OT- Airliner lightning strike

This says a lot about grounding internal electronics and fuel tanks in
airliners: http://www.coasttocoastam.com/gen/pa...ml?theme=light
One of the problems that composite aircraft structures face is they may
not be electrically conductive enough to transmit lightning safely to an
exit point when they are struck, so the composites are burned and
shattered. It would be interesting to know how Boeing is dealing with
this on the the new 787's composite structure.

Pat

On Tue, 28 Aug 2007 12:25:40 -0500, Pat Flannery
wrote:

One of the problems that composite aircraft structures face is they may
not be electrically conductive enough to transmit lightning safely to an
exit point when they are struck, so the composites are burned and
shattered. It would be interesting to know how Boeing is dealing with
this on the the new 787's composite structure.

Probably the same way the B-2 and F-117 do.

Brian

Brian Thorn wrote:
It would be interesting to know how Boeing is dealing with
this on the the new 787's composite structure.


Probably the same way the B-2 and F-117 do.


Lightning strike was a major concern during the B-2's design phase.
They thought carbon nanotubes might work:
http://www.newscientist.com/article/...lightning.html
Because of its "clear night" attack technique the F-117 probably doesn't
do a lot of flying in the vicinity of thunderstorms.
With the 787, stealth isn't a concern, so maybe they can put something
conductive in the paint it's finished with, or a thin metal film over
the composite parts.
They should go back to Howard Hughes' wild idea for the Convair 880, and
gold anodize the whole aircraft. :-)

Pat

Pat Flannery wrote:
:
:This says a lot about grounding internal electronics and fuel tanks in
:airliners: http://www.coasttocoastam.com/gen/pa...ml?theme=light
:One of the problems that composite aircraft structures face is they may
:not be electrically conductive enough to transmit lightning safely to an
:exit point when they are struck, so the composites are burned and
:shattered. It would be interesting to know how Boeing is dealing with
:this on the the new 787's composite structure.
:

I believe that's a problem that's already been solved. They embed
metal fibers in the composite structures. Remember, we've been
building composite military aircraft for a long time now.


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world." -- Mary Shafer, NASA Dryden

Pat Flannery wrote:

It would be interesting to know how Boeing is dealing with
this on the the new 787's composite structure.

Google, as it almost always is, is your friend.

D.
--
Touch-twice life. Eat. Drink. Laugh.

http://derekl1963.livejournal.com/

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

On Aug 28, 10:25 am, Pat Flannery wrote:
[...]
The site cited evidently is run by someone who doesn't fly from the
midwest.

One of the problems that composite aircraft structures face is they may
not be electrically conductive enough to transmit lightning safely to an
exit point when they are struck, so the composites are burned and
shattered.

To add to Derek's comment, google for "On the composite fuselage of
the 787 a strike is unlikely to penetrate more than the outer layers
of carbon fiber."

The article continues, "Such damage needs repair but is not a big
deal." and then goes on to explain what is a big deal.

/dps

On Tue, 28 Aug 2007 17:50:31 -0500, Pat Flannery
wrote:

They should go back to Howard Hughes' wild idea for the Convair 880, and
gold anodize the whole aircraft. :-)

....Switching his geese from spruce to gold, then?

OM
--
]=====================================[
] OMBlog - http://www.io.com/~o_m/omworld [
] Let's face it: Sometimes you *need* [
] an obnoxious opinion in your day! [
]=====================================[

On Tue, 28 Aug 2007 12:25:40 -0500, Pat Flannery
wrote:

This says a lot about grounding internal electronics and fuel tanks in
airliners: http://www.coasttocoastam.com/gen/pa...ml?theme=light

....Otay, I'm now worried about Patrick. I mean, I've got an *excuse*
to be listining to any incarnation of the Fart Smell show(s), as I
need the absurdity to keep me awake on the way home from SA about four
times a week now. But Pat, last I heard, doesn't. Is it boredom at
night, or is he just being sadomasochistic?

OM
--
]=====================================[
] OMBlog - http://www.io.com/~o_m/omworld [
] Let's face it: Sometimes you *need* [
] an obnoxious opinion in your day! [
]=====================================[

Derek Lyons wrote:
Pat Flannery wrote:


It would be interesting to know how Boeing is dealing with
this on the the new 787's composite structure.


Google, as it almost always is, is your friend.


And we need a article address on that one if you've found it, as it
would be fun to read the technical specs on the technique being used. :-)

Pat

snidely wrote:
To add to Derek's comment, google for "On the composite fuselage of
the 787 a strike is unlikely to penetrate more than the outer layers
of carbon fiber."


Carbon fiber is a excellent conductor (I used to have a bundle of near
microscopic carbon fiber used as a car's main lead to its distributer),
but there's the resin matrix it's held in to consider. If that
superheats during the lightning strike, it could generate a severe
shockwave into the composite skin's structure as it vaporizes...at the
very least, you are talking about a pretty involved burn repair compared
to the normal pointy-surface-in; pointy-surface-out damage caused by a
lightning strike on a aluminum aircraft structure. Tests NASA did with
that by flying a F-106 through a thunderstorm supersonically showed
strike heating damage limited to around a radius of of a couple of
inches on either end of the lightning strike.

Pat