Calcium CArbide

Post questions and info about combustion (flammable vapor) powered launchers here. This includes discussion about fuels, ratios, ignition systems and anything else relevant to launchers powered by igniting things like hairspray or propane.

Postby sgort87 » Sun Dec 10, 2006 2:32 pm

BLB, you should know better than that, Mr. EVBEC.

And I'd like to know where you got the number 156 when 1 bar is equal to 14.5 psi...
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Postby BewareOfDog » Sun Dec 10, 2006 3:37 pm

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by sgort87
[br]BLB, you should know better than that, Mr. EVBEC.

And I'd like to know where you got the number 156 when 1 bar is equal to 14.5 psi...
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

"What? Why, if I told you, you would not believe me. But I am wearied of conversation with you; it is less fatiguing to destroy a walled city than it is to frame my thoughts in words a brainless barbarian can understand."

sgort87, do you any idea of how BigBang estimates the Peak Combustion Pressure of propane, for each atmospheric mix?

... And if I'm a lousy 2/10 of a psi off on converting bar to psi, would it change my point significantly?
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Postby sgort87 » Sun Dec 10, 2006 5:02 pm

DR, I was talking to BLB. I'm on YOUR side here.
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Postby natanddiane » Sun Dec 10, 2006 6:03 pm

amazing. I started a war. Does anyone realise, when you pull your head away from your slide rule, that the pressure always gets released against a spud? ust how strong is the grip of a tater against the walls of pvc pipe? CAn it hold all that pressure long enough to blow the walls open? Some of your dynamics remind me of our local weather man. "Clear and dry, 20 % chance of showers" he says, while the real temp is 20 degrees F, the snowis 5 feet deep, and the wind is over 30 mph. So smart your'e stupid. Just look. Observe. Empirical evidence can outweigh figures. Even Mark Twain knew about statistics. "There are 3 kinds of lies. Lies, damndable lies, and statistics"
Let's wake up. smell the spuds. Teck all the fun out of everything... Come on! ( and yes, I said TECH... not take)
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Postby natanddiane » Sun Dec 10, 2006 6:12 pm

Chicks would rather go to bed with someone who owns a Ferrari than one who owns a chevy. It is more of a status symbol than a car.
drive a Ferrari, increase your chances of getting an STD.

--------------------------------------------------------------------------------

Oh, come on DR. You've said that you fill your pneumatics to rather high pressures, so I'm very surprised that you are intimidated by the "10.6 bar" max pressure generated by oxyacetelene.

I do not use oxyacetylene. It is carbide rocks and water. Anyone using OA will end up dead, or worse.

Let's see: 156psi plus itself ... ten times, equals 1,1560
14.7 plus itself... 9 times, equals 132.3
1,560 + 132.3, equals...

NUmbers numbers numbers. That is why we do not have any more men on the moon. too many kids with laptops proving it cannot be done.

Let us all get to REALITY.. Fire our spudders, and live doing it.
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Postby benstern » Sun Dec 10, 2006 6:15 pm

"I do not use oxyacetylene. It is carbide rocks and water. Anyone using OA will end up dead, or worse."
hmmm that produces acetylene and wait! there is oxygen in the air! Omg you a [intercourse]ing ignorant retard!
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Postby boilingleadbath » Sun Dec 10, 2006 6:46 pm

If you want to persue that line of thought, DR... propane generates ~6.85 barA at a 1x mix. Thusly, combustion in the prepressurized mix will produce 46.9 barA - or 676 psig.

Somehow, I think that's a bit above the pressure rating - ney, the bursting pressure - of a large percentage of our combustion chambers.
For that matter, I think that 1700 psi is a bit above the bursting pressure of cell-core ABS. But you know what? OA has been succesfully used in ABS cannons, with projectiles in the bore, several times in a row.

And yes, I acnolaged that C#C is unfreindly stuff.
I was just saying that you quoted an incorrect reason not to use it.

edit: (and I'm the fool who can't read the post and realize that you are stating the reason he want to use C#C, not why he shouldn't)

gort... I accidentaly used 14.7 instead of 14.5
Does it really matter? (no)

...while I'm here...

natandiene, the friction of a bullet in a gun's bore is only a few hundred pounds, which corresponds to only a couple thousand PSI. Guns typicaly operate at 20-70 <i>thousand</i> psi.
Thus, no matter how much (or how fast-burning of a) powder you put behind a bullet, the gun will NEVER blow up!
(and this is faulty reasoning, as any reloader will tell you)
[in more technical terms, the bullet has inertia - the ability to resist changes in movement - and this esentialy 'glues' it in place.]

natandiene, it's quite possible to get a payload to the moon; I've done the [delta V] calculations myself.
It's not as easy as LEO insertion, though, and they don't see a point right now.

benstern, there are significant differences in combustion rate and final pressure between C#C/air and C#C/pure_O2. Duh.
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Postby clide » Sun Dec 10, 2006 6:47 pm

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by natanddiane
Just how strong is the grip of a tater against the walls of pvc pipe? CAn it hold all that pressure long enough to blow the walls open?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Your plans for your future launcher seem to be perfectly safe, but it seems to me like you're still trying to justify that it is safe for PVC with faulty logic.
The friction of the tater is not what holds the pressure, it's the inertia of the tater.
By your logic an oxyacetylene mix wouldn't blow up the gun either, but you know just as well as us that it will.

And yeah, I'm sure the folks at NASA went to the moon just by winging it. No numbers and calculations involved there. :|
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Postby SpudBlaster15 » Sun Dec 10, 2006 7:56 pm

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by natanddiane
[br]amazing. I started a war. Does anyone realise, when you pull your head away from your slide rule, that the pressure always gets released against a spud? ust how strong is the grip of a tater against the walls of pvc pipe? CAn it hold all that pressure long enough to blow the walls open? Some of your dynamics remind me of our local weather man. "Clear and dry, 20 % chance of showers" he says, while the real temp is 20 degrees F, the snowis 5 feet deep, and the wind is over 30 mph. So smart your'e stupid. Just look. Observe. Empirical evidence can outweigh figures. Even Mark Twain knew about statistics. "There are 3 kinds of lies. Lies, damndable lies, and statistics"
Let's wake up. smell the spuds. Teck all the fun out of everything... Come on! ( and yes, I said TECH... not take)
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Wow, ok, I have been following this thread as your retarded comments and everyone's replies to them have been amusing, but this just crosses the line.

"The pressure always gets released against a spud"

Ever heard of inertia? The inertia of a potato can provide an adequate delay to allow the immense pressure of acetylene combustion to build and rupture the chamber walls. At this point, you are more or less a pin cushion.

"Some of your dynamics remind me of our local weather man. "Clear and dry, 20 % chance of showers" he says, while the real temp is 20 degrees F, the snowis 5 feet deep, and the wind is over 30 mph."

I fail to see how this analogy applies. What people have been telling you is the whole story, not a watered down version that consists only of the "bad" aspects of acetylene. It may seem this way to you, and that is because the use of acetylene in a combustion gun has so few advantages that relaying them to you when the dangers are so prominent is pointless.

"So smart your'e stupid. Just look. Observe. Empirical evidence can outweigh figures. Even Mark Twain knew about statistics. "There are 3 kinds of lies. Lies, damndable lies, and statistics"."

This is where most of your issue lies. You cannot seem to understand that figures are FAR more important than one's assumptions in situations such as this. When you choose to ignore theories and the experience of others, you set yourself up for a bad experience.

"Let's wake up. smell the spuds. Teck all the fun out of everything... Come on! ( and yes, I said TECH... not take)"

Ignorance is bliss. Sure, maybe those who choose to elude the technical aspects of life do enjoy it more, until their ignorance costs them a hand, an arm, or their life. Around here, that is not how it works.
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Postby DK » Mon Dec 11, 2006 4:02 am

<center><img src="http://img.villagephotos.com/p/2006-5/1185861/applause.gif"></img></center>

Spudblaster, you are my hero. :D
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