SpudFiles

As we all know hydrogen can make a big boom. such as the hydrogen bomb. But, could we take that boom and make it work with a combustion potato cannon. It seems possible but i don't see anybody make cannons that use it. Is it because its hard to obtain? I've seen home made hydrogen fuel cells that produce lots of hydrogen. People even run their cars off the hydrogen they make. discuss.

I was reading the rules. hydrogen seems to be aloud. its not a solid propellant and its a gas like propane and mapp (kinda).

Sure it can work, but why bother? Its a PITA to obtain compared to propane and unless your aim is extreme velocity, anything that can be done with hydrogen could be done easier with propane. So why bother?

D_Hall wrote:Sure it can work, but why bother? Its a PITA to obtain compared to propane and unless you're aim is extreme velocity, anything that can be done with hydrogen could be done easier with propane. So why bother?

eh, today i was looking at hydrogen fuel cells and potato cannons came to mind.

Marffy wrote:hydrogen seems to be aloud.

Use asilencer then

As we all know hydrogen can make a big boom. such as the hydrogen bomb. But, could we take that boom and make it work with a combustion potato cannon.

The hydrogen bomb uses the fusion of hydrogen which produces massive amounts of energy (most of the energy doesn't come from pure fusion in these bombs). Can you use this technology in a spugun? No. So far, the only reliable fusion achieved with hydrogen by humans is in an atomic bomb, which isn't exactly controlled. No chamber will contain this.

hydrogen seems to be aloud. its not a solid propellant and its a gas like propane and mapp (kinda).

Indeed.

Is it because its hard to obtain?

Most likely, yes. A big problem is that a common route of obtaining hydrogen is through the use of electrolysis. You need a substantial energy input to get respectable output.

You can get oxygen from the decomp. of chlorates, and hydrogen from HCl (or NaOH) and aluminum etc. Electrolysis is really the easiest (well not easiest, but practical for most) method.

Problem is, you need a huge input for a large output.

People even run their cars off the hydrogen they make.

No, they don't. The law of thermodynamics is superior to these people and has decided they cannot get more efficiency, free power or money.

You can however run cars of hydrogen (no, not from a machine attached to your alternator). The msot efficient method of doing this is by using a fuel cell, which is much closer to a battery (well, it is one) to an engine or a spudgun.

It seems possible but i don't see anybody make cannons that use it

I've made one. For the aforementioned reasons (large energy input required) it is fairly small in size.

Hydrogen really isn't used because it's impractical. You need to take into account your chamber as well (especially seen as if you derive your hydrogen from electrolysis you will probably be using pure oxygen as well).

inonickname wrote:So far, the only reliable fusion achieved with hydrogen by humans is in an atomic bomb, which isn't exactly controlled. No chamber will contain this.

Not true. Chambers capable of containing atomic explosions have been used by the thousands. They're just a bit expensive and the words "underground rock strata" tends to come up quite often during construction.

Although... there WAS an all-steel chamber built to contain the Trinity explosion although it wasn't used (hard to see blast effects if you contain the blast!).

the Trinity explosion although it wasn't used (hard to see blast effects if you contain the blast!)

wasn't it used to contain all the plutonium in case something goes wrong (meaning - explosives go boom but there's not chain reaction?)

I've seen a documentary where they mentioned that it was really expensive but they didn't show it

D_Hall wrote:Although... there WAS an all-steel chamber built to contain the Trinity explosion although it wasn't used (hard to see blast effects if you contain the blast!).

Uh, no not really. No conceivable metal container of practical dimensions is going to contain a nuclear explosion. Not fission (uranium or plutonium based) or fission/fusion (using a fission bomb to trigger a hydrogen based fusion bomb).

For a fusion bomb based on uranium the minimum critical mass is about the size of a softball. You can't make a simple uranium fusion device any smaller than that since it won't detonate. The energy released in the smallest possible uranium only bomb, that detonates through a true nuclear reaction, is not going to be contained by a steel container. The container might as well be made of tissue paper for all it would accomplish.

Back to the thread...

Hydrogen can be used but generally isn't for two reasons;

1. Effectiveness. H2 is really not significantly more energetic than is say propane or butane. Why use an exotic fuel when you can get something at the local bodega for $1 that works just as well?

2. Safety. Hydrogen is more likely to DDT than are most others fuels. DDT presents some problems. It increases the risk of chamber failure even thought he energy in the chamber is about the same as with a more common fuel. Why risk a chamber failure when there is no performance advantage?

EDIT:

Only real advantage of hydrogen is that it is a very fast burning fuel. For a lightweight low friction ammo hydrogen might have some small advantage over propane. H2's initial flame speed is about 8X faster than propane, and 2X faster than acetylene. But the peak pressure in a H2 explosion is about 13% less than for a propane explosion.

jimmy101 wrote:Uh, no not really. No conceivable metal container of practical dimensions is going to contain a nuclear explosion. Not fission (uranium or plutonium based) or fission/fusion (using a fission bomb to trigger a hydrogen based fusion bomb).

Did a bit of googling since I was *certain* I remembered such a device and that the container actually had a name ("Jumbo") so it'd be easy to google for.

We're both right.

Jumbo was designed to contain the explosion in the event of a fizzle. Plutonium was valuable enough that they didn't want to lose it in the event the bomb didn't go correctly. If it did, the container would go away. If it didn't, the bomb would be contained.

So... you're correct: Jumbo would not contain a proper Trinity blast but in the same breath, Jumbo was designed to contain a Trinity blast should that blast go less than optimally.

Some talk of Jumbo....
http://www.cddc.vt.edu/host/atomic/trin ... nity2.html

http://www.gutenberg.org/files/277/277- ... /jumbo.jpg

which basically means the same as

wasn't it used to contain all the plutonium in case something goes wrong (meaning - explosives go boom but there's no chain reaction?)

You can get better power from a low mix hybrid and without the headache.

I've seen a mini combustion on here that used a hydrogen fuel cell. I wanted to make one but never did...

Spanks (thanks) for the comments lots of usefull info. i still plan on attempting to make a hydrogen fuel cell some how and attempting to make a cannon out of it. it might work, probably not but its worth a shot.

Wait a minute, by fuel cell do you mean some sort of electrolysis apparatus? Hydrogen fuel cells react hydrogen with oxygen to produce an electric current. The byproduct is water and hydrogen is consumed rather than produced. An electrolysis apparatus effectively does the reverse of this process and uses electricity to split water molecules producing oxygen and hydrogen gas. The gas produced could then be used as a combustion fuel. I think this is the process you are talking about.

Marffy wrote: People even run their cars off the hydrogen they make. discuss.

I think you're referring to "HHO" from home grown electrolysis cells. People DON'T run their cars on it. The only add it to the engine as a supplement......with mixed results. If you're planning on handling HHO gas, you might think about booking your hospital room (or mortician) in advance! That s*** is seriously dangerous!