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The BFSG-4000

Built a combustion cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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The BFSG-4000

Unread postAuthor: KlugeBoy » Tue Feb 28, 2006 3:13 pm

My first spudgun. Propane powered, 4 Liter combustion chamber, electronic ignition, laser sight. Blowing holes in 3/4" plywood.

Image
A new look. Thanks pimpmann22 for the Black Hose suggestion.

Gun Specifications:
http://klugeboy.net/BFSG-4000/BFSG-4000.html

Projectiles and Damage:
http://klugeboy.net/BFSG-4000/Gallery/GalleryOfDestruction.html


The New Laser Sight Mod!
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Last edited by KlugeBoy on Sun Mar 05, 2006 1:38 am, edited 8 times in total.
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Unread postAuthor: dragon finder » Tue Feb 28, 2006 3:16 pm

Nice and welcome to spudfiles.
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Unread postAuthor: KlugeBoy » Tue Feb 28, 2006 3:22 pm

Thanks. Got lots of ideas from this forum and thought I might make a contribution back to it.
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Unread postAuthor: dragon finder » Tue Feb 28, 2006 4:13 pm

I would love to make something like that I even have an idea but I have low funds. That is a very creative gun expecialy(sp) the ignition system. Keep up the good work :D :D
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Unread postAuthor: saladtossser » Tue Feb 28, 2006 4:30 pm

damn that looks very proffesional, keep up the good job, i love how you put hoses over the clamps.
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Unread postAuthor: boilingleadbath » Tue Feb 28, 2006 6:41 pm

Nice looking gun... I particuraly like the well-done job with the name - very well done, to the point where I questioned weather that was just stuck there with MS paint.

That being said, what's the large dorsal knob? (painted magenta)
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Unread postAuthor: CS » Tue Feb 28, 2006 6:49 pm

NICE!!! (is it me or do new members cannons get nicer and nicer? lol)

I dont think ive ever seen a paint job so flawless like yours. As ST noted, I very much like the hoses incasing the hose clamps. If you see the idea of incasing the hose clamps with tubing on mine or others cannons, dont be suprised.

Three suggestions:

Shorten the hosing. I think people are scared of tubing being to short, which then results in this longer tube that juts out more then it needs to because of it length.

The hose you used on the injection system is it the same as the hosing you incase the hose lamps with?
If YES: Simply paint the tubing black, so it will match the hosing used for the hose clamps.
If NO: Get the same tubing that you used to hold the propane cylinder and exchange out for clear braided tubing. Then paint it.
(this will help your cannon look cleaner, instead of a mixture of two differnt tubing, it will only be one)

The second is you can connect tubing using fittings, rather then slipping the hosing over the fitting, you can actually use brass fitting to go from the torch to hose. The way to do this is to remove the angled torch thingy. Then you can screw in a brass fitting. This thread on the valve is a compression thread though. So you will need a brass compression thread to NPT thread. Once in you can go from the NPT fitting to the a hose barb.

Yes, I also welcome you to the forums and look forward to your future cannons...
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Unread postAuthor: KlugeBoy » Tue Feb 28, 2006 10:06 pm

boilingleadbath
Check out the http://klugeboy.net/BFSG-4000/BFSG-4000.html home page. The Red Dorsal knob is a removable ignition system (so I can swap it out or over to another gun).

As for the name I just painted a strip of red, stuck on some plastic letters (Office Supply stuff) painted black over that and pealed off the letters. I use that technique all the time, much better than stencils.

-----[21:13 PM]-----
pimpmann22
I like the idea about painting the hose black. I may have to do that if I can find a durable paint.

That hose is much larger than the black rubber hose. I used a long piece of reinforced hose to eliminate any crimping. I needed a minimum of back pressure since I was using the torch nozzle to pre-mix the propane with air. Any back pressure causes the mix to be too rich. Since I'm not using Direct Propane Injection I had to use a huge hose and fittings.

I didn't use fittings on the torch end because I wanted to be able to fiddle with the fuel/air mix on the fly.

It's all explained on the home page...

-----[21:22 PM]-----
pimpmann22
Dude, just saw the SDR21 golf ball barrel material you've got. I read about it but no one in this podunk town sells it. Does it require any sabot at all? If not how do you get a good seal?

NOTE FROM PIMPMANN22: Fixed triple post. Since replys are organized in chronological order, if you want to reply, but no one else has reply. You should edit your post to include the infromation. This saves space... (veiwing not memory)
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Unread postAuthor: cardinals08 » Tue Feb 28, 2006 10:28 pm

KlugeBoy
You are supposed to use the edit button instead of double posting.
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Unread postAuthor: dragon finder » Tue Feb 28, 2006 11:13 pm

Or triple posting....listing all that in one post I beleve(sp) saves web room(I think :?: :?: )
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Unread postAuthor: KlugeBoy » Wed Mar 01, 2006 12:48 am

With all due respect cardinals08 and dragon finder I've been writing software and web sites for about 20 years and I'm pretty sure reediting old posts would just make it tough to follow the flow of the conversation and since this is mainly text data I doubt it makes much difference with respect to storage space how it's broken up.

If however I have broken with the local customs I humbly apologize and promise to mend my heathen ways...

Now, does anyone know if it's possible to calculate the optimum weight for a projectile to achieve maximum penetration for a 2" x 12" pine board target? I'm not enough of a physics guy to know this one and I really want to punch a nice clean hole in one of those suckers.
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Unread postAuthor: CS » Wed Mar 01, 2006 1:29 am

C08 & DF: No need to go off topic to say "dont triple post". Either wait it out or PM a moderator or admin.

BLB (BoilingLeadBath), is our "physics guy" round' here.

I dont know if you did or didnt understand me correctly... Im not talking about completly removing the whole torch head just after the vavle. If you put the "bent" peice in the vice and put a cresent wrench on the body of the valve. Then *twist*.

No sabots. I need to take a picture of a GB sitting in some SDR-21... Its a really close fit. On my 4' barrel it will take a GB muzzle loaded 2-4 seconds to reach the bottom, becuase of the small space between GB's OD and barrels ID (this of course is with endcap off). I think why the preform so well is because of the following: GB is built to be aerodynamic, and thats its a good balance between seal and friction.
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Unread postAuthor: dragon finder » Wed Mar 01, 2006 1:33 am

I am not upset or mad at it myself but some other people do however(Just a heads up :D ) I don't know about calculating it but I sugest something heavy and pointed for easier penitration(sp). I like experimentation rather than mathmatics.
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Unread postAuthor: KlugeBoy » Wed Mar 01, 2006 3:33 am

pimpmann22

I guess I'm being denser than usual (which is actually fairly impressive, we're talking depleted uranium here). Are you talking about attaching the torch stem directly to the 5/8" hose via a compression fitting? If I get rid of the business end of the torch (the piece that screws on to the end of the stem, usually used to adjust the flame) then I'd lose the ability to have the torch mix air with the propane as it was being fed into the combustion chamber. I'd be injecting pure propane. In this case that would be a bad thing as I designed it specifically to mix the air in for me. That way I never have to clear the chamber. Just feed in more pre-mixed propane/air.

Am I missing something here? If there is a way to improve this thing I don't want to miss it.

Check the home page linked above. I have a bunch of pics and a detailed explanation of the design.

Also, don't miss the Gallery Of Destruction link at the top of that page. Got some good pics of violence being done to various innocent pieces of wood.

From my 3/4" plywood test:
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Unread postAuthor: boilingleadbath » Wed Mar 01, 2006 6:12 pm

I think it would depend apon how you are trying to penetrate it.

With a pointed projectile (that will hold it's shape) you would want something like the kinetic energy penetrator rounds tanks use these days - which look suspiciously like finned railroad spikes with a sharper tip, to apply the most force practical to the smallest area.
I would think that your primary goal would be to maximize energy transfer... however, we don't know the muzzle-energy curve of combustion spuguns, so I can't tell you where that'd be - although a good geuss would be about 200-300g... a railroad spike, maybe?

For something like at potato, with less structual integrity, I would think that you can basicaly ignore it's strength (in the same way you can ignore the strength of the metal(s) in a shaped charge and treat it simply as a hydrodynamics problem).
With the target being as hard as it is, you could probably simply optimize it for exerted force. Simply transfered energy devided by impact time should do, although Energy/(projectile length/velocity) would be a more revealing way to say this (a shorter disk would make impact time shorter)
A lightweight, thin disk of potato seems to be the conclusion. Assuming that's a 2" bore, I'd try maybe 50g or so.

For hard projectiles (non-pointed) I'd say you'd want them to be as hard (to minimize impact time by minimizing projectile squishing - same reason as for soft impactors) and as small (same reason as the pointed impactors) as possible. I'm not sure weather it'd be better to get them going fast or have them be heavy, so just go with a moderate mass like 100g.

However, with the timescales of impact involved here (less than a milisecond) even odd things like soundwaves in the target media might effect the impact, nevermind diving-board type bending of the target. And I don't know how to deal with those.
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