# rockets: fuels+oxidisers

## Recommended Posts

i am building a rocket and would like some help with fuels and oxidizers.

i know the standard KNO3 with sugar, but i have managed to find a supplier of KClO3 and i thought this would be better as it releases 3 moles of oxygen per mole when thermally decomposed, a lot better than KNO3's meager 1 to 1 ratio, any thoughts?

does anyone know what would be a good fuel to replace sugar providing more energy or gasses but still be safe? i was thinking coal dust but i cant balance the equation as i don't know its molecular formula or work out how much energy per mole would be released.

dont be too mean im just a shed scientist!!! also any tips on rocketry would be highly appreciated:-)

##### Share on other sites

generally it's best not to try and make these things too powerful, since you're entering the realm of making explosives at home, which is often frowned upon by authorities. Check our hazmat policy out (it's stickied in general chemistry)

##### Share on other sites

hazmat? explain please lol i have only just joined the site

and what would you recommend as a good source of power?

##### Share on other sites

hazmat is short for hazardous materials. here is the link

a good source of power is a plug socket :0)

##### Share on other sites

a good source of rocket power that is open to the shed scientist? sugar and KNO3 just isn't good enough

##### Share on other sites

coal dust or charcoal should work great, but it depends... i ran two equations for energy (except my calculator didnt have sucrose or KClO3 so i used glucose and KClO4)

C6H12O6(s) + 3KClO4(s) = 3KCl(s) + 6CO2(g) + 6H2O(g) + 2549.8kJ

2C(s) + KClO4(s) = KCl(s) + 2CO2(g) + 790.999kJ...

as you can see, the energy output per mole of KClO4 is just slightly higher with glucose...

but energy output by weight or volume is higher with charcoal...

##### Share on other sites

and another factor to remember is that the kinetics may be much slower for a different fuel.

##### Share on other sites

• 2 weeks later...

...The kinematics in solid-fuel rockets does vary depending upon the different fuels. We're talking about the ideally controlled release of energy that's stored chemically.

This has been experimented with quite a bit many years ago. Also, I am just now getting re-associated with a high-powered rocketry group, and may soon be forking over the dough for my federal permits to start making my own rockets again (there once was a time when federal, state, and local laws didn't give a crap about model rocketry - and amateur experimentation was A-Okay).

KClO3 isn't really all that great of a fuel and as mentioned, if you're not careful when making them you WILL be creating an explosive - a big federal no-no. In fact, making your own KNO3 rocket engines (with a different compound) is also illegal if your mass exceeds a certain amount.

I'd suggest sticking with commercially produced rocket motors - it will help you avoid a great many SERIOUS problems! If you attempt to persue making your own solid fuel engines I'm sure eventually you'll encounter some (if not all) of these problems:

- Expenses to replace destroyed motor bodies, remachining or replacing custom machined nozzles.

- Rebuilding your motor testing stand (because you blew it up 6 times already).

- Serious injury to yourself or an innocent bystander - possible severe burns, or death.

- A wonderful 5-10 years in prison for making illegal explosives without a federal license.

- In the event you DO get some motors working you have to deal with inconsistent performance from a variety of contributing factors...

This is seriously something I suggest avoiding if you wish to avoid any of these problems. There are waaaaaaaaay too many factors involved that are often out of the limits of control for amateur home-built solid fuel rocket engine.

• Mixing your Fuel & Oxidizer properly, evenly, and SAFELY.
• Properly bonding with a synthetic or polymer agent.
• Properly & Consistently compacting it into the motor body.
• Precise formation of the prill/grain and its center channel.
• Replacing your test nozzles periodically with a new custom-machined one - because even your 'successful' tests will result in heat erosion of your nozzles - increasing their diameter, and reducing their performance - creating inconsistency.
• Proper design & construction of an efficient motor body to withstand the pressures generated while remaining lightweight.
• Proper design & machining of a nozzle to produce the thrust necessary to not only make your rocket perform, but to regulate the pressures generated throughout the full course of the burn.

You also have to test & launch everything with a long-distance secured frequency remote control launching devise from a VERY long distance or you'll be in a world of hurt.

Seriously, avoid making your own. It takes YEARS of research, experimentation, data collection & review, TONS of time & expense fabricating new parts or repairing things you've blown up - before you even get a GOOD, SUCCESSFUL, HIGH-PERFORMANCE rocket motor!

If you think commercially produced 'Estes' motors aren't powerful enough, and KNO3 based solids aren't enough - get the federal permits to buy commercially produced reloadable rocket motors. It's the only SAFE way to avoid any headaches and untold sums of money wasted on trial & error experimentation. That's likely what I'll be doing soon enough.

Most consistent & safe high-power solid fuel motors these days operate with a phase stabilized ammonium nitrate based fuel/oxidizer recipe - and it has to be PROPERLY phase stabilized or you're just wasting your time with regular ammonium nitrate. There are other solid fuels that have proven to work with limited success using all sorts of chemicals, binders, and compaction techniques. Each different recipe provides dramatically varying performance based upon the varying amounts of energy stored in their chemical composition. It will even vary depending upon the different sources chosen to acquire the chemicals...

It's just far too inconsistent to be worth anybody's time or effort - my own as well.

## Create an account

Register a new account