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For those who like potato guns


InigoMontoya

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For comparison, my design goal is 100 lbs to 1000 fps (680 mph).
Damn... can I come over and watch?

 

 

edit... Something's not right here. 1.5 MJ compared to "2+" MJ for a significantly smaller projectile that's slower as well?

 

PUMPKIN

10 lbs = 4.545 kg.

600 mph = 268.2 m/s

Energy = 0.5 * 4.545 * 268.2^2 = 196 kJ

 

Mine

100 lbs = 45.45 kg.

1000 fps = 304.8 m/s

Energy = 0.5 * 45.45 * 304.8^2 = 2.11 MJ

Sure enough, I screwed that one up. Misplaced the decimal.
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  • 5 months later...
  • 1 month later...

This potato gun could obviously fire potatoes by the sackfull. If you used the bolts at the muzzle to hold a grid of strong wire it could easily be converted into a potato chip producer of industrial proportions. Patent it and make some money!

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I've been working on a project for a number of years now. It's *almost* completed. In short, I believe it will be the world's most powerful gun powered by "hardware store-level technology". Not the largest, mind you, but the most powerful. Muzzle energy should be in excess of 2 MJ.

 

That is quite simply ... awesome.

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  • 3 months later...

Somebody asked me for an update so I figured I'd give it here....

 

There's not really tooo much to report as work has been incredibly busy and things are only getting worse (will probably be working 7 days a week next month). VERA (the gun) is a side project so she has been largely neglected during this time. Granted, "insanely busy" is a good problem to have these days so I'm not complaining, but it doesn't help my dreams for VERA come to completion.

 

HOWEVER....

 

Right now there's a video that's working it's way through our public affairs office. It was supposed to have been a rough cut of a marketing video but it too has been overtaken by events and there's a desire to get something out there fast. So the rough cut will be the final cut. In any event, I expect the video to be released in about a month. When that happens I'll put it up on youtube and put a link in this thread.

Edited by InigoMontoya
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Inigo ,

 

Why is there a preference for propane / air mixtures ?

 

I like to throw a few numbers into my calculator to see what I get , can you say what the amount of propane used is per explosion ?

 

Would it be possible to use acetylene / oxygen mixtures ?

Edited by hal_2011
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Why is there a preference for propane / air mixtures ?

Propane/air results in a very stable, well behaved combustion.

 

Oh, and it's dirt cheap and everybody is familiar with it. It's nice to be able to turn to the safety department and be completely honest when I say, "This gun is safer to operate than your backyard BBQ grill."

 

can you say what the amount of propane used is per explosion ?

Off the top of my head? Meh... Something like 3 or 4 pounds.

 

Would it be possible to use acetylene / oxygen mixtures ?

Depends on your definition of possible. Could I pump acetylene/oxygen into the gun? Sure. Would I want to? Hell no. I want a deflagration, not a detonation. Acetylene and oxygen would assuredly detonate. That's bad.

Edited by InigoMontoya
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Inigo , Would a propane / oxygen mixture give an unwanted detonation ?

I can't speak authoritatively on that front, but I believe it would. Mind you, a bit of O2 to augment the burn would probably be OK, but as O2 levels rise so too would the odds of detonation.

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