787 flawed

On Sep 19, 11:22 pm, Richard Riley wrote:
On Wed, 19 Sep 2007 17:22:59 -0700, Andrew Sarangan


The people that really matter - the FAA - already know.

That assumes that FAA and Boeing are being faithful to their
practices. I am not suggesting that they are not, but there are
reasons to be cautious. We have seen examples in recent times where
that assumption turned out to be false due to company financial
pressures.


If I were the
head of Boeing's PR department, I'd hold off on trying to convince the
public until it's clear whether the story has legs or not.


Even the epoxies used for thing like this aren't as heat resistant as
aluminum - but at some point it doesn't really matter. If the
fuselage is seeing 400 degrees, there's something very seriously
wrong, like the airplane is sitting in a giant pool of burning jet
fuel.

I can agree with that. But there are scenarios where the fuselage does
not have to be soaking in burning jet fuel to see 400C. For example a
service truck could be parked with its exhaust directly aimed at the
fuselage. That may sound too simple and silly, but it was a silly
thing like a foam block that caused catastrophic results for the space
shuttle.



In a situation like that I'm not sure whether aluminum or carbon will
last longer. Aluminum WILL burn, once it gets hot enough, and is very
energetic (think thermite). The carbon fibers themselves can
withstand very high temperatures (think the leading edge of the space
shuttle wing - carbon fibers in a carbon matrix). Epoxy will burn,
but not all that energetically.

As for crashworthyness - I know of three Berkuts that were absolutely
totalled, where the occupants survived. One tumbled down the runway,
one struck a high tension powerline, one deadsticked onto a freeway,
got it's wing torn off by a tree and went head on into an SUV. I saw
the wreck of Bill Davenport's Long EZ - engine out, wires tore off a
wing, went inverted into a garage. He lived. Race cars are all
composite now - and race driver deaths are very rare.

Composite structures CAN be absolutely crashworthy. For the same
weight as an aluminum structure, it can provide much more crash
protection. I don't know how the 787 is being engineered, but I'd be
very surprised if they were deliberately making it LESS crashworthy.
After all - Boeing executives fly on these airplanes too. - Hide quoted text -



I agree that composites have many advantages, and that's why I decided
to build a composite aircraft. However, thermal stability is not one
of their high points.

Andrew Sarangan wrote:
On Sep 19, 11:22 pm, Richard Riley wrote:
On Wed, 19 Sep 2007 17:22:59 -0700, Andrew Sarangan


The people that really matter - the FAA - already know.

The FAA? That's a warm fuzzy. They can't find their ass with
both hands most of the time.

FredGarvinMaleProstitute wrote in
:

Andrew Sarangan wrote:
On Sep 19, 11:22 pm, Richard Riley wrote:
On Wed, 19 Sep 2007 17:22:59 -0700, Andrew Sarangan


The people that really matter - the FAA - already know.

The FAA? That's a warm fuzzy. They can't find their ass with
both hands most of the time.


Wheras you're probably expert at that.


Bertie

On Sep 18, 11:35 am, C J Campbell
wrote:
On 2007-09-18 07:06:06 -0700, WhoGivesAFig? said:

This could be huge

http://seattletimes.nwsource.com/ABP...2003889769.pdf

Hmmm. A retired employee who worked for Boeing for 46 years claims to
know more than the FAA and Boeing about how planes should be crash
tested. He concludes that composites are not as crashworthy as metal,
but does not back his assertions up with any hard data.

His complaint is that composite materials are stronger in some
directions than they are in others, that cracking is less visible, and
that composites are more subject to fire and more vulnerable to
lightning. He points out that g levels in a crash are unlikely to be
uniform all along a composite structure. All of this is true, but he
seems to be alleging some sort of Boeing coverup of these facts. He
discounts actual experience with other composite aircraft, saying that
either they are not airliners subjected to the stress and number of
flights that airliners get, or that the numbers of such composite
aircraft are too few to be statistically significant.

Of course, his report will make great fodder for trial lawyers when the
first 787 crashes, no matter what the actual cause of death of the
passengers is. Weldon seems to be down at the site trying to tell
people how to crash test an airplane even though he no longer works
there. No doubt his experience is valuable, but he cannot possibly be
aware of everything that Boeing is doing to mitigate these problems and
Boeing is certainly not going to give corporate secrets to former
employees.

--
Waddling Eagle
World Famous Flight Instructor

Plus his degrees are obsolete, BS 1960, MS 1970 JG

On Sep 20, 11:56 am, Andrew Sarangan wrote:
On Sep 19, 11:22 pm, Richard Riley wrote:

On Wed, 19 Sep 2007 17:22:59 -0700, Andrew Sarangan

The people that really matter - the FAA - already know.

That assumes that FAA and Boeing are being faithful to their
practices. I am not suggesting that they are not, but there are
reasons to be cautious. We have seen examples in recent times where
that assumption turned out to be false due to company financial
pressures.

If I were the
head of Boeing's PR department, I'd hold off on trying to convince the
public until it's clear whether the story has legs or not.

Even the epoxies used for thing like this aren't as heat resistant as
aluminum - but at some point it doesn't really matter. If the
fuselage is seeing 400 degrees, there's something very seriously
wrong, like the airplane is sitting in a giant pool of burning jet
fuel.

I can agree with that. But there are scenarios where the fuselage does
not have to be soaking in burning jet fuel to see 400C. For example a
service truck could be parked with its exhaust directly aimed at the
fuselage. That may sound too simple and silly, but it was a silly
thing like a foam block that caused catastrophic results for the space
shuttle.





In a situation like that I'm not sure whether aluminum or carbon will
last longer. Aluminum WILL burn, once it gets hot enough, and is very
energetic (think thermite). The carbon fibers themselves can
withstand very high temperatures (think the leading edge of the space
shuttle wing - carbon fibers in a carbon matrix). Epoxy will burn,
but not all that energetically.

As for crashworthyness - I know of three Berkuts that were absolutely
totalled, where the occupants survived. One tumbled down the runway,
one struck a high tension powerline, one deadsticked onto a freeway,
got it's wing torn off by a tree and went head on into an SUV. I saw
the wreck of Bill Davenport's Long EZ - engine out, wires tore off a
wing, went inverted into a garage. He lived. Race cars are all
composite now - and race driver deaths are very rare.

Composite structures CAN be absolutely crashworthy. For the same
weight as an aluminum structure, it can provide much more crash
protection. I don't know how the 787 is being engineered, but I'd be
very surprised if they were deliberately making it LESS crashworthy.
After all - Boeing executives fly on these airplanes too. - Hide quoted text -

I agree that composites have many advantages, and that's why I decided
to build a composite aircraft. However, thermal stability is not one
of their high points.

All commercial airports have a fleet of foam cannon fire trucks, don't
worry be happy !