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Hypervelocity Advanced* Combustion - WARTLv1

Built a combustion cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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Unread postAuthor: Zeus » Mon Sep 19, 2011 11:32 pm

Warhead, just rivet a small sheet over the hole on the inside after the ragged edge of the hole is dressed.

It'll look almost good as new and only cost a few cents.
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/sarcasm, /hyperbole
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Unread postAuthor: danielrowell » Tue Sep 20, 2011 1:21 am

Absolutely amazing work DYI! I bow to your mastery of physics and chemistry. :notworthy:

As others have said, "Mastery of Puppets" is a very good track for your video. It's so good in fact that I turned up the volume at first, expecting there to be at least a bit of sound leveling during the shots. :shock: ...oh my poor ears.
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Unread postAuthor: DYI » Tue Sep 20, 2011 8:04 am

Firstly, I'd like to say that the whole bit about the singularity is wrong - a black hole must be a black hole in any inertial reference frame, and in its own frame the airsoft round still has a mass of 0.2g. As such there would be no gravitational collapse, and it would simply be scattered on impact (physically destroying the planet in the process).


Your chamber support looks a bit excessive to me. Is this just for sealing?


I'm not sure what "chamber support" you're referring to here. If it's the threaded rod: when the seal doesn't work (which is usually the case) the chamber pressure of twice the yield strength of those bolts is applied to a 3/4" surface area. Throw in a safety factor of between one and two, and you get about eight rods. If I'd used stronger rods, it would be excessive. The closest place I can buy such rods is a significant drive for me, and I didn't think it was worth the trouble.



It's so good in fact that I turned up the volume at first...


:lol:
That's to give a better idea of just how loud this thing is... Ever fired off a .270 in your basement? :roll:
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Last edited by DYI on Tue Dec 13, 2011 10:58 am, edited 2 times in total.
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Unread postAuthor: mattyzip77 » Tue Sep 20, 2011 10:22 am

warhead052 wrote:Not really. I knew he would be pissed, but I didn't think it would actually go through. Seeing as I was standing like 20 feet away.

I blast golfballs through 3/4 inch thick plywood @ 80 psi with a barrel sealer from a measured 25 feet. Always expect the worst and hope for the best, however I do not know what the best thing was in this case, lol! :D
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Unread postAuthor: danielrowell » Tue Sep 20, 2011 1:39 pm

DYI, I'm not sure if you could do this without using a high explosive as your propellant, but, since you know so much about physics and chemistry, you could probably say "yay" or "nay" without even having to try it. It's probably a "nay," but you would know better than me.

You've probably heard of the Munroe effect, which is used in shaped charge rounds to... shape the projectile into a semi-liquid mass of metal. I wonder if you could somehow rig your cannon to do that on a small scale. :shock:
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Unread postAuthor: Labtecpower » Tue Sep 20, 2011 1:45 pm

I think DYI would love to, but he had some troubles with explosives in the past. :roll:
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Unread postAuthor: danielrowell » Tue Sep 20, 2011 2:18 pm

I think DYI would love to, but he had some troubles with explosives in the past.


:shock: Ah. I just read the post in question.
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Unread postAuthor: SpudBlaster15 » Tue Sep 20, 2011 2:26 pm

danielrowell wrote:You've probably heard of the Munroe effect, which is used in shaped charge rounds to... shape the projectile into a semi-liquid mass of metal. I wonder if you could somehow rig your cannon to do that on a small scale. :shock:


The pressures generated in this launcher are nowhere near sufficient to create an effective shaped charge. The Munroe effect requires 1-2MPSI at minimum to work properly, which is roughly an order of magnitude greater than what DYI is achieving here.

Electrothermal launchers can reach pressures in the millions of PSI, but those setups are likely well beyond the scope of what's achievable with an amateur budget.
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Unread postAuthor: inonickname » Thu Sep 22, 2011 4:25 am

DYI, surely the next step now is to obtane some cubane? :wink:

Edit:

But in all seriousness here's some suggestions...

Ignoring oxidizer, graphite will yield 72.9 MJ/L, compared to 83.8 MJ/L for aluminium. Comparing the masses of aluminium oxide and CO2, I'd suggest graphite to be a better propellant if you could find a suitable oxidant. Water could even work with the kind of input energies you're dealing with I suppose. Hydrogen peroxide would certainly work. Graphite, being readily available and completely safe in a fine powder is another good feature. Ignition energy would obviously be high due to the inherent stability of graphite but I'm sure your setup would manage it.

If you could obtain beryllium powder (I understand it can be bought in sizes of 300-400 mesh in ~5g samples) you could bump it up to 125.1 MJ/L, i.e. more than 50% more energetic than aluminium, and with lighter products as a result.

Edit: Beryllium isn't majorly reactive, but will still displace hydrogen so you would be fine with water as an oxidant. Beryllium oxide at 25.007g/mol is a much more desirable product than aluminium oxide at 101.96g/mol too. However, BeO melts at roughly 500K higher than aluminium. I'll leave it to you to judge if it's worth a shot though ;)
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Unread postAuthor: DYI » Thu Sep 22, 2011 7:35 am

Beryllium oxide at 25.007g/mol is a much more desirable product...


Unless one happens to be filling one's living quarters with a cloud of BeO dust, yes...

The beryllium is very tempting, but it would need to be done either outside or in a sealed vessel, severely limiting its use. As to the graphite: looking at the enthalpies of formation, I don't think it would even be energetically favourable for water to oxidize it.

I'll update this post with more comments when I get some time, my schedule is pretty packed at the moment.
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Unread postAuthor: inonickname » Thu Sep 22, 2011 7:45 am

DYI wrote:
Beryllium oxide at 25.007g/mol is a much more desirable product...


Unless one happens to be filling one's living quarters with a cloud of BeO dust, yes...

The beryllium is very tempting, but it would need to be done either outside or in a sealed vessel, severely limiting its use. As to the graphite: looking at the enthalpies of formation, I don't think it would even be energetically favourable for water to oxidize it.

I'll update this post with more comments when I get some time, my schedule is pretty packed at the moment.


I wasn't sure on the graphite. Could be worth a try with a different oxidizer too. NH4NO3 will yield nice light reaction products and be a fair oxidizer.

The sealed vessel is hardly out of the question- lots of high velocity/research accelerators fire directly into a sealed chamber containing the target medium. Something could be rigged up pretty easily. Or outside is of course an option. It would be prohibitive for extensive firing but I'd imagine that energy density to be quite alluring for you.

Just to give you a hint on what I'm up to... It might involve a certain inorganic nitrogen compound formed by a ketazine process... :wink:
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Unread postAuthor: warhead052 » Thu Sep 22, 2011 10:52 am

mattyzip77 wrote:
warhead052 wrote:Not really. I knew he would be pissed, but I didn't think it would actually go through. Seeing as I was standing like 20 feet away.

I blast golfballs through 3/4 inch thick plywood @ 80 psi with a barrel sealer from a measured 25 feet. Always expect the worst and hope for the best, however I do not know what the best thing was in this case, lol! :D


I think its obvious non of you really know me that well. I live by expect the worst, hope for the best. Remember the April 27th tornadoes here in bama? Yeah I didn't get phased by it at all, the only thing that happen'd was my mom breaking down and crying a lot. I kinda need to work on that aspect of me a bit, but other wise we are kinda off topic now. Sorry guys I will get back on topic.

DIY, I showed the thread to my friend, literally all he said was this, "Bull crap, there's no way he actually did that". I said, "Oh yeah? Would you like to live chat with him at some point?", "No, I wouldn't, I just want to know how this did that, and if he cheated by using a high powered rifle instead of that cannon and then put the cannon in the pics.". So there's the question I need to answer to him. I just need you to officially say you didn't so I can show him.
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Unread postAuthor: SpudBlaster15 » Thu Sep 22, 2011 11:19 am

inonickname wrote:Ignoring oxidizer, graphite will yield 72.9 MJ/L, compared to 83.8 MJ/L for aluminium. Comparing the masses of aluminium oxide and CO2, I'd suggest graphite to be a better propellant if you could find a suitable oxidant. Water could even work with the kind of input energies you're dealing with I suppose.


H<sub>2</sub>O + Al -> -8.8kJ/g

H<sub>2</sub>O + C -> 1.9kJ/g

Considering the water/graphite reaction is endothermic, I'm fairly certain it would be a waste of time.

As I've suggested before, magnesium is likely the only readily available fuel that could provide any kind of performance boost in this application. Magnesium/water would give an enthalpy change of about -8.5kJ/g, which is lower than the aluminum reaction, but the low molar mass of MgO (40.3g/mol) would produce a higher average SOS in the chamber and barrel during firing.

Beryllium is also quite favourable, but as DYI mentioned, it's obviously far too significant of a health risk to use at an indoor test site.

NH4NO3 will yield nice light reaction products and be a fair oxidizer.


For obvious reasons, I don't see DYI intentionally coming within 1km of any solid oxidizer in the near future.

Just to give you a hint on what I'm up to... It might involve a certain inorganic nitrogen compound formed by a ketazine process...


:D
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Unread postAuthor: DYI » Thu Sep 22, 2011 1:42 pm

Warhead, the large Maxwell capacitors are clearly visible in the video. The launcher in operation is clearly visible in the video. The output energy and products of the reaction can be found by consulting any basic chemistry text, and there are several extant papers documenting the activation of said reaction with high voltage capacitor discharge. Surely the ability of a sphere at v>3000m/s to punch through a target twice as dense and half as thick as it is not being called into question. If your friend thinks I would go to all the effort of fabricating the video, then he's welcome to his opinion.

Now, as to the beryllium: it is apparently considered a hazardous material for shipping purposes when in powdered form. I'm not too keen on the idea of converting ingots to powder for myself either, and the foil looks to be difficult to find and horribly expensive. I'm even less keen on the idea of having any sort of hazardous material shipped to me, for obvious reasons.
If anyone can come up with a reasonable solution to the above mentioned problems, I'd be happy to try it out next summer.

Also note that without a good deal of work to modify the pulsed power apparatus for portability, outdoor testing is impossible.

The choice of aluminum is almost solely for legal purposes. The incredibly vast majority of useful chemicals would be very dangerous for me to purchase at the moment.

Good luck on your project, ino. I've always been a fan of those inorganic nitrogen compounds... :wink:
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Unread postAuthor: inonickname » Fri Sep 23, 2011 3:53 am

SpudBlaster15 wrote:
inonickname wrote:Ignoring oxidizer, graphite will yield 72.9 MJ/L, compared to 83.8 MJ/L for aluminium. Comparing the masses of aluminium oxide and CO2, I'd suggest graphite to be a better propellant if you could find a suitable oxidant. Water could even work with the kind of input energies you're dealing with I suppose.


H<sub>2</sub>O + Al -> -8.8kJ/g

H<sub>2</sub>O + C -> 1.9kJ/g

Considering the water/graphite reaction is endothermic, I'm fairly certain it would be a waste of time.

NH4NO3 will yield nice light reaction products and be a fair oxidizer.


For obvious reasons, I don't see DYI intentionally coming within 1km of any solid oxidizer in the near future.

Just to give you a hint on what I'm up to... It might involve a certain inorganic nitrogen compound formed by a ketazine process...


:D


H2O2 of reasonable concentration would be a good oxidant for either aluminium or carbon. Peroxide watergels make respectable HE's at decent concentrations too. Of course H2O2 distillation can be tricky and unsafe, and you of course have the issues with dangerous materials if you try buy it. There's a world of oxidizers out there that could be made to work though.

I managed to get to the sulfate salt, but my yields were poor due to the low concentration or the NaClO I used. I verified it with a silver mirror test with AgNO3. I'm not sure I'm game to do an anhydrous distillation from the salt, even though it's an easy process. I'm sure Spud and DYI understand the hesitation.

For the rest of you, I'd describe it as a step up from dealing with 70% HF and a step down from packing AP for the taliban.
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