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Candybar (Milkyway) Rocket Engine

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Quelab (My local Hackerspace in Albuquerque NM),  Had a project theme of "Hacking Chocolate" for the month of February.  I'm allergic to eating chocolate, so I wanted to think of a use that was a bit more exciting than just watching others eat the stuff. 

So I decided to experiment with making a chocolate (candybar) powered rocket engine.  A quick googling showed me that I was remembering right that people do make Sugar and Potassium Nitrate rockets. (And even pixi stick rockets), so I decided to see if i could do it too but using a candybar! (you know how many calories there are in them Right?

Figuring sticking with a space theme, and avoiding complex compounds such as peanuts.  That a Milkyway candybar was just the ticket.  (turns out that was a lucky decision,  more on that later)

 
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Step 1: Materials,

You will need the following Tools

- A small scale
- A hammer
- A grinder (mortar and pestle like i show here, or a coffee grinder you don't plan to use for food again)
- An anvil or chunk of steel or other hard object to pound on
- A Domed head carriage bolt (I believe the head size of mine was 3/4" and it was about 4" long)
- A drill, with, 7mm drill bit. and a counter sink drill bit, (or a  larger 1/2" bit will do too. 
- A permanent marker.

You Will need the following materials.
- Some clay kitty litter (a few ounces of clean clay based kitty litter will do) this will make the fire proof plugs at both ends of the engine
- A MilkyWay Candybar,  this will provide the fuel
- Some Potassium Nitrate (salt peter) (as pure as you can get) Oxidizer, 
- some thin wall PVC pipe (about the same internal diameter as the carriage bolt head), cut it into 2.5" lengths
- some cannon fuse,  or model rocket engine igniter.
killbox (author) 2 years ago
For full disclosure, a lot of my engine building design was strongly influenced by these videos. And by talking to other amateur rocket enthusiasts.

https://www.youtube.com/watch?v=5zNYMRaFS3M
& part2
https://www.youtube.com/watch?v=hzuX4Vw15HM
ssykes69 months ago
Did you try Three Musketeers?
killbox (author)  ssykes69 months ago
I don't think so, twixt, tolberone, dove, hershys, mars, and milkyway were what got tested the day after the event (after figuring out that hershys worked less like rocket fuel and more like fire extinguisher.)
Todd225510 months ago
could you also add or use hydrogen peroxide, with or for the salt peter
H2(mic)O41 year ago
can same one please show me how to make saltpeter
you buy it from gardening supply stores
cre814me1 year ago
Your creativity with chocolate has no boundaries, and having the knowledge of chocolate fueled rocket engines must be a story in itself. Hats off to you and keep up the wonderful uniqueness that you have displayed.i
I made one and it worked great! Thanks for the idea.
milkywaybar2 years ago
i like this instructable. Why? Look who posted this comment.
to be more green you should make your own kno3 from wizz buckets or muck from chicken coops and then use organic sugar fair trade sugar, or a candy bar from Trader Joes, chcukle!

seriously melting sugar adding nitrates is a recipe for death or disfigurment or mangling and blindness. Adding water to the mix at any point is counterproductive. Look up old alt.fireworks and see their files. you buy tubes and clays and insert mold bore s. (all the wrong words, but they will make sense when you see how you make them. The mix is put in tubes you mold in nozzles, then you put in the part that makes the bore and it is on a platform that you "tamp down" (can you feel th esurgeons knife yet as she slices out the damaged eyesockets/), then you add parachute charge or flashover to next stage.

As a person with many many scars, you do this at your own risk, and from experience it is not worth the risk. I was almost killed and do not suggets you even try this.

Just pay the price and buy Estes. Safer ,Faster, most cost effective. (considering investment learning curve, medical costs legal fees etc.

If you live in the larger open places with next to NO NEIGHBORS, you can do high altitude rocketry. You will get visits from ATF and who know what other alphabet organization. Could get you a work offer or free trip to Gitmo.

buy the freaking things
mcrotteau12 years ago
It needs to be pointed out that making your own rocket motors is extremely dangerous. Even the professional companies have had catastrophic fires as a result. Under no circumstances should these motors be made indoors. Also make sure you check local ordinances (as well as adhering to ATF regs) as it may be illegal in the area you're in.
(removed by author or community request)
That is without a doubt the dumbest attempt at logic I've ever heard. It doesn't change the fact that this is an extremely dangerous thing to do. I fly both model and high power rockets and it gets harder and harder to find a spot to launch because of stuff like this.
I had the same problem 57 years ago,for solid fueled rockets and came up with a simple answere that allowed the rocket to go higher faster then vanish .I made the body of the rocket out of thin aluminum, lined it with thermite that burnt slightly slower than the fuel this allowed the rocket to slowly vaporize as it sped up. No waste,no trace,no falling on people. if you make the first fuel fast burn no vapour,it cant be detected ,secondary burn slower increases height as acceleration point now matched.
@MC I removed my comment. Didn't want to make you cry. It's called sarcasm, just a little different from real logic.
No I'm sorry, that wasn't sarcasm. Whatever, I'm done with this. Take a little advice and remove this before the ATF gets wind of it. It's funny, they don't seem to have a sense of humor about this sort of thing.
Can iron oxide be used as the oxidizer? My neighbors car is 90% iron oxide so I'm sure he wouldn't miss a lb or so.
killbox (author)  Green Silver2 years ago
Yes and no, im pretty sure we are not providing enough heat for it to give up its oxygen, but you might consider looking into grinding it up for thermite. (with his permission)
Is this a full size or a fun size milky way?
killbox (author)  Kaptain Kool2 years ago
used full size, ironically the chocolate is the least useful part, so you kinda want more of the middle than a fun size.
Thanks!
erudite1772 years ago
You could've just used plain sugar for this. And melted them, in a pan, until they were a caramel color. I won't give ratios, you have to find that yourself, just look for making a smoking "device". Plus going with the melted way would allow you to have more of a pre-shaped nozzle base (I assume).
Haven't done this myself, but I've read that it's very important to melt the sugar first, then add the potassium nitrate. Also, some water in the sugar helps melting, but then has to be boiled off.

Keep in mind that doing this wrong can produce a potential bomb. Overheating and casting with a crack are both dangerous failure modes.
killbox (author)  erudite1772 years ago
True, but that is already well traveled ground, wanted to try something new, and chocolate themed. (February we did a big chocolate hacking expo). Even poured, you need a form to pour it around, or you have to do the same drill and form technique.
Could you use molasses instead of heated sugar?
Molasses has a high water content, so it wouldn't be a very good alternative.
Carmelite2 years ago
I suggest dehydrating the candy bar somehow before you add it as fuel. Water is not good for rocket engines
al_packer2 years ago
Just a general point regarding safety when working with propellants: Make sure all your metal tools are non-sparking. Aluminum and bronze are a better choice than steel.
druthernot2 years ago
You say "mix the candybar and the powdered chocolate" Okay fine, I've ground up the milkyway candy bar, but where did the powdered chocolate come from?
killbox (author)  druthernot2 years ago
oops, good catch, Fixed! should have read "powdered Candybar powdered potassium nitrate."
Its amazingly easy to leave out a step of something one has done themselves. I left out steps for making a water bottle rocket 20 years ago in print. Thanks for the reply, and overall easy instructions!
druthernot2 years ago
Did you try malted milk balls?
killbox (author)  druthernot2 years ago
nope, didnt try them.. twixt was as close as we got, and in powder test burns it was almost as good.
Thanks, I've a 60mm black powder mortar, so things along this vein are of interest. The mortar scares too many people, looking for other less dangerous outlets for my imagination
Try icing sugar and salt peter !
More 'bang for your buck'
We made a bunch of these back in the day :)
Agree with the 'smoke was white when the mixture was right' from Krayfishkc !
Nice engine ! +++

PS. Don't try buying saltpeter, sulphur and carbon from your local chemists ! They don't like it ! lol
crayfishkc2 years ago
I made caramel candy rocket fuel (saltpeter and sugar) in high school in 1966 and never put into a rocket. I used a bunch of 2 oz dixie cups and it was a little tricky melting it on the gas burner. It would burn with a 14" flame and the smoke was white when the mixture was right. I set one off in the shower at the dorm and the bright red flame reflected off the glossy tile just fine. I thought the smoke would go out the windows, but the airflow was opposite and the hallways filled with smoke instead. Nothing got destroyed and this was before smoke detectors. I was lucky, nobody got hurt. I would have eaten the candy bar.
mr_bandit2 years ago
I wonder what different mixes of chocolate bar and sugar or other filler (ie crushed malted milk balls) would have.
killbox (author)  mr_bandit2 years ago
Im not sure, we did try tolberone, hersheys, oreo bar, and twixt, found milkyway was the best of all of them. but we did not alter the oxidizer ratio.. i expect one could balance the equation based on only the caloric content per gram. and try to match sugar .
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