[AR] Re: High pressure storage tanks and thermal shielding
- From: William Valliant <wnvalliant@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Mon, 17 Oct 2016 22:30:04 -0700
Hey guys,
About the cryogenic tank, what about spun formed stainless steel 304 liner
with carbon fiber over wrap for the oxygen? Isn't that what they are
already doing?
About the thermal shielding or unburnium thread, what about actively
venting gas into a slightly recessed surface that would then be vaporized?
You could have the expanded plasma overflow off the edges while the
relatively cooler gas near the surface replaces it? Maybe even design the
thing to push against the rare atmosphere a bit and just go in norm to the
vel vector of the atmosphere? As long as the flow rate isn't insane it
could work
On Oct 17, 2016 10:08 PM, "FreeLists Mailing List Manager" <
ecartis@xxxxxxxxxxxxx> wrote:
arocket Digest Mon, 17 Oct 2016 Volume: 04 Issue: 253
In This Issue:
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Long March 2F panel ejection?
[AR] Re: Long March 2F panel ejection?
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
[AR] Re: SpaceX failure update
----------------------------------------------------------------------
From: Craig Fink <webegood@xxxxxxxxx>
Date: Mon, 17 Oct 2016 07:49:17 -0700
Subject: [AR] Re: SpaceX failure update
On Sun, Oct 16, 2016 at 8:19 PM, Randall Clague <rclague@xxxxxxxxx> wrote:
Nonburnite ((c) XCOR Aerospace) is a useful structural material. I'm not
at liberty to say how difficult it is to ignite in LOX, or how well (if it
all) it sustains ignition in LOX, but XCOR sent it off to WSTF for
flammability testing, and the results were really, really good.
Things that are already burnt, teflon, SiC would be good to use in entry
vehicles too.
http://www2.dupont.com/Teflon_Industrial/en_US/assets/
downloads/PTFE_62_Product_Sheet_DCFTeflon62_K24255.pdf
--
Craig Fink
WeBeGood@xxxxxxxxx
------------------------------
Date: Mon, 17 Oct 2016 12:40:22 -0400 (EDT)
From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
On Mon, 17 Oct 2016, Craig Fink wrote:
Things that are already burnt, teflon, SiC would be good to use in entry
vehicles too.
Uh, neither Teflon nor SiC is "already burnt". Both will burn in extreme
circumstances (and reentry can be pretty extreme).
As already noted, Teflon burned in the Apollo 13 accident. Even without
combustion, it decomposes starting at around 250degC, so it's not a
high-temperature material. (Teflon-coated frying pans notwithstanding --
they are often operating quite near the limits of the material, and a bit
of care is needed not to overheat them.)
SiC is normally very resistant to oxidation because it forms a durable
oxide layer (of SiO2), but it can burn -- it is sometimes used as a
supplementary *fuel* in basic-oxygen steelmaking. Its widespread use for
high-temperature applications hinges on the fact that it's very hard to
ignite, not that it can't burn.
About the only materials that really, truly cannot burn (in air) are
things that are already fully oxidized -- the highest-valence oxides and
nitrides. Unfortunately, they generally aren't good structural materials,
as witness the fragility of the shuttle tiles.
Henry
------------------------------
Date: Mon, 17 Oct 2016 12:47:23 -0400
From: Ed Kelleher <Pres@xxxxxxxxxxxxxxxxxxxxx>
Subject: [AR] Long March 2F panel ejection?
Was watching the Shenzhou 11 launch and saw some white panels falling
off the vehicle just a few seconds after liftoff.
At 2:11 in this video:
http://spaceflight101.com/shenzhou-11-launch-videos/
What are they for?
They're too regular in shape to be ice.
Also, non cryo propellants, so don't think it would be pre-launch
insulation.
They appear to be over the 2nd stage engine compartment, right above
where the 2nd stage exhaust port opening are.
I understand that like the Titan II, LM 2F 2nd stage starts while
still attached to the 1st stage.
Maybe they block the ports to keep the birds out?
Fume control to protect pad personnel?
They fall off too soon after launch to be anything for vibration
control or sound insulation.
Anyone have a clue?
Ed Kelleher
------------------------------
Date: Mon, 17 Oct 2016 12:55:46 -0400 (EDT)
From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
Subject: [AR] Re: Long March 2F panel ejection?
On Mon, 17 Oct 2016, Ed Kelleher wrote:
Was watching the Shenzhou 11 launch and saw some white panels falling off
the
vehicle just a few seconds after liftoff...
...non cryo propellants, so don't think it would be pre-launch insulation.
Don't be too sure of that. If you look at photos of old Ariane launches
(before Ariane 5), you'll see panels falling off the second stage -- they
*are* insulation, meant to keep the second-stage propellants (N2O4/UDMH)
from warming up to Kourou daytime ambient temperatures! In effect, the
old Ariane second stage used slightly-chilled propellants, to get a bit
more mass into the same tanks and/or keep the N2O4 pressure down (not sure
which was the more important issue). Could be that some of the Long
Marches do the same thing.
Henry
------------------------------
Date: Mon, 17 Oct 2016 21:19:53 +0200
From: Uwe Klein <uwe@xxxxxxxxxxxxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
Am 17.10.2016 um 18:40 schrieb Henry Spencer:
About the only materials that really, truly cannot burn (in air) are
things that are already fully oxidized -- the highest-valence oxides and
nitrides. Unfortunately, they generally aren't good structural
materials, as witness the fragility of the shuttle tiles.
asbestos?
uwe
------------------------------
From: "John Dom" <johndom@xxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
Date: Mon, 17 Oct 2016 21:40:31 +0200
Henry Spencer & Uwe on 171016:
About the only materials that really, truly cannot burn (in air) are
things that are already fully oxidized -- the highest-valence oxides and
nitrides. Unfortunately, they generally aren't good structural materials,
as witness the fragility of the shuttle tiles.
Like glass or quartzglass siliconoxide which was (or is) used next to
ablative layers inside ICBM noses.
jd
------------------------------
Date: Mon, 17 Oct 2016 16:15:59 -0400 (EDT)
From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
On Mon, 17 Oct 2016, Uwe Klein wrote:
About the only materials that really, truly cannot burn (in air) are
things that are already fully oxidized ... Unfortunately, they
generally aren't good structural materials...
asbestos?
Asbestos is fibers of a few specific silicates. By itself, you can weave
cloth out of it (should you be suicidally inclined :-) ) but it's not a
structural material. Embed the fibers in a matrix material to make a
composite and it has some structural strength, but what material do you
use as the matrix?
Henry
------------------------------
Date: Mon, 17 Oct 2016 16:24:30 -0400 (EDT)
From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
On Mon, 17 Oct 2016, John Dom wrote:
About the only materials that really, truly cannot burn (in air) are
things that are already fully oxidized -- the highest-valence oxides
and nitrides. Unfortunately, they generally aren't good structural
materials, as witness the fragility of the shuttle tiles.
Like glass or quartzglass siliconoxide which was (or is) used next to
ablative layers inside ICBM noses.
In other words, silica -- which is what the shuttle tiles are made of.
That's the sort of fragile, structurally-useless material you get when you
try to use silica by itself.
Embed silica fibers in a matrix of something else and you can have a
useful structural material, yes, but what do you use as a matrix? All the
common matrix materials -- including, yes, the ones used in ablators --
are flammable organic resins. Some of them don't burn easily, but they
will all burn, so they're irrelevant to the impossible pipe dream of
trying to use only non-flammable materials in reentry vehicles.
Henry
------------------------------
Date: Mon, 17 Oct 2016 22:26:43 +0200
From: Uwe Klein <uwe@xxxxxxxxxxxxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
Am 17.10.2016 um 22:15 schrieb Henry Spencer:
On Mon, 17 Oct 2016, Uwe Klein wrote:
About the only materials that really, truly cannot burn (in air) are
things that are already fully oxidized ... Unfortunately, they
generally aren't good structural materials...
asbestos?
Asbestos is fibers of a few specific silicates. By itself, you can
weave cloth out of it (should you be suicidally inclined :-) ) but it's
not a structural material. Embed the fibers in a matrix material to
make a composite and it has some structural strength, but what material
do you use as the matrix?
cement.
asbestos fibers in a cement binding was the established solution.
The question one would have to answer is:
are virginity concepts applicable to asbestos?
( same goes for a range of other materials.
what real environmental impact forex does "Lead glass" have.)
------------------------------
From: Andrew Burns <burns.andrew@xxxxxxxxx>
Date: Tue, 18 Oct 2016 09:42:07 +1300
Subject: [AR] Re: SpaceX failure update
Alumina?
On Tue, Oct 18, 2016 at 9:15 AM, Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Mon, 17 Oct 2016, Uwe Klein wrote:
About the only materials that really, truly cannot burn (in air) are
things that are already fully oxidized ... Unfortunately, they generally
aren't good structural materials...
asbestos?
Asbestos is fibers of a few specific silicates. By itself, you can weave
cloth out of it (should you be suicidally inclined :-) ) but it's not a
structural material. Embed the fibers in a matrix material to make a
composite and it has some structural strength, but what material do you
use
as the matrix?
Henry
------------------------------
From: "Troy Prideaux" <troy@xxxxxxxxxxxxxxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
Date: Tue, 18 Oct 2016 08:47:19 +1100
Of course the obvious material selection for structural strength is
fibreglass which can't be burnt. That still leaves you with a binder
requirement which as Henry says is the challenge - mainly because you
generally need some elasticity in your matrix. If you didn't need any
elasticity or ductility you can settle for a refractory ceramic compound but
the resulting matrix will likely be too fragile for most practical
applications.
Regarding Teflon: sometimes it's important to distinguish between the trade
name "Teflon" and PTFE which is a specific material. Teflon can mean various
fluoroplastics, some of which can be extruded (which PTFE can't) some of
which can tolerate >300deg C (which PTFE can't) some of which can be used
as coatings for frying pans (which PTFE generally isn't used) although
similar temperature limits apply. Then there are other fluoroplastics with
very similar properties to the Teflons like PCTFE...
https://www.chemours.com/Teflon_Industrial/en_US/products/product_by_name/te
flon_af/grades.html
Troy
-----Original Message-----
From: arocket-bounce@xxxxxxxxxxxxx [
mailto:arocket-bounce@xxxxxxxxxxxxx] On
Behalf Of Henry Spencer
Sent: Tuesday, 18 October 2016 3:40 AM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: SpaceX failure update
On Mon, 17 Oct 2016, Craig Fink wrote:
Things that are already burnt, teflon, SiC would be good to use in
entry vehicles too.
Uh, neither Teflon nor SiC is "already burnt". Both will burn in extreme
circumstances (and reentry can be pretty extreme).
As already noted, Teflon burned in the Apollo 13 accident. Even without
combustion, it decomposes starting at around 250degC, so it's not a
high-temperature material. (Teflon-coated frying pans notwithstanding --
they are often operating quite near the limits of the material, and a bit of
care is needed not to overheat them.)
SiC is normally very resistant to oxidation because it forms a durable oxide
layer (of SiO2), but it can burn -- it is sometimes used as a supplementary
*fuel* in basic-oxygen steelmaking. Its widespread use for high-temperature
applications hinges on the fact that it's very hard to ignite, not that it
can't burn.
About the only materials that really, truly cannot burn (in air) are things
that are already fully oxidized -- the highest-valence oxides and nitrides.
Unfortunately, they generally aren't good structural materials, as witness
the fragility of the shuttle tiles.
Henry
------------------------------
Subject: [AR] Re: SpaceX failure update
From: George William Herbert <george.herbert@xxxxxxxxx>
Date: Mon, 17 Oct 2016 15:05:11 -0700
Alumina fiber is not a horrible choice.
Sent from my iPhone
On Oct 17, 2016, at 1:42 PM, Andrew Burns <burns.andrew@xxxxxxxxx> wrote:
Alumina?
On Tue, Oct 18, 2016 at 9:15 AM, Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Mon, 17 Oct 2016, Uwe Klein wrote:
About the only materials that really, truly cannot burn (in air) are
things that are already fully oxidized ... Unfortunately, they generally
aren't good structural materials...
asbestos?
Asbestos is fibers of a few specific silicates. By itself, you can
weave cloth out of it (should you be suicidally inclined :-) ) but it's not
a structural material. Embed the fibers in a matrix material to make a
composite and it has some structural strength, but what material do you use
as the matrix?
Henry
------------------------------
From: Andrew Burns <burns.andrew@xxxxxxxxx>
Date: Tue, 18 Oct 2016 11:21:09 +1300
Subject: [AR] Re: SpaceX failure update
I wonder what kind of high-temperature composite could be made using
something like this as a reinforcement:
https://zircarzirconia.com/products/type-al-alumina-fibers-textiles/
Andrew
On Tue, Oct 18, 2016 at 11:05 AM, George William Herbert <
george.herbert@xxxxxxxxx> wrote:
Alumina fiber is not a horrible choice.
Sent from my iPhone
On Oct 17, 2016, at 1:42 PM, Andrew Burns <burns.andrew@xxxxxxxxx> wrote:
Alumina?
On Tue, Oct 18, 2016 at 9:15 AM, Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Mon, 17 Oct 2016, Uwe Klein wrote:
About the only materials that really, truly cannot burn (in air) are
things that are already fully oxidized ... Unfortunately, they
generally
aren't good structural materials...
asbestos?
Asbestos is fibers of a few specific silicates. By itself, you can weave
cloth out of it (should you be suicidally inclined :-) ) but it's not a
structural material. Embed the fibers in a matrix material to make a
composite and it has some structural strength, but what material do you
use
as the matrix?
Henry
------------------------------
From: "John Dom" <johndom@xxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
Date: Tue, 18 Oct 2016 00:43:16 +0200
Henry Spencer wrote on 171016
Like glass or quartzglass siliconoxide which was (or is) used next to
ablative layers inside ICBM noses.
In other words, silica -- which is what the shuttle tiles are made of.
That's the sort of fragile, structurally-useless material you get when you
try to use silica by itself.
Embed silica fibers in a matrix of something else and you can have a
useful structural material, yes, but what do you use as a matrix? All the
common matrix materials -- including, yes, the ones used in ablators -- are
flammable organic resins. Some of them don't burn easily, but they will all
burn, so they're irrelevant to the impossible pipe dream of trying to use
only non-flammable materials in reentry vehicles.
AKA tektites:
http://www.tektites.co.uk/Missiles.html
jd
------------------------------
Date: Mon, 17 Oct 2016 19:58:01 -0400
From: Norman Yarvin <yarvin@xxxxxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
On Mon, Oct 17, 2016 at 04:24:30PM -0400, Henry Spencer wrote:
Embed silica fibers in a matrix of something else and you can have a
useful structural material, yes, but what do you use as a matrix?
In principle, one could imagine a tight enough three-dimensional weave
of fibers that a matrix wouldn't be necessary: they'd be under enough
stress that friction alone would keep them in place.
In practice, I wouldn't want to have to build the weaving machine. (I
think it would need to keep hundreds if not thousands of fibers each
individually under high stress while weaving them around each other in
some complicated pattern under computer control -- an expensive and
slow process.) It'd be an interesting research project, though.
------------------------------
Subject: [AR] Re: SpaceX failure update
From: "Jake Anderson" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender "jake"
Date: Tue, 18 Oct 2016 11:13:38 +1100
On 18/10/16 10:58, Norman Yarvin wrote:
On Mon, Oct 17, 2016 at 04:24:30PM -0400, Henry Spencer wrote:
Embed silica fibers in a matrix of something else and you can have a
useful structural material, yes, but what do you use as a matrix?
In principle, one could imagine a tight enough three-dimensional weave
of fibers that a matrix wouldn't be necessary: they'd be under enough
stress that friction alone would keep them in place.
In practice, I wouldn't want to have to build the weaving machine. (I
think it would need to keep hundreds if not thousands of fibers each
individually under high stress while weaving them around each other in
some complicated pattern under computer control -- an expensive and
slow process.) It'd be an interesting research project, though.
Actually would it though? you are basically just making a big flat
braided thing (if its for a heat shield) like nylon webbing essentially.
------------------------------
From: Steve Traugott <stevegt@xxxxxxx>
Date: Mon, 17 Oct 2016 18:10:49 -0700
Subject: [AR] Re: SpaceX failure update
On Mon, Oct 17, 2016 at 5:13 PM, Jake Anderson <dmarc-noreply@xxxxxxxxxxxxx>
wrote:
Actually would it though? you are basically just making a big flat braided
thing (if its for a heat shield) like nylon webbing essentially.
I think this digression (on arocket? no way!) started with the idea of
removing flammable fibers and resins from COPV tanks immersed in LOX. So
the science experiment, then, would be to use something like alumina fibers
woven tightly enough to form an He-tight pressure vessel (is that even
going to be possible at molecular scale?).
------------------------------
Date: Mon, 17 Oct 2016 21:19:20 -0400
From: Norman Yarvin <yarvin@xxxxxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
On Tue, Oct 18, 2016 at 11:13:38AM +1100, Jake Anderson wrote:
On 18/10/16 10:58, Norman Yarvin wrote:
In principle, one could imagine a tight enough three-dimensional weave
of fibers that a matrix wouldn't be necessary: they'd be under enough
stress that friction alone would keep them in place.
In practice, I wouldn't want to have to build the weaving machine. (I
think it would need to keep hundreds if not thousands of fibers each
individually under high stress while weaving them around each other in
some complicated pattern under computer control -- an expensive and
slow process.) It'd be an interesting research project, though.
Actually would it though? you are basically just making a big flat
braided thing (if its for a heat shield) like nylon webbing essentially.
Nylon webbing is a normal sort of weave; the fibers aren't under any
serious tension. Some webbing is a bit stiff, yes, but I'm thinking
of a situation where each fiber is stressed to maybe a third of its
tensile strength while being woven, and stays that way in the finished
weave. I don't think anybody would even try to achieve that level of
tension in nylon webbing; it'd probably make it too hard to penetrate
with a sewing needle.
Also, nylon webbing is pretty much two-dimensional: it's just one
layer of threads (and another layer of cross-threads). I'm thinking
of multiple layers, all woven together by some sort of fiendishly
complicated and expensive machine. (It'd have to weave them directly
into final form, likely around a mold; there could be nothing like
today's production of fiber cloth by one company which then goes to
other companies to get cut into pieces, draped in layers into a mold,
then cured together.)
This would be Gordian Knot territory, or rather what the Gordians
could have done if they'd had computer-controlled knotting machines.
------------------------------
From: "Troy Prideaux" <troy@xxxxxxxxxxxxxxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
Date: Tue, 18 Oct 2016 12:24:16 +1100
I once tried something like this (well not really) with a pressure vessel
experiment. I was using a PETE softdrink bottle as a bladder and wrapped a
couple of layers of carbon sock over the outside that was destined to be
non wetted with binder ie. Provide the structural support, but not in a
"composite" matrix - dry fibres only . As an attempt to evenly tension all
the fibres, I allowed extra length of the sock at each end and wetted those
ends with resin which were squeezed together inside various bands of
stretched rubber band. The idea was to provide some initial tension to the
sock then pressurize the bladder (bottle) to expand it which would pull all
the fibres through the tight bands (uncured resin) at each end to
"theoretically" evenly tension the fibres. Then you'd wait until the resin
cured, then remove the elastic bands and replace them with something more
structural - maybe wraps of carbon fibre tow in composite form. Anyway, it
never really went anywhere ...
Troy
-----Original Message-----
From: arocket-bounce@xxxxxxxxxxxxx [
mailto:arocket-bounce@xxxxxxxxxxxxx] On
Behalf Of Jake Anderson (Redacted sender "jake" for DMARC)
Sent: Tuesday, 18 October 2016 11:14 AM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: SpaceX failure update
On 18/10/16 10:58, Norman Yarvin wrote:
On Mon, Oct 17, 2016 at 04:24:30PM -0400, Henry Spencer wrote:
Embed silica fibers in a matrix of something else and you can have a
useful structural material, yes, but what do you use as a matrix?
In principle, one could imagine a tight enough three-dimensional weave
of fibers that a matrix wouldn't be necessary: they'd be under enough
stress that friction alone would keep them in place.
In practice, I wouldn't want to have to build the weaving machine. (I
think it would need to keep hundreds if not thousands of fibers each
individually under high stress while weaving them around each other in
some complicated pattern under computer control -- an expensive and
slow process.) It'd be an interesting research project, though.
Actually would it though? you are basically just making a big flat braided
thing (if its for a heat shield) like nylon webbing essentially.
------------------------------
From: "Troy Prideaux" <troy@xxxxxxxxxxxxxxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
Date: Tue, 18 Oct 2016 12:28:05 +1100
Unlikely, but if you could find some kind of nanoscopic oxidized powder
that you can fill the vessel with, pressurize and utilise as some kind of
leak filler?
Troy.
From: arocket-bounce@xxxxxxxxxxxxx [
mailto:arocket-bounce@xxxxxxxxxxxxx] On
Behalf Of Steve Traugott
Sent: Tuesday, 18 October 2016 12:11 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: SpaceX failure update
On Mon, Oct 17, 2016 at 5:13 PM, Jake Anderson <dmarc-noreply@xxxxxxxxxxxxx
<
mailto:dmarc-noreply@xxxxxxxxxxxxx> > wrote:
Actually would it though? you are basically just making a big flat braided
thing (if its for a heat shield) like nylon webbing essentially.
I think this digression (on arocket? no way!) started with the idea of
removing flammable fibers and resins from COPV tanks immersed in LOX. So
the science experiment, then, would be to use something like alumina fibers
woven tightly enough to form an He-tight pressure vessel (is that even
going to be possible at molecular scale?).
------------------------------
Date: Mon, 17 Oct 2016 21:38:45 -0400
From: Norman Yarvin <yarvin@xxxxxxxxxxxx>
Subject: [AR] Re: SpaceX failure update
On Mon, Oct 17, 2016 at 06:10:49PM -0700, Steve Traugott wrote:
On Mon, Oct 17, 2016 at 5:13 PM, Jake Anderson <dmarc-noreply@xxxxxxxxxxxxx
wrote:
Actually would it though? you are basically just making a big flat
braided
thing (if its for a heat shield) like nylon webbing essentially.
I think this digression (on arocket? no way!) started with the idea of
removing flammable fibers and resins from COPV tanks immersed in LOX. So
the science experiment, then, would be to use something like alumina fibers
woven tightly enough to form an He-tight pressure vessel (is that even
going to be possible at molecular scale?).
To be even remotely practical, you'd need to use alumina fibers that
were much larger than molecule-wide. So no, something like this
couldn't be helium-tight or even airtight (and likely not even
watertight). But if you have a fiber structure that can hold its
shape without a matrix, you can apply a liner to it, and let that keep
the fluids in (or out).
Of course, this is all just conceptual: not at all what's done at the
moment, and perhaps altogether impractical.
------------------------------
From: Steve Traugott <stevegt@xxxxxxx>
Date: Mon, 17 Oct 2016 19:21:49 -0700
Subject: [AR] Re: SpaceX failure update
Probably-stupid question: What does sodium silicate do in LOX? Anyone
know?
On Mon, Oct 17, 2016 at 6:38 PM, Norman Yarvin <yarvin@xxxxxxxxxxxx> wrote:
On Mon, Oct 17, 2016 at 06:10:49PM -0700, Steve Traugott wrote:
On Mon, Oct 17, 2016 at 5:13 PM, Jake Anderson <
dmarc-noreply@xxxxxxxxxxxxx>
wrote:
Actually would it though? you are basically just making a big flat
braided
thing (if its for a heat shield) like nylon webbing essentially.
I think this digression (on arocket? no way!) started with the idea of
removing flammable fibers and resins from COPV tanks immersed in LOX. So
the science experiment, then, would be to use something like alumina
fibers
woven tightly enough to form an He-tight pressure vessel (is that even
going to be possible at molecular scale?).
To be even remotely practical, you'd need to use alumina fibers that
were much larger than molecule-wide. So no, something like this
couldn't be helium-tight or even airtight (and likely not even
watertight). But if you have a fiber structure that can hold its
shape without a matrix, you can apply a liner to it, and let that keep
the fluids in (or out).
Of course, this is all just conceptual: not at all what's done at the
moment, and perhaps altogether impractical.
------------------------------
Subject: [AR] Re: SpaceX failure update
From: Thomas Janstrom <thomas@xxxxxxxxxx>
Date: Tue, 18 Oct 2016 13:57:01 +1000
Colloidal alumina binder is regularly used in the furnace industry to
create low density alumina fibre based solids. Full vitrification occurs
at ~400C depending on brand used (I've used Wesoloc R in the past).
Adding some anhydrous alumina powder will get you a water resistant,
i.e. will hold water (but not indefinitely) vessel. Not real sure on the
tensile strength though, but thermally its AWESOME.
Thomas.
On 18/10/2016 8:05 AM, George William Herbert wrote:
Alumina fiber is not a horrible choice.
Sent from my iPhone
On Oct 17, 2016, at 1:42 PM, Andrew Burns <burns.andrew@xxxxxxxxx
<mailto:burns.andrew@xxxxxxxxx>> wrote:
Alumina?
On Tue, Oct 18, 2016 at 9:15 AM, Henry Spencer
<hspencer@xxxxxxxxxxxxx <mailto:hspencer@xxxxxxxxxxxxx>> wrote:
On Mon, 17 Oct 2016, Uwe Klein wrote:
About the only materials that really, truly cannot burn
(in air) are things that are already fully oxidized ...
Unfortunately, they generally aren't good structural
materials...
asbestos?
Asbestos is fibers of a few specific silicates. By itself, you
can weave cloth out of it (should you be suicidally inclined :-)
) but it's not a structural material. Embed the fibers in a
matrix material to make a composite and it has some structural
strength, but what material do you use as the matrix?
Henry
------------------------------
Subject: [AR] Re: SpaceX failure update
From: David Weinshenker <daze39@xxxxxxxxxxxxx>
Date: Mon, 17 Oct 2016 21:07:40 -0700
On 10/17/2016 08:57 PM, Thomas Janstrom wrote:
Colloidal alumina binder is regularly used in the furnace industry to
create low density alumina fibre based solids. Full vitrification occurs
at ~400C depending on brand used (I've used Wesoloc R in the past).
I've been wondering if it's possible to do some sort
of "glass-glass" composite - high-melting-point glass
fibers in a fused binder of lower-melting-point glass.
Perhaps the fabrication would involve powdering the binder,
making a suspension, applying this in the layup, and then
baking the assembly to fuse the binder into a solid glassy
matrix (like firing glaze on a ceramic pot).
-dave w
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End of arocket Digest V4 #253
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