A520
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How Ready Is Cfrp Technology?

Fri Jun 02, 2006 1:40 am

Boeing is surely taking a big step with the 787. If it works as expected, they'll sure get more than 50% market share in each segment they compete in.

But if something gets wrong? For example the fire resistance of CFRP appears to be quite low (imagine AF A340 crash last year with fire spreading fast, and lost of smoke: how many people would have remained in the plane?). And there is the delamination problem, and probably many more not even yet known. If problems appear before certification, it certainly means delays. If problems are discovered, say, 5 years after EIS and 500 planes are grounded, this will be a serious situation for Boeing.

Isn't it safer to go step by step: first wings with AlLi fuselage (and may be a smaller market share), then complete composite? I am not saying Airbus in right if they go this way, I am just asking.

[Edited 2006-06-01 18:45:24]

[Edited 2006-06-01 18:46:45]
 
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Stitch
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RE: How Ready Is Cfrp Technology?

Fri Jun 02, 2006 1:49 am

Asked and answered so many times...  Smile

That being said, CFRP is not an unknown technology, nor is it's application in aerospace, even if not to the level Boeing is planning.

It really should be blatantly obvious that Boeing has performed, is performing, and will continue to perform due dilligence and testing to ensure that all of the parts are as safe as possible. Boeing is also offering a full maintenance contract option which further reduces the upfront costs of operating the plane (spares, training, facilities) and maintaining it.

Airlines, traditionally risk-averse and conservative entities, are blatantly obviously in agreement, as they have ordered hundreds of them.
 
Oykie
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RE: How Ready Is Cfrp Technology?

Fri Jun 02, 2006 2:38 am

Quoting A520 (Thread starter):

Welcome to Airliners.net A520.

To answer the question, I think they are ready. The use of CFRP has been used in the military for years in the fuselage. And with the fuel at current prices, I think the reduction in fuel consumption saves the airline more money than the added cost of the complexity of CFRP.
Dream no small dream; it lacks magic. Dream large, then go make that dream real - Donald Douglas
 
A520
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RE: How Ready Is Cfrp Technology?

Fri Jun 02, 2006 5:07 pm

Thanks for the info. I agree that CFRP has probably been extensively tested and that construction and assembly methods are efficient.

However, the resistance to fire is a "property" of the material which cannot be improved by "engineering approach".

Irnknow that it has been used in the military aircraft industry, but I'mrnnot sure that the security requirements are the same for a F-35 with arnsingle pilot equippedrnwith an eject seat than for a 400 pax aircraft. (What is the FatalrnEvent Rates of a F-15?) Beside, military airplane don't often flyrnacross the pacific.
 
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Stitch
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RE: How Ready Is Cfrp Technology?

Fri Jun 02, 2006 9:34 pm

The biggest threat to passengers in a fire is smoke and toxic gas inhalation from the burning of interior materials like seats. Since Boeing will have to meet whatever FAA/JAA/EUAA requirements are in existence for commercial aircraft when it comes to fire resistance, those requirements will be engineered into the plane.
 
deltadc9
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RE: How Ready Is Cfrp Technology?

Fri Jun 02, 2006 10:07 pm

Quoting A520 (Thread starter):
For example the fire resistance of CFRP appears to be quite low

People so easily forget that aluminum is flammable. The Space Shuttle uses it as fuel in the SRB. Look at the pictures of plane crashes, like the recent AF 340, and you can see that the aluminum did not melt, it burned.

In extreme heat, aluminum can begin to burn (similarly to magnesium), and can even burn under water by stealing the oxygen from water.

Quoting A520 (Thread starter):
And there is the delamination problem,

CFRP is not new, and its properties are well known, GM even uses it for body panels now.

Quoting A520 (Thread starter):
Isn't it safer to go step by step

Safety is a driving factor in civil aircraft design. Boeing knows how to do this.

Quoting A520 (Reply 3):
but I'mrnnot sure that the security requirements are the same for a F-35 with arnsingle pilot equippedrnwith an eject seat

Ever check out the price tag on a F-15 much less an F-22 or F-35? Ejecting is the last thing anyone wants. Survivability of the airframe is just as important.

Quoting A520 (Reply 3):
Beside, military airplane don't often flyrnacross the pacific.

They do it all the time. The CFRP B2 flies out of the midwest, across the Atlantic, drops its bombs, and returns without landing. Fighters routinely ferry across oceans to get to where they will operate from, or for heavy maintenance. In fact, I am having a hard time thinking of a military plane that doesn't routinely fly across oceans, since the US is at least one ocean away from most of the world.
Dont take life too seriously because you will never get out of it alive - Bugs Bunny