SpudFiles

Do a little research on the wiki.

You can find plans for pneumatics just searching around on the internet. I have a good engineering brain and have figured out how to build a hybrid, combustion-piloted piston hybrid, REAL piston hybrid, and normal metered combustion. I have not the resources to build much beyond what I have which is a simple pneumatic. If you can demonstrate that you have the common sense and respect for high-powered spudguns, I know that there are those who will help you out with diagrams, plans, supply lists and the like.

Depending on what you have access to, this bet could easily cost more than $500 to win, and would result in a heavy, awkward, loud cannon that would be rather expensive to operate. Also, good luck hitting close enough to the target area to see the splash with binoculars...

To start you on your quest, the cheapest way to do it is with a high pressure pneumatic using a rupture disk valve. In the long run, a hybrid would be cheaper due to its lack of reliance on expensive compressed gases.

ok so i've read up on burst disks and unions but i'm still not understanding it. can you clarify on how a union works?

A .22 rifle can travel over a mile I thought. But about the spud gun, yeah man, check it out...immagine a cannon with enough force to send something that far, then immagine it failing upon ignition. What you have is a HUGE hand grenade. I would go with a large burst disc hybrid made out of high strength steel and remote detonate it from about 50 yards away behind a blast shield. It would have to be large and high mix. Thats very dangerous and would have to cost a decent penny to be anywhere near safe. Will your dad hire an engineer and pay the money to have it manufactured just to lose a bet? I doubt it.

lol so this idea is impractical, expensive, and unsafe. i don't like the sound of that

reedfe wrote:lol so this idea is impractical, expensive, and unsafe. i don't like the sound of that

Now you're thinking.

EDIT: There is no reason you can't still build something totally impressive. Don't do it on a bet. It will motivate you to go beyond your comfort zone and you could end up with a magnificent FAIL.

A .22 rifle can travel over a mile I thought. But about the spud gun, yeah man, check it out...immagine a cannon with enough force to send something that far, then immagine it failing upon ignition. What you have is a HUGE hand grenade. I would go with a large burst disc hybrid made out of high strength steel and remote detonate it from about 50 yards away behind a blast shield. It would have to be large and high mix. Thats very dangerous and would have to cost a decent penny to be anywhere near safe. Will your dad hire an engineer and pay the money to have it manufactured just to lose a bet? I doubt it.

Speaking of hand grenades, a modern one would be 500kJ to 1MJ energy, released in microseconds, generating millions of psi shock pressure, and specifically designed to throw fragments.

Compare to this thing, running perhaps 50kJ potential energy stored in a relatively low pressure gas, or generated by combustion reaching one or two thousand psi in several milliseconds. The energy density is vastly lower, and the (much more malleable) container's mass considerably greater. So it's more like a TINY hand grenade, with the fragments removed and the RDX replaced with black powder.

With a decent SCH 80 seamless steel body and appropriate fittings, a 1 mile pneumatic or hybrid is no more of a threat than a properly maintained water heater, so long as you don't stand downrange .

The real threat is that of wasting time and money by pushing forward on a project beyond one's abilities. As Moonbogg said, build something more "practical" to get you started. See where it goes from there.

I would say that it is possible... I ggdted a simple burst disk gun built from 1.75" pipes... at 400 psi, with a 150cm long chamber, 500 cm long barrel you can achieve over 1 km with 0.5kg projectile

you could probably get much more with the use of a sabot...
but yeah as DYI has pointed out it is very far form being practical

I would suggest something like my big pneumatic...
http://www.spudfiles.com/forums/4in-coa ... 18237.html

At 100psi you should get nearly 1/2 mile with a bouncey ball. More with a dart (which I've never done) but I think you'd get nearly 3/4 mile...

DYI wrote:

A .22 rifle can travel over a mile I thought. But about the spud gun, yeah man, check it out...immagine a cannon with enough force to send something that far, then immagine it failing upon ignition. What you have is a HUGE hand grenade. I would go with a large burst disc hybrid made out of high strength steel and remote detonate it from about 50 yards away behind a blast shield. It would have to be large and high mix. Thats very dangerous and would have to cost a decent penny to be anywhere near safe. Will your dad hire an engineer and pay the money to have it manufactured just to lose a bet? I doubt it.

Speaking of hand grenades, a modern one would be 500kJ to 1MJ energy, released in microseconds, generating millions of psi shock pressure, and specifically designed to throw fragments.

Compare to this thing, running perhaps 50kJ potential energy stored in a relatively low pressure gas, or generated by combustion reaching one or two thousand psi in several milliseconds. The energy density is vastly lower, and the (much more malleable) container's mass considerably greater. So it's more like a TINY hand grenade, with the fragments removed and the RDX replaced with black powder.

With a decent SCH 80 seamless steel body and appropriate fittings, a 1 mile pneumatic or hybrid is no more of a threat than a properly maintained water heater, so long as you don't stand downrange .

The real threat is that of wasting time and money by pushing forward on a project beyond one's abilities. As Moonbogg said, build something more "practical" to get you started. See where it goes from there.

The point is if you are close to a failing chamber like that, or even if an end cap blows off, it might as well be a hand grenade because you can be just as dead.

I've tried to range test golf balls, but I can never find them. I need to get some with some sort of homing beacon in them. This summer I am planning on drilling a few to add LED lights or mini glow sticks for some night tracking and retrieval. With a GPS, I'll be able to get some better distance measurements with golfballs.

Apples that don't explode on launch are good for about 600 feet. They are not as aerodynamic as golf balls.

I've shot a 30" arrow at 6x with the hybrid, in a 1,5 ft barrel, horizontal shot. (saboted) It did fly fast, actually we didn't see it , but about half a second later, it landed 150 meters downrange in the water. Now, HGDT gives almost 60% more initial speed with a 3 feet barrel. The recoil was quite noticeable though.... I have a video i'll edit right away of a similar shot, at 5x, with heavier arrow.

I think one mile is possible, with a good angle, an arrow, and a high power spudgun, either pneumatic or hybrid.

D_Hall wrote:It's not that bad... There are several golf ball launchers on this site that should be able to do on the order of 1/3ish mile...

Several?

Mathematically speaking, a golfball needs to be pulling about 500 m/s at the muzzle in order to be capable of the ~536 metres that equates to.
I know there are a handful of golfball hybrids that are up to that velocity, but they're not exactly numerous.

Any of them could do a 1/2 mile+ with a saboted dart (I'd even lay money on a full mile but until I study the problem I'm just going with my gut, nothing more).

Quite easily. Although I never intend to do it because of how dangerous it is, I've got a prototype dart on my desk that would come down about three miles away if I fired it for distance - and that's from a far less powerful launcher.

Any golfball launcher that had the power to put a golfball a 1/3rd of a mile could easily put a good saboted dart five miles or more.

Ragnarok wrote: ... I've got a prototype dart on my desk that would come down about three miles away if I fired it for distance - and that's from a far less powerful launcher.
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How about a picture then?