02-08-2013, 02:54 PM | #11 | ||
Wielder of Smart Pants
Join Date: Aug 2004
Location: Ventura CA
|
Re: Low/High-Tech Military Air Guns
Quote:
Quote:
|
||
02-08-2013, 03:07 PM | #12 | |
Join Date: Feb 2005
Location: Berkeley, CA
|
Re: Low/High-Tech Military Air Guns
Quote:
It could; you'd probably fire a streamlined sheaf of darts that would split shortly before impact, or at lower effectiveness you could just fire a canister of metal balls. |
|
02-08-2013, 03:20 PM | #13 | ||
Wielder of Smart Pants
Join Date: Aug 2004
Location: Ventura CA
|
Re: Low/High-Tech Military Air Guns
Quote:
Quote:
|
||
02-08-2013, 11:06 PM | #14 |
Join Date: Jan 2009
Location: Fryers Forest Australia
|
Re: Low/High-Tech Military Air Guns
Looking at the ballistics of the Girondoni, [150 grains at about 800 fps is 213 ft/lbs, about twice the energy of a .22 lr] and the .458 Quackenbush mentioned in one of the posts above [430 grains at 730 fps, 500 ft lbs] you can see air guns don’t have a lot of power.
If I remember correctly air guns were available thought most of the gunpowder age, but they were always expensive and low powered. I can imagine bows and crossbows would remain popular. If you wanted to push an air gun up to modern levels of power, whilst observing the low pressures available with stored air [A scuba tank is 3000 psi, a .223 round can be loaded up to 62,000 psi] it would have to be something in the order of a .600 calibre rifle firing a 900 grain bullet at say 750 fps for about 1100 ft/lbs. That's about equivalent to a .223, but a bigger hole [pi++] with less penetration [4d?]. At around 15 ft/lbs of recoil in a 10 lb rifle it should be aboutt recoil 3. I think pushing those volumes of air you would need a backpack mounted cylinder [or ISO-tensoid or what ever floats your boat] tank to feed it.
__________________
A fine blend of hillbilly and permaculturist. Last edited by Green-Neck; 02-08-2013 at 11:09 PM. |
02-08-2013, 11:29 PM | #15 |
Untagged
Join Date: Oct 2004
Location: Forest Grove, Beaverton, Oregon
|
Re: Low/High-Tech Military Air Guns
Bows and crossbows can't come close to a round a second like air guns. I imagine that would make a big difference for individuals rather than volleys.
__________________
Beware, poor communication skills. No offense intended. If offended, it just means that I failed my writing skill check. |
02-09-2013, 01:18 AM | #16 |
Join Date: Jan 2009
Location: Fryers Forest Australia
|
Re: Low/High-Tech Military Air Guns
It's a little hard to project exactly what stats a gun might have as we don't have a defined TL from the OP. I'm imagining a late TL5 item, I suppose.
Given a Girondoni costs $1000, anything we create that’s more complicated will probably be more expensive. If we say a .600 cal pump action air rifle costs $1500, then that's ten crossbowmen you can equip for every rifleman [who has a half damage range of 60 yards!]. I suspect [especially in the absence of explosive artillery] that you would have some units equipped with air rifles as shock troops, and many other regular units with muscle powered ranged weapons.
__________________
A fine blend of hillbilly and permaculturist. |
02-09-2013, 01:00 PM | #17 |
Wielder of Smart Pants
Join Date: Aug 2004
Location: Ventura CA
|
Re: Low/High-Tech Military Air Guns
Crossbows (and other sorts of spring powered launchers) certainly can be made to use a magazine and even to retain stored energy for subsequent shots. It was a dead end technology here, but so are air guns.
|
02-09-2013, 02:58 PM | #18 |
Join Date: May 2011
|
Re: Low/High-Tech Military Air Guns
re: Paintball guns and their applicability
The most up to date paintball guns shoot a .68 ball at around 300 feet per second. They employ compressed air, and use a regulated pressure to control velocity. The lowest pressure used is around 100 psi, the highest is more like 850 psi. Valve geometry has a lot to do with the proper pressure in a given gun. Older guns use unregulated CO2. The output pressure was variable, between 800 and 1800 psi. Obviously, velocity from the guns is less consistent, but with the top safe speed of 300 fps, they were adjusted to shoot at a lower velocity so that pressure spikes don't hurt someone. Velocity was adjusted by varying spring force on a valve, restricting the diameter of air channels feedi the valve, or similar means. I would call the older style TL 7, the newer TL 8. The newer style use solenoid valves to control valve cycles, which are controlled by printed circuit boards. The PCBs were obviously around during TL 7, but the solenoids didn't get small enough until the late 1990s. TL7 paintball guns could cycle fast, but in practice, a RoF of 4 seems most realistic to the way most people could pull the mechanical trigger. A Perk might allow for up to twice that, but I only met a few people in my competitive career (encountering thousands of players) who could shoot a mechanical CO2 gun that fast. The accuracy was worse, because of variable working pressure; one just had more trouble with longer range shoots not going high or falling low. TL8 paintball guns have a much higher RoF, with the electronics permitting burst fire and full auto modes, as well as relying on trigger pulls of 25 grams. Most computer mouse buttons require 150 grams, so we are talking about a VERY light pull. Even semi auto modern guns will shoot 10-12 balls per second without difficulty, and full auto might do up to the high 20s before mechanical difficulties start to assert themselves. The velocity was far more consistent, and out to 60 yards, the arc was pretty predictable, allowing for better accuracy at a distance. CO2 tanks are about a pound and a half, allowing a couple thousand shots. the maximum output will be 1800 psi, but due to the CO2 changing phase, output drops as the ambient temperature changes or as RoF increases. Compressed air tanks are heavier, about 2-3 pounds, with a steady, regulated output of 800 psi easily achieved. They hold 4500 psi, 50% more than a scuba tank, and capable of powering 1000-1800 shots, depending on the design of the gun they're attached to. Different guns have wildly different efficiency with air. The best are shooting up to 2200 on the same amount of air that most guns will use for 1200 shots. I would think that making the guns shoot a smaller, denser projectile at weapon speeds would divide the shots available by a factor of 4 or 5, but that's speculation. At 300 fps, a 3 gram paintball will usually break unprotected skin at less than 15 yards, and sometimes at longe distances. It doesn't do a HP of damage usually, but a hit in the eye is likely to blind that eye permanently. Cloth as heavy as denim will almost always reduce what would have been a bloody welt to a circular bruise. Neoprene will reduce it to a nearly invisible mark. I hear that paintballs travel like an arrow. I am not very experienced with a bow, so I couldn't vouch for that, but it implies that a heavier, sharper projectile fired from an airgun could compete with a bow. |
02-09-2013, 07:50 PM | #19 |
Join Date: Jan 2009
Location: Fryers Forest Australia
|
Re: Low/High-Tech Military Air Guns
Just out of curiosity:
A 2.64 gram paint ball at 300 fps = 8 ft.lbs
__________________
A fine blend of hillbilly and permaculturist. |
02-09-2013, 08:23 PM | #20 |
Join Date: Jan 2005
Location: Down in a holler
|
Re: Low/High-Tech Military Air Guns
There are commercial air guns (airbows?) that are shooting arrows in excess of 600fps.
That is enough juice to shoot completely through an elephant and kill the elephant on the other side. |
Tags |
air guns, fantasy tech, high-tech, low-tech, worldbuilding |
|
|