ballistic knife WOW

They are around but beware. they are VERY ILLEGAL in most if not all the states. They are also not very effective but would make a great toy.
 
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15 years ago or so, the pages of certain magazines were full of ads for these. Weren't they supposed to be Russian Spetznaz or something?! The knife had a round steel sheath, so you could fire it as a baton or as a knife. No idea how well it worked as they were always totally illegal in the UK, but it looked like a James Bond-style gimmick.
 
Like already mentioned, them things are cute lookin', but seriously baaaaad news to get caught with....like as bad as gettin' busted with RPGs, or handgrenades. Seriously not worth the risk. Courtesy of Cold War paranoia if I had to venture a guess on exactly why da man came down on those goofy little trinkets so hard.

Vampire Gerbil once upon a time had pics of one that were taken by a friend of a friend of a cousin of an uncle of an aunt removed of a orphans stepchilds friends neighbors pet (or something like that...:D ) who used to have one. Showed pretty good penetration on some boards. Who knows, he might still have 'em up somewhere.

Don Rearic also used to have a review of sorts on one I'd read somewhere. Not sure if it's still around, but it made me laugh 'till I cried, not to mention the coffee ejecting out my nostrils and onto the keyboard.
 
it seems like people would just make there own by hollowing out a wood handle sticking a 1/4 inch pipe into it then putting a spring in the pipe then taking another slightly smaller in diameter pipeing with a blade welded to the end and placing it on top of the spring inside the larger piping. Then all that would be needed would be a small clip or trigger type thing that when trigger is pulled would allow the blade to be pushed out by the spring thus being shot into the air. a knife maker it seems could easily make a custom made one has anyone ever seen some one try making one.
 
s0rce said:
You can carry a handgun but not a little spring powered knife?
Click to expand...

Not in Fla, even with a CCW. Switchblades (autos), are ok though.

What if you missed? Throw the handle?

Rob
 
Think of a ballistic knife as a really oddball crossbow. Think of how big a crossbow is to be effective. Even the pistol style crossbows are big. This is because you need to put energy into the projectile for it to achieve penetration at the target. The energy comes out of a compressed spring or tensioned bow. The energy in a spring is (1/2) *(K)*(D-squared). K is a function of how stiff the spring is and D is the distance that you compress the spring. Notice that the energy goes up dramatically as D is increased since it is a squared coefficient. If you try and use a short spring you need to have a really stiff spring (high-K). Implicitly you need the spring to be under really high tension when it is cocked. This makes the knife hard to cock and applies lots of force to your trigger mechanism. This means that your knife frame and trigger needs to be heavy and strong. It is hard to cock the knife, it is hard to trigger the knife, and the trigger is vulnerable to failure and thus release the knife when not intended.

A practical (and I use the term loosely) implementation might use two or three sections of lightweight telescoping tubing to support the spring and guide the knife. When the knife fires the spring might extend to twice the length of the knife. This would allow a high-D implementation with a lower K. You need to keep the structure light so that most of the energy goes into accelerating the knife and less into accelerating parts of the spring and its frame. It is pretty clumsy to have the projectile shaped like a knife. It would be better if it looked more like a thick crossbow bolt.
 
kryptonite love that part of the movie, bring a knife to a gun fight :D .
A MA teacher of mine had one of these but kept it disassembled in a case but he has lots of stuff that needed NFA tax's and such. never seen one fire in real life just on film and in movies. a Ka-bar version would be cool :)
 
Vampire Gerbil is our local expert (possbily the western world's leading expert) on these things. He's made many excellent -- and, as always, humorous -- posts on the subject.
 
s0rce said:
You can carry a handgun but not a little spring powered knife?
Click to expand...

I Coloardo, with my permit, I can carry a concealed handgun but I can't carry a blade over 3.5 inches concealed. Laws don't necessarily have to make sense. :barf:
 
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