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Volitox Ignis
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[*] posted on 28-1-2016 at 16:48
Better propellants,anybody?


I have an interest in rocketry,though I am still somewhat new. After watching Grant Thompson's series on homemade rockets on Youtube,I am starting to get the idea to attach a camera to a rocket and then launch it. Before anybody wonders,yes,there will be a parachute system. I am wondering if there is a propellant composition that is better than the "Potassium Nitrate-Sugar" mixture to account for the extra weight added to the rocket. Any help is appreciated.
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[*] posted on 28-1-2016 at 16:56


Hi, VI. Welcome to SM.
Sorry, I can't answer your question but I am sure that one of the EM freaks will be along soon. I do know that there are a large number of options for propellants but also that the risk increases as you get into more powerful ones.

As a rule, around here, all new threads that begin that don't contain references go into the "beginnings" section. And we prefer that old relevant threads be resurrected rather than new ones being started -- it keeps all of the information in one place. I suspect that a quick search will find quite a few threads that are relevant to your question. It might happen that a mod merges this with a pre-existing thread.

So, have some fun reading. Stick around and enjoy SM.




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[*] posted on 28-1-2016 at 17:08


powdered Zn & S mixtures cast into the tube with a wax center come to mind from amateur rocket builders handbook or similar title



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[*] posted on 28-1-2016 at 18:07


Black powder. It is basically high-power R-Candy: they both have KNO3 and a fuel. Charcoal has a greater energy density by weight than sugar, and with the addition of the sensitizer, sulfur, you have a very fast burning, high-output fuel. Cheap too, and you can make it yourself.



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[*] posted on 28-1-2016 at 18:27


You can get super smAll spy cam type devices cheaply and being so small they will add very little weight to the rocket and it won't matter so much if you lose it. These KNO3 sugar mixtures can produce quite a surprisingly strong thrust for their sizes



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[*] posted on 29-1-2016 at 00:16


Quote: Originally posted by Detonationology  
Black powder. It is basically high-power R-Candy: they both have KNO3 and a fuel. Charcoal has a greater energy density by weight than sugar, and with the addition of the sensitizer, sulfur, you have a very fast burning, high-output fuel. Cheap too, and you can make it yourself.


That is not true. Sugar is better than charcoal. Higher ISP. There is no reason of thinking a more powerful rocket fuel. You can just increase your size of your motor. Add more fuel - grains. Nasa uses APCP for their solid rocket motors (250 ISP). You can use ammonium perchlorate than potassium nitrate for much more better ISP. You can use also ammonium nitrate for better ISP but it is a difficult oxidizer to play with. You can also alter your fuel to burn slower. For me the slower it burns, the better it woul be, as you can put more fuel with the same diameter into your rocket casing. Diameter of your rocket REALLY affects your peak aktitude because of drag. Two stage rocket goes much higher than an one stage rocket with the same fuel mass. This is because of the outside diameter

[Edited on 29-1-2016 by underground]
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[*] posted on 29-1-2016 at 01:09


There really isn't many alternatives to the KNO3/sugar-mix than can compete with cost, availability and simplicity. Simply scale the motor for the task at hand and you should be fine. If you're interested in rocketry you should visit Nakka's site, it's THE page on sugar fuels.



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[*] posted on 29-1-2016 at 04:12


Quote: Originally posted by underground  
Two stage rocket goes much higher than an one stage rocket with the same fuel mass. This is because of the outside diameter


I don't think that is correct. AFAIK, multiple stages are better due to the non-zero mass of the casing; it is inefficient to use your thrust to accelerate all that dead weight, so you eject it in stages. I remember doing an assignment on this in a course on classical mechanics almost 20 years ago.

Concerning better rocket propellants, KNO3/sucrose is really all you need for the kind of rocket you are talking about. It is a very forgiving propellant with decent performance. However, there is also the AN/Al/silicone rubber propellant which is smoke-free and has higher performance. If you modify it with burn rate catalysts, phase stabilize the AN and incorporate a decent amount of NC/NG in the grain, you can make an insanely powerful propellant.
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[*] posted on 29-1-2016 at 06:17


https://en.wikipedia.org/wiki/Energy_density
https://en.wikipedia.org/wiki/Energy_content_of_biofuel

Carbohydrates (including sugars): 17,000 kJ/kg

Charcoal: 30,000 kJ/kg




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[*] posted on 29-1-2016 at 07:04


https://www.youtube.com/watch?v=-SxHDlawuP0

heres my recipe on something i call acetate substitute whistle mix
composition:
60%KClO3
20%CH3COONa
10%Sugar
2%iron oxide
8%vaseline

[Edited on 29-1-2016 by mysteriusbhoice]
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[*] posted on 29-1-2016 at 07:16


Quote: Originally posted by mysteriusbhoice  
https://www.youtube.com/watch?v=-SxHDlawuP0

heres my recipe on something i call acetate substitute whistle mix
composition:
60%KClO3
20%CH3COONa
10%Sugar
2%iron oxide
8%vaseline

[Edited on 29-1-2016 by mysteriusbhoice]

Impressive burn rate. Is that you in the video? From my experience with chlorates, they tend to much more sensitive and unstable than perchlorates. Whistle mix in general is very sensitive shit. Have you tried compressing your comp. in a tube to see if it will actually whistle?




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[*] posted on 29-1-2016 at 08:44


Quote: Originally posted by Detonationology  

Impressive burn rate. Is that you in the video? From my experience with chlorates, they tend to much more sensitive and unstable than perchlorates. Whistle mix in general is very sensitive shit. Have you tried compressing your comp. in a tube to see if it will actually whistle?


www.youtube.com/watch?v=P8VLAo1k8aA
this is my older video on the same recipe and the chlorate i used there was made differently through decomposition of calcium hypochlorite and i used another brand of KCl one that contained no ferrocyanide anti caking agent
and it was recrystalized twice

acetate based whistle mix is SUPER STABLE if the chlorate is pure in this older video i hammered the crap out of it and microwaved it

i also microwaved my new whistle mix made from my new chlorate and caught fire while inside

the only downside to this recipe is acetate being hygroscopic but i added a little vaseline to solve that

also yes i did try it and it makes a whistle!! and flies but my cheap rolled aluminum foil tube melted afterwards

[Edited on 29-1-2016 by mysteriusbhoice]
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[*] posted on 29-1-2016 at 10:53


Quote: Originally posted by Detonationology  
Black powder. It is basically high-power R-Candy: they both have KNO3 and a fuel. Charcoal has a greater energy density by weight than sugar, and with the addition of the sensitizer, sulfur, you have a very fast burning, high-output fuel. Cheap too, and you can make it yourself.


You have your fuel performance backwards. Specific impulse of rocket candy is higher than BP.

Yes, it takes rocket science to understand why.





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[*] posted on 29-1-2016 at 11:02


Quote: Originally posted by Detonationology  

Carbohydrates 17,000 kJ/kg
Charcoal: 30,000 kJ/kg

Energy isn't everything. You also need to consider molar mass of the exhaust as this affects exhaust velocity and thus thrust. This makes black powder less than ideal as the sulfur will increase molar mass significantly. The increased burn rate it provides has little benefit in a rocket motor, the same result can be done by adjusting grain surface area and nozzle diameter.

In reality BP has an Isp of appr 80s while KNO3/sucrose can achieve 120-130s.




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[*] posted on 29-1-2016 at 11:14


Quote:
In reality BP has an Isp of appr 80s while KNO3/sucrose can achieve 120-130s.

Yeah, it's simply a question of moles of gas produced and their lower mol. weight . . . ?

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[*] posted on 29-1-2016 at 11:33


Quote: Originally posted by underground  
Quote: Originally posted by Detonationology  
Black powder. It is basically high-power R-Candy: they both have KNO3 and a fuel. Charcoal has a greater energy density by weight than sugar, and with the addition of the sensitizer, sulfur, you have a very fast burning, high-output fuel. Cheap too, and you can make it yourself.


That is not true. Sugar is better than charcoal. Higher ISP. There is no reason of thinking a more powerful rocket fuel. You can just increase your size of your motor. Add more fuel - grains. Nasa uses APCP for their solid rocket motors (250 ISP). You can use ammonium perchlorate than potassium nitrate for much more better ISP. You can use also ammonium nitrate for better ISP but it is a difficult oxidizer to play with. You can also alter your fuel to burn slower. For me the slower it burns, the better it woul be, as you can put more fuel with the same diameter into your rocket casing. Diameter of your rocket REALLY affects your peak aktitude because of drag. Two stage rocket goes much higher than an one stage rocket with the same fuel mass. This is because of the outside diameter

[Edited on 29-1-2016 by underground]
I'd agree with that, if you're looking for a cheap and easy alternative to sugar rockets ammonium perchlorate is the way to go. Add to it a bit of aluminum, rust, and usually a binder and you're good to go. If you're thinking of buying it I'd reccommend this site (Note: I'm not affiliated with this site in any way) http://www.aerotech-rocketry.com/default.aspx
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[*] posted on 29-1-2016 at 16:50



Quote:

if you're looking for a cheap and easy alternative to sugar rockets ammonium perchlorate is the way to go. Add to it a bit of aluminum, rust, and usually a binder and you're good to go.


You have not scratch made and flown amonium Perchlorate composite fuel engines, judging by that statement.

Cheaper it will not be. Much more expensive.

Easier it will not be. Candy or rammed black powder are the easiest motors to make, APCP is an order of magnitude more difficult, everything from making the nozzles to cleaning your tools just got harder (and more expensive-)

Safer it will not be either. Shock and friction sensitivity of the basic dry mixture with perchlorate/Aluminum/catalysts is much higher than BP, although the finished APCP propellant is less susceptible to sparks and static after consolidation into grains.

Higher performance, that it could be. But you will need to build rather better quality air frames to handle those snorty engines! Balsa fins and spiral wound cardboard won't do, you go to aluminum or plywood, carbon fiber, fiberglass and epoxy to stand up to the stresses.

Don't let that stop you though. Just understand where you're going-

[Edited on 30-1-2016 by Bert]




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[*] posted on 29-1-2016 at 18:15


Hello,
I'm very surprised that among all these talks for a better propellant than KNO3 / Sucrose no one mentioned Sorbitol? :o

I use the mixture for smoke generation (no consideration of nozzle design, specific impulse etc) in my weird hobbies (I'll tell you more once I've found the "presentation section" and I love it for many reasons:

- First and foremost, it becomes liquid around 100 degrees Celsius
This gives you a considerable margin of safety even though decomposition temperature of KNO3 is much much higher. Usually, the safer I am, the happier I am. And yeah, I do realize that these mixtures are not inherently safe. I do batches of 300 grams as many times as needed and even then, if 300 grams where to take fire in the pot I sure would looks stupid even though I am blessed with comprehensive neighbours that know not to call the fireman in case of smoke or weird smells coming from my place. (Maybe offering dry ice cubes for the drinks at a neighbour gathering helped)
Also, to be on the safe side, I start by melting the Sorbitol and then add the KNO3 + Fe2O3 premixed.

- I doesnt "caramelize" and starts to decompose as sugar does. Also, when melted it's a lot more liquid than sugar which will remain more viscous.

For these reasons it will be easier to cast into a mould than sugar. I've sometimes seen irregularities in the burn, but If I had a dessicator and a little vacuum pump I sure would test some more designs.

- Last and not least: cleaning ! Both KNO3 and Sorbitol are food additives so a Spill will not be catastrophic. I have everything I need in my kitchen but got myself another set of cooking pots for melting wax, "cooking" KNO3 & Sorbitol and I even have another pot I use when I need boiling water (ok, this is overkill but sometimes you put nasty things in hot water that you dont want in your morning tea no matter how careful you are).
Both dissolve so well in water that usually when I turn the faucet on the only thing left at the bottom of the pot I've put into the sink (I'm sure you wont ask why I do this with a full sink at the ready) is some Fe2O3.

I've used a lot of other oxydizers for different purposes (other nitrates, perchlorates, chlorates mostly). But I find this one so easy, less risky and so cheap to make that I'm a bit surprised it hasnt popped in the conversation yet :P
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[*] posted on 29-1-2016 at 20:39


Wow, I never knew that BP had a significantly lower isp than KNO3/Sugar. Why is it then that commercial model rockets use black powder? Moisture concerns, perhaps?

Also Herr Haber feel free to write something in the Prepublications forum if you have something to present to us.
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[*] posted on 30-1-2016 at 00:35


Oscillator: Simplicity. With BP you can make simple case-bound end-burners with decent performance for next to nothing. And as you mentioned, it is far less sensitive to moisture.



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[*] posted on 29-2-2016 at 18:47


i just discovered a chlorate based heat safe Rcandy that will not burn even at 200 degrees heat on stove
https://www.youtube.com/watch?v=h7cbygReqks


2nd video is decomposing the mixture at 200 degrees without chlorate reacting a new stupid way to make H3
https://www.youtube.com/watch?v=gdmF16cvoGk
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[*] posted on 1-3-2016 at 16:40


Quote: Originally posted by mysteriusbhoice  
i just discovered a chlorate based heat safe Rcandy that will not burn even at 200 degrees heat on stove
https://www.youtube.com/watch?v=h7cbygReqks


2nd video is decomposing the mixture at 200 degrees without chlorate reacting a new stupid way to make H3
https://www.youtube.com/watch?v=gdmF16cvoGk


Nice burn rate,that looks like a suitable alternative to the standard R-Candy composition.When I have time, I will try out the new mixture.



I tried out the APCP composition outlined in:
https://www.youtube.com/watch?v=TllMf7DzYkA

After a lot of trouble, I was able to get some ammonium perchlorate...and then I realized that it could be bought from Ebay( :mad: )Anyway,the results were less than satisfactory.
As for your whistle mix,it seems to be more of an explosive than a propellant. Will using more vaseline make the mixture usable for fuel?

[Edited on 2-3-2016 by Volitox Ignis]
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[*] posted on 2-3-2016 at 02:36


I'd stick with perchlorates . . .

Chlorates make very iffy propellants ─ is it a rocket or is it a pipe-bomb?

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[*] posted on 2-3-2016 at 03:09


Quote: Originally posted by hissingnoise  
I'd stick with perchlorates . . .

Chlorates make very iffy propellants ─ is it a rocket or is it a pipe-bomb?


with my composition so far i had no explosions!!
the starch somehow tames the chlorate in both the cooking of the candy and the launch of the rocket

i even desperately tried to make it explode by making a very thin nozzle and instead of exploding it let out a lot of gas like an air cannon just a fast deflagration!!

but if its in powder form and not candy form it can and will explode thats the reason why cooking chlorate is better

BUT only if you got starch mixed in or it will explode while cooking
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[*] posted on 2-3-2016 at 03:29


Quote: Originally posted by Volitox Ignis  


Nice burn rate,that looks like a suitable alternative to the standard R-Candy composition.When I have time, I will try out the new mixture.



I tried out the APCP composition outlined in:
https://www.youtube.com/watch?v=TllMf7DzYkA

After a lot of trouble, I was able to get some ammonium perchlorate...and then I realized that it could be bought from Ebay( :mad: )Anyway,the results were less than satisfactory.
As for your whistle mix,it seems to be more of an explosive than a propellant. Will using more vaseline make the mixture usable for fuel?


well i gave up on using my whistle mix as propellant because one of the rockets i made exploded and sent pvc shrapnel 15 feet from it and made a very loud sound that made my ears ring.

also one problem i notice with it and it probably is due to the fact that i had no proper pressing equipment is that the rockets didn't fly that high because most of the fuel is being kicked off from the motor and burning outside of it evident by that huge yellow flame on my whistle rocket vid.

vaseline in my experience acts as a 2ndary fuel and does seem to slow it down if i added alot of it but this mix has another wierd property

my whistle mix can reduce iron oxide into iron metal!!
its as if the iron oxide is a 2ndary oxidizer as well as a catalyst??

but that effect is only observed in my acetate substituted whistle mix and doesn't seem to happen in my citrate substituted whistle mix batches
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