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Conductive Cloth
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Mark
Mar 15, 2013, 12:56:04 AM3/15/13
to
Looking for conductive cloth.
Need small quantity.
Needs to be very flexible.
Needs to have a cloth i.e. non-conductive (cotton, poly etc) surface on
both sides.
Needs to shield against RF.
Where can I find it?
Need small quantity.
Needs to be very flexible.
Needs to have a cloth i.e. non-conductive (cotton, poly etc) surface on
both sides.
Needs to shield against RF.
Where can I find it?
miso
Mar 15, 2013, 1:29:32 AM3/15/13
to
> http://www.lessemf.com/fabric.html
Tap Plastics stocks carbon fiber, but I don't think it is as suitable as
the cloth in the link above.
Tap Plastics stocks carbon fiber, but I don't think it is as suitable as
the cloth in the link above.
Sjouke Burry
Mar 15, 2013, 3:01:39 AM3/15/13
to
Mark <nospa...@nospam.com> wrote in news:khu9hm$r16$1...@dont-email.me:
Buy silver or goldlaced cloth.
Robert Macy
Mar 15, 2013, 11:12:19 AM3/15/13
to
owned by a French company that one time designed a flexible pullover
type shirt with inbedded conductors. They might pass on the name of
the company that made the prototype shirts.
try contacting Bob Stone 408 684 5110
Tronics MedTech, Inc.
1525 McCarthy Blvd., Suite 212
Milpitas, CA 95035
Tel: 408 541 1212
Fax: 408 541 1763
info AT tronicsmedtech.com
Being an EMC Expert, I don't think you'll get the type of shielding
you want, you could try firms that make flexible EMC shielding, but
those products are pretty metallic.
There is a company that makes 'home' products, and from memory may
sell clothing specifically designed for shielding. Again from memory,
ELF shielding. I just did a search in my data base and since can't
remember their name, can't find it!
Let me know if you want their name, and I'll make an effort to knock
cobwebs off brain and find for you..
John Larkin
Mar 15, 2013, 11:36:27 AM3/15/13
to
Small quantity = sample!
--
John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com
Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
lang...@fonz.dk
Mar 15, 2013, 12:40:56 PM3/15/13
to
On Mar 15, 4:36 pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
http://www.norad4u.com/emr-protection/rf-protection
;)
-Lassse
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Thu, 14 Mar 2013 21:56:04 -0700, Mark <nospamm...@nospam.com> wrote:
> >Looking for conductive cloth.
>
> >Need small quantity.
> >Needs to be very flexible.
> >Needs to have a cloth i.e. non-conductive (cotton, poly etc) surface on
> >both sides.
> >Needs to shield against RF.
>
> >Where can I find it?
>
> http://www.lairdtech.com/products/emi-solutions/
>
> Small quantity = sample!
>
can be sure that someone like these will sell something:
> >Looking for conductive cloth.
>
> >Need small quantity.
> >Needs to be very flexible.
> >Needs to have a cloth i.e. non-conductive (cotton, poly etc) surface on
> >both sides.
> >Needs to shield against RF.
>
> >Where can I find it?
>
> http://www.lairdtech.com/products/emi-solutions/
>
> Small quantity = sample!
>
http://www.norad4u.com/emr-protection/rf-protection
;)
-Lassse
George Herold
Mar 15, 2013, 1:27:20 PM3/15/13
to
hat!
(I liked the pic of the office with RF protecting fabric... and all
the computer gear on the desk.)
Fun,
George H.
>
> ;)
>
> -Lassse- Hide quoted text -
>
> - Show quoted text -
Jeff Liebermann
Mar 15, 2013, 1:34:46 PM3/15/13
to
On Thu, 14 Mar 2013 21:56:04 -0700, Mark <nospa...@nospam.com>
wrote:
>Looking for conductive cloth.
>
>Need small quantity.
Is that a quantity of less than one?
>Needs to be very flexible.
How flexible? Does it need to stretch? If not, something like
aluminum window screening, sandwiched between two layers of ordinary
cloth, might work. If that's too stiff, just find someone that can do
rubber calendaring (screening) over the aluminum window screen.
<http://wirecloth.com/pdf/Spec_Cat.pdf>
>Needs to have a cloth i.e. non-conductive (cotton, poly etc) surface on
>both sides.
It will be interesting to see how you make an electrical connection to
the shielding through the cloth.
>Needs to shield against RF.
At what frequency?
How much attenuation do you require?
Any FCC, IEC, etc specs involved?
>Where can I find it?
Dunno, but I've had to wear RF protective overalls when climbing radio
towers. I've seen two types of material. One is an aluminized mylar
sheet glued to the outside of ordinary cloth. The other has a mesh of
fine sliver wires woven into the material. You might ask the vendors
of such overalls where they buy their material.
<http://www.unitechus.com/content/services/rf_protection.php>
<http://www.radhaz.com/projects.php?id=34>
<http://www.rfsafetysolutions.com/RF%20Radiation%20Pages/RF_Protective_Garments.html>
The overalls were a bit on the heavy side but quite comfortable. The
fully metalized version was like wearing a sauna, which also stored
the body odors of the previous occupants.
There are also vendors that sell to the RF paranoia and
electrosensitive market what sells everything from RF shielded
underwear to "drag as you walk" grounding anchors:
<http://www.lessemf.com/personal.html>
<http://www.norad4u.com/emr-protection/rf-protection>
If you can't find anything, send me an email and I'll ask my former
friends in the Smog Angeles garment district if they have a source.
Although my fathers business was making lingerie, we also did some
heavy metal clothing, which might qualify.
--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
wrote:
>Looking for conductive cloth.
>
>Need small quantity.
>Needs to be very flexible.
aluminum window screening, sandwiched between two layers of ordinary
cloth, might work. If that's too stiff, just find someone that can do
rubber calendaring (screening) over the aluminum window screen.
<http://wirecloth.com/pdf/Spec_Cat.pdf>
>Needs to have a cloth i.e. non-conductive (cotton, poly etc) surface on
>both sides.
the shielding through the cloth.
>Needs to shield against RF.
How much attenuation do you require?
Any FCC, IEC, etc specs involved?
>Where can I find it?
towers. I've seen two types of material. One is an aluminized mylar
sheet glued to the outside of ordinary cloth. The other has a mesh of
fine sliver wires woven into the material. You might ask the vendors
of such overalls where they buy their material.
<http://www.unitechus.com/content/services/rf_protection.php>
<http://www.radhaz.com/projects.php?id=34>
<http://www.rfsafetysolutions.com/RF%20Radiation%20Pages/RF_Protective_Garments.html>
The overalls were a bit on the heavy side but quite comfortable. The
fully metalized version was like wearing a sauna, which also stored
the body odors of the previous occupants.
There are also vendors that sell to the RF paranoia and
electrosensitive market what sells everything from RF shielded
underwear to "drag as you walk" grounding anchors:
<http://www.lessemf.com/personal.html>
<http://www.norad4u.com/emr-protection/rf-protection>
If you can't find anything, send me an email and I'll ask my former
friends in the Smog Angeles garment district if they have a source.
Although my fathers business was making lingerie, we also did some
heavy metal clothing, which might qualify.
--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Mark
Mar 15, 2013, 3:43:53 PM3/15/13
to
Anyone know?
There is no electrical connection. It is to be used as a barrier
surrounding a sensitive device.
Jeff Liebermann
Mar 15, 2013, 7:45:57 PM3/15/13
to
On Fri, 15 Mar 2013 12:43:53 -0700, Mark <n...@spamnot.com> wrote:
>I wonder if the electrostatic jackets and lab coats would work?
>Anyone know?
It's easy enough to test. Fire up your cell phone, wireless PDA, or
>I wonder if the electrostatic jackets and lab coats would work?
>Anyone know?
cordless phone, and see if you can make a call or connection while
wearing an anti-static lab coat over your head. When you're done
feeling foolish about this test, you might consider that the typical
conductivity of an antistatic sheet is in the hundreds of kilo ohms
per square, while that of a wire mesh RF shield is in factions of an
ohm per square.
>There is no electrical connection.
>It is to be used as a barrier
>surrounding a sensitive device.
reflectors, and absorbers. In this case, the last thing you want is a
conductor or reflector. At best, these will take your unspecified RF
source, and bounce the signal around your unspecified sensitive
device, going in directions unknown. Reflectors do not diminish the
signal very much, were you can easily end up with a stronger RF signal
in places. On the other foot, absorbers convert the RF into heat,
which is not going to affect your unspecified sensitive device, and
will not reflect all over the unspecified surroundings. When you're
done trying to make a reflector or conductor work, think about using
an absorber.
Ecnerwal
Mar 15, 2013, 9:46:53 PM3/15/13
to
In article <khu9hm$r16$1...@dont-email.me>, Mark <nospa...@nospam.com>
wrote:
saran wrap
reynolds wrap
saran wrap
Available at your grocery store. You might also find something suitable
in a smaller quantity by ordering a hot sandwich (foil-paper composite
and add a napkin.) Depending how small a quantity you need, gum,
chocolate or cigarettes will also serve.
--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.
wrote:
reynolds wrap
saran wrap
Available at your grocery store. You might also find something suitable
in a smaller quantity by ordering a hot sandwich (foil-paper composite
and add a napkin.) Depending how small a quantity you need, gum,
chocolate or cigarettes will also serve.
--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.
upsid...@downunder.com
Mar 16, 2013, 3:22:14 AM3/16/13
to
For low frequencies, it should look like a Faraday cage. This at least
requires some electric connections between the conductive surfaces in
the trousers and in the jacket.
Zippers are problematic, you may have to use some overlapping cloth
and metallic snap buttons to cover the zipper. Depending on frequency,
you may have to use metallic snap buttons at every 3 cm, making
dressing and undressing quite painful.
How about the head/face ? Is it covered or not ?
The largest risk for RF damage is the eyes, since there are no thermal
sensitive neurons in our eyes, so never look into a waveguide, which
might even theoretically be powered up.
The next sensitive part is our brain due to heat damage.
What is the point of protecting the body from RF exposure, if the head
is not protected ? If the head/face is not properly protected, any
microwave radiation will penetrate from the opening for the neck into
the lower body parts.
Jan Panteltje
Mar 16, 2013, 5:15:12 AM3/16/13
to
On a sunny day (Fri, 15 Mar 2013 16:45:57 -0700) it happened Jeff Liebermann
<je...@cruzio.com> wrote in <s7c7k85iolchu6u3o...@4ax.com>:
>On Fri, 15 Mar 2013 12:43:53 -0700, Mark <n...@spamnot.com> wrote:
>
>>I wonder if the electrostatic jackets and lab coats would work?
>>Anyone know?
>
>It's easy enough to test.
http://en.wikipedia.org/wiki/Plate_armour
<je...@cruzio.com> wrote in <s7c7k85iolchu6u3o...@4ax.com>:
>On Fri, 15 Mar 2013 12:43:53 -0700, Mark <n...@spamnot.com> wrote:
>
>>I wonder if the electrostatic jackets and lab coats would work?
>>Anyone know?
>
>It's easy enough to test.
Jeff Liebermann
Mar 16, 2013, 12:33:16 PM3/16/13
to
On Sat, 16 Mar 2013 09:15:12 GMT, Jan Panteltje
<pNaonSt...@yahoo.com> wrote:
> http://en.wikipedia.org/wiki/Plate_armour
Cute.
Speaking of plate armor, Boeing's "solution" to the 787 Dreamliner
burning battery problem is to fortify it inside 150 lbs of steel
casing.
<http://www.nytimes.com/2013/03/16/business/boeing-details-its-fixes-for-787.html>
So much for the weight advantages of LiIon. I wonder if it includes a
barbeque grill on top.
<pNaonSt...@yahoo.com> wrote:
> http://en.wikipedia.org/wiki/Plate_armour
Cute.
Speaking of plate armor, Boeing's "solution" to the 787 Dreamliner
burning battery problem is to fortify it inside 150 lbs of steel
casing.
<http://www.nytimes.com/2013/03/16/business/boeing-details-its-fixes-for-787.html>
So much for the weight advantages of LiIon. I wonder if it includes a
barbeque grill on top.
Jan Panteltje
Mar 16, 2013, 3:50:59 PM3/16/13
to
On a sunny day (Sat, 16 Mar 2013 09:33:16 -0700) it happened Jeff Liebermann
<je...@cruzio.com> wrote in <vc79k898e3c2khlta...@4ax.com>:
>On Sat, 16 Mar 2013 09:15:12 GMT, Jan Panteltje
><pNaonSt...@yahoo.com> wrote:
>
>> http://en.wikipedia.org/wiki/Plate_armour
>
>Cute.
>
>Speaking of plate armor, Boeing's "solution" to the 787 Dreamliner
>burning battery problem is to fortify it inside 150 lbs of steel
>casing.
><http://www.nytimes.com/2013/03/16/business/boeing-details-its-fixes-for-787.html>
>So much for the weight advantages of LiIon. I wonder if it includes a
>barbeque grill on top.
I like the sentence:
"Mr. Sinnett said that Boeing engineers had identified 80 different ways that the batteries could fail"
Does not make me that optimistic...
Yes the heat must go somewhere, maybe bring bacon and eggs...
:-)
<je...@cruzio.com> wrote in <vc79k898e3c2khlta...@4ax.com>:
>On Sat, 16 Mar 2013 09:15:12 GMT, Jan Panteltje
><pNaonSt...@yahoo.com> wrote:
>
>> http://en.wikipedia.org/wiki/Plate_armour
>
>Cute.
>
>Speaking of plate armor, Boeing's "solution" to the 787 Dreamliner
>burning battery problem is to fortify it inside 150 lbs of steel
>casing.
><http://www.nytimes.com/2013/03/16/business/boeing-details-its-fixes-for-787.html>
>So much for the weight advantages of LiIon. I wonder if it includes a
>barbeque grill on top.
"Mr. Sinnett said that Boeing engineers had identified 80 different ways that the batteries could fail"
Does not make me that optimistic...
Yes the heat must go somewhere, maybe bring bacon and eggs...
:-)
Jeff Liebermann
Mar 16, 2013, 5:34:27 PM3/16/13
to
On Sat, 16 Mar 2013 19:50:59 GMT, Jan Panteltje
research is necessary". Claiming that there are XX number of unsolved
problems is largely a poorly veiled solicitation for a consulting
contract. I add phrases like that to most of my reports reminding the
customer that if he happens to have some money left for research, I
wouldn't mind getting a piece of the action.
>Yes the heat must go somewhere, maybe bring bacon and eggs...
>:-)
Well, Boeing did add a "new titanium venting system" which presumably
will act as a chimney or smoke stack.
The Boeing fix (800KBytes):
<http://787updates.newairplane.com/Boeing787Updates/media/Boeing787Updates/Certification/Webcast/Boeing-787-solution-presentation-English.pdf>
The technical briefing (90 min video... yawn)
<http://787updates.newairplane.com/certification/webcast>
The Boeing press release:
<http://boeing.mediaroom.com/index.php?s=43&item=2619>
Just in case, the start of a cover up or plausible denial.
What? No fire?
<http://www.theregister.co.uk/2013/03/15/boeing_787_fix/>
"Venting batteries produced 'smoke' that wasn't, no fire,
performed as planned."
and:
"a deep discharge event occurred in one cell of the
planes' batteries, heating it to the point at which
it vented so much hot electrolyte that an adjacent
cell warmed and also vented."
Domino effect for batteries by thermal transfer via electrolyte spray.
Truly amazing. More research is necessary on this apparently new and
previously unknown phenomenon.
<pNaonSt...@yahoo.com> wrote:
>On a sunny day (Sat, 16 Mar 2013 09:33:16 -0700) it happened Jeff Liebermann
><je...@cruzio.com> wrote in <vc79k898e3c2khlta...@4ax.com>:
>
>>On Sat, 16 Mar 2013 09:15:12 GMT, Jan Panteltje
>><pNaonSt...@yahoo.com> wrote:
>>
>>> http://en.wikipedia.org/wiki/Plate_armour
>>Cute.
>>
>>Speaking of plate armor, Boeing's "solution" to the 787 Dreamliner
>>burning battery problem is to fortify it inside 150 lbs of steel
>>casing.
>><http://www.nytimes.com/2013/03/16/business/boeing-details-its-fixes-for-787.html>
>>So much for the weight advantages of LiIon. I wonder if it includes a
>>barbeque grill on top.
>I like the sentence:
> "Mr. Sinnett said that Boeing engineers had identified 80 different ways that the batteries could fail"
>Does not make me that optimistic...
That phrase is part of the standard tag line ending in "... more
>On a sunny day (Sat, 16 Mar 2013 09:33:16 -0700) it happened Jeff Liebermann
><je...@cruzio.com> wrote in <vc79k898e3c2khlta...@4ax.com>:
>
>>On Sat, 16 Mar 2013 09:15:12 GMT, Jan Panteltje
>><pNaonSt...@yahoo.com> wrote:
>>
>>> http://en.wikipedia.org/wiki/Plate_armour
>>Cute.
>>
>>Speaking of plate armor, Boeing's "solution" to the 787 Dreamliner
>>burning battery problem is to fortify it inside 150 lbs of steel
>>casing.
>><http://www.nytimes.com/2013/03/16/business/boeing-details-its-fixes-for-787.html>
>>So much for the weight advantages of LiIon. I wonder if it includes a
>>barbeque grill on top.
>I like the sentence:
> "Mr. Sinnett said that Boeing engineers had identified 80 different ways that the batteries could fail"
>Does not make me that optimistic...
research is necessary". Claiming that there are XX number of unsolved
problems is largely a poorly veiled solicitation for a consulting
contract. I add phrases like that to most of my reports reminding the
customer that if he happens to have some money left for research, I
wouldn't mind getting a piece of the action.
>Yes the heat must go somewhere, maybe bring bacon and eggs...
>:-)
will act as a chimney or smoke stack.
The Boeing fix (800KBytes):
<http://787updates.newairplane.com/Boeing787Updates/media/Boeing787Updates/Certification/Webcast/Boeing-787-solution-presentation-English.pdf>
The technical briefing (90 min video... yawn)
<http://787updates.newairplane.com/certification/webcast>
The Boeing press release:
<http://boeing.mediaroom.com/index.php?s=43&item=2619>
Just in case, the start of a cover up or plausible denial.
What? No fire?
<http://www.theregister.co.uk/2013/03/15/boeing_787_fix/>
"Venting batteries produced 'smoke' that wasn't, no fire,
performed as planned."
and:
"a deep discharge event occurred in one cell of the
planes' batteries, heating it to the point at which
it vented so much hot electrolyte that an adjacent
cell warmed and also vented."
Domino effect for batteries by thermal transfer via electrolyte spray.
Truly amazing. More research is necessary on this apparently new and
previously unknown phenomenon.
josephkk
Mar 16, 2013, 9:59:27 PM3/16/13
to
On Sat, 16 Mar 2013 09:22:14 +0200, upsid...@downunder.com wrote:
>On Thu, 14 Mar 2013 21:56:04 -0700, Mark <nospa...@nospam.com>
>wrote:
>
>>Looking for conductive cloth.
>>
>>Need small quantity.
>>Needs to be very flexible.
>>Needs to have a cloth i.e. non-conductive (cotton, poly etc) surface on
>>both sides.
>>Needs to shield against RF.
>>
>>Where can I find it?
>>
>
>What frequency range ?
>
>For low frequencies, it should look like a Faraday cage. This at least
>requires some electric connections between the conductive surfaces in
>the trousers and in the jacket.
>
>Zippers are problematic, you may have to use some overlapping cloth
>and metallic snap buttons to cover the zipper. Depending on frequency,
>you may have to use metallic snap buttons at every 3 cm, making
>dressing and undressing quite painful.
Not at all. Conductive hook and loop fastenings (Velcro (Tm)) are
>On Thu, 14 Mar 2013 21:56:04 -0700, Mark <nospa...@nospam.com>
>wrote:
>
>>Looking for conductive cloth.
>>
>>Need small quantity.
>>Needs to be very flexible.
>>Needs to have a cloth i.e. non-conductive (cotton, poly etc) surface on
>>both sides.
>>Needs to shield against RF.
>>
>>Where can I find it?
>>
>
>What frequency range ?
>
>For low frequencies, it should look like a Faraday cage. This at least
>requires some electric connections between the conductive surfaces in
>the trousers and in the jacket.
>
>Zippers are problematic, you may have to use some overlapping cloth
>and metallic snap buttons to cover the zipper. Depending on frequency,
>you may have to use metallic snap buttons at every 3 cm, making
>dressing and undressing quite painful.
available. Elastic conductive fabrics are available as well.
>
>How about the head/face ? Is it covered or not ?
Conductive hat and veil, again with hook and loop fastenings.
>How about the head/face ? Is it covered or not ?
>
>The largest risk for RF damage is the eyes, since there are no thermal
>sensitive neurons in our eyes, so never look into a waveguide, which
>might even theoretically be powered up.
>
>The next sensitive part is our brain due to heat damage.
>
>What is the point of protecting the body from RF exposure, if the head
>is not protected ? If the head/face is not properly protected, any
>microwave radiation will penetrate from the opening for the neck into
>the lower body parts.
Actually, protecting the feet and hands are the toughest problems.
>The largest risk for RF damage is the eyes, since there are no thermal
>sensitive neurons in our eyes, so never look into a waveguide, which
>might even theoretically be powered up.
>
>The next sensitive part is our brain due to heat damage.
>
>What is the point of protecting the body from RF exposure, if the head
>is not protected ? If the head/face is not properly protected, any
>microwave radiation will penetrate from the opening for the neck into
>the lower body parts.
?-)
Jan Panteltje
Mar 17, 2013, 6:24:27 AM3/17/13
to
On a sunny day (Sat, 16 Mar 2013 14:34:27 -0700) it happened Jeff Liebermann
<je...@cruzio.com> wrote in <9bn9k8dbints04et9...@4ax.com>:
I have read that pdf no, very comprehensive.
A few questions pop up:
Is it worth it (added weight of enclosure) cost of all that testing yet to be done, possible repeat of events,
it is not enough that is is not dangerous due to fire, it is also a backup of flight systems (in flight),
so it SHOULD NEVER HAPPEN, this solution looks as though they expect it to happen frequently,
so why not go back to nicads, or some other technology (Airbus is working of fuel cells).
>The technical briefing (90 min video... yawn)
><http://787updates.newairplane.com/certification/webcast>
>
>The Boeing press release:
><http://boeing.mediaroom.com/index.php?s=43&item=2619>
>
>Just in case, the start of a cover up or plausible denial.
>What? No fire?
><http://www.theregister.co.uk/2013/03/15/boeing_787_fix/>
> "Venting batteries produced 'smoke' that wasn't, no fire,
> performed as planned."
>and:
> "a deep discharge event occurred in one cell of the
> planes' batteries, heating it to the point at which
> it vented so much hot electrolyte that an adjacent
> cell warmed and also vented."
>Domino effect for batteries by thermal transfer via electrolyte spray.
>Truly amazing. More research is necessary on this apparently new and
>previously unknown phenomenon.
Yes, but everyday the fleet is grounded costs airlines, and I am sure they will sue Boeing, money.
Yes, industry at it best, that poor technician who warned the FAA those batteries were a flying bomb fired,
wonder if they will compensate him in some way.
There is also something else,
years ago when the A480 was presented (by big time politicians), I looked at he wing, and said (its on usenet)
"That construction is not OK": Now they have cracks in the wing.
I look at he dreamliner wing, and it sucks. It sucks from an aerodynamic POV.
But just again a gut feeling.
I like delta wings:
http://www.youtube.com/watch?v=WYDGTd5ND-4
That is flying:
http://www.youtube.com/watch?v=Cf-xsxPMWnE
That thing flies up to 160 km/h
:-)
May be a while before we see that for passenger planes..
<je...@cruzio.com> wrote in <9bn9k8dbints04et9...@4ax.com>:
A few questions pop up:
Is it worth it (added weight of enclosure) cost of all that testing yet to be done, possible repeat of events,
it is not enough that is is not dangerous due to fire, it is also a backup of flight systems (in flight),
so it SHOULD NEVER HAPPEN, this solution looks as though they expect it to happen frequently,
so why not go back to nicads, or some other technology (Airbus is working of fuel cells).
>The technical briefing (90 min video... yawn)
><http://787updates.newairplane.com/certification/webcast>
>
>The Boeing press release:
><http://boeing.mediaroom.com/index.php?s=43&item=2619>
>
>Just in case, the start of a cover up or plausible denial.
>What? No fire?
><http://www.theregister.co.uk/2013/03/15/boeing_787_fix/>
> "Venting batteries produced 'smoke' that wasn't, no fire,
> performed as planned."
>and:
> "a deep discharge event occurred in one cell of the
> planes' batteries, heating it to the point at which
> it vented so much hot electrolyte that an adjacent
> cell warmed and also vented."
>Domino effect for batteries by thermal transfer via electrolyte spray.
>Truly amazing. More research is necessary on this apparently new and
>previously unknown phenomenon.
Yes, industry at it best, that poor technician who warned the FAA those batteries were a flying bomb fired,
wonder if they will compensate him in some way.
There is also something else,
years ago when the A480 was presented (by big time politicians), I looked at he wing, and said (its on usenet)
"That construction is not OK": Now they have cracks in the wing.
I look at he dreamliner wing, and it sucks. It sucks from an aerodynamic POV.
But just again a gut feeling.
I like delta wings:
http://www.youtube.com/watch?v=WYDGTd5ND-4
That is flying:
http://www.youtube.com/watch?v=Cf-xsxPMWnE
That thing flies up to 160 km/h
:-)
May be a while before we see that for passenger planes..
mpm
Mar 17, 2013, 11:23:00 AM3/17/13
to
They are very lightweight, or so I understand, and were able to keep (most of) the shuttles from burning up on re-entry.
Jeff Liebermann
Mar 17, 2013, 12:32:44 PM3/17/13
to
On Sun, 17 Mar 2013 08:23:00 -0700 (PDT), mpm <mpmi...@aol.com>
wrote:
>Wouldn't Space Shuttle tiles be a better solution for the Boing 787?
>They are very lightweight, or so I understand, and were able to keep
>(most of) the shuttles from burning up on re-entry.
It wasn't the silica tiles that failed on the Columbia. It was the
reinforced carbon-carbon leading edge panel that crumbled when
impacted by rather light weight, but high velocity, foam insulation.
I think Boeing is trying to contain an potential explosion and not
just deal with the heat produced. The pure silica glass shuttle tiles
are rather brittle and would probably make a nice fragmentation bomb.
My guess(tm) is that the steel box is temporary and a quick fix to get
the 787 back in the air, and that a more elegant solution will quietly
be developed somewhat later.
Each 787 carries TWO such battery boxes. One powers the APU, which is
where the two "non-fires" happened. The other box powers the cockpit
instruments, which might explain the current crisis mode.
I wonder how thick the battery box will be. The modifications added
68Kg (150 lbs) to the weight of the two battery boxes, most of which
is probably in the steel box. I couldn't find any dimensions on the
battery box, but my guess(tm) from the photos and the Yuasa LVP-65
battery dimensions is about 40cm x 28cm x 20cm (LWH). That's a
surface area of about 5,000 sq-cm. Steel has a density of 7.8
grams/cm^3. For 34Kg, that's:
34Kg * 1000gm/Kg / 7.8gm/cm^3 = 4400 cm^3
Therefore, the approximate thickness of the steel box is:
5000 cm^2 / 4400 cm^3 = 1.1 cm or .43 inches
not including the weight of original box, which presumably is much
lighter than 34Kg. This 7/16" thick box will probably stop a small
explosion, which I guess(tm) is the justification for the weight.
wrote:
>Wouldn't Space Shuttle tiles be a better solution for the Boing 787?
>They are very lightweight, or so I understand, and were able to keep
>(most of) the shuttles from burning up on re-entry.
reinforced carbon-carbon leading edge panel that crumbled when
impacted by rather light weight, but high velocity, foam insulation.
I think Boeing is trying to contain an potential explosion and not
just deal with the heat produced. The pure silica glass shuttle tiles
are rather brittle and would probably make a nice fragmentation bomb.
My guess(tm) is that the steel box is temporary and a quick fix to get
the 787 back in the air, and that a more elegant solution will quietly
be developed somewhat later.
Each 787 carries TWO such battery boxes. One powers the APU, which is
where the two "non-fires" happened. The other box powers the cockpit
instruments, which might explain the current crisis mode.
I wonder how thick the battery box will be. The modifications added
68Kg (150 lbs) to the weight of the two battery boxes, most of which
is probably in the steel box. I couldn't find any dimensions on the
battery box, but my guess(tm) from the photos and the Yuasa LVP-65
battery dimensions is about 40cm x 28cm x 20cm (LWH). That's a
surface area of about 5,000 sq-cm. Steel has a density of 7.8
grams/cm^3. For 34Kg, that's:
34Kg * 1000gm/Kg / 7.8gm/cm^3 = 4400 cm^3
Therefore, the approximate thickness of the steel box is:
5000 cm^2 / 4400 cm^3 = 1.1 cm or .43 inches
not including the weight of original box, which presumably is much
lighter than 34Kg. This 7/16" thick box will probably stop a small
explosion, which I guess(tm) is the justification for the weight.
josephkk
Mar 19, 2013, 10:11:40 PM3/19/13
to
r-value around 1000 and weighs about 1 pound per square foot. It becomes
ablative around 1200 C.
?-)
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