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View Full Version : Remarks, Questions, and Theories on a Couple of Things


markfh11q
April 6th, 2007, 02:59 PM
First post on here, so I have no clue who I'm dealing with, so let's hope I can meet a few people here as well.

I've been playing with various things like this, but for the past few years I've been playing around with cannons instead of pyrotechnics. You can see some of the cannon's I've built on my web-site here (http://www.markfh11q.net). I'm now getting bored with that, though, so I'm starting to get back into pyrotechnics.

I've been wanting to get back into making "standard" rocket mixtures and report compositions for payloads, as well as brighter stars in the payload as well. I've been looking into ammonium perchlorate as an oxidizer for both and all of these applications, and I've already got an order of a few pounds of NH<sub>4</sub>ClO<sub>4</sub> on the way, as well as a simple 3 pound ball mill.

The main thing I've been concerned about for the past few days are my choices for fuels. I've been looking at a few choices, but there are some concerns and questions I've got left.

Sugar
I particularly liked this idea for fuel because it's so friggin' flexible. You can make it crystallized, uncrystallized, (as in you hardened it quickly from a heated simple syrup), you can get it granular in small crystals, powdered finely as in confectioner's sugars, and you can make it a specific mesh by crystallizing to a low mesh, and then milling until you can screen it to the desired mesh, (McMaster-Carr is a good supply for mesh screens).
Only thing concerning me is the specific composition. Try as I might, I can't Google or search on these forums for the impurities in standard sugar you would buy from the supermarket. If anybody had these data just "lying around", I would appreciate your help.

Paraffin Wax
The refined stuff, while I assume it is, is C<sub>25</sub>H<sub>52</sub>. I have no clue as to the validity of this, because paraffin wax is more of a "range" of hydrocarbons, like gasoline. My question is, would this equation be at least close enough stoichiometrically for me to make a workable composition based of it?

Thanks in advance for any help you guys have to offer, and I look forward to communication here.

tomu
April 8th, 2007, 07:20 AM
Wikipedia has an analysis of household sugar with all impurities and a good article on paraffin as well.

For rocket engine construction the impurities of household sugar are irrelevant it's purity is at least 97% saccharose.

Btw. there are many proven and tested rocket engine compositions around and none of them use high purity analytical grade fuel.

Alexires
April 9th, 2007, 10:19 PM
Not a bad first post Mark. You don't seems like your typical shit eating kewl.

As I understand the water cooler is still off limits at the moment, I'm sure you have read the rules and feel that you have something to contribute by posting this here.

Mark, there are a plethora of fuels that can be used in rocket mixtures. Sugar, Paraffin wax, Carbon, Dextrose, NC, etc. I suppose it can best be described as "If it burns, its a fuel."

Look here (http://science.nasa.gov/headlines/y2003/28jan_envirorocket.htm) in regards to interesting Paraffin.

Here (http://en.wikipedia.org/wiki/Rocket_fuel) for a little wikipedia.

Interesting Hydrogen rocket here (http://www.thinkgeek.com/clearance/86c3/) by Estes.

You might want to do a search in google for "Rocket Propellants"

If you do, you will find sites like this (http://www.braeunig.us/space/propel.htm).

There is a shitload if information out there on the internet. When you learn something you think is interesting or would like to share, post it here huh?

Cobalt.45
April 10th, 2007, 09:45 AM
Nakka's site is good, as is James Yawn's. Here http://www.jamesyawn.com/syrup/improved/index.html is a formula for a corn syrup derivative of the standard KNSU-type fuel.

I am partial to KNSU melted together then powdered. Mixed 50/50 with good BP, it rocks.

markfh11q
April 10th, 2007, 03:23 PM
Thanks for the info! Alexires' link to the NASA paraffin research, although for hybrid rockets, was helpful. I think we've all seen the mythbusters episode where they used paraffin in a hybrid rocket, and no doubt, it is powerful. It's just time for me to test it with solid oxidizers...

Cobalt.45, your post was interesting as well. I was doing almost the same thing as on that site as well today, but I was trying to accomplish something else. I kept heating a simple syrup, (same as corn syrup, really, a 2:1 volumetric mixture of sucrose to water), until it reached the "hard crack" stage, (as confectioners call it), and then dumped it into a pyrex pan. I solidified it too slowly, though, and I wound up with large crystals that smelled like honey, but not an amorphous solid mass, like I wanted. Maybe next time I'll try dumping it into a cool bucket of water. End result tasted pretty good, though.

Thanks for all the replies over that last few days. I'm going to start testing some of these things once I get the ammonium perchlorate in.

ApJunkie
April 26th, 2007, 03:45 AM
Oddly enough, this will be my first post as well, but I think I can help you out.
I'm currently Level 2 certified for High Power Rockets with the Tripoli Rocketry Association. (meaning total impulse up to ~1,200 Lb/s), and have flown rockets over 2 miles high, and past the speed of sound.

Sugar fuels are interesting because they can be made using the fuel as a binder, and simply melted in a pot for casting, simple and easy, but with a considerably lower specific impulse than an APCP load. I've made motors using anything from Dextrose to Xylitol, Erythritol, Sorbitol and regular old sugar. Believe it or not, the stuff from the super market actually works suprisingly well, but be sure not to grind your KNO3 too small or it'll get too goopy to cast efficiently. If you get too many voids in your propellant the extra surface area can cause an overpressurization.

Parrafin Wax is an interesting idea, but a pretty poor choice if you're considering oxidizing it with either KNO3 or AP. Your best bet for total impulse in this category would be to do a hybrid system using liquid N20 as the oxidizer, run through a combustion chamber with a single grain of the reducer/fuel (paraffin).

As of right now, unless you want to get into dealing with liquid oxygen, your current best bet for maximum "oomph" per gram of propellant is Ammonium Perchlorate Composite propellant. I see you have a couple lbs on the way, good choice on that. :) you might be surprised at how quickly it dissapears though. one or two of these and 30lbs. are out the door!
http://mbrocketry.com/images/roc5.jpg

Edit: sorry that picture's so big. Also, I forgot to ask what binder you're planning on using with your AP?

GalFisk
May 25th, 2007, 08:51 AM
Hello Mark, I see you're here as well. I have gone the same route form cannons to rocketry, I too am interested in making fireworks.
An extremely simple rocket that I've had success with is KNO3+powdered sugar, simply hammered into a cardboard tube. They fly well with a core of about 1/3 of the tube ID drilled all the way through, and bentonite for a plug/nozzle.
I've made them ranging from 10 to 43mm ID, a disadvantage is that the larger ones take quite a long time building up pressure before they take off.
It would be interesting to know if hammered AP+powdered sugar works better, I like the simplicity of hammered/pressed propellant as opposed to melting or recrystallization.

knowledgehungry
May 25th, 2007, 05:36 PM
It would be interesting to know if hammered AP+powdered sugar works better, I like the simplicity of hammered/pressed propellant as opposed to melting or recrystallization.

I pray that you mean Ammonium Perchlorate not Acetone Peroxide! I know that AP means Ammonium Perchlorate in most rocketry/pyrotechnic circles, but here it ALWAYS means Acetone Peroxide. If some idiot happens to stumble across a post like " For my rocket engines I always use AP crushed with a hammer and sugar"(and they will), you will have a picture perfect example of natural selection.

GalFisk
May 25th, 2007, 09:31 PM
I pray that you mean Ammonium Perchlorate not Acetone Peroxide! I know that AP means Ammonium Perchlorate in most rocketry/pyrotechnic circles, but here it ALWAYS means Acetone Peroxide. If some idiot happens to stumble across a post like " For my rocket engines I always use AP crushed with a hammer and sugar"(and they will), you will have a picture perfect example of natural selection.
Of course, I'll remember that :)
Someone stupid enough to try that would deserve to be kicked out of the gene pool (at a velocity of several thousand m/s), but it always ends up hurting everyone else when that happens in this field.

Guerilla
May 26th, 2007, 09:38 AM
It would not be too safe to ram ammonium perchlorate compositions either.. Actually, according to Shimizu its impact sensitivity figures with milk sugar are quite similar to corresponding KClO3 mixes (with >50% oxidizer content). So no, don't try to hammer that fuel. If you are only looking for simplicity case-bonded APCP's are the way to go. APerch is forgiving when it comes to experimenting, Isp of >200s comes pretty easily even with less optimized designs.