If you cannot meet the rules, change them
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While this does paint the FAA as a bunch of cowboys, there are (as always) unstated/unanswered questions that may indicate this action isn't unreasonable.
- What are the EASA standards for this subject - are they more or less stringent than what the FAA a) currently imposes, and b) what they intend to regress to?
- The statement "To this day, we have not had one manufacturer that has been able to demonstrate compliance with that rule" is made. That surprised me, until I saw that even the A380 was certified before this rule came into force - given that a fair amount of the A380 is made (like the Dreamliner) of composites, the two probably aren't that far apart in terms of lightning protection
Ka?l wrote:
Planes made of aluminum are Faraday cages and are very safe against lightning, when planes made of composite materials are not. When a lightning strikes a carbon-made section, it makes a hole in it.
Composite parts have been flying for a long time. Can you really make that statement with 100% confidence? Are you a materials/aeronautical engineer?
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
Just a side note --- the B-2 bomber is an all-composite (I believe) aircraft. To date, AFAIK, there have been no lightning tragedies regarding this aircraft. And it has been flying for a number of years.
AF Pilot
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73Zeppelin wrote:
because of the use of a composite material, the total weight of aluminum mesh + composite would still be less than that of solid aluminum construction
Good luck with the metallic meshing when you'll have to do some maintenance after a lightning strike.
73Zeppelin wrote:
. Grounding could easily be done by fixing electrical equipment at designated grounding points on the mesh
There is way to much current to use the metallic meshing - It would not be able to dissipate the power, and it would be good for the carbon around. There's around 1MW of electricity produced in today's aircrafts, and it's growing.
73Zeppelin wrote:
I believe they laminate the mesh onto the composite.
It can be also coated on the surface. New technologies are also develop to 'chemically' depose a metallic layer on top of the carbon panel.
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
I think the problem has already been solved. 1. http://www.compositesworld.com/articles/lightning-strike-protection-for-composite-structures.aspx[^] 2. http://www.newscientist.com/article/mg18625061.600-striking-planes.html[^] 3. http://www.youngeagles.org/questions/afmviewfaq.asp?faqid=566[^]
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KaЯl wrote:
I'm an engineer with a background in mechanics, materials and structure calculations
Similar to most mechanical and structural engineers - still doesn't qualify them to speak authoritatively about the specifics of that subject.
KaЯl wrote:
Weldon, a 46-year veteran of Boeing and a pioneer in aerospace design
Who, according to various sources never worked on composites. Way to stay up with the state of the art. Oh, and he might just have an axe to grind, given he was fired from Boeing for "threatening the life of a supervisor". Still, we wouldn't want to let anything get in the way of a good conspiracy theory, would we.
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
Stuart Dootson wrote:
still doesn't qualify them to speak authoritatively about the specifics of that subject.
Please, what are your qualifications?
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
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Just a side note --- the B-2 bomber is an all-composite (I believe) aircraft. To date, AFAIK, there have been no lightning tragedies regarding this aircraft. And it has been flying for a number of years.
AF Pilot
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Ka?l wrote:
composite materials is an argument for commercials, it is not an engineer choice.
Bollocks. Fibre composites are extraordinary (and BTW I was a mechanical engineer before I decided to waste my life in computers). While dural is damn tough, you just cant beat FRPs.
Morality is indistinguishable from social proscription
fat_boy wrote:
Fibre composites are extraordinary
Who said they are not? They are just suited yet to build entirely a commercial aircraft, they are way too many problems not faced to make a safe design for now. I'm not claiming that their mechanical properties are not interesting, even if one could raise question about the studies related to fatigue - for instance how can you preemptively detect micro-cracks in carbon? I say that carbon based materials are not ready to replace aluminum in commercial flights because some other aspects (electrical, thermal, maintenance) are not prospected enough.
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
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Thanks for your comment, it add a lot to the talk as usual. Now please take your pills.
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
Ka?l wrote:
it add a lot to the talk as usual
It certainly did. Rob answered the single-most important question that would have occurred to anyone after your rant.
Jon Smith & Wesson: The original point and click interface Algoraphobia: An exaggerated fear of the outside world rooted in the belief that one might spontaneously combust due to global warming.
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Stuart Dootson wrote:
the weight advantage is very significant
This advantage will disappear when you will have to add all the extras to compensate for all the lost properties of metal-based designs.
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
Ka?l wrote:
This advantage will disappear when you will have to add all the extras to compensate for all the lost properties of metal-based designs
All these stupid American designers. So easy for you to show them up.
Jon Smith & Wesson: The original point and click interface Algoraphobia: An exaggerated fear of the outside world rooted in the belief that one might spontaneously combust due to global warming.
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Don't forget to tale the blue one.
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
Ka?l wrote:
Don't forget to tale the blue one.
Just like Heinze. You had a dream and when you woke up you needed to share your new 'reality.'
Jon Smith & Wesson: The original point and click interface Algoraphobia: An exaggerated fear of the outside world rooted in the belief that one might spontaneously combust due to global warming.
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fat_boy wrote:
Fibre composites are extraordinary
Who said they are not? They are just suited yet to build entirely a commercial aircraft, they are way too many problems not faced to make a safe design for now. I'm not claiming that their mechanical properties are not interesting, even if one could raise question about the studies related to fatigue - for instance how can you preemptively detect micro-cracks in carbon? I say that carbon based materials are not ready to replace aluminum in commercial flights because some other aspects (electrical, thermal, maintenance) are not prospected enough.
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
Ka?l wrote:
I say that carbon based materials are not ready to replace aluminum in commercial flights because some other aspects (electrical, thermal, maintenance) are not prospected enough.
That's ridiculous. They're used in military grade aircraft.
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73Zeppelin wrote:
because of the use of a composite material, the total weight of aluminum mesh + composite would still be less than that of solid aluminum construction
Good luck with the metallic meshing when you'll have to do some maintenance after a lightning strike.
73Zeppelin wrote:
. Grounding could easily be done by fixing electrical equipment at designated grounding points on the mesh
There is way to much current to use the metallic meshing - It would not be able to dissipate the power, and it would be good for the carbon around. There's around 1MW of electricity produced in today's aircrafts, and it's growing.
73Zeppelin wrote:
I believe they laminate the mesh onto the composite.
It can be also coated on the surface. New technologies are also develop to 'chemically' depose a metallic layer on top of the carbon panel.
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
Provide a site where these declarations can be checked - or a book - anything. . .I guess you can't.
Jon Smith & Wesson: The original point and click interface Algoraphobia: An exaggerated fear of the outside world rooted in the belief that one might spontaneously combust due to global warming.
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I think the problem has already been solved. 1. http://www.compositesworld.com/articles/lightning-strike-protection-for-composite-structures.aspx[^] 2. http://www.newscientist.com/article/mg18625061.600-striking-planes.html[^] 3. http://www.youngeagles.org/questions/afmviewfaq.asp?faqid=566[^]
- First link: look at the strike test impact (http://www.compositesworld.com/uploadedimages/Publications/CW/Articles/Internal/1366-b.jpg): The damages are reduced, they are not suppressed. Imagine also what will be the maintenance after a lightning strike (every 1000h for a plane). - Second link: the solution on the Typhoon is what I was saying: a metallic layer on the the surface of the plane: you loose then some of the weight you gain by using composite - Third link: WTF? Lightning strike and composites is not a solved problem, see http://www.dcs.eads.net/1024/de/career/jobmarket/jobmarket_search/Stellensuche?job=4923F808C7F55D36E1000000C2CE163F[^]
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
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Stuart Dootson wrote:
still doesn't qualify them to speak authoritatively about the specifics of that subject.
Please, what are your qualifications?
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
Aside from working on safety-critical avionics systems (including some work on their reaction to EMI events) for almost 20 years?
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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Ka?l wrote:
I say that carbon based materials are not ready to replace aluminum in commercial flights because some other aspects (electrical, thermal, maintenance) are not prospected enough.
That's ridiculous. They're used in military grade aircraft.
73Zeppelin wrote:
They're used in military grade aircraft
Has a military aircraft to transport safely hundreds of passengers? Do military aircraft have to be as reliable as their civilian counterparts? Haven't military aircrafts any problem with their composite parts? - IIRC an unexpected problem of electrical reaction between the carbon and the metallic layers led to the destruction of F/A18 tails for instance.
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
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I don't see any moral hazard here on the part of the aircraft companies, either. If they were to allow lightning susceptible aircraft onto the market, they would lose their business after the first lightning related disaster. There would be no logic behind producing an aircraft that is vulnerable to a lightning strike, not even for short-term profit motives. Doesn't make any sense - it's not like they could divest themselves from such a problem and just ignore it. It would threaten their existence. I also think it is a problem that has already been solved through the incorporation of laminated aluminum mesh. No conspiracy here that I see.
73Zeppelin wrote:
Doesn't make any sense
:laugh: You're still like a 2007 Greenspan, you think the system works. Some prefer deliver a product on schedule avoiding penalties and make a product recall later.
73Zeppelin wrote:
not even for short-term profit motives
Even if it means the dissmissal of the 787 and the consequent fall of Boeing?
73Zeppelin wrote:
It would threaten their existence
If Boeing does not produce a 787 soon, it will threaten its existence.
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
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Aside from working on safety-critical avionics systems (including some work on their reaction to EMI events) for almost 20 years?
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
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Aside from working on safety-critical avionics systems (including some work on their reaction to EMI events) for almost 20 years?
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p
Stuart Dootson wrote:
Aside from working on safety-critical avionics systems (including some work on their reaction to EMI events) for almost 20 years?
As the Warcraft computer would have it: "Karl has been pwned."
Jon Smith & Wesson: The original point and click interface Algoraphobia: An exaggerated fear of the outside world rooted in the belief that one might spontaneously combust due to global warming.
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73Zeppelin wrote:
They're used in military grade aircraft
Has a military aircraft to transport safely hundreds of passengers? Do military aircraft have to be as reliable as their civilian counterparts? Haven't military aircrafts any problem with their composite parts? - IIRC an unexpected problem of electrical reaction between the carbon and the metallic layers led to the destruction of F/A18 tails for instance.
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
KaЯl wrote:
Has a military aircraft to transport safely hundreds of passengers
Sometimes, yes. Think personnel transport, large-scale evac and um, extraordinary rendition ;)
KaЯl wrote:
Do military aircraft have to be as reliable as their civilian counterparts
I would say absolutely! If not more so. The military have the same duty of care as an airline operator.
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Just a side note --- the B-2 bomber is an all-composite (I believe) aircraft. To date, AFAIK, there have been no lightning tragedies regarding this aircraft. And it has been flying for a number of years.
AF Pilot
There are 20 B2s in service, with a low serviceability because of a high maintenance time - One crashed, that make 5% of them. . B2s are more often on the ground than flying, contrary to a commercial aircraft. None of them flies 350 days per year and 15 hours a day. I guess also B2s are equipped with many ECM systems and design that could have an impact on lightning strike management - the same with the antiradar coatings. Also, AFAIK, "More recent issues with the bomber have included cracks in the tail", so the composite design would not be that perfect.
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
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Ka?l wrote:
This advantage will disappear when you will have to add all the extras to compensate for all the lost properties of metal-based designs
All these stupid American designers. So easy for you to show them up.
Jon Smith & Wesson: The original point and click interface Algoraphobia: An exaggerated fear of the outside world rooted in the belief that one might spontaneously combust due to global warming.
Yeah, with Karl, we know that's the real agenda here. Boeing must be on his cell's "enemies of socialism" list this week.
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Stuart Dootson wrote:
given that a fair amount of the A380 is made (like the Dreamliner) of composites, the two probably aren't that far apart in terms of lightning protection
These planes are very different. A380[^] is mostly made of aluminum when the B787[^] is mostly made of composite.
Stuart Dootson wrote:
Composite parts have been flying for a long time.
We are not talking about models or fighter jets with a high attrition ratio but of commercial jets. We are not talking about small parts but about entire jets.
Stuart Dootson wrote:
Can you really make that statement with 100% confidence?
Yes.
Stuart Dootson wrote:
Are you a materials/aeronautical engineer?
I'm an engineer with a background in mechanics, materials and structure calculations - I am not the only one to claim these planes are less safe: Weldon, a 46-year veteran of Boeing and a pioneer in aerospace design, talks about major safety problems affecting the brand new Boeing 787 Dreamliner. [...] Weldon believes it will be very difficult for Boeing to make the 787 as safe as an aluminum plane and he adds that Boeing management repeatedly ignored his concerns and those of his colleagues about the plane's design.[^]
The law, in its majestic equality, forbids rich and poor alike to sleep under bridges, to beg in the streets, and to steal their bread Fold with us! ¤ flickr
