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Posted: Sat Aug 15, 2009 9:22 am
by ramses
GalFisk wrote: using vacuum from the projectile in an overly long barrel).
The long barrel is not necessary if a piston valve type thing is used as a burst disk. My piston hybrid pulls a lot of vacuum when I open the fill valve. This is because the valve closes at say 10psi while the air is at a high temperature. When the gas cools, it contracts, leaving a vacuum.

Posted: Wed Aug 19, 2009 4:10 am
by GalFisk
The thing is, pulling a vacuum is not enough because we need to fill the entire chamber with fresh air for s sustainable cycle. If we have hot exhaust gasses that contract to 10% of their original volume, only 90% of the chamber will fill with fresh air and the next shot will only be at 90% power. This will mean even less air and less power for subsequent shots, until there's not enough air left to sustain the cycle.
we know that a regular valved pulsejet will draw in enough air for a sustained cycle, the question is if the projectile hindes this cycle or helps it.

Posted: Thu Aug 20, 2009 4:14 pm
by ramses
GalFisk wrote:This will mean even less air and less power for subsequent shots, until there's not enough air left to sustain the cycle.


No, the gas from cycle 2 will also draw in 90% of the chamber volume, too. then all the gas would be heated, contract to 10% and so on until the chamber heated up to the point where, yes, the cycle would stop. So an active cooled metal chamber would be a great idea.

Posted: Thu Aug 20, 2009 7:09 pm
by Moonbogg
Actually, Ragnarok, I believe the CO2 causes the slowing of molecules, which in turn bores the pants off the fire, causing it to go to sleep.

Posted: Thu Aug 20, 2009 8:24 pm
by chenslee
Moonbogg wrote:Actually, Ragnarok, I believe the CO2 causes the slowing of molecules, which in turn bores the pants off the fire, causing it to go to sleep.
THAT'S NOT WHAT HAPPENS YOU ARE STUPID.

It blows out the fire like the big bad wolf, actualy the one in Ragnarok's user pic.

Image

I mean just look at that triple fire suppression wolf breath.

Posted: Fri Aug 21, 2009 4:44 am
by GalFisk
ramses wrote:
GalFisk wrote:This will mean even less air and less power for subsequent shots, until there's not enough air left to sustain the cycle.


No, the gas from cycle 2 will also draw in 90% of the chamber volume, too. then all the gas would be heated, contract to 10% and so on until the chamber heated up to the point where, yes, the cycle would stop. So an active cooled metal chamber would be a great idea.
Wouldn't cycle 2 draw in less air, because it has less fuel and therefore generates less heat/expansion/vacuum?

Posted: Fri Aug 21, 2009 1:52 pm
by ramses
cycle 2 would draw in less air, but every cycle after it would draw in as much as cycle 2 did. Actually a bit less as the chamber heats up, but that can be controlled.

Posted: Fri Aug 21, 2009 2:01 pm
by Davidvaini
chenslee wrote:
Moonbogg wrote:Actually, Ragnarok, I believe the CO2 causes the slowing of molecules, which in turn bores the pants off the fire, causing it to go to sleep.
THAT'S NOT WHAT HAPPENS YOU ARE STUPID.

It blows out the fire like the big bad wolf, actualy the one in Ragnarok's user pic.

I mean just look at that triple fire suppression wolf breath.
yeah and thats not what happens here. We dont like people who insult. Calling someone stupid, especially in all caps is not accepted here. This is a peaceful community that likes to share knowledge and have fun.

regardless if the person is wrong.. you don't call them stupid. You point out they were wrong and let them know why.

Posted: Fri Aug 21, 2009 3:04 pm
by chenslee
chenslee wrote: THAT'S NOT WHAT HAPPENS YOU ARE STUPID.
I apologize. I was trying to be sarcastic and funny and I guess it came off ruder than I intended. In addition to this, I was blatantly hijacking the thread.

My previous post should have read:

That's not what happens, you are insufficiently informed. Unless I am mistaken (and I often am) fires do not have pants.