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blackshire 06-29-2019 07:36 AM

Liquid-fuel model rocket option...
 
Hello All,

Tonight/this morning I watched the YouTube video of Rocket Lab's latest satellite launch (aboard their Electron vehicle: http://www.youtube.com/watch?time_c...2&v=idKCy8LdyKo ), which occurred on Saturday. Although I was aware of their rocket's new kick stage, whose rocket engine is named Curie (see: http://www.google.com/search?source...i67.VDmLwn7-ZQs ), I had never thought of its other possibilities until now, and:

The Curie engine, which is 3D printed, produces a thrust of just 120 N (27 lbf), with an unspecified specific impulse, burning an as-yet-undisclosed "green" monopropellant that is pressure-fed to the engine. There are some speculations--informed by a patent that Rocket Lab obtained (its link is on the below-linked webpage)--about what this "mystery propellant" is, though (see: https://space.stackexchange.com/que...ayload-kickstag ). It is thought to be some kind of liquid (or perhaps even gel-consistency) organic nitrate. (The British Jetex [and later, Jet-X] motors' solid fuel pellets were guanidinium nitrate [more commonly--and incorrectly--called guanidine nitrate], which decomposed, giving off much heat and some smoke when ignited by burning Jetex/Jet-X wick.) Now:

Since the pressure-fed Curie rocket engine produces relatively little thrust when burning its "green" monopropellant (which has a low specific impulse), this type of propellant and engine could be ideal for liquid propellant model rockets. At last, just as the R/C jet modelers eventually got real gas turbine jet engines to power their scale models, we could build liquid propellant flying scale models of liquid propellant guided missiles, ballistic missiles, satellite launch vehicles, and sounding rockets. Even smaller rocket engines (smaller than the 27 lb thrust Curie) would be perfect for scale (and non-scale) liquid propellant model rockets that used the same--or a similar--"green" pressure-fed monopropellant, and lower tank pressure (produced using a hand pump) would also suit such models well. Like the old Cold Propellant (and Coldpower Convertible) model rockets, these monopropellant ones could lift off slowly, and be really perking along at burnout, increasing the scale realism.

tbzep 06-29-2019 10:32 AM

Quote:
Originally Posted by blackshire
Jetex [and later, Jet-X] motors' solid fuel pellets were guanidinium nitrate [more commonly--and incorrectly--called guanidine nitrate],

My first though when reading this was "bat $#it crazy rocket propellant"! After reading about it, sure enough, it was first synthesized from Peruvian bat crap!

blackshire 06-30-2019 02:23 AM

Quote:
Originally Posted by tbzep
My first though when reading this was "bat $#it crazy rocket propellant"! After reading about it, sure enough, it was first synthesized from Peruvian bat crap!
Yep--it put the "guano" in the "guanidine!" Also:

I have never flown a Jetex (or Jet-X) model jet (thanks to the USPS folks in Anchorage, who let my order of Jet-X fuel pellets and two Jet-X motors [ordered from Davis Diesel years ago] get covered with snow out on the runway, then didn't brush the snow off after bringing the cart indoors, resulting in the fuel pellets getting soaked...), but I did try burning one of the dried-but-crumbled fuel pellets (in a washed pot pie pan) in the kitchen of my old house down the street. It produced a lot of bluish smoke, which definitely smelled of guano (think mouse, rat, gerbil, or hamster "residue"), mixed with an ammonia-like odor. (From what I have read, Jetex and Jet-X motors, in which the fuel pellets burn under pressure [having just a pinhole-like jet orifice], produce relatively little smoke, which just has an ammonia-like smell, although not intense enough to be irritating or noxious. But:

The "green" monopropellant that the Electron's Curie kick stage uses is--judging by the four spherical pressure vessels directly ahead of the Curie rocket engine--a liquid organic nitrate, and possibly even a gel-type organic nitrate. While the monopropellant is probably a chemical relative of guanidine nitrate (it's actually guanidinium nitrate, but most people use the shorter name, just as people mean "dinitrogen tetroxide" when they refer to "nitrogen tetroxide"), that doesn't mean that it's made from some kind of animal (Kiwi or Emu? :-) ) guano, as such organic chemicals are easily synthesized (in high school chemistry class, we made apple juice in laboratory glassware, and urea is also easily synthesized from reagents). I would love to be able to build and fly (if I could get another flying field, but others don't have that problem) such liquid propellant model rockets, especially scale models.

teflonrocketry1 06-30-2019 10:32 PM

AF-M315E, LMP-103S, are 2 of the newer green mono propellants that Rocket Labs probably uses, these are a lot less toxic and hazardous than hydrazine. Even though they are lass toxic and hazardous than hydrazine, they still are toxic and energetic.

Monopropellant LMP-103S is:
60-65 % Ammonium DiNitramide (ADN) ,
15-20 % Methanol ,
3-6 % Ammonia
and the balance Water (by weight).
I doubt ADN or the mixture LMP-1035S would be made available for our hobby visit: https://ndiastorage.blob.core.usgov...e/8Asjoberg.pdf

Monopropellant AF-M315E is a hydroxylammonium nitrate (HAN, NH3OHNO3) fuel/oxidizer blend, composed of:
65-75 % hydroxylammonium nitrate (HAN),
0-1% 2,2'-dipyridy,
0.5-10 % Ammonium Nitrate,
5-15 % 1,2,4-triazole,
0-10% 1H-pyrazole
and the balance is 0.5-10% Water.
I doubt HAN or the mixture AF-M315E would be made available for our hobby visit: https://static1.squarespace.com/sta...M+Mod+3+SDS.pdf

Hydroxylammonium nitrate, itself is a dense energetic ionic liquid, the hydroxylamine portion is a known irritant and mutagen. As a chemist I have worked with both hydrazine and hydroxylamine and will definitely say hydroxylamine salts are much easier of the 2 to work with as long as you don't heat them up.

frognbuff 07-01-2019 06:21 AM

Nice rundown, Teflon. So, in this case, "green" simply means you don't need a SCAPE suit to load it on a spacecraft? No toxic fumes?

teflonrocketry1 07-01-2019 08:01 PM

Quote:
Originally Posted by frognbuff
Nice rundown, Teflon. So, in this case, "green" simply means you don't need a SCAPE suit to load it on a spacecraft? No toxic fumes?


Green means you don't need heavy personal protection (like from a SCAPE suit) to work around the materials and there is much less potential for them to spread into the environment.

I handled hydrazine in a chemical fume hood. If that stuff spilled while a tank was being filled on a rocket it could potentially react with something nearby and probably cause an explosion or fire. Hydrazine is volatile like ammonia and would spread rapidly and get everywhere in the nearby area. You would need special gloves air tight clothing and a separate source of breathing air to clean up the mess.

The ionic liquid mixtures on the other hand are for the most part non-volatile and could be handled and cleaned up without a separate air source, although I would still wear protective clothing and gloves.

blackshire 07-09-2019 04:11 PM

Quote:
Originally Posted by teflonrocketry1
Green means you don't need heavy personal protection (like from a SCAPE suit) to work around the materials and there is much less potential for them to spread into the environment.

I handled hydrazine in a chemical fume hood. If that stuff spilled while a tank was being filled on a rocket it could potentially react with something nearby and probably cause an explosion or fire. Hydrazine is volatile like ammonia and would spread rapidly and get everywhere in the nearby area. You would need special gloves air tight clothing and a separate source of breathing air to clean up the mess.

The ionic liquid mixtures on the other hand are for the most part non-volatile and could be handled and cleaned up without a separate air source, although I would still wear protective clothing and gloves.
My father was a Fire Chief in the Miami Fire Department, and he was terrified of hypergolic reactants (having fought a few warehouse fires in which such substances were involved) because they can't be extinguished until they're all reacted; the only option is to cover them with lots of dirt, cordon off the area, and wait. Also:

As I read and saw in a 1950s-vintage issue of "Popular Science" (in which it was touted as a shining example of modern scientific progress), hydrazine used to be sprayed onto onions (and possibly also garlic bulbs) to prevent them from sprouting in grocery stores. It was also used as a defoliant (applied using garden pump sprayers) along railroad tracks, to kill weeds--a lot of college students made a little money doing that work. The article didn't say what variety of hydrazine it was (monomethyl hydrazine [the monopropellant thruster type] or the "regular" N2H4 type), or if it was diluted in some other substance, but I wouldn't care to inhale or ingest any type of hydrazine, in any concentration (although I imagine that after being sprayed on onions, it reacted to make other substances--but they might not be exactly beneficial, either).

ghrocketman 07-09-2019 06:40 PM

Hydrazine on Onions ?
Just one more reason for me to HATE stinkin' Onions.
Equally as disgusting as Kraut.

How could ANYONE think spraying ROCKET FUEL (Hydrazine) on a FOOD could possibly be good ?
Ignorant beyond belief.

blackshire 07-09-2019 07:03 PM

Quote:
Originally Posted by ghrocketman
Hydrazine on Onions ?
Just one more reason for me to HATE stinkin' Onions.
Equally as disgusting as Kraut.

How could ANYONE think spraying ROCKET FUEL (Hydrazine) on a FOOD could possibly be good ?
Ignorant beyond belief.
Those were the days of "Better living through chemistry." :-) Agent Orange (and Agent Pink--there was such a defoliant) were also touted as wonder products (before their "side effects" became well-known), and:

I have said (only half-jokingly), on occasions when a local Asian buffet's delicious Kimchi *wasn't* hot beyond the pain threshold, "Good--they left out the nitric acid today..."

ghrocketman 07-09-2019 08:05 PM

I actually believe in the old DuPont slogan of "Better living through Chemistry", but some things are beyond ridiculous.

I am definitely NOT of the camp of "OOH... CHEMICAL... MUST be BADDDD".
Will NEVER buy into the "Enviro-WHACK" agenda; most ALL of the "green" agenda is WHACK CRAPOLA we don't need AT ALL, EVER !

Actually I do believe in an environmental agenda; just not one any stricter than that followed by Dow Chemical, General Motors, Ortho/Chevron, and DuPont in 1957.

Same for the EPA; no more power than they had in 1957; NONE !


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