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combustion marble gun....
Posted: Thu Jan 03, 2008 7:41 am
by nightshot
I want to build a marble rifle, but I don't have a compressor, and I want to make a combustion, so I have 2 questions... Is it safe ?? How much meters the marble can go ??
Posted: Thu Jan 03, 2008 7:44 am
by Hubb
Yes
It depends on the setup, C:B ratio, fuel, fuel / air mix, etc.
Posted: Thu Jan 03, 2008 7:46 am
by jackssmirkingrevenge
If you can make something like
this with a barrel suitable for marbles you'll be fine, as to range it depends on the variables hubb017 mentioned, but the bigger you make it the better.
Posted: Thu Jan 03, 2008 7:57 am
by nightshot
Specs:
Combustion Chamber = 7cm x 45cm
Barrel = 3cm x 90cm
C:B Ratio = 1:2
Propane powered
With a Computer Fan on chamber ...
If this specs are not good please tell me ;D
Posted: Thu Jan 03, 2008 8:24 am
by Hubb
Some have said that to make an efficient combustion, one would need a ratio of around .8:1. Also, is there a computer fan that small? I've never seen one and was just wondering.
Posted: Thu Jan 03, 2008 9:28 am
by TurboSuper
Yeah, a standard fan is 80mm, and they go much smaller.
Anywho, i'd reccomend a .8:1 for a propane-powered one.
Posted: Thu Jan 03, 2008 9:48 am
by nightshot
well, can you recommend me a good setup for my cannon with at least 150cm of Length please... =]
thx
Posted: Thu Jan 03, 2008 10:44 am
by Hubb
I don't feel like doing math right now, but the
RatCalc should be able to help you. Also, the rest of Burnt Latke's site may be able to answer any othe questions you may have. If not, we can.
Posted: Thu Jan 03, 2008 1:11 pm
by jimmy101
nightshot wrote:Specs:
Combustion Chamber = 7cm x 45cm
Barrel = 3cm x 90cm
C:B Ratio = 1:2
Propane powered
With a Computer Fan on chamber ...
If this specs are not good please tell me ;D
Chamber volume = Pi(r<sup>2</sup>)L = (3.14)(7/2)<sup>2</sup>(45) =1730 cm<sup>3</sup>
Barrel volume = Pi(r<sup>2</sup>)L = (3.14)(3/2)<sup>2</sup>(90) = 635 cm<sup>3</sup>
C:B ratio = 1730/635 = 2.72
The chamber is way too big for the barrel.
Perhaps drop the chamber to 25cm and increase the barrel to 150cm.
Chamber volume = (3.14)(7/2)<sup>2</sup>(25) =961 cm<sup>3</sup>
Barrel volume = Pi(r<sup>2</sup>)L = (3.14)(3/2)<sup>2</sup>(150) = 1060 cm<sup>3</sup>
C:B ratio = 961/1060 = 0.9
Posted: Thu Jan 03, 2008 6:31 pm
by TwitchTheAussie
Cough nerd cough
. Yeah mate the ratcalc can help you heaps trust me. But if ya wanna do things the easy way, try the water method. Block one end of the pipe to be your barrel, fill your chamber with water and tip it into the barrel. Minor equations can be used to get you .8:1 ratio
Posted: Fri Jan 04, 2008 7:01 am
by f.c
look up the amc made by me. its a combustion powered marble gun.
Posted: Fri Jan 04, 2008 7:34 am
by Pyro Ninja
I believe "experiment_u2" made a nice combustion marble gun.
Its called the "famas combustion"
Posted: Fri Jan 04, 2008 7:37 am
by ALIHISGREAT
Pyro Ninja wrote:I believe "experiment_u2" made a nice combustion marble gun.
Its called the "famas combustion"
dude thats one sick looking cannon, dead space could have been a problem but i see he used a burst disc which would counteract the dead space.