IAD787 From United States of America, joined Jun 2005, 472 posts, RR: 40 Posted (1 year 4 months 3 weeks 2 days 7 hours ago) and read 11739 times:
Hey All,
Just found out that 787 static testing begins next week on ZY997 in Building 40-23. The first is the high-blow test to check all the cabin pressure seals.
The testing is not directly impacted by the strike.
The 777 blew one out around the aft door during its test, but was fixed (temporarilly) by putting tape along the doorway. See 21st century airplane (amazing documentary) for the full story of all those tests.
Also, Boeing still hasn't decided to break the wings yet. One way or another, they need to prove 150% of max design load.
MCIGuy From United States of America, joined Mar 2006, 1790 posts, RR: 0 Reply 2, posted (1 year 4 months 3 weeks 2 days 7 hours ago) and read 11568 times:
Thanks Jon, I've been hoping for some news of the 787 in the wake of the strike!
I personally think they will break the wings, it'd sure be a big bragging point if they made it to 180%.
B747forever From United States of America, joined May 2007, 14381 posts, RR: 12 Reply 3, posted (1 year 4 months 3 weeks 2 days 7 hours ago) and read 11572 times:
XT6Wagon From United States of America, joined Feb 2007, 1895 posts, RR: 3 Reply 5, posted (1 year 4 months 3 weeks 2 days 5 hours ago) and read 11360 times:
Quoting Tdscanuck (Reply 4): Yes it would...for Airbus. If the wings are good to 180% they're grossly overdesigned.
Its possible to have a design "overbuilt" for one test to meet some other requirement. I'm betting a 1st gen conservative design will be far stronger than they need given the skin thickness required to prevent people from poking holes in it with ease is far thicker than the minimum needed to merely replace the metal skin strength for strength.
474218 From United States of America, joined Oct 2005, 3975 posts, RR: 1 Reply 6, posted (1 year 4 months 3 weeks 2 days 5 hours ago) and read 11286 times:
Quoting Tdscanuck (Reply 4): If the wings are good to 180% they're grossly overdesigned.
Is it be grossly over designed or designed for future weight increases?
Quoting XT6Wagon (Reply 5): ...given the skin thickness required to prevent people from poking holes in it with ease...
How thick does the skin have to be to prevent people from poking holes in it with ease, 0.020", 0.032", 0.040", 0.063", 0.080", 0.100" maybe 0.125" or thicker?
WarRI1 From United States of America, joined Sep 2007, 2541 posts, RR: 4 Reply 7, posted (1 year 4 months 3 weeks 2 days 5 hours ago) and read 11220 times:
Quoting MCIGuy (Reply 2): Thanks Jon, I've been hoping for some news of the 787 in the wake of the strike!
I personally think they will break the wings, it'd sure be a big bragging point if they made it to 180%.
I always thought that breaking the wings was a mandatory test for new airliners. Is it not done sometimes?
Quoting Tdscanuck (reply 4): If the wings are good to 180% they're grossly overdesigned.
Is it be grossly over designed or designed for future weight increases?
For future weight increases the skins and structural members should be re-gauged. For our parts of the plane we have different loads for the -9 and -3 compared with the baseline -8. I can't imagine why the wing would be any different.
That said, I expect the wing to sail past 150% due to conservatism in the analysis to account for the relatively lower knowledge of composite structures compared with aluminium alloy structures.
I had wondered why they wouldn't test the wing to breaking point so that they could determine just how conservative the analysis was. I visited Everett a month or so ago and having walked around the assembly lines and seen the static test rig and airframe in the flesh I now understand how big a job it would be to clean up the mess if they did that.
Quoting 474218 (Reply 6):
How thick does the skin have to be to prevent people from poking holes in it with ease, 0.020", 0.032", 0.040", 0.063", 0.080", 0.100" maybe 0.125" or thicker?
Depends on the area. There are design requirements for handling loads which depend on where the part is located and how likely it is to be subject to different types of loads - handling, stepping, etc., and how severe those loads are expected to be. The wing skins look extremely thick near the root where you can see them. I don't know how thin they get further out.
Nws2002 From United States of America, joined Feb 2008, 367 posts, RR: 0 Reply 9, posted (1 year 4 months 3 weeks 2 days 5 hours ago) and read 11203 times:
Quoting WarRI1 (Reply 7): I always thought that breaking the wings was a mandatory test for new airliners. Is it not done sometimes?
If they test it to 150%, and no further, then the wings will not necessarily break.
Dynamicsguy From Australia, joined Jul 2008, 392 posts, RR: 0 Reply 10, posted (1 year 4 months 3 weeks 2 days 5 hours ago) and read 11191 times:
Quoting WarRI1 (Reply 7):
I always thought that breaking the wings was a mandatory test for new airliners. Is it not done sometimes?
Proving that the wings can get past 150% is mandatory. Anything beyond that it up to the manufacturer. The proof is not always by testing - e.g. derivatives aren't re-tested, or the A380 wing which didn't quite pass but which was certified based on analysis of the modified wing.
WarRI1 From United States of America, joined Sep 2007, 2541 posts, RR: 4 Reply 11, posted (1 year 4 months 3 weeks 2 days 4 hours ago) and read 11162 times:
Rheinbote From Germany, joined May 2006, 1645 posts, RR: 49 Reply 12, posted (1 year 4 months 3 weeks 1 day 20 hours ago) and read 10634 times:
Quoting Tdscanuck (Reply 4): Yes it would...for Airbus. If the wings are good to 180% they're grossly overdesigned.
Funny that you say that, Tom. As a matter of fact, Airbus' strategy with the A380 was to capture the 150% limit from below in an effort to avoid exactly that - overdesign.
Wasn't it Randy Tinseth who was bragging how a fuselage barrel specimen didn't brake, not even when tested far beyond 150%? Go figure...
By the way, the max blow test may prove the pressure seals. The maximum load that needs to be demonstrated is 150% of the design load (the most prominent design load case probably being the 2,5g maneuver) PLUS the load from internal pressure.
Thijs89 From Netherlands, joined Sep 2008, 6 posts, RR: 0 Reply 13, posted (1 year 4 months 3 weeks 1 day 20 hours ago) and read 10478 times:
They said it was going to it's maiden flight in the last quarter of 2008..
Do you guys think they're gonna make it? Seems hard to me when the static testing hasn't even started..
Justloveplanes From United States of America, joined Jul 2004, 490 posts, RR: 0 Reply 14, posted (1 year 4 months 3 weeks 1 day 20 hours ago) and read 10467 times:
Quoting Dynamicsguy (Reply 8): I had wondered why they wouldn't test the wing to breaking point so that they could determine just how conservative the analysis was. I visited Everett a month or so ago and having walked around the assembly lines and seen the static test rig and airframe in the flesh I now understand how big a job it would be to clean up the mess if they did that.
I think the wings have to be broken, this is something Boeing has to know to validate their design models for optimization of the next composite plane. Whether this is done for the 150% certification test I doubt. I think it will be kept confidential for obvious reasons and it will be an internally conducted destructive test.
Moo From , joined Dec 1969, posts, RR: Reply 15, posted (1 year 4 months 3 weeks 1 day 20 hours ago) and read 10468 times:
Quoting Rheinbote (Reply 12): As a matter of fact, Airbus' strategy with the A380 was to capture the 150% limit from below in an effort to avoid exactly that - overdesign.
Thats a little revisionist, is it not? Airbus were expecting to achieve 150% in the test straight off, they didn't but the wing passed after a known amount of strengthening was done.
WithaK From Australia, joined Apr 2007, 228 posts, RR: 0 Reply 16, posted (1 year 4 months 3 weeks 1 day 20 hours ago) and read 10409 times:
Quoting Rheinbote (Reply 12): As a matter of fact, Airbus' strategy with the A380 was to capture the 150% limit from below in an effort to avoid exactly that - overdesign.
Do you have a source for this statement? It's just it goes completely against everything I've been taught (so far) in structural design. I find it hard to believe that engineers at Airbus designed a wing to fail below the loads to achieve certification. What about all the work to strengthen the wing so that it can be certified and then applying these modifications to the wings already built? Wouldn't that add weight, cost and time to the aircraft? Wouldn't a manufacturer rather spend that time better optimizing the wing to reduce weight or even not changing it at all if the costs don't outweigh the benefit?
Rheinbote From Germany, joined May 2006, 1645 posts, RR: 49 Reply 17, posted (1 year 4 months 3 weeks 1 day 20 hours ago) and read 10314 times:
Quoting WithaK (Reply 16): Do you have a source for this statement? It's just it goes completely against everything I've been taught (so far) in structural design. I find it hard to believe that engineers at Airbus designed a wing to fail below the loads to achieve certification.
That's not what I wrote. Capturing from below means that you try to get as close as possible to 150% from below. They made it to 147,x% or so (don't recall exactly what it was) and then beefed up the structure to close the comparably small gap. That's what Airbus chief engineer Alain Garcia told the public immediately after the event. You can read it up here, to provide just one source: http://www.freerepublic.com/focus/f-news/1579967/posts
It's easier to close the gap from below, because you see where the weak area is. If the wing withstands 150% you won't get as good an idea where the excess strength is unless you test it to failure. There's no need for an additional safety margin beyond 150%, because ulitmate load already means a 50% margin.
MadameConcorde From Antigua and Barbuda, joined Feb 2007, 5138 posts, RR: 27 Reply 18, posted (1 year 4 months 3 weeks 1 day 19 hours ago) and read 10239 times:
Is there any chance that the 787 be on display at the Paris Air Show next Spring?
Wishing the new plane all the best all the way through testing on ghe ground and up in the air.
There was a better way to fly. It was called Concorde.
Thanks for the link. So if I read the article correctly Airbus loaded the wing up to a certain point and then modified their FEM models accordingly to improve their accuracy. They continued this process until the wing failed at 147% of the maximum expected loads. Then using these refined FEM models they were able to prove that the production wing would pass the 150% mark. Shows how interesting the real world really is. You learn something new everyday.
Moo From , joined Dec 1969, posts, RR: Reply 20, posted (1 year 4 months 3 weeks 1 day 19 hours ago) and read 10125 times:
Quoting MadameConcorde (Reply 18): Is there any chance that the 787 be on display at the Paris Air Show next Spring?
Its entirely possible - the A380 only flew a month and a half before appearing at the 2005 Paris Air Show, so its very possible that the 787 could appear next year.
Alessandro From , joined Dec 1969, posts, RR: Reply 21, posted (1 year 4 months 3 weeks 1 day 18 hours ago) and read 9638 times:
Moo, but Toulose and Paris is definitly nearer than Seattle and Paris. A380 did fly at Le Bourget 2005, but only with the landing gear down.
Thijs89, I doubt myself, I expect both the B787 and B748 to preform their maiden flights next year.
Stitch From United States of America, joined Jul 2005, 16767 posts, RR: 64 Reply 22, posted (1 year 4 months 3 weeks 1 day 18 hours ago) and read 9551 times:
One of the reasons Boeing may not test the 787's wings to destruction is because the containment and clean-up of the carbon fiber shards and dusts will be both time-consuming and expensive (I have heard the cost could be over a million USD).
Moo From , joined Dec 1969, posts, RR: Reply 23, posted (1 year 4 months 3 weeks 1 day 17 hours ago) and read 9435 times:
Quoting Alessandro (Reply 21): Moo, but Toulose and Paris is definitly nearer than Seattle and Paris. A380 did fly at Le Bourget 2005, but only with the landing gear down.
Whats that got to do with anything? The reason the A380 flew with the gear down at Paris 2005 was not because of any technical issues, but because of the flight test program - it required a set amount of straight and level flight for the gear to be retracted in, the aircraft couldn't turn during that time. The demonstration flight was never going to have that amount of straight and level flight in it, because it would have meant the aircraft departing, disappearing from sight and then returning to do its demonstration, then disappearing again and landing.
The 787 will be under similar restrictions for the first duration of its flight test program - the restrictions disappear later on when the systems have proven themselves.
It was an artificial limitation imposed by Airbus, not the airframe.
If Boeing get the aircraft flying by the end of this year, or veyr early next year, there is no doubt in it appearing at Paris.
Quoting Stitch (Reply 22): One of the reasons Boeing may not test the 787's wings to destruction is because the containment and clean-up of the carbon fiber shards and dusts will be both time-consuming and expensive (I have heard the cost could be over a million USD).
So, basically any crash site, should a 787 ever come to harm godforbid, would essentially be an ecological nightmare above and beyond the hazards a crash site today produces?
Alessandro From , joined Dec 1969, posts, RR: Reply 24, posted (1 year 4 months 3 weeks 1 day 17 hours ago) and read 9326 times:
Depleted Uranium is used in some airframes, not something to healthy in case of a crash.
Carbon fiber makes nice dust that make shorts everywhere, something you don´t want in a airplane factory.
As for the A380, they had problems with the landinggear at the time and surely it wasn´t ready
for a full show. I don´t think they going to fly the half ready B787 over the atlantic to participate in LeBourget airshow. Perhaps Farnborough 2010 is the year for the first B787 visit to europe?
25 474218: I wasn't asking about loads, I was asking XT6Wagon about "the skin thickness required to prevent people from poking holes in it with ease"? See Reply
26 Moo: Its not used in new airframes, they phased it out after several high profile crashes - I know that it was used in the 747 for instance, not sure what
27 Alessandro: Yes, I´m aware of that DU isn´t used anymore on airliners, but there are still planes flying with it, like DC-10s and older B747. OK, thanks for the
28 474218: Depleted Uranium poses no health hazard providing it is not drilled, filed or sanded and it is not corroded. It is the dust that is harmful, not the
29 Alessandro: 474218, yes, but in a crash, I reckon DU will turn into dust?
30 Justloveplanes: If the cost of cleanup / premitigation is in the low millions, I think its for sure Boeing will break the wings. Consider for a moment how valuable it
32 Moo: Yes, there is metallic dust present whenever metal hits something - but the real worry is when the plane burns, as you then have contaminants in the
33 Pygmalion: they dont need to test this particular one airplane to do that. There are other test sections and coupons to test to failure that are not located in
34 Glideslope: I would think they could devise some type of containment area. Perhaps some type of canopy so particles simply drop down in one area?
35 YULWinterSkies: By being as honest as possible, no.... IMHO. Yes, i think we all meant the toxicity of the uranium metal (if dust is present), not the radioactivity.
36 HapppyLandings: Well, they are spending a 100 million/day to stick it to the union workers (money well spent if you ask me) what the Hey is another million??? If the
37 Manfredj: And eveyone wonders why the 320's useful life is rubbish compared to the 737's. There's your answer. The end result is a rush on Airbus' part to INCR
38 Moo: So? It hasn't hurt A320 sales in the slightest, and increasing the airframe life seems to be more of an analysis job for Airbus using older airframes
39 WingedMigrator: They didn't intentionally undershoot 150%. More precisely, they designed to the 150% case with no margin. Sometimes that cuts the wrong way. Yes, and
40 Dynamicsguy: I wasn't asking about loads, I was asking XT6Wagon about "the skin thickness required to prevent people from poking holes in it with ease"? See Reply
41 Nomadd22: Airbus was allowed to add a little reinfircement to get the 150%. That doesn't mean that Boeing would be allowed to shave material to lighten the stru
42 WingedMigrator: I don't see why that would be the case. Once the analytical structural models are validated and calibrated by real-world test data, there is no less
43 Justloveplanes: Interesting, Interesting and very strong rationale However, scaling/extrapolating models from lab size to full size can engender suprises of all kind
44 Rheinbote: One of Bair's lousy statements. Wing tip travel is obviously limited by the test rig. There's no way they could make the tips touch.
45 XT6Wagon: It didn't mean that Airbus was certain that they wouldn't have been required to break a wing that DID meet the required strength.
46 Tdscanuck: I believe that's true of the fuselage, but I'd be very surprised if it was true of the wing. From the photos going around in public, the fuselage ski
47 474218: What I was tiring to point out to "Dynamicsguy" is that even if the skin is only 0.016" thick, you are not going to be able to poke a finger through
48 HawkerCamm: If the wings make 180% they are 20% stronger than required. That could be as much as 20% over weight. I would "educated guess" the B787-8 wings are a
49 Justloveplanes: How different is this from the 777 wings Boeing broke in it's certification tests? Dust aside...
50 Dynamicsguy: Sorry. I thought it was a question about how thick, not an attempt to explain to me. Anyway, I hope others find it interesting that we don't just des
51 Tdscanuck: The major difference is that aluminum can store a lot of energy by yielding. The FAR's require that it get up to limit load without permanent deforma
52 Khobar: Considering DU is used for armor piercing, it seems like it's pretty tough stuff. In an air crash, the resulting fire is fuel-fed and isn't likely to
53 Lightsaber: The 788 is well over its promise weight. If its over-engineered at the cost of range than there is a HUGE issue. Right now, the rumors are the 788 is
54 Tdscanuck: It's used for armour piercing because it's dense, not because it's particularly tough. It's just got huge kinetic energy. The fire starts as fuel-fed
55 Pygmalion: the fuel lights the aluminum, which lights the magnesium in the engines and wheels.... airplane fires are hot, damn hot. When it gets going the metal
56 HawkerCamm: Yes but the B777 will mostly like be the reference aircraft used in the prediction of the B787 drag. I heard "information from the industry grapevine
57 Dynamicsguy: That's about the number I heard about a year ago. Anyone know if it's improved or worsened since then?
58 Swallow: By 5MT according to TC. Most of that will be shaken out by 2012 enabling Emirates to fly DXB-LAX with at least 400 pax Wonder how long it will take t
59 474218: DU is just a little harder than lead. But as as pointed out above much more dense. The reason DU was used was because it was that you could add a lot
60 Stitch: Boeing likely has been able to take little out of the 787-8's OEW because they have yet to be able to test the plane as a complete package. Once the d
61 Khobar: "Uranium 238 is a very hard metal, the second hardest common metal to Tungsten (apart from rare metals like Osmium). It is 2 times harder than Titani
62 Wukka: I have a hard time taking anyone who uses rense.com as a "source" seriously. No offense, but Mr. Rense is a bit of a conspiracy theorist, and that's p
63 WINGS: What a load of crap. Please read the article I provided below. It will clearly put your flayed theory ( urban myth) to rest. Airbus begins testing to
64 Brendows: It will be an issue if MZFW stays the same, or if MZFW isn't increased as much as the aircraft is overweight. That would lead to a lower max payload-
65 Khobar: No offense taken, but you should realize that even the most zealous whacko's most often rely on real photographs to "prove" their theories. Also, the
66 Tdscanuck: Yep...because 1) they're much more massive structures and it's much harder to light a chunk of metal with a low surface/mass ratio and 2) they're on
67 474218: While I have never drilled or ran a Rockwell test on any DU. I have handled many of the the 1/4 pound incremental DU weights we used to balance the L
68 Lightsaber: That would keep the *costs* the same, but as already noted: If I may nitpick, they must also increase the maximum landing weight as well as the MZFW
69 Baroque: Try 1405.3 K ?? That is what Wiki prefers. A bit of a difference between 1100F and just over 1100 C - no? I always liked the line, "tungsten because
70 Khobar: Yes, it's amazing how many pictures of wreckage have the top of the fuselage burned away but the rest of the aircraft survives, especially the ones t
72 Stitch: Well hopefully it won't turn out to be a dog and see the bulk of it's orders canceled.
73 Swallow: Apparently the engines have been taken off ZA001, so RR is probably tweaking engine performance. The IAM strike has given both RR & GE time to fine t
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As a matter of fact, Airbus' strategy with the A380 was to capture the 150% limit from below in an effort to avoid exactly that - overdesign. 
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