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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Mon Jun 25, 2012 2:04 am

To do all these tests, I plan to make a Exterminator II.
there will be an opportunity to make a simple ignition, a multi-point and at any point of the chamber.
The fuel can also be injected at different locations.
the only problem being to put the fan ...

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Petitlu
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Mon Jun 25, 2012 11:05 am

taser for ignition :

[youtube][/youtube]
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Petitlu
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Mon Jun 25, 2012 4:04 pm

tests :

[youtube][/youtube]
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Technician1002
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Mon Jun 25, 2012 7:30 pm

Watching the videos suggest a Marx Generator inside and the length of the chamber would be the ultimate ignition for a long multi gap spark strip.
http://en.wikipedia.org/wiki/Marx_generator

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Petitlu
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Tue Jun 26, 2012 12:26 am

Yes I know!
and I thought to my future tests!
But we must make a ...
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Petitlu
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Tue Jun 26, 2012 2:52 am

I modified the taser to be more practical.
I put a push button instead of the switch.

[youtube][/youtube]
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Petitlu
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Tue Jun 26, 2012 2:06 pm

[youtube][/youtube]
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Petitlu
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Wed Jun 27, 2012 3:23 pm

Today, with a test electrode multi point! :)
In one test, the piezo, the AGM and AGE were not triggering the explosion, I put the tazer and then .. boom at first!
You take a taser + a multi electrode point => TOP

[youtube][/youtube]
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Petitlu
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Wed Jun 27, 2012 3:55 pm

Test with a central ignition and ignition system flash + transformer.
And a test gas with a lighter electronics

[youtube][/youtube]
Last edited by jrrdw on Sun Nov 17, 2013 11:09 am, edited 1 time in total.
Reason: Fixed video.
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jackssmirkingrevenge
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Thu Jun 28, 2012 1:49 am

VERY nice!

That looks like a proper detonation, the high energy spark really makes a difference!

Excellent R&D work, keep it up :)
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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Thu Jun 28, 2012 2:11 am

Thank you!
It is essential to have a good spark and the taser is excellent for that.
If I make a PAL, it will be multi-point!
:D

By cons, multipoint ignition is really powerful if the fuel / oxidant is well done, if combustion is done in one place
jazzman56
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Thu Jun 28, 2012 4:38 am

Petitlu

Very very interesting of how the internal flame front acts with obstacles, the type of spark gaps and the where it is placed in relation to the chamber. :) :)

Is there any chance of getting a picture/schematic of your Flash And Transformer ignitor i am curious of how you achieve these better sparks.


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Petitlu
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Thu Jun 28, 2012 5:13 am

Voici un schéma et une photo :
I replaced the push button by a 12v car relay, the black cube that you see in the picture.
Precision: the primary of the transformer connects to the capacitor and the secondary to the electrodes.

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Image[/img]
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DYI
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Thu Jun 28, 2012 7:39 am

That looks like a proper detonation, the high energy spark really makes a difference!
This is definitely NOT a detonation - the VoD in propane/air is roughly 1800m/s for a steady detonation (it goes faster as an overdriven detonation during the DDT process). Even if the chamber were two meters long, 1000fps filming would only capture it "in progress" for a single frame, if you were lucky.

Also, "high energy spark"? A 30g tetryl charge will not directly initiate detonation in unconfined propane air, and I'm guessing that Petitlu is dumping a lot less than 150kJ across that spark gap :roll:
I see nothing here to indicate either direct initiation or DDT.
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Petitlu
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Thu Jun 28, 2012 7:47 am

For this reason JSR wrote "looks" and not "it's a detonation"

:D
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