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Posted by on May 17, 2006, 6:04 am
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Since the success of SS1, there has been greater interest in rockets
using N2O as an oxidizer.
The pluses of N2O seem to be:
1) Availability - You can buy a tanker truck full of rocket grade
nitrous without much trouble.
2) Self Pressurizing - simplifies pressure-fed systems.
3) Non-cryogenic - liquid at room temp. under high pressure or slightly
chilled at modest pressure.
4) Low toxicity/high safety
and the minuses appear to be:
1) Cost - not as cheap as LOX
2) Low density
3) Low performance - compared to LOX, H2O2, N2O4, etc. (under 250s with
hydrocarbons)
Recently, I noticed that nitrous oxide should make an IDEAL oxidizer
for Aluminum Borohydride AlB3H12. The Aluminum reacts preferentially
with the oxygen, while the boron ends up reacting only with the
nitrogen. The chamber temperature is 3000K, and the exhaust is
non-toxic.
As I understand it, BN is much less problematic in the exhaust than
B2O3 is, and handling Al2O3 is established engineering.
Running the numbers through ProPEP, I see that performance could rival
LOX/LH2 when using a VERY high expansion ratio - 1:5000 gives a
theoretical ISP of about 452. If a working engine using this
combination could be built with an ISP over 400, I imagine it would be
far better suited as a lunar lander engine than NASA's current hope for
LOX/Methane.
The physical properties of N2O and Aluminum borohydride would also make
them very useful for an orbital fueling station.
So what do you all think?
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Posted by Bruno Berger on May 17, 2006, 4:10 pm
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notarealuser@wireless.co.il schrieb:
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> The physical properties of N2O and Aluminum borohydride would also make
> them very useful for an orbital fueling station.
>
> So what do you all think?
Maybe... but the handling seems to be a nightmare.
As usual... Clark's Ignition! mentions it in several paragraphs (along
with Beryllium and Lithium borohydride:
page 128:
"The third type includes the aluminum and beryllium borohydrides,
Al(BH4)3 and Be(BH4)2. These are covalent compounds, with unusual
bonding, liquids at room temperature, and violently hypergolic with air.
Nobody has ever had enough beryllium borohydride all together in one
place and at one time for a motor firing, but Armstrong and Young at
Aerojet fired aluminum borohydride with oxygen in 1950, and the next
year Wilson, also at Aerojet, burned it with liquid fluorine. The
results were not sufficiently encouraging to outweigh the difficulties
involved in handling the fuel, and aluminum borohydride lay more or less
dormant for some ten years."
I guess you don't want to deal with this stuff...
Bruno
www.spl.ch
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Posted by TC on May 17, 2006, 10:22 pm
Please log in for more thread options Salami is a good fuel for N2O.
See
http://kwc.org/mythbusters/2006/04/episode_51_myths_reopened.html
Tom
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Posted by delt0r on May 18, 2006, 5:09 am
Please log in for more thread options On the down side it is self Pressurizing. ie requires big heavy tanks.
It is real hard to beat LOX. Its dense so pumps are quite a lot easier.
Really hard to make a case for other oxidisers. By the way I use N2O
with my High Power Rockets. Real good for that size were min gauge
issues eat you up whole. SS1 motor was also tiny. So i don't think this
is a good reason to switch to N2O for a general oxidizer.
But for smaller engines then yea it could make sense. Cheaper to deal
with that H2O2 and Co.
By the way a Nozzel with 1:5000 expansion ratio is going to be *way*
too heavy. You will lose more than you gain.
Greg
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Posted by on June 3, 2006, 1:04 pm
Please log in for more thread options I think the main application for NO2 in spaceflight is as a competitor
for N2O2 in situations where a storable propellant is needed,
particularly on manned spacecraft. Years ago it was assumed N2O4 would
get "easier" to handle with time, but the cost of working with
hazardous materials has not declined; the requirements for contingency
preparations, training, medical support, PPE, etc remain a major cost
that can outweigh the mass advantage of N2O4. NO2 is essentially
nontoxic, though NASA requirements could end up specifying an (in my
opinion) unnecessary level of protection that would make it just as
expensive to use as N2O4.
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> them very useful for an orbital fueling station.
>
> So what do you all think?