After the accident they still insisted that they
were going ahead with manned flights but they are
also putting a lot of money into a new rocket for
use with the White Knight Two as an air launch to LEO for smaller satellites.
http://www.telegraph.co.uk/finance/newsbysector/industry/11816213/Virgin-Galactic-boldly-goes-into-small-satellites-telling-future-astronauts-you-have-to-wait.html
Robert
At 06:34 PM 12/6/2015, you wrote:
What ever happened to that thing?
Anthony.
Sent from my iPhone
On Dec 6, 2015, at 5:00 PM, <mailto:qbert@xxxxxxxxxxxxxxx>qbert@xxxxxxxxxxxxxxx wrote:
So what your saying is not to buy a ticket for a ride on "Spaceship 2".
Robert
At 12:25 PM 12/6/2015, you wrote:
We have this discussion about nitrous every six months. There is plenty of it in the archives for anyone curious. There are pictures of HPR nitrous hybrid rockets turning into a constellation of small pieces. Tim Pickens just posted to Facebookà a pic of a burst Marotta high pressure solenoid from a nitrous event. If you google car nitrous explosion it is clear that it is not a rare experience there either.Ã
Ã
On Sunday, December 6, 2015, Paul Mueller <<mailto:paul.mueller.iii@xxxxxxxxx> paul.mueller.iii@xxxxxxxxx> wrote:
I'd be interested in seeing the original source for the 1/4" liquid nitrous oxide critical diameter number--it does seem to contradict the extensive experience with liquid nitrous in racing applications that David mentions. After all, if liquid nitrous could detonate like that, I would think someone would have tested it as an explosive (strap a detonator onto or inside a bottle of nitrous). Maybe that would work, but TNT is better...?
The SPG site ( http://www.spg-corp.com/nitrous-oxide-safety.html) states "it is highly unlikely that a deflagration or detonation wave can be sustained in pure (uncontaminated) liquid nitrous oxide." So I'm not sure what to think.
On Sat, Dec 5, 2015 at 11:02 AM, David Gregory <<mailto:david.c.gregory@xxxxxxxxx>david.c.gregory@xxxxxxxxx> wrote:
The only literature I've located on the subject of N2O stability is here: Ã <http://docs.google.com/viewer?a=v&pid=sites&srcid=cm9ja2V0bW9vbmxpZ2h0aW5nLmNvbXxob21lfGd4OjExOTMyNTk1MTE4ZTYzYjA>http://docs.google.com/viewer?a=v&pid=sites&srcid=cm9ja2V0bW9vbmxpZ2h0aW5nLmNvbXxob21lfGd4OjExOTMyNTk1MTE4ZTYzYjA
They have some very interesting conclusions. Ã Ã One of them is that liquid N2O is largely stable and difficult to ignite. Ã However gaseous N2O is remarkably easy to ignite, even with sudden compression. Ã Ã The critical diameter for gaseous N2O is on the order of a few inches.
I take these conclusions to be consistent with the data for automotive and HPR uses of N2O (few if any reported incidents). Ã Ã And also consistent with the scaled accident - cold flows of liquid N2O inevitably also involve two phase flows, and the SS2 motor would have been well above the critical diameter.Ã Pg 28 has an interesting short discussion on unexplained decomposition anomalies - several of which occurred when venting from a pipe.
Note that quenching by the liquid phase is a common phenomenon - liquid oxygen fires in most "compatible" materials are only ignitable in the presence of the gaseous phase.Ã
-David
On Fri, Dec 4, 2015 at 12:53 PM, Lloyd Droppers <<mailto:ldroppers@xxxxxxxxx>ldroppers@xxxxxxxxx> wrote:
Yes, saying that a liquid N2O has a 1/4" critical diameter means that a tube larger that 1/4" will propagate a detonation wave while a smaller tube can damp the detonation wave depending on the material, length, etc. à 1/4" is actually a reasonable size as far as critical diameters for rocket monopropellants. For Refà <http://permalink.lanl.gov/object/tr?what=info:lanl-repo/lareport/LA-UR-10-01464>90%HTP is 1.0" critical diameter, <http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.2263489>Nitromethane is 0.1", and I couldn't find anything else quickly.
I think that you might be setting up a false dichotomy in thinking gaseous nitrous is the real bogeyman, as liquid nitrous is still a monopropellant and potentially dangerous if not handled with care. You have probably seen this but SPL has a nice <http://www.spl.ch/publication/SPL_Papers/N2O_safety_e.pdf>intro on Nitrous safety.
Lloyd
On Sat, Dec 5, 2015 at 7:24 AM, Paul Mueller <<mailto:paul.mueller.iii@xxxxxxxxx>paul.mueller.iii@xxxxxxxxx> wrote:
Thanks for the info and I'll try to educate myself. Meanwhile, does this mean that a 1/4" tube full of liquid nitrous could propagate a detonation wave due to dissociation (presumably the only energy source that could cause a detonation wave)? This seems to contradict my previous understanding that it is very difficult to have a dissociation reaction in liquid nitrous. Gaseous nitrous is the real boogey-man here. Am I up in the night?
Paul M
On Fri, Dec 4, 2015 at 11:08 AM, George Herbert <<mailto:george.herbert@xxxxxxxxx>george.herbert@xxxxxxxxx> wrote:
You really want Paul Coopers grad level textbook "Explosives Engineering".
George William Herbert
Sent from my iPhone
> On Dec 4, 2015, at 9:54 AM, Ed LeBouthillier <<mailto:codemonky@xxxxxxxxxxxxx>codemonky@xxxxxxxxxxxxx> wrote:
>
> Paul Mueller said
>
>> Yeah, I'm not familiar with the "critical diameter" and what it means that it is about 1/4" for liquid nitrous oxide.
>
> The critical diameter is the diameter at which a detonation can proceed down a tube.
> Smaller than that, the detonation should not propagate, large than that, it should.
>
> It's touched on here:
>
> <https://en.wikipedia.org/wiki/Explosive_material>https://en.wikipedia.org/wiki/Explosive_material
>
> and is more detailed here:
>
> <https://books.google.com/books?id=5P-mCAAAQBAJ&lpg=PA285&ots=42Lfa7DirE&dq=critical%20diameter%20detonation&pg=PA285#v=onepage&q=critical%20diameter%20detonation&f=false>https://books.google.com/books?id=5P-mCAAAQBAJ&lpg=PA285&ots=42Lfa7DirE&dq=critical%20diameter%20detonation&pg=PA285#v=onepage&q=critical%20diameter%20detonation&f=false
>
>