787 flawed

On Sep 18, 10:46 pm, "Dan Luke" wrote:
"Andrew Sarangan" wrote:
I have personally witnessed the post-crash fire of an experimental
Velocity. When the fire was out, there was nothing left on the ground
except some metal parts from the wheels, avionics and control links.

IOW, about the same as what's left of a burned out aluminum airplane.

I have only seen photos of metal airplane crashes, and in most cases
you can tell that it was an airplane crash. Many tell tale parts of
the airplane will remain intact. In this case you would not have known
that this was an airplane crash. There were no discernible parts.
Aluminum melts around 650C. Fiberglass epoxy will turn into a gel at
a far lower temperature, around 100C. Most fiberglass airplanes can't
even withstand normal heat from the sun unless they are painted
white. So the fact that the glass airplane simply vaporized in the
fire makes sense to me.

In any case, my observations are only anectodal, and are based on
homebuilt aircraft. Boeing may be using advanced epoxies with superior
thermal and mechanical properties. If that is the case, it would be
trivial for them to put these concerns to rest. I hope that is indeed
the case, and that the 787 is not built with the same epoxy I am using
on my homebuilt.

In any case, my observations are only anectodal, and are based on
homebuilt aircraft. Boeing may be using advanced epoxies with superior
thermal and mechanical properties. If that is the case, it would be
trivial for them to put these concerns to rest. I hope that is indeed
the case, and that the 787 is not built with the same epoxy I am using
on my homebuilt.

Did you lay your composites up on a frame and bake them at high
temperature and pressure in a giant autoclave to cure them? If not,
then I bet you aren't using the same materials or processes...

"Andrew Sarangan" wrote:
Fiberglass epoxy will turn into a gel at
a far lower temperature, around 100C.

It won't withstand boiling water?

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

Richard Riley wrote:
On Tue, 18 Sep 2007 10:06:06 -0400, WhoGivesAFig?
wrote:

This could be huge

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


Or it could be nothing. Real world experinece with smaller composite
airplanes have showed them to be MUCH more crashworthy than aluminum
airplanes. Composite small planes have been certified for lightning
strike before.

You are correct. I should have said "May" be flawed