Just wanted to get some help with my plans and inform. I plan on making three potato guns that use popcorn in some way number one will be simple a used 12 gram c02 cartridge cut in half and threaded, I am going to drill out the neck of the cartridge and put a burst disk there and an aluminum barrel, then I will fill the cartridge with popcorn kernels and heat it up with a blowtorch until it goes off.
The next idea is more difficult because I need to find the stoichiometry of popcorn gas, which I will use to power a combustion cannon.
And a third that will be a simple BBMG that shoots popcorn kernels.
Any comments are welcome and ideas are needed if anyone knows the stoichiometry of wood gas that would help me finish the project much more quickly.
Posted: Thu Nov 19, 2009 10:11 pm
by maverik94
And a third that will be a simple BBMG that shoots popcorn kernels.
nice Idea, but that will jam on every shot I'll bet.
Posted: Thu Nov 19, 2009 10:56 pm
by ThegunGuy
lol Keeping it from jamming is going to be the hard part. There would be nothing special about it if it didn't have any special challenges.
Posted: Thu Nov 19, 2009 11:04 pm
by jackssmirkingrevenge
ThegunGuy wrote:lol Keeping it from jamming is going to be the hard part.
With a big enough diameter barrel this won't be an issue, though don't expect terribly good ballistic performance.
The next idea is more difficult because I need to find the stoichiometry of popcorn gas, which I will use to power a combustion cannon.
...are you going to try and burn water? A popkorn kernel is simply a small steam grenade:
Each kernel of popcorn contains a certain amount of moisture and oil. Unlike most other grains, the outer hull of the popcorn kernel is both strong and impervious to moisture, and the starch inside consists almost entirely of a hard, dense type.
As the oil and the water are heated past the boiling point, they turn the moisture in the kernel into a superheated pressurized steam, contained within the moisture-proof hull. Under these conditions, the starch inside the kernel gelatinizes, softening and becoming pliable. The pressure continues to increase until the breaking point of the hull is reached: a pressure of about 135 psi (930 kPa) and a temperature of 180 °C (356 °F). The hull ruptures rapidly, causing a sudden drop in pressure inside the kernel and a corresponding rapid expansion of the steam, which expands the starch and proteins of the endosperm into airy foam. As the foam rapidly cools, the starch and protein polymers set into the familiar crispy puff.
Posted: Thu Nov 19, 2009 11:04 pm
by vardas
umm.try lubing the barrel with butter...whats popcorn without butter,im just saying
Posted: Thu Nov 19, 2009 11:39 pm
by deathbyDWV
Technicly pop corn seeds would be against the rules since they are solid propellant. Sounds like a good challenge.
Posted: Thu Nov 19, 2009 11:56 pm
by ThegunGuy
You don't see what I am trying to do, not burn popcorn put it in a oxygen free environment and heat it up so that flammable gasses are released, and then use those gasses to power the combustion cannon. If this is confusing you look up wood powered car they work by gasifyng (sorry I don't know how to spell it and spellchecker won't help) wood, all I want to do is use popcorn instead of wood.
Posted: Fri Nov 20, 2009 5:12 am
by inonickname
deathbyDWV wrote:Technicly pop corn seeds would be against the rules since they are solid propellant. Sounds like a good challenge.
Popcorn kernels don't contain their own oxidizer anyway.
Solid propellant: Any substance containing all the chemical elements required to enable sustained combustion without the presence of additional oxidizers. This includes but is not limited to gunpowder, thermite, and many commercial and/or homemade pyrotechnic compounds.
1. For this purpose, nitroglycerine, though liquid, would qualify.
2. For this purpose, ordinary flour, though solid, would not qualify.
The BBMG sounds interesting, I'm always up for different ammo that's easy to get down under.
Posted: Fri Nov 20, 2009 5:51 am
by jackssmirkingrevenge
inonickname wrote:The BBMG sounds interesting, I'm always up for different ammo that's easy to get down under.
It would be a fun project but given the amount of tolerance the barrel would need to reliable feed such irregular projectiles, performance would be quite pathetic, even with higher pressures.
Posted: Fri Nov 20, 2009 6:32 am
by john bunsenburner
How about a combination of idea 1 and 3?
You have a launcher that shoots popped pop corn(better seal, will compress to fit into barrel, self lubing due to the oil in the kernel), the popping will also power each projectile down the barrel. You need to find out how much water is in each kernel, and then see what volume of steam you get(considering not all water will evaporate before the corn pops), so you need the failing pressure of and amount of water in a kernel. Then calculate barrel length from it, and make the chamber as small as possible.
I could think of heating mechanisms...any way good luck, this sounds like fun!
Posted: Fri Nov 20, 2009 7:04 am
by psycix
gasifyng
Vaporizing.
The pressure continues to increase until the breaking point of the hull is reached: a pressure of about 135 psi (930 kPa) and a temperature of 180 °C (356 °F). The hull ruptures rapidly, causing a sudden drop in pressure inside the kernel and a corresponding rapid expansion of the steam, which expands the starch and proteins of the endosperm into airy foam. As the foam rapidly cools, the starch and protein polymers set into the familiar crispy puff.
This gives me an idea. If you would surround the popcorns with pressure, they will blow later then usual, at a higher temperature.
But what would happen if you would heat em while in an atmosphere of ~30 bar, just until the first ones start popping, and then quickly vent off pressure? (QEV)
They would all pop, and maybe become MOAR foamy because they have a higher internal pressure! ULDPC! Ultra Low Density PopCorn!
But I'm going off topic...
Posted: Fri Nov 20, 2009 8:33 am
by Ragnarok
deathbyDWV wrote:Technically pop corn seeds would be against the rules since they are solid propellant.
To add to what inonickname said, Rule 3 is best summed up as "no non-gaseous oxidisers".
If you're building a combustion, whatever your oxidiser is, it must be a gas.
psycix wrote:ULDPC! Ultra Low Density PopCorn!
Interesting idea, but you'd be dealing with temperatures of 250 Centigrade if you did that. Finding a valve that's good to 30 bar at those temperatures could be a little expensive.
... also, I suspect at 30 bar, you'd end up spraying the popcorn out of the valve like confetti.
Posted: Fri Nov 20, 2009 9:02 am
by jackssmirkingrevenge
Are you suggesting high mix hybrid popcorn?
Spudding, the only hobby where edible flora meets mad science
Posted: Fri Nov 20, 2009 9:17 am
by john bunsenburner
haha
yeah, a hybrid popcorn cooker would do what you want...hehe!
Posted: Fri Nov 20, 2009 9:56 am
by ThegunGuy
I think someone has already made high pressure extra foamy popcorn this is what gave me the idea for project one. I think i will make the popcorn BBMG's barrel an oval shape with a little hopup in it for maximum efficiency with these irregular projectiles. I think to make up for low accuracy it will have to have high RoF.
popcorn also makes great wadding for small barrels.
