Sciencemadness Discussion Board

Rocket Fuel Query

Dylan Hann - 7-2-2013 at 01:36

Model Rocket Fuel


I came across this Forum while searching for a formula or recipe for producing “Candy Rocket Fuel". I have a question relating to Sodium Nitrate as a substitute for Potassium Nitrate.

Most Experimental Model Sites I have come across have mentioned the use of Kno3 but very few show results for the use of sodium nitrate in the production of model rocket fuel.

I have made a batch of grains for my test rocket for a larger project that I am working on and would like an opinion on the ratio in my recipe.

The recipe is as follows;

Sodium Nitrate 65%
Glucose 33%
Liquid Sorbitol 1% (not able to obtain the powdered kind)
Iron Oxide 1%


I am using the liquid Sorbitol as a binding agent as done with corn syrup, The Glucose melts at a low temp and does not degrade during mixing under heat, and the Iron Oxide acts as a catalyst for maintaining a constant burn.

I am I close or does someone have a better Idea relating to the use of the ingredients available to me?


Thanks

Dylan
South Africa:cool::cool:

Metacelsus - 7-2-2013 at 05:42

I have had success with sodium nitrate "rocket candy". It's even somewhat better than the potassium nitrate variety, due to sodium nitrate's lower molar mass and thus higher oxygen balance. However, it's even more hygroscopic (it might be deliquescent, but I haven't tested it) than the potassium candy, so take necessary precautions.

[Edited on 7-2-2013 by Cheddite Cheese]

Dylan Hann - 7-2-2013 at 10:48

I have a simple solution to that issue, I use those bags you find in shoe boxes, medicine bottles
that absorbes moisture. My Friend organised large bags of it so we use them while storing the fuel grains.

Thanks for the feed back its great to know that I'm on the right track.

MrHomeScientist - 8-2-2013 at 13:25

Don't double-post, especially within only a few hours of your original post. Good answers take time to arrive.


As mentioned above, sodium nitrate is quite a bit more hygroscopic than potassium nitrate. I would think that as long as you take the reduced molar mass into account (about 59% less), the cation of your nitrate shouldn't make a difference in the fuel formula.