It's a pipe dream....


Postby D_Hall » Fri Sep 22, 2006 9:59 am

Let's see.....

Yeah, it should cost very little to build. We actually already have almost everything you see. What we don't have? The wheels for the barrel carriage and about 20' of 6" square tubing. Other than that, everything you see is already in our inventory. Of course, labor isn't cheap, but if we use it as a "do this when nothing else is going on" we've gotta pay the money anyways. Too, I'm working on a white paper to get actual funding for this.... If that happened? Cooool.

As for power, it's looking like it'll push a 100 lb projectile to 1000 fps. 50 lbs to 1300 fps.

Fuel meter... Just to annoy you folks, I'll mention that I've got several hundred meters of 8" pipe (rated to 1200 psi) that I plan on using some of. Oh, and volume has gone down significantly. Where earlier in the thread I was talking about using 60 feet of the 29 inch pipe, I'm only using 40 feet of it (plus fittings). Chamber volume is down to about 250 ft^3 (what's that in liters?)

And I don't know what hell cracking open sounds like, but I assure you I've been present for bigger booms than this will make. That said, I agree that it should be spectacular! :D

Final thought: IF this ever gets built, I all but assure you that there will be a press release. Heck, the other gun I'm lord over (the Mach 7+ one) should be releasable. We *want* it released (free advertising, yeah!). We just haven't gotten all the paperwork filled out yet.
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Postby Mosif » Fri Sep 22, 2006 10:08 am

Why do I see this ending as a crater on CNN and somehow the headline would read "Teens with spud gun cause explosion"?
lol j/k

I really hope you guys can pull this off, because this I gotta see.
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Postby boilingleadbath » Fri Sep 22, 2006 3:16 pm

You've got about 6350 L of chamber volume.
For the record, that makes it 2000x as big as latke's L3, and about 200x as big as DR's basketball gun.
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Postby joannaardway » Fri Sep 22, 2006 3:44 pm

Can I have some of that 8" pipe? I can foresee uses of such uber pressure ratings.

If pictures/videos are released, then I can only imagine the damage pics!

I remember some of those "fake spudguns" that were posted a few months back, with damage pics of collapsing buildings/etc.

You might almost do that with something like this!
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Postby D_Hall » Fri Sep 22, 2006 5:56 pm

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by boilingleadbath
[br]You've got about 6350 L of chamber volume.
For the record, that makes it 2000x as big as latke's L3, and about 200x as big as DR's basketball gun.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Not familiar with those other guns but your post inspired me to (finally) calculate the chamber volume (rather than the guesstimating I've been doing). I just built a model of the void (does that make sense?) and had the software give me the volume.

454440 in^3 = 262.9 ft^3 = 7447 litres = 7.447 m^3


As an aside: Since my main chambers are 240 inches long, that's probably what I'll do with my metering pipe as well. Why not? So I'll have an 8" x 240" metering pipe. That'll allow me to go up to a 2.25 Nx load(*) with a single fill at a reasonably low pressure.


(*) I lied previously, the pipe will actually go to 250 psi, not 200. But I'm designing around 200 until I get to see real pressure data.



edit: And just for fun... <a href="http://www.thehalls-in-bfe.com/Bender/19inchgun.gdt">the GGDT file</a>.
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Postby D_Hall » Fri Sep 22, 2006 9:09 pm

Note to the moderators... Although this thread started out firmly in the pneumatic world, since it's moved to the hybrid world should the thread be moved to that area of the forums?
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Postby SpudMonster » Fri Sep 22, 2006 9:32 pm

To IMadeGodsGun:

<font size="9"><b>NAH NAH NAH NAH NAH!!!!!!!</b></font>
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Postby D_Hall » Tue Sep 26, 2006 11:29 pm

OK, I've totally got the fueling/inflation thing worked out from a safety and mixing perspective. 'Tis so simple it's stupid!

As I said, I've got a mess of 8" pipe lying around.

Using a length of that pipe as a fuel metering pipe is a no-brainer.

But what I can also do is use some other lengths of pipe as an air metering pipe. So what I end up with is a two "pipes." One is filled with propane. The other is filled with air. I fill them at my leisure before the test. This is very safe since combustible mixtures of the gases are never present.

When both pipes are full to the prescribed level, I disconnect the propane bottle and the air compressor and fall back to the bunker. Then I open up two solenoid valves that simultaneously dump the air and the propane. Voila. At the time the gun is fueled (ie, combustible mixtures present) there is nobody within 1/4 mile of the gun.

Further, since I was adding my fuel and my air at the same time, there's no reason why I can't use impinging gas streams to mix the fuel much as you would expect to see it done in the interior of a rocket motor.
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Postby BewareOfDog » Wed Sep 27, 2006 12:10 am

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by D_Hall
[br]Note to the moderators... Although this thread started out firmly in the pneumatic world, since it's moved to the hybrid world should the thread be moved to that area of the forums?

<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Done.
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Postby SpudStuff » Wed Sep 27, 2006 11:23 am

Enter it in the pumpkin chucking contest!
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