Spud Showdown

A place for general potato gun questions and discussions.
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rcman50166
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Thu Mar 20, 2008 4:22 pm

Well well well, aren't we cocky? Just kidding. :D I'm surprised just as much as you are. I'd imagine that a 1/4 in. steel plate would be a rediculously hard target to penetrate. But that's not what everyone else is saying. I had to make a huge overhaul on the "General" to even think that I might have a chance. The test you suggested is a simple and effective way to see. I'd wish I'd thought of that. :x But a nice hole in steel isn't the only thing that I want to do. I want to try to match the video that you always see of the M1 A2 Abrams tank, the one where you see a round arc down range, punch a hole in something, and then erupt the hill behind it in a big plume of dust.

BTW what cannon and what ammo did you use to drop that plate?
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pizlo
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Thu Mar 20, 2008 4:43 pm

PLEASE read his post about it, he used a s7 grade tool steel hole punch, it was much harder than whatever nail you're shooting.
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elitesniper
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Thu Mar 20, 2008 4:56 pm

i dont even have access to those kinds of things :shock: im making good old fashion getto household slugs, not for shooting holes though, shooting holes in a video gets kind of boring.. need to shoot some thing that really does something when hit.
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DYI
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Thu Mar 20, 2008 5:18 pm

I don't feel like going through it again, I explain everything in
"Carnage, v2.0...". The real interesting thing was the 9/16" wide hole I punched. The SCTBDC will be completely obsolete in a few months, but I'll likely get at least one shooting day with it before then, and it certainly won't be decommissioned or scrapped.

And shooting a hole through an impressive target and then making a mound of dirt erupt behind it is going to take a lot more energy than any of us (except maybe Killjoy) have available.
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MaxuS the 2nd
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Thu Mar 20, 2008 5:55 pm

Rcman: I think it is unlikely you would be able to punch through a 1/4" steel plate with a simple sabot and nail, it sounds rather over-optimistic.
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SpudFarm
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Thu Mar 20, 2008 6:20 pm

god i miss the "best shot on video" topic :roll: :roll:
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pizlo
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Thu Mar 20, 2008 6:35 pm

MaxuS the 2nd wrote:Rcman: I think it is unlikely you would be able to punch through a 1/4" steel plate with a simple sabot and nail, it sounds rather over-optimistic.
Yeah, if he gets through 1/4 inch steel I'll crap my pants in school, and get it on video for him!
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potatoflinger
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Thu Mar 20, 2008 6:43 pm

I think that Big Blue definitely has the stuff to win this one. I've always been a fan of pneumatics, and I probably always will be, and I haven't seen anything that would make me want to change my mind.
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SpudFarm
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Thu Mar 20, 2008 6:56 pm

potatoflinger: hybrid's...
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Jared Haehnel
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Thu Mar 20, 2008 7:01 pm

I wonder if a heavier RR spike might have more penatration moving at a lower speed then a faster moving lighter punch. I think he could achieve it if the object was fialry heavy. His spike is going to be a bit heavier then the ounch was. I would like to give him the benifit of the doubt on this one.
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DYI
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Thu Mar 20, 2008 7:56 pm

Considering all the secondary targets I punched through, I wouldn't be hugely surprised if he does manage to penetrate the plate. Look at what spudfarm did with a small, low mix hybrid.

Penetration is a factor of cross-sectional density, energy, velocity, and hardness and grain properties of the projectile and target. It is rather difficult to know for sure without trying, but I'd advise that rcman hardens the spike first.

On a side note, if I can get a few more suitable punches, I'll take another shot or two at the plate so I can get the results on video.
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elitesniper
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Thu Mar 20, 2008 8:20 pm

haha, com on spud farm, its not always about hybrids, sometimes it can be high pressure pneumatics :)
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Ragnarok
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Thu Mar 20, 2008 9:46 pm

rcman50166 wrote:Also Ragnarok, that does sound optimistic... Sabot rounds are very unstable when they leave the muzzle of the gun. A sabot can deflect the direction of the round it carries up to 15 degrees. That's a worse case scenario though. An average sabot will cause about a degree of deflection, so in the end, you may be taking pot shots at something well beyond the round's effective range.
As predicted by Maxus, it's the (reasonably) long post that says why I think it's possible:

Sabot isn't quite the right word, but it's the closest equivalent I can think of. Where sabot implies it supports the round, the basic principle matches JSR's idea from here, but refined a bit : http://www.spudfiles.com/forums/viewtop ... tml#156690

To avoid the problem you describe, I've already got a smart plan that means the dart will separate from the "sabot" before it's left the muzzle - don't ask how just yet, I'm still perfecting it. The dart will leave the muzzle slightly ahead of the sabot/wadding and because of this the dart's path will neither be affected by the muzzle blast or the sabot.

The design is not quite of the exacting military standards people are talking about, but is certainly a step up on what some spudders have used. Given I'm using a combination of stabilisation techniques to get the best result, I'm not that worried about the dart's stability - the only real concern I have about the accuracy of the dart is it's fairly high susceptibility to side winds, given it's large flank area, poor normal Cd and fairly low mass. However, that can be guestimated for.

If I can get accuracy of 3 MOA - or maybe a little worse - which isn't hopelessly optimistic, then with a handful of darts, I should be able to get at least one hit on the plate I have at 400 metres.
spudfarm wrote:that is something you will need a hybrid to do..
... quite fittingly, one of the original objectives for HEAL was that it would be able to "give a hybrid a run for it's money".
I think the objective was met - although HEAL doesn't have quite the same velocity capacity as a hybrid, the energy at 300 psi is almost the equal of what a 4x hybrid in this size range might achieve. At 30 bar, I have no doubt I could compete with a 5x hybrid.

Now, I couldn't begin to pretend that HEAL had the sheer energy of large cannons like the SCTBDC, but believe it or not, for it's size, HEAL is actually more powerful, being one of the few pneumatics capable under "non-extreme" conditions of generating more than 1 Joule of muzzle energy per cubic centimetre of barrel.

It would be hopelessly optimistic to put a similarly large hole to what DYI managed, so I'm not trying to manage more than about half the diameter on that front.
Even then, I'll be a little short on the energy per unit area to what DYI achieved, but considering the secondary damage he racked up, I don't think it's inachievable.

While we're here, we mustn't forget that Nova's Brass Bruiser nearly penetrated 5mm plate steel with his "Pimpin' Ammo".
And, no offence intended to Nova of course, but HEAL, by virtue of it's larger size, has a bit more muzzle energy than the Brass Bruiser.

So, getting HEAL to pierce 6mm plate at short range wouldn't be too much of a task. Now, what you're going to ask now, is: "What about at 400 metres?"

That shouldn't be too much of a stretch either. After drag, the dart should be able to carry over 80% of it's KE from the muzzle to the target.

I never said it was going to be easy. It's going to take what is a pretty powerful launcher, a truckload of patience, and a lot of work - but I think it can be done.
I wouldn't have said I thought I could do it if I didn't believe it at least possible.
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iknowmy3tables
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Thu Mar 20, 2008 10:00 pm

hey I run the spudfiles youtube group I'll send a message although its not a very active group
http://youtube.com/group/spudfiles
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MaxuS the 2nd
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Fri Mar 21, 2008 6:22 am

How are you going to sight the plate at 400m, Rag?

That's a bloody long way to be looking for a (I'm guessing relatively small) steel plate.
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