combustion cartridge prototypes

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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jackssmirkingrevenge
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Wed Sep 05, 2007 9:57 am

Just thought I'd host the diagrams and photos from my R&D into combustion cartridges here as they no longer appear in the archived spudtech thread.
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v.2 breech at rest
v.2 breech at rest
P5100003.JPG (32.96 KiB) Viewed 8676 times
3/4" cartridge v.2 with breech
3/4" cartridge v.2 with breech
3/4" cartridge v.2 breech area with pneumatic recoil buffer
3/4" cartridge v.2 breech area with pneumatic recoil buffer
P5100001.JPG (37.14 KiB) Viewed 8676 times
3/4" cartridge v.2 construction
3/4" cartridge v.2 construction
75cartv2.JPG (28.01 KiB) Viewed 8676 times
6mm co-axial cartridge design
6mm co-axial cartridge design
6mm cartridge prototype
6mm cartridge prototype
6mmcart.JPG (21.6 KiB) Viewed 8676 times
6mm cartridge design
6mm cartridge design
smallcart.JPG (22.42 KiB) Viewed 8676 times
breech area for 3/4" cartridge v.1 design
breech area for 3/4" cartridge v.1 design
3/4" cartridge prototype v.1 with test 3/4" barrel
3/4" cartridge prototype v.1 with test 3/4" barrel
3/4" cartridge prototype v.1
3/4" cartridge prototype v.1
original cartridge construction
original cartridge construction
cartcut.JPG (21 KiB) Viewed 8676 times
operating principle
operating principle
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spud yeti
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Wed Sep 05, 2007 10:08 am

JSR, I really and truly love the ingenious and absolutely awesome ideas you perceive, not to mention your drawings! :D
How well did/does it work though?
hall of great spudguns tour, pretty lady giving tour: "And here we have another beautiful piece of ingenuity by jackssmirkingrevenge to our left..."
really good quote/phrase here
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jackssmirkingrevenge
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Wed Sep 05, 2007 10:16 am

Thanks, I try :oops:

The 6mm cart was a real sissy of a round and next to useless but the 3/4" one worked quite well and was powerful enough to easily put a marble through 1/4" ply, plus it had more than enough energy to eject the cartridge.

I still have the prototypes but I had put them aside as the "coaxial" style cartridge requires a certain precision to get things aligned and working smoothly, it's something I couldn't achieve with my limited tools. With combustions you need cartridges that are larger in diameter than the barrel to get enough power so the problem is unavoidable.

I might revisit the idea in the future but for no it's happily gathering dust on the shelf.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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spud yeti
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Wed Sep 05, 2007 10:26 am

Thats pretty darn powerful! (especially for the gun design and complexity)
Yeah, combustions can be quite finicky compared to pneumatics when they get advanced. But I think its a cool concept, so perhaps you should try revisit it from a pneumatic stance next time :D (I guess thats basically your preloaded pneumatic cartridge preoject then though :wink: )
What tools do you have to work with?
really good quote/phrase here
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jackssmirkingrevenge
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Wed Sep 05, 2007 10:33 am

perhaps you should try revisit it from a pneumatic stance next time
already did that :wink:
What tools do you have to work with?
What I use for spudguns is basically a hacksaw, a vice, hand files, a powerdrill and sandpaper. Not exactly precision engineering :roll:
hectmarr wrote:You have to make many weapons, because this field is long and short life
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spud yeti
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Wed Sep 05, 2007 12:11 pm

already did that
Too true, as I said in the above posts. How would you revisit it in combustion though, better precision and workmanship/quality/functionality?
What I use for spudguns is basically a hacksaw, a vice, hand files, a powerdrill and sandpaper. Not exactly precision engineering
Snap, except take the plural away from "files" :D
really good quote/phrase here
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Wed Sep 05, 2007 2:05 pm

How dus the ejecting of the shel work?
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jackssmirkingrevenge
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Wed Sep 05, 2007 2:10 pm

If you have a look here:

Image

Note how the on the closed side of the breech, it narrows at the end. The base of the cartridge hits the edge, and simply tips outward towards the open end of the breech.
How would you revisit it in combustion though, better precision and workmanship/quality/functionality?


Ideally it would be a hybrid cartridge so it would have power to spare, but then it's too complex to make unless you had a machine shop.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Wed Sep 05, 2007 2:15 pm

Now this is creativity as it should be! Awsome job.
iknowmy3tables
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Wed Sep 05, 2007 3:01 pm

I'm sure its been thought of many times, but your the first to make it which makes all the difrence

I belive you mentioned it but now i finally see the whole thing, I really like this

so what do you think about this is it a practical concept, should it be brought to hybrid level
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Wed Sep 05, 2007 10:17 pm

iknowmy3tables wrote:so what do you think about this is it a practical concept, should it be brought to hybrid level
At hybrid level I see it as being powerful enough to work reliably in a firearm-style blowback configuration, my vision is something like the diagram attached.

Any takers with a lathe and machining 5k1LLz? :D
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hybrid cartridge and action
hybrid cartridge and action
hectmarr wrote:You have to make many weapons, because this field is long and short life
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FeLeX
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Wed Sep 05, 2007 10:50 pm

Why not make it a oxy-propane hybrid so that you wouldn't have to have lathe skills?
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jackssmirkingrevenge
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Wed Sep 05, 2007 10:56 pm

FeLeX wrote:Why not make it a oxy-propane hybrid so that you wouldn't have to have lathe skills?
That's an idea...
hectmarr wrote:You have to make many weapons, because this field is long and short life
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FeLeX
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Wed Sep 05, 2007 11:02 pm

Just meter it out with a syringe and just inject it in there and put the marble in and there ya go. I mean it wont be that easy but a heck a lot easier then the traditional style.
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jackssmirkingrevenge
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Wed Sep 05, 2007 11:05 pm

My difficulty is that I'm not at all keen on working with oxygen, it's the giver of life and all that but nasty stuff when highly concentrated.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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