iceflyin
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NG as Rocket Fuel
Exactly how can NG be used as a rocket fuel oxidizer? Is it more powerful or comparable to KNO3/Sorbitol rockets? Anyone here tried using ETN as a
rocket fuel additive because of it's positive OB?
I have looked around and not found any information on the ratios or what chemical powders to add to the NG... Would you use a mixture of NG, KNO3, and
Charcoal/Sugar or something? That is the only thing I could think of. (Uhh, that kinda sounds like dynamite...)
These rockets just sound like they could have some rather impressive Catos... LoL!
[Edited on 26-4-2010 by iceflyin]
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hissingnoise
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| Quote: | (Uhh, that kinda sounds like dynamite...)
These rockets just sound like they could have some rather impressive Catos... LoL!
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Double-base propellants like ballistite and cordite are essentially blasting gelatine with a high NC content.
Composites with NH4ClO4 are safer and have slightly higher Isps.
A cato with Ngl/NC isn't something you'd want to be anywhere close to when it happens.
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quicksilver
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Some years back I was interested in this topic & compiled a bit of information as to compositions of single based smokeless powders , DBSP, &
TBSP. The addition of polyester as well as varieties of stabilizers and physical formats influenced burning rates. The TBSP had mixed within them
nitroguanadine but were generally used for quite large ballistic projectiles & forms often included extruded tubes with holes within their
lengths. The DBSP with the highest % of NG of course were Allient BULLSEYE 40%, Hodgeden TITEGROUP 37.2%, & a VitaVouri (# unk as I don't have the
notes in front of me). Others have a level of NG from single percentile - into the 20's of a percentage(Nitro 100, AA#2, etc). This copies dynamite;
as stumping grade (20%) and ditching grade (40%). That the remaining absorbent is often NC makes this material significant as it is certainly standard
explosive material.
Generally speaking these products were marketed as propellants as such was their use by nature of a initiator that held emphasis on flame spit (lead
styphnate & tetrazene were generally the strongest primary utilized in firearms primers as opposed to azides, etc). The level of powder (as well
as surface area ignited by primer) was also extremely important to the utilization of a powerful secondary to be tamed to provide "push" instead of
DDT.
IN reloading firearms ammunition a very strict warning was issued to never LOWER the level of powder in certain cases - for to do so would turn the
propellant to an explosive. This was also given the name "detonation" for those who chose to ignore the warning & saw the firearm explode.
The inclusion of a larger area of "room to burn" within the bullet case meant that a DDT often would result. The obvious reality was that standard
secondary explosives were tamed to propellants by a very demanding set of circumstances. Indeed, if the primer itself were not of a composition that
was designed to issue flame instead of primary train detonation, the propellant physics would be side-stepped in favor of the secondary's common
action of detonation.
A great deal of research was expended upon the delicate balance of taming the explosives. Most individuals who reload firearms projectiles know the
seriousness of overloading but in this case the under loading lead to a DDT with (often) more serious results in that the weapon's chamber was
shattered rather than with overloading; the distortion of barrel, chamber, etc [taking place in a slower catastrophic event].
That being said, the level of research into energetic materials lead to case-less ammunition, alteration of flight path of rocketry, & certainly
the accuracy of "area weapons" & their payload.
To alter the response of energetic materials has always been the focus of their utilization. Is smokeless powder a propellant or an explosive? In
Europe the canisters are labeled explosive; in the US, they are labeled propellant. obviously, they are both. The transportation laws &
bureaucratic twists are really the reason for the need for labeling as the conditions necessary for their action on either part is so weighed on a
complex set of conditions that to brand a polyester bound pellet of a nitric ester distinctly one or the other is superfluous.
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Microtek
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I have experimented quite a lot with ballistite typr propellants in the past, in an effort to develop a rocket small arm (essentially reinventing the
gyrojet).
I used a NG:NC ratio of 1:1 with various additives to regulate the pressure dependency of the burn rate. According to PATR 2700 (IIRC), a few percent
of CuO gave a plateau in the burn rate vs pressure plot, and I think lead compounds had an effect too but I didn't experiment with that due to health
concerns.
I found that the biggest problem with this kind of propellant was that it was difficult to achieve high enough burn rates when the grain was ignited
by a fuse. This was probably because of the necessary hole for the fuse (through the nozzle). When the grain was ignited electrically, and a diaphragm
was employed to allow pressure to build up, I got CATOs.
I did find that adding fine Al powder to the propellant made the burn rate accelerate much more effectively, and got some impressive liftoffs with
this system (and fuse ignition). However, I don't know if the increase in performance was due to the Al or Al2O3 clogging up the nozzle to a certain
degree (this certainly happens as evidenced by recovered nozzles) or some sort of propellant interaction such as increased opacity or increased heat
from the combustion of the Al.
All things considered, I found the ballistite propellants to be too temperamental to be used on their own, but they work very well as additives in
other propellants. One example which works very well is the AN/Al/silicone propellant which has been described elsewhere on this forum (not by me).
This propellant is incredibly powerful when prepared carefully, but very hard to ignite (a thermite pellet at the top of the core does not ensure
ignition). By incorporating 20 % of a 50:50 ballistite propellant, ignition by simple fuse is very reliable.
When making NC for these purposes, I prefer using microcrystalline cellulose since this produces NC in powder form. This makes it much easier to add
it to the main propellant, which outweighs the fact that it is not as highly nitrated as regular NC from cotton wool.
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quicksilver
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If I am correct both Ballistite & Cordite had the highest level of NG of all DBSP (50%+) and actually continued to rise with certain production
runs.
I actually remember the Gyrojet! I think I was in my early 20's. The folks that bought the rights to it were working on a barrel that had tighter
& tighter concentric rifling.....And I think it was functional but no one had interest. Now I think the company H&K owns it and is working on
a "big bore" version (at least that's what I read a year or so back). The idea was to make a combination of a rocket-grenade & a 50 bmg in one
unit. There is some military advertisement Email thing I get that has all that in it (like the Military channel on cable TV).
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