Air Rifles--Literally.

[TOSDOC]

I just finished reading the third novel in the Alex Hunter series by Greig Beck (www.greigbeck.com) . It’s imaginative and fun brain candy about a US Special Forces soldier who’s been Captain Americanized (by a bullet in his brain pan) and who now takes on the most dangerous military missions no one else can. This includes strange creatures on the fringes of cryptozoology as well as the elite of the Russian/Iranian/etc bad guys. Besides plenty of action, the soldier’s slow and insidious transformation into a super-human is an ongoing theme in the books. They also include some exotic weaponry, different for each mission and handed to him in “Q” fashion. One of which I wanted to highlight for discussion here:
Spoiler

“Do you really think it’s a good idea to be spraying bullets around in this cave, Captain? Forget about the danger from ricochet, but do you have any idea of how easy it is to ignite a natural gas leak this close to the surface?”
“No, Dr. Weir, I’m afraid I don’t.” Alex shouldered the rifle and then proceeded to aim at the tail section of the crashed plane and pull the trigger. There was a hiss and a sound like air being blown through a pipe and a small section of the tail fin of the broken plane magically wanged off into the darkness. “No ricochets, no loud noises, no gunpowder. The gas projectile M98 is a variation of the M16 except it’s probably closer to a paintball gun. It still uses a gas-powered rotating bolt, and will release up to 900 cyclic rounds per minute at 2,900 feet per second. However, Dr. Weir, the major difference is it doesn’t need to have a magazine reload. It simply fires an unlimited supply of super compressed balls of air. It can be calibrated to punch a ball-bearing-sized hole through half-inch steel, or set to the size of a softball and knock a man flat from fifty feet. Extremely light and folds away to the size of a dinner plate; only weakness is its effective range is limited to around 250 feet. Shouldn’t be a problem in a cave I would think, Dr. Weir.”

--Beneath The Dark Ice, by Greig Beck

Being a paintball enthusiast myself, I had to ask here: how on earth would you go about engineering this kind of weapon?

[ryacko]

You can't. It's like plasma weapons.

Air would dissipate a few meters away from the weapon. If he held it down long enough, someone fifty meters away might feel a light breeze.

[Dr. Trainwreck]

If you use a very heavy gas, and if you're able to condense it. Thin air would simply dissipate very quickly. But still, such a reverse vacuum cleaner couldn't work and even if it could, it'd be easier to just give your man another tool to use.

[Terralthra]

Well, this one is human-powered and has a range of 20 feet. Using the chemical energy of an M16 cartridge might extend that, though 250 feet is pretty far.

[TOSDOC]

Well, this one is human-powered and has a range of 20 feet. Using the chemical energy of an M16 cartridge might extend that, though 250 feet is pretty far.

Neat. That looks like it could fold up to the size of a dinner plate too.

[Formless]

Sounds like a vortex cannon:



Upscale:


Only problem is, while you can miniaturize the concept (like the toy model Terralthra posted) I don't know if its possible to make it both powerful enough and conveniently sized enough for a man portable weapon. But the concept is there, and as you can see the large scale version is powerful enough to possibly dent the wall of a house.

[ryacko]

That's not quite correct, just because you could knock down a freestanding wall doesn't mean you could harm or knock out a human being, even at that range. I'm of course focusing on blast pressure effects as opposed to sound effects, the sound might (not sure) deafen a person or knock him out.

Keep in mind a person has far less surface area then a wall, and in a combat situation, the visible profile of a person might just only be half a torso and a head.

[Iron Bridge]

There's a difference between exerting a high pressure at a distance and firing a coherent "air bullet" out to that distance.

In principle, you can use compressed air to produce a high enough pressure to kill a person. This is not conceptually different to the overpressure from a bomb which is known to be able to kill people without the need for them to be hit by sharpnel, falling debris, etc. But I do not think an "air bullet" is possible. It would dissipate while still inside the barrel, and compressing it further only increases the speed of dissipation.

[Terralthra]

Iron Bridge, you may want to read the thread before you make grandiose statements about possibilities of coherent air projectiles. Both Formless and I have posted links to weapons that fire projectiles of air.

[Iron Bridge]

Those don't fire "air bullets". As the (second) video Formless posted explained, the apparent 'edge' of the pressure wave is just where water vapour is being condensed. There is a region of high pressure with a finite and increasing width, which drops continuously from a peak. A bullet exerts a constant pressure dropping abruptly to zero at the edge.

[Formless]

Oh, don't be a stupid pedant. If I cave your lungs in with a pressure wave, are you going to argue that it isn't an "air" rifle? Are you going to argue that there is no rifling, ergo its not a personal weapon?

This is like saying that a laser pistol doesn't qualify as a gun because there is no projectile coming out the business end. If you are dead either way then it has done its job.

Edit: Here, wikipedia for your dumb ass. The air moves in a toroidal vortex. Here's the money quote: "Unlike a sea wave, whose motion is only apparent, a moving vortex ring actually carries the spinning fluid along."

[Iron Bridge]

In your opinion does a bomb "fire an air bullet" when it explodes?

[Formless]

In your opinion does a bomb "fire an air bullet" when it explodes?

There is no toroidal vortex coming out of a bomb, thus its not comparable to the weapon we're talking about except in how it transfers energy into the target. Idiot.

[Iron Bridge]

You said, "If I cave your lungs in with a pressure wave, are you going to argue that it isn't an "air" rifle?". A bomb can collapse your lungs with a pressure wave.

If you are now arguing that it's like a bullet because it is shaped like a bullet, rather than just its terminal effects, then you're plain wrong.

[Formless]

Read fucking wikipedia, you massive sack of shit. Its in an edit in my very post. Your problem is that it doesn't carry a "projectile" to the target. It in fact does, in the form of a toroidal ring. Besides which, the concept clearly creates a directional pressure wave and a bomb does not. Now fuck off.

[Connor MacLeod]

You know, I was expecting one of those old fashioned air powered rifles that flung a heavy bullet at subsonic speeds when I read this.

[Iron Bridge]

Bullets are not vague swirling toruses that expand as they move. The OP is quite clear that it fires a "compressed ball of air" that can "punch a ball-bearing-sized hole through half-inch steel".

[Formless]

Here, since I was using wikipedia, here's some useful info I found in my brief research. [url="http://en.wikipedia.org/wiki/Vortex_ring_gun]Apparantly[/url], these weapons have been tested before to see if they could be used for crowd control (mostly to see how well they carry irritants to the target). Also, there is this video of one being tested for knockdown power:

suddenly the youtube tags stopped working so here's a link

[Formless]

Bullets are not vague swirling toruses that expand as they move. The OP is quite clear that it fires a "compressed ball of air" that can "punch a ball-bearing-sized hole through half-inch steel".

You have no idea what a goddamn pressure wave is, do you. Also, stop being a moron and understand that when people ask if something like this is possible, they don't require it to be identical to the weapon described. They asked if it is possible in concept, which it is. Fuckwit.

[TOSDOC]

I was hoping to avoid the pedantic "rifle" arguement. Those are some fascinating videos, by the way.

The weapon concept is clearly looking to solve the problem of ammunition supply and it's weight in an exotic environment (cave). Besides launching an effective pressure wave at range, I was also trying to wrap my brain around the idea of a compact air compressor built into this thing that was still operating in total silence.

[Formless]

The idea of it operating in total silence is basically incompatible with the idea of a weapon that fires air. Pretty much the instant you have a pressure wave, you have sound. Even pellet rifles make some noise, though they can be silenced using the same methods as normal guns. This thing pretty much can't be silenced, I think.

[Connor MacLeod]

It doesn't even say it operates in total silence, it just says it doesn't have 'loud noise' - relative to what we don't know, maybe gunpowder. It might be that the noise it makes is dependent upon setting, since it indicates it has lethal and non/less than lethla modes.

also I'm not sure where Iron Bridge is getting this overly specific definition of 'bullet' - given the ones I've ever seen (or googled) they can be alot more open ended, depending on whose interpretation you use and the definition you opt for. And even if that weren't the case, fixating on one word to take in the whole context is a bit silly.

[TOSDOC]

I apologize, it's not total silence, since there's a "hiss" and the sound of air being blown through a pipe. But I've listened to too many compressors in dental machines and scuba shops to think of anything quieter.

[Formless]

Yeah, as I read it it emitted a hissing sound when fired. A real vortex cannon will emit a loud bang. Just look at them-- the business end has the same shape as a fog horn for crying out loud.

[Connor MacLeod]

I imagine anything which has any real penetration or lethality will generally be rather noisy, but the described 'hiss' seems to come from something more akin to the nonlethal settings (my guess would be 'knock someone over as a joke' setting )