This is a topic that tests your grasp of several related disciplines,

Question:

Design a gun that has the same offensive capabilities of your regular field firearm, but instead of bullets, it uses water as ammo.

How do you propel water with the same destructive velocity of a bullet?

if you can propel a liquid with such velocity as bullet, why not use it to propel solid object with more mass? you get much more damage out of it.

maybe with decade of research....with certain chemical reaction added ....mmmm....hehe

just a cylinder containing water with a piston on one end and the other end built with weak material. behind the piston put some explosive and you are good to go. since water cannot be compressed it can penetrate any object as long as it has a high enough velocity.
the only problem is distance. since water changes its shape, it loses it's aerodynamic properties once it leaves the cylinder and accuracy and energy is rapidly lost.

http://en.wikipedia.org/wiki/Water_jet_cutter

to avoid leaving solid evidence behind?

and it vaporize due to absorbing thermal energies from the explosion

Similar thing like you're trying to fire an ice bullet

why yes, but there's the issue of portability too

erm.....i lazy to draw....


difference with the ice bullet is complete separation with blast chamber by a piston and higher volume of water.

edit: pic removed due to noobness in drawing


This post has been edited by slimey: Mar 20 2010, 11:56 PM

the simplest but still not very small (and very dangerous) is to use a railgun method of acceleration. of course you need some metal (like a small pin) to be in the ice, but after that, ur good to go.

the thing is due to terminal velocity and normal drag force applied by the ice surface, the range of the bullet wont be far.

but what if it was very impure water, like some substance holding the water together, imagine those small jelly water balls travelling at 300m/s. they hold shape better. and they definitely dont leave a damn trace.

bit of calculations : max initial velocity of a 4mm jelly ball. (rough est.)
=sqrt((2x9.81x)/(1.184x4xPix0.004^2))
= 287.03 m/s
~bout 260-270m/s (max initial velocity) after taking into account drag constant.

so, it can travel bout... (yadda yadda yadda..) ~ 0-20 meters effective range. (kinda near right)

hmm... so. all we need is an explosive behind it and 'water shotguns' will be a reality.

Air guns would work well too, but speeds will only reach about 140m/s. basically same principle as paintball gun.

This post has been edited by rafazafar: Mar 21 2010, 02:31 PM

how about instead of a solid piece of metal in the ice, metal dust mixed evenly into the ice?

that could work actually, but we need to apply the railgun method.. huhu. kinda interested in making one actually..

i think it is more likely to be trace back to the killer, since such high tech weapon will be expensive and only small number of manufacturer able to made then. while guns and bullet are every where.

This post has been edited by robertngo: Mar 21 2010, 02:30 PM

very true, you probably have to make it yourself and dismantle it immediate after usage n find somehow to hide it.

Ice bullets would do.

maybe pykrete would work replacing a bullet in a normal gun

This wouldn't be easy to do, sounds easy but not. You need the metal to stay in a very well disperse form as metal is very dense compare to water and tends to sink to the bottom before the water get frozen. To achieve this, you need, extremely fast freezing which is not easily achieve and the process would be costly as you'd need to source out the correct chemicals to do so (something like liquid nitrogen?) and a very good insulating vessels.
The other method can be done is through solid-liquid colloidal suspension, which you need to source the correct surfactant for it and grinding of the metal to very fine dust, which...is more or less as difficult as the former method.


And ...

If the purpose of making such weapon is to eliminate any traces after using it, then adding any substance into the water to enhances it physical resistance to heat and impact would not be ideal as those substances would become uncommon and more likely lead to getting trace back after all plus the process of sourcing out the apparatus and chemicals to do such a weapon makes you even easier to get trace back, which is not ideal at all. Might as well use a normal gun.

if it was to cause as much damage as hollow point bullet, i should shatter on impact thus causing massive damage to organ.

anyway using exotic weapon will not be ideal if you want to hide your identity, you are more likely to be track down then a black market or stolen gun.

Laser gun.

I don't think you can use the water similar as a bullet. Even if we manage to shoot it out of the gun at the velocity of a bullet, i think it will get heated and evaporate before it reaches the target.

This post has been edited by pheonix71: Mar 23 2010, 03:43 PM