All-Poly

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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Petitlu
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Fri Jun 08, 2012 8:21 am

But you have no fan inside ?
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jackssmirkingrevenge
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Fri Jun 08, 2012 9:19 am

Petitlu wrote:But you have no fan inside ?
Yes, here it is:
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fan.png
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Petitlu
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Fri Jun 08, 2012 9:25 am

ok !
Good ! :D
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Petitlu
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Fri Jun 08, 2012 1:36 pm

test fan on :

[youtube][/youtube]
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POLAND_SPUD
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Fri Jun 08, 2012 4:13 pm

got me a new fridge compressor - got to build a hybrid
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Petitlu
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Fri Jun 08, 2012 4:19 pm

well!
Attention, the air leaving the compressor freezer often contains oil !
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ramses
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Fri Jun 08, 2012 8:58 pm

Interesting video. I don't really seem much difference in propagation between fan on and fan off. Perhaps even the existence of the fan in the chamber creates enough turbulence to accelerate the burn...
POLAND_SPUD wrote:even if there was no link I'd know it's a bot because of female name :D
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Petitlu
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Sat Jun 09, 2012 2:25 am

I agree with you! obstructs the fan in the chamber and that's enough for combustion
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POLAND_SPUD
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Sat Jun 09, 2012 4:38 am

Attention, the air leaving the compressor freezer often contains oil !
OH RLY ?? :D
Interesting video. I don't really seem much difference in propagation between fan on and fan off.
Sure but a fan can help in mixing
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boyce123
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Sat Jun 09, 2012 9:49 am

the burn patterns are surely different, but its hard to tell which propogates at a faster rate. The one with the fan on shows a spiraling burn pattern that entirely burns all to fuel, where as the one without the fan on appears to burn with a convection chamber pattern, with the initial burn, and a subsequent burn of all the fuel that was missed by the initial burn (because of fan's intrusion generating a convection cycle). The double burn was shown in the first videos quite well. The exsistance of the double burn, as shown in the first videos, appears to require a longer barrel to utilize the full power of the second burn; so if anything, the fan being on would allow the full potential of the gun to be met with a shorter barrel (or for more power to be utilized out of a given length of barrel).
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Petitlu
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Thu Jun 14, 2012 2:57 pm

I did further testing by placing the electrode in the center. The ignition system is always a flash + transformer It is crucial to a fan in a chamber!

[youtube][/youtube]
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Thu Jun 14, 2012 3:12 pm

Ignition behind the fan seems more effective to me!
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Petitlu
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Thu Jun 14, 2012 3:15 pm

the fan obstructs the combustion when the ignition is in the center
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ramses
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Thu Jun 14, 2012 9:04 pm

I wonder what all those little "balls" of fire were in the last video? I would have to guess either poor mixing (not likely if you ran the fan before the shot).

It cannot be dieseling or anything, since it only occurs where the flamefront has passed.
POLAND_SPUD wrote:even if there was no link I'd know it's a bot because of female name :D
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Petitlu
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Fri Jun 15, 2012 12:27 am

These are small pieces of Kleenex paper from the barrel ! :D

EDIT :
I just had an idea but I do not know if it's good! : face:

By putting a mano on the chamber, we could measure the peak pressure during combustion is not it?
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