 15):
Quoting Zvezda (Reply 7):
Why on earth would Airbus overstress a wing that they knew would later be used for certification testing? It makes no sense.

More importantly, why did they use a wing section they knew had been damaged for this all-important test?

Let's assume that this is actually what happened and someone goofed. Now what does that say about Airbus's management? More important, what would the wolf pack of lawyers do with that in court of law?

This is a VERY bad situation for Airbus. They need to sort this out. Their best solution is to break another wing, one that is used on the production aircraft. $50 million is cheap compared to what could happen in a law suit.
Now so, have ye time fer a pint?
 
RichardPrice
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RE: A380 Wing Test

Wed May 03, 2006 12:33 am

Quoting Poitin (Reply 17):
While the FAA can't be sued (they are part of the government), the airline that bought the plane can. As can Airbus. And, of course, the FAA would have to answer to Congress. So, basically, the FAA will cover their butts and say "break it!"

The FAA can be sued, they just have to give you permission to go ahead first  Smile Same with most US governmental branches, but not all.
 
Poitin
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RE: A380 Wing Test

Wed May 03, 2006 12:41 am

Quoting RichardPrice (Reply 18):
The FAA can be sued, they just have to give you permission to go ahead first Smile Same with most US governmental branches, but not all.

And of course, they will give you permission, which is why I said you can't sue.
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lightsaber
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RE: A380 Wing Test

Wed May 03, 2006 12:43 am

Quoting OldAeroGuy (Reply 11):
Quoting Antiuser (Reply 3):
Maybe they'll be able to certify it by analysis, didn't GE do that with the GE90 after it failed a blade-out test?

No, they re-ran the test.

And GE failed the 2nd test.  flamed  But that gave them enough data to certify by analysis. I have a great photo on the 2nd blade out test where you can see matter leaving the engine radially which is forbidden.  Smile Click on the thumbnail for a better view. This was the screensaver of choice cica 1999 at Pratt.  spin 

Big version: Width: 620 Height: 480 File size: 187kb


Does anyone have a link to any FAA comments? I'd rather not guess as to which way they're going on this important issue. Its possible the FAA, after reviewing test data will accept Airbus' analysis. However, its also possible that they will go the other way... Just hope the decision isn't made by some old codger who was the intern on the Lockheed Electra when it had wing failurs!  duck  Seriously, how the FAA goes in a decision is unfortunately sometimes driven by the personality of the committee selected for review.  Sad

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halls120
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RE: A380 Wing Test

Wed May 03, 2006 12:48 am

Quoting RichardPrice (Reply 16):
Quoting Halls120 (Reply 15):
More importantly, why did they use a wing section they knew had been damaged for this all-important test?

It may have not been apparent until after all the data had been collected and analysed from the entire testing regime that the wing had exceeded the limits earlier on, it may have occured in a test where that load wasnt the primary resultset and thus wasnt looked at in much depth until after the wings failure later on.

Why didn't they use a "fresh" wing for this critical test?
"Suppose you were an idiot. And suppose you were a member of Congress. But I repeat myself." Mark Twain, a Biography
 
RichardPrice
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RE: A380 Wing Test

Wed May 03, 2006 12:54 am

Quoting Halls120 (Reply 21):
Why didn't they use a "fresh" wing for this critical test?

Because wings cost a lot, Airbus is a for profit company, wings arent available on demand and the wing wasnt supposed to have exceeded the limit before.

Its all well and good people here on a forum saying 'Why didnt they do this ... why didnt they do that ...' but when people talk about millions of dollars, it really is a lot of money even for a large company that routinely deals with these sorts of figures. If they can avoid spending more than they have to, they will.
 
Kangar
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RE: A380 Wing Test

Wed May 03, 2006 12:54 am

Quoting Halls120 (Reply 21):
Why didn't they use a "fresh" wing for this critical test?

Because the lock was jammed shut on the fresh wing cupboard on the day they started testing.....
 
JayinKitsap
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RE: A380 Wing Test

Wed May 03, 2006 12:59 am

I must assume that Airbusses test stand uses computer controlled equipment to properly load each of the many hydraulic cylinders (or actuators) at the various points out on the wing to simulate the distributed pressures on a wing for each test. The wing test is supposed to be at 150% of the maximum wing design load. However, I can imagine there are other tests that are unusual cases that may be at 125% or 133% of design load.

I would expect that each cylinder has pressure limits and each test has specific procedures and programming to test various conditions. Also, there would be a boatload of strain gauges installed that the stress levels would be recorded. In the much more mundane (and much more budget limited) building world, we would know right then in a test that were were up at the strength limits of the structure.

If it was my program and it came to my attention that we have made an excursion over the test limit stresses, I would have logged it, identified this to the agency representative (or independant lab representative) that is witnessing the test what had occurred. When the later test came up, yes it would be performed, but it would have been documented beforehand that the performance would have been degraded somewhat because this portion had failure level loads.

With all of the sophisticated computers that they have, this response sounds like they have been leafing thru reams of trifold computer paper printed by dot matrix printers.
 
Poitin
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RE: A380 Wing Test

Wed May 03, 2006 1:02 am

Quoting Lightsaber (Reply 20):
This was the screensaver of choice cica 1999 at Pratt

It looks like it had been "enhanced" by Photoshop.

The flames coming out of the rear are fairly real, streaming vigorously, and there is glow reflecting from the metal of the test stand, but the cloud coming out of the front is not consistant. For that to happen you would need air coming out of the front, which is completely inconsistant with the flames streaming out of the rear.

And are you sure the GE-90-115 was not tested?
Now so, have ye time fer a pint?
 
RichardPrice
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RE: A380 Wing Test

Wed May 03, 2006 1:07 am

Quoting Poitin (Reply 25):

The flames coming out of the rear are fairly real, streaming vigorously, and there is glow reflecting from the metal of the test stand, but the cloud coming out of the front is not consistant. For that to happen you would need air coming out of the front, which is completely inconsistant with the flames streaming out of the rear.

The pictures of the RR Trent 900 testing for the A380 are similiar, with flame and cloud coming out the front. When I get home I shall take a screen capture of the video and post it.
 
787engineer
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RE: A380 Wing Test

Wed May 03, 2006 1:08 am

Quoting Texfly101 (Thread starter):
An in-depth analysis has shown that the wing in question had been subject to loads in excess of the ultimate load targets ahead of the official test. Airbus found the structure was damaged in the earlier test so that it could not hold up a second time to the specified breaking point.

This may well be true, and the test engineers of course were pressured to re-use the wing that they've been testing all along to save costs. But now that this has happened, Airbus should probably work out a way to test a new wing to put all these concerns to rest. Now if they aren't completely sure the extent (and affect) of the damage, decide to make no changes, and it fails prematurely again Airbus would be in a real bind. The problem is that these wings don't come off the assembly line just anytime they please. I'm sure all the wings they're producing now will go on production A380s; to take a wing out now to test would probably delay at least one delivery.
 
Poitin
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RE: A380 Wing Test

Wed May 03, 2006 1:13 am

Quoting RichardPrice (Reply 26):
The pictures of the RR Trent 900 testing for the A380 are similiar, with flame and cloud coming out the front. When I get home I shall take a screen capture of the video and post it.

Are they using an explosive device and how large if so? That could be it, if large enough.
Now so, have ye time fer a pint?
 
A319XFW
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RE: A380 Wing Test

Wed May 03, 2006 1:16 am

Quoting RichardPrice (Reply 22):
Its all well and good people here on a forum saying 'Why didnt they do this ... why didnt they do that ...' but when people talk about millions of dollars, it really is a lot of money even for a large company that routinely deals with these sorts of figures. If they can avoid spending more than they have to, they will.

 checkmark 

Quoting Halls120 (Reply 15):
More importantly, why did they use a wing section they knew had been damaged for this all-important test?

See above - cost and availability.
But there are a few plausible explanations for the early test specimen failure, but as before - an aviation forum is not the place for such things. That is up to the FAA and EASA to decide.
 
RichardPrice
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RE: A380 Wing Test

Wed May 03, 2006 1:18 am

Quoting Poitin (Reply 28):
Are they using an explosive device and how large if so? That could be it, if large enough.

An explosive bolt iirc, but unless they have a pyromaniac on the team, it should in no way produce the above result.

In the RR test you can see the glare begin behind the fan and make its way forward. I will post a series later on when I get home.
 
widebodyphotog
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RE: A380 Wing Test

Wed May 03, 2006 1:49 am

Quoting Poitin (Reply 25):
It looks like it had been "enhanced" by Photoshop.

It's fake, there was no airframe cowling on the engine during the test. Test engines have the large velocity horn mounted. There is no need for anti-ice during an FBO test...IIRC the second test was done in Nov '94 with the FAA present and the GE90 passed without issues...a momentary shot of flames out the back, but no big explosion. That doctored photo is as ridiculous as the AA 777-200ER with the Trent exploding on TO that continuously floats around the internet.



-widebodyphotog
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RichardPrice
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RE: A380 Wing Test

Wed May 03, 2006 1:55 am

Poitin, here is a quick capture of the Trent 900s bladeoff test.

Big version: Width: 637 Height: 365 File size: 72kb
 
Molykote
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RE: A380 Wing Test

Wed May 03, 2006 2:00 am

Quoting RichardPrice (Reply 30):
An explosive bolt iirc, but unless they have a pyromaniac on the team, it should in no way produce the above result.



Quoting Poitin (Reply 25):
It looks like it had been "enhanced" by Photoshop.

The flames coming out of the rear are fairly real, streaming vigorously, and there is glow reflecting from the metal of the test stand, but the cloud coming out of the front is not consistant. For that to happen you would need air coming out of the front, which is completely inconsistant with the flames streaming out of the rear.

The following is by no means perfect or complete but it may get some of you started in realizing how the above photo scenario can happen. I have no knowledge of whether or not the photo was manipulated but I wouldn't doubt the feasibility of what we are seeing. I just got off of a 12 hour night (up for 18) and am having a beer so forgive my haste....

- A compressor stall is (in a nutshell) caused by disrupted airflow through the compressor stages. The loss of a fan blade generating thousands of pounds of thrust would certainly qualify.

- Compressors (rather than turbines) tend to stall because the incoming airflow is negotiating an adverse pressure gradient through each subsequent compressor stage. This isn't a world apart from an airplane wing stalling - each device is attempting to turn the flow to a degree greater than nature will allow. The result of an excessive adverse pressure gradient in separation.

- Slight disruptions of airflow can sufficiently foul up the compressor airflow to the point where a compressor stall happens.

- When a compressor stall happens the affected blades essentially loose their "authority" of the local fluid (air).

- If compressor stage 4 experiences a stall, what do you think happens to the higher stage air in compressor stage 5?
Speedtape - The aspirin of aviation!
 
RichardPrice
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RE: A380 Wing Test

Wed May 03, 2006 2:27 am

Quoting Molykote (Reply 33):

My comment that you quoted was meant to convey that the blade seperation charge wouldnt have produced the result shown, not that the result shown is false. The explosive charge is tiny and would not have produced a fireball like that, which would be produced in the manner you describe.

Here are some more shots of the RR Trent 900 test:

Big version: Width: 631 Height: 364 File size: 57kb
Big version: Width: 634 Height: 364 File size: 56kb
Big version: Width: 633 Height: 363 File size: 53kb
Big version: Width: 637 Height: 364 File size: 35kb
Big version: Width: 637 Height: 364 File size: 74kb
 
Molykote
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RE: A380 Wing Test

Wed May 03, 2006 2:37 am

Quoting RichardPrice (Reply 34):
My comment that you quoted was meant to convey that the blade seperation charge wouldnt have produced the result shown, not that the result shown is false. The explosive charge is tiny and would not have produced a fireball like that, which would be produced in the manner you describe.

Here are some more shots of the RR Trent 900 test:

Understood now. Thanks for the clarification!
Speedtape - The aspirin of aviation!
 
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lightsaber
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RE: A380 Wing Test

Wed May 03, 2006 2:58 am

Quoting Poitin (Reply 25):
It looks like it had been "enhanced" by Photoshop.

I have done nothing to the photo, I've had the file for years and many a Pratt engineer pointed out details on how it was a blade out test. I can't prove anything more than that.

What I do know, is an engine passing a test looks just as spectacular. Let me repeat, due to the out of balance nature of a fan blade out test, the bearings *always* vent the engines oil. (Ok, not every drop, but a spectacular amount.) So an engine passing looks the same as one failing *except* if there are parts sent out radially. As Molykote noted the compressors stall and fuel from the combustor also shoots out the front, creating a

As to GE passing... Yes... but not the test. Pratt was *SO* pissed when the FAA let them get by with analysis that five years after the fact Pratt engineers were still stewing over it. I'll look for a link when I have time.

Quoting Poitin (Reply 25):
And are you sure the GE-90-115 was not tested?

Sorry I wasn't clear, the GE-90A wasn't retested after failing two blade out tests.

The GE-90-115 is a new fan and thus a new test. I did not mean to imply that the GE-90-115 wasn't tested. Mea culpa.

Quoting Widebodyphotog (Reply 31):
It's fake, there was no airframe cowling on the engine during the test.

As to the cowling, its always mounted for a blade out test. In fact, every Pratt blade out test I've seen video of had a full nacelle! (I never was on a team to see the actual event.)  Sad How else do you prove in a blade out event you're not going to push the nacelle into the wing or send it flying off though the passenger cabin! Recall how many engines are normally "consumed" in certification testing. The same engine where emissions are done is not the same engine (usually) that does the bird strike testing. Nor do you want to do ice ingestion testing on a fan already weakened by the bird strike test so one sacrifices a new engine, etc.

Quoting Widebodyphotog (Reply 31):
Test engines have the large velocity horn mounted.

Totally false for a blade out test. The horn is *never* mounted for a blade out test. You're thinking of ground performance testing. For many tests, including ice ingestion, the engine must be tested in its flight nacelle sans horn. Those horns are expensive and would be shattered as the front bearing vents its oil and the resulting pressure wave created by the explosion that often happens in the fan duct during these tests. Not to mention the fireball puked out the front due to the compressor stalling and venting already burning combustor gasses out the front.

I've never seen any photo of a blade out test where the engine didn't vent oil out of the bearings in a spectacular fashion. If that's a man in a Trent blade out test, that is a doctored photo... I agree that the Trent photo is most like a compressor stall. Its not spectacular enough to be a blade out test. Anyone close to an engine in a blade out test is in a bunker. The explosions are spectacular and dangerous. Ok, maybe a military "leaky turbojet" might not vent bearings so much during a blade out test... But all high bypass commercial engines during a blade out test vent so much oil from the now deformed bearings that it looks like a napalm bomb went off.

I do not doctor photos nor offer evidence that is patently false. This is the only photo of a blade out test that I have. I admit I probably have my dates wrong on the 2nd test.

Note: my photo is pretty much the FAA definition of a "little flame shot out the back."

And yes, the amount of parts shot out radially were minor enough that GE was able to prove that the GE-90 (original version) had such a strong fan root that a full blade out event was impossible in that engine.  spin  Or maybe I know nothing about engines.  Wink

Quoting Molykote (Reply 33):
I wouldn't doubt the feasibility of what we are seeing.

Thank you for your comments. I forgot about the compressor stall until I read your post.  Smile

And people, that photo is at NASA's test stand in Cleveland where GE does their blade out tests... I'm not saying I can prove the photo is real. But I swear, if its a fake, its fooled hundreds of engine engineers and has all of the right details.

Lightsaber
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lightsaber
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RE: A380 Wing Test

Wed May 03, 2006 3:06 am

Quoting RichardPrice (Reply 34):

Here are some more shots of the RR Trent 900 test:

Thanks for the photos...

Quoting RichardPrice (Reply 34):
The explosive charge is tiny and would not have produced a fireball like that, which would be produced in the manner you describe.

First, thanks for the photos. And didn't RR prove by simularity that their nacelles were ok and thus why its tested with the horn... But then again, maybe RR doesn't use the nacelle as secondary containment?

Also, with a tripple spool, its possible only the low spool bearings would vent. Thus its possible the oil didn't see an ignition source and would produce that less spectacular a result.

I'm suprised they risked a horn... but hey, each company has its own test philosophy. Or maybe I was at Pratt when they were having to prove something about a nacelle. I'll admit I don't know why the difference.

Lightsaber
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RichardPrice
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RE: A380 Wing Test

Wed May 03, 2006 3:06 am

Quoting Lightsaber (Reply 36):
If that's a man in a Trent blade out test, that is a doctored photo... I agree that the Trent photo is most like a compressor stall. Its not spectacular enough to be a blade out test. Anyone close to an engine in a blade out test is in a bunker. The explosions are spectacular and dangerous.

Out of interest, where can you see a man in the Trent image?

Its definately real, it was taken from the 'A380: Worlds Largest Airliner' video from Channel 4 so if its fake, then a lot of people have a lot to answer for. I can maybe post a clip from the video if it will help at all.
 
RichardPrice
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RE: A380 Wing Test

Wed May 03, 2006 3:18 am

Quoting Lightsaber (Reply 37):
First, thanks for the photos. And didn't RR prove by simularity that their nacelles were ok and thus why its tested with the horn... But then again, maybe RR doesn't use the nacelle as secondary containment?

During the footage you see the side of the engine during the test, it bulges but not even significantly and nothing seperates from the main shroud, so I would imagine the external nacelle isnt part of the containment strategy.

Quoting Lightsaber (Reply 37):
I'm suprised they risked a horn... but hey, each company has its own test philosophy.

Maybe RR need the horn (I assume by that you mean the forward intake) to bring the engine to full power, as it assists in intake air flow and is thus needed to fulfil the test satisfactorily.
 
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lightsaber
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RE: A380 Wing Test

Wed May 03, 2006 3:21 am

First, RichardPrice, I owe you an appology. Please read the following to understand why my opinion has changed on your photo... except I would like to know if that's a man or not. But I was quick to judge your photo on features always present in a double spool blade out test that might not be in a triple spool blade out test. Mea Culpa.

Quoting RichardPrice (Reply 38):

On the man:
Out of interest, where can you see a man in the Trent image?

I see a man in the photo front to the left center. He appears to be wearing a leather jacket. However, if I'm wrong on that being a man... I owe you an appology (part two). He looks like he's squating. Its at the very bottom of the photo very close to the center. I'll be rather embarrased if that's just a circuit breaker box with a weather tarp.  Wink Also, what is that black figure at 7 to 8 o'clock relative to the engine front? However, it doesn't look "man like" enough for me to arque that one.  Wink

I admit it didn't look like a blade out test shot as I've always worked in the land of two spool engines. While sitting back and having my coffee, I come to realize that a triple spool have such a more rigid bearing arrangement that the double spools...  scratchchin  So the oil spray I have come to expect as unavoidable might not happen in a Trent! Wow! To me this in inconcievable to not have a fireball in a blade out test!

Put in line: "I don't think that word means what you think it means."  Wink

But your later Trent photos are certainly a blade out test... and are not as spectacular as the two spool tests I normally would review.

Due note: my part of blade out tests was simply to ensure fuel neither surged to dangerous levels when the combustor lost pressure (due to compressor stall) and thust the pressure drop across the fuel injector increases (thus increasing fuel delivery). E.g., orificing the fuel delivery. The other part was as part of a team to ensure the FADAQ could recognize a dangerous event and cut the fuel yet not cut the fuel in normal flight events. Someone else has the fun job of making sure the FADAQ survives long enough to shut off fuel delivery or at least the fuel shutoff valves would fail shut in the event of a FADAQ failure.

I love it when I learn something new. Out of the 20 to 26 quarts of oil in a large engine, 8 to 16 quarts are often vented out during a test in a very short period of time as a "rule of thumb" for double spools... Do you know the rule of thumb for a triple spool?

Lightsaber
7 months without TV. The best decision of my life.
 
Dougloid
Posts: 7248
Joined: Tue Jul 05, 2005 2:44 am

RE: A380 Wing Test

Wed May 03, 2006 3:37 am

Quoting Zvezda (Reply 7):
Why on earth would Airbus overstress a wing that they knew would later be used for certification testing? It makes no sense.

It doesn't make any sense ot me either. And if it was my problem to fix, the people who overstressed it before the Trophy Run would be out looking for jobs at McDonalds.

Ehhh, you wan' les fries with le burger?
If you believe in coincidence, you haven't looked close enough-Joe Leaphorn
 
RichardPrice
Posts: 4474
Joined: Sat Apr 23, 2005 5:12 am

RE: A380 Wing Test

Wed May 03, 2006 3:37 am

No apologies necessary, really  Smile

Quoting Lightsaber (Reply 40):

I see a man in the photo front to the left center. He appears to be wearing a leather jacket. However, if I'm wrong on that being a man... I owe you an appology (part two). He looks like he's squating. Its at the very bottom of the photo very close to the center. I'll be rather embarrased if that's just a circuit breaker box with a weather tarp.

I see what you mean, but if you look to the right you can see something on the stairs which is almost exactly the same. Not 100% sure what it is, but its certainly not living  Smile

Sorry, Im not an engine technician (much the pity, its one of the things I would love to do - maybe its something to consider for a career change) so I cant help you with the inner workings  Sad
 
Poitin
Posts: 2651
Joined: Wed Jan 25, 2006 6:32 am

RE: A380 Wing Test

Wed May 03, 2006 3:38 am

Quoting Lightsaber (Reply 36):
Quoting Poitin (Reply 25):
It looks like it had been "enhanced" by Photoshop.

I have done nothing to the photo, I've had the file for years and many a Pratt engineer pointed out details on how it was a blade out test. I can't prove anything more than that.

I am not saying you did anything, but since it was a popular screen saver at PW, I am still suspicious that someone "made it look better."

To wit, the smoke coming out the front has a puffy cottonball appearence, about what I can get with Photoshop using a "splatter" brush with about 20% transparency. In addition, looking at the apparent movement of the smoke coming out, it appears to be curving around the cowl. It is not moving at high velocity at all, yet it was ejected out of the intake against a very strong incoming wind. If you look at the shrapnel blasting out of the front, it is moving directly out of the front at a high velocity, which I would expect.

While I am sure the flame coming out of the back is real, I think someone doctored the photo to some degree.

Below is a Photoshop enlargement of what I am talking about.

Now so, have ye time fer a pint?
 
OldAeroGuy
Posts: 3928
Joined: Sun Dec 05, 2004 6:50 am

RE: A380 Wing Test

Wed May 03, 2006 4:04 am

Quoting Lightsaber (Reply 20):
And GE failed the 2nd test. But that gave them enough data to certify by analysis. I have a great photo on the 2nd blade out test where you can see matter leaving the engine radially which is forbidden. Click on the thumbnail for a better view. This was the screensaver of choice cica 1999 at Pratt.

I was referring to the GE90-115B blade out test. The first one failed, the second one passed.

I didn't know about the earlier GE90 blade out failure.

Quoting RichardPrice (Reply 30):
An explosive bolt iirc, but unless they have a pyromaniac on the team, it should in no way produce the above result.

When the blade fails, the compressor stalls. The reduced pressure allows the hot flow to exit the front of the engine.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
 
widebodyphotog
Posts: 885
Joined: Wed Jun 30, 1999 9:23 am

RE: A380 Wing Test

Wed May 03, 2006 4:14 am

Quoting Lightsaber (Reply 36):
As to the cowling, its always mounted for a blade out test. In fact, every Pratt blade out test I've seen video of had a full nacelle! (I never was on a team to see the actual event.) How else do you prove in a blade out event you're not going to push the nacelle into the wing or send it flying off though the passenger cabin! Recall how many engines are normally "consumed" in certification testing. The same engine where emissions are done is not the same engine (usually) that does the bird strike testing. Nor do you want to do ice ingestion testing on a fan already weakened by the bird strike test so one sacrifices a new engine, etc.

Sorry I don't have a way of posting it right now but in the video of the GE90 FBO test I have the engine does not have the full flight nacelle mounted during the test...In the slo-mo you can even see the containment bulge as the disintegrating blade goes round...Flames yes, but not even as spectacular as the Trent images from RichardPrice...Looking at those images it seems apparent that the full flight nacelle is not installed on the Trent either...is it not very expensive to sacrifice a full cowling as well?

Edit: looked at the vid again...it's a "dummy" nacelle but only the forward cowling installed...

Quoting Lightsaber (Reply 36):
I do not doctor photos nor offer evidence that is patently false. This is the only photo of a blade out test that I have. I admit I probably have my dates wrong on the 2nd test.

Of course I'm not challenging your integrity, and you obviously have a wealth of experience to back up what you are saying. Dates? In '99 the -94B was being certificated, I can't recall how many and the results of FBO testing during that time, but I don't think that they were still grenading engines at that time in such spectacular fashion.

As usual a good string of info from you though



-widebodyphotog

[Edited 2006-05-02 21:24:26]
If you know what's really going on then you'll know what to do
 
RichardPrice
Posts: 4474
Joined: Sat Apr 23, 2005 5:12 am

RE: A380 Wing Test

Wed May 03, 2006 4:16 am

Quoting OldAeroGuy (Reply 44):
When the blade fails, the compressor stalls. The reduced pressure allows the hot flow to exit the front of the engine.

I know, read my clarification in reply 34.
 
tockeyhockey
Posts: 882
Joined: Fri Feb 04, 2005 10:57 pm

RE: A380 Wing Test

Wed May 03, 2006 4:34 am

Quoting Ikramerica (Reply 2):
That's good news as to why it failed. It is very reasonable too.

it's reasonable that airbus went into the most important wing test in the company's history without knowing that the wing had been damaged in a previous test?

i'm guessing someone is going to get fired for this, if it is truly the case.
 
Poitin
Posts: 2651
Joined: Wed Jan 25, 2006 6:32 am

RE: A380 Wing Test

Wed May 03, 2006 4:35 am

Quoting Lightsaber (Reply 40):
I love it when I learn something new. Out of the 20 to 26 quarts of oil in a large engine, 8 to 16 quarts are often vented out during a test in a very short period of time as a "rule of thumb" for double spools... Do you know the rule of thumb for a triple spool?

While I have no idea about the triple spool engine, there is clearly evidence of oil being burned in both the flame coming out of the back of your posted picture, as well as jetting forward from inside the back of the engine towards the front cowl ring. You can see streaked red and yellow flame jetting out under high velocity. In addition, if you look at the right hand edge of your photo, you can see a pink foamy like cloud. I suspect that is from some internal explosion in the engine during the test. Notice how streaky it is. It is moving at high velocity.

The white smoke in the front is not from oil as it burns dark gray. This is an honest test image, but with a little help from someone who wanted to improve it. I really question the white smoke.
Now so, have ye time fer a pint?
 
halls120
Posts: 8724
Joined: Sun Jun 05, 2005 3:24 am

RE: A380 Wing Test

Wed May 03, 2006 4:41 am

Quoting Kangar (Reply 23):
Quoting Halls120 (Reply 21):
Why didn't they use a "fresh" wing for this critical test?

Because the lock was jammed shut on the fresh wing cupboard on the day they started testing.....

LOL, good response. I recognize that people think it might be a silly question, but if I was trying to get my brand new aircraft certified, I would have made damn sure that when it came to the critical 150% test, I was using as near to flawless subject I could find. I understand wings are expensive, but if they have to re-do the test, or make sturctural changes at this point, just how expensive will that be?
"Suppose you were an idiot. And suppose you were a member of Congress. But I repeat myself." Mark Twain, a Biography

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