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stoicfaux
256
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Posted - 2011.10.05 00:57:00 -
[1] - Quote
Summary We can use in-game numbers to show that Lead projectiles for 425mm Railguns have, as an upper bounds, less mass than methane gas (aka a fart.) (For the metric impaired, 425mm == 16.7 inches.)
The Numbers a) The ship's capacitor is measured in GJ or giga-joules.
b) Railguns use cap to fire. This gives us an upper bound on the amount of energy that can be imparted upon the projectile. (If you use 10 GJ to fire a lead round, the lead round's projectile will have up to 10 GJ of energy with which to propel it.)
Please note that the term "round" refers to ammo as it is in your cargo hold. The "projectile" denotes the bullet (or mass) that actually leaves the muzzle of the Railgun.
c) 250km is the upper range of large railguns. Since guns hit "instantly" we will use a value of 0.1 seconds for the projectile's travel time. This means that the lead projectile is traveling at 2,500,000 m/s (2.5 million meters per second.)
d) A Rokh with three gun-cap reducing rigs (specifically Large Hybrid Discharge Elutriation rigs, 2xTII, 1xT1) firing a lead round (-50% reduction to gun cap) from Kaikka's Modified 425mm Railgun uses 3.807GJ of cap to fire.
e) Using the formula for kinetic energy we can compute the upper bounds of the mass of the projectile like so:
Kinetic Energy (in joules) = (1/2) * mass * velocity^2
3,807,000,000 J = 0.5 * x * (2,500,000 m/s)^2
x = 3,807,000,000 J / (0.5 * (6,250,000,000,000 m^2/s^2))
Since 1 J = (kg * m^2 / s^2) that reduces to:
x = 3,807,000,000 kg / 3,125,000,000,000
x = .00121 kg (or 0.0027 lbs or 0.04 ounces)
f) Thus using 3.807 giga-joules of energy to launch a railgun projectile 250km in 0.1 seconds means that the railgun projectile's mass can be no greater than 0.00121 kg (or 0.04 ounces.)
The Numbers for Methane By comparison, an equialent volume of methane gas (aka a fart) weighs more:
a) A Large Hybrid round has a volume of 0.05 m^3. Methane at 0 degrees C has a volume of 0.717 kg/m^3
b) The same volume of methane gas at 0 degrees Celsius has a mass of 0.05m^3 * 0.717 kg/m^3 = 0.0359 kg (or 0.079 lbs or 1.26 ounces.)
Conclusion Thus a 425mm Lead Railgun round can weigh at most 0.00121 kg ( or 0.04 ounces) whereas an equivalent sized "fart" (aka methane gas) weighs 0.0359kg (or 1.26 ounces.) The "fart" has 29.7 times greater mass.
Proposal Can we buff railguns to fire fart gas? Use the in-game Cattle (or other livestock) to use in PI to create Methane gas Railgun projectiles. |

0ld School
SON OF RAVANA League of Reprobates
1
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Posted - 2011.10.05 01:07:00 -
[2] - Quote
What a hilarious misuse of armchair science.
stoicfaux wrote:If you use 10 GJ to fire a lead round, the lead round's projectile will have up to 10 GJ of energy with which to propel it.
Nope. The actual force of a modern hammer striking a modern round is not the energy used to actually propel the round.
Modern projectiles are propelled by the chemical energy within the round. Same could be said for hybrid rounds, as far as you know.
Also: its a scifi game. |

Cipher Jones
50
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Posted - 2011.10.05 01:10:00 -
[3] - Quote
Plasma has very little mass.
Can't tell if serious?
See what happens when fat neckbeards try to ride little ponies? The ponies die. |

stoicfaux
256
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Posted - 2011.10.05 01:14:00 -
[4] - Quote
0ld School wrote: Nope. The actual force of a modern hammer striking a modern round is not the energy used to actually propel the round.
Modern projectiles are propelled by the chemical energy within the round. Same could be said for hybrid rounds, as far as you know.
Go look up how railguns work: http://en.wikipedia.org/wiki/Railgun
Also read the description of hybrid rounds: http://wiki.eveonline.com/en/wiki/Lead_Charge_L
Quote: Consists of two components: a shell of titanium and a core of lead atoms suspended in a plasma state. Railguns launch the shell directly...
Quote:Also: its a scifi game. You're probably one of those people who don't think twice about correcting (criticizing) your girlfriend. Sorry, former girlfriend.
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0ld School
SON OF RAVANA League of Reprobates
1
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Posted - 2011.10.05 01:25:00 -
[5] - Quote
stoicfaux wrote:Quote:Also: its a scifi game. You're probably one of those people who don't think twice about correcting (criticizing) your girlfriend. Sorry, former girlfriend.
Aww, did your boyfriend criticize you?
Also, notice that you're the one attacking and scrutinizing the game mechanics, whereas my last line was "take it and don't as questions." You do see how your response is laughably ironic?
Maybe you should read your own links? Neither titanium nor lead are terribly conductive, so neither could effectively be used as a railgun projectile in the first place.
This is like trying to analyze Alice in Wonderland for inaccuracies. Its just not supposed to make sense. |

Foofad
Yulai Guard 1st Fleet Yulai Federation
6
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Posted - 2011.10.05 01:26:00 -
[6] - Quote
At 2.5 million meters per second, that is one hard hitting fart. |

DarkAegix
Acetech Systems
66
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Posted - 2011.10.05 01:27:00 -
[7] - Quote
Where can I buy a fart to improve my Rokh's DPS? |

Handsome Hussein
17
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Posted - 2011.10.05 01:36:00 -
[8] - Quote
Foofad wrote:At 2.5 million meters per second, that is one hard hitting fart. A mighty wind, in fact. Leaves only the fresh scent of pine. |

Bloody Wench
23
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Posted - 2011.10.05 02:08:00 -
[9] - Quote
c) 250km is the upper range of large railguns. Since guns hit "instantly" we will use a value of 0.1 seconds for the projectile's travel time. This means that the lead projectile is traveling at 2,500,000 m/s (2.5 million meters per second.)
Should be Lim T->0
That's as far as I got before deciding your maths is flawed.
Gee gratz dewd on your mastery of Ke=1/2MV^2 |

Ehris Bok
United Kings
2
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Posted - 2011.10.05 02:29:00 -
[10] - Quote
Have you thought that at 2.5 million meters per second even a light substance is going to pack a sizable kinetic punch. |

stoicfaux
257
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Posted - 2011.10.05 02:39:00 -
[11] - Quote
Bloody Wench wrote:c) 250km is the upper range of large railguns. Since guns hit "instantly" we will use a value of 0.1 seconds for the projectile's travel time. This means that the lead projectile is traveling at 2,500,000 m/s (2.5 million meters per second.)
Should be Lim T->0
That's as far as I got before deciding your maths is flawed.
Yeah, yeah. At 2.5 million m/s, you're at 83% of the speed of light. Plus, the faster the projectile travels, the less mass it will have. I guess could have just plugged in 0.0008 seconds of flight time as the upper boundary, but it gets really silly.
If you assume 99% of c for the projectile, you're looking at a mass of 8.6437277081851349276334261731994e-8 kg (or 0.000000086 kg (or 0.000003 ounces.))
I'm not sure why you would need a 425mm (aka 16.7 inch) gun to fire something with less mass than a mouse fart. (Which also implies that 425mm doesn't represent an Eve railgun's bore size.) It would also mean that you should be able to carry a nearly lifetime supply of railgun ammo in your pocket.
Quote:Gee gratz dewd on your mastery of Ke=1/2MV^2
Hey, I wasn't the one who created the numbers. Blame someone at CCP for not doing some basic number crunching.
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stoicfaux
258
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Posted - 2011.10.05 02:48:00 -
[12] - Quote
Ehris Bok wrote:Have you thought that at 2.5 million meters per second even a light substance is going to pack a sizable kinetic punch
Yes. We're looking at 0.91 tons of TNT (less than a ton.) By comparison a cruise missile traveling at ~8400m/s and hitting with only 10% of its mass (assume the rest was fuel) will hit with 2.1 tons of TNT in kinetic energy.
A nuclear tipped missile would deliver thousands to millions of times the energy of a lead round from a rail gun.
Quote:. also 2.5mill m/s is a little slow from what ive read about railguns the US millitary has managed to fire a slug at speeds of around 8.6 mill m/s
Yeah, but every time they fire it, it goes back in time and kills the guys loading the railgun which prevents it from being fired in the first place.
Quote:given this is set 1000s of years in the future speeds of 20mill or more should be more like it. That & these are being fired in space so friction isnt much of an issue :)
Nope. You're greatly exceeding the speed of light. Personally, I would speculate that Eve guns deliver their rounds via micro-warp tunnels.
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Headerman
Quovis Shadow of xXDEATHXx
143
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Posted - 2011.10.05 02:54:00 -
[13] - Quote
Pro tip: rail guns use a 'shoe' to fit over the sabot to accellerate it. the 'shoe' then falls away from the sabot after firing. The 'shoe' is a great conductor of electricity, allowing the railgun to work.
Pro tip: (someone has to say it) I FART in your general direction!!
Pro tip: For more details, ask "I'm Farting" in game. [img]http://i53.tinypic.com/bebnf8.jpg[/img] |

ThisIsntMyMain
Republic University Minmatar Republic
28
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Posted - 2011.10.05 03:27:00 -
[14] - Quote
stoicfaux wrote:Summary stuff
The server clock tick is 1 second so lets assume a travel time of 1 second for the maximum range - not 0.1 seconds - so v = 250,000 m/sec
The activation cost of a 425mm railgun is 30 GJoules
E = 0.5 * m * v2
=> m = E / (0.5 * v2)
m = 30 * 10E9 / (0.5 * (250000*250000) = 0.96 kg
So if the railgun is 100% efficient and accelerates the round with 30 GJoules, the rest mass of the projectile is 0.96 kg - which means it is made up of not much titanium but has LOTS of space for the highly destructive PLASMA payload - which is what really does the damage. |

Hugo Junkers
High Sec Risk Management Services Waterboard
1
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Posted - 2011.10.05 03:50:00 -
[15] - Quote
stoicfaux wrote:
Yeah, yeah. At 2.5 million m/s, you're at 83% of the speed of light. Plus, the faster the projectile travels, the less mass it will have. I guess could have just plugged in 0.0008 seconds of flight time as the upper boundary, but it gets really silly.
If you assume 99% of c for the projectile, you're looking at a mass of 8.6437277081851349276334261731994e-8 kg (or 0.000000086 kg (or 0.000003 ounces.))
It's the other way around : the more the projectile approaches the speed of light, the bigger its mass. |

0ld School
SON OF RAVANA League of Reprobates
1
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Posted - 2011.10.05 03:58:00 -
[16] - Quote
Headerman wrote:Pro tip: rail guns use a 'shoe' to fit over the sabot to accellerate it. the 'shoe' then falls away from the sabot after firing. The 'shoe' is a great conductor of electricity, allowing the railgun to work.
From evelopedia:
Quote: The weapon commonly referred to as a 'Railgun' does not utilize rails within the barrel of the gun that the charge slides on - mounting lugs are not visible on images of the charges.
Pointless. Its a made up game about made-up spaceships using made-up technologies.
Further attempts to use maths/real logic will be met with contradicting quotes from a made-up wiki. |

Meridith Akesia
Stimulus Rote Kapelle
48
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Posted - 2011.10.05 04:04:00 -
[17] - Quote
lol |

Mara Rinn
Cosmic Industrial Complex Cosmic Consortium
118
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Posted - 2011.10.05 04:09:00 -
[18] - Quote
Speed of light in a vacuum is 299,792,458 m/s, thus 2M m/s is less than 1% of the speed of light.
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Jiska Ensa
School of Applied Knowledge Caldari State
3
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Posted - 2011.10.05 04:17:00 -
[19] - Quote
Hugo Junkers wrote:stoicfaux wrote:
Yeah, yeah. At 2.5 million m/s, you're at 83% of the speed of light. Plus, the faster the projectile travels, the less mass it will have. I guess could have just plugged in 0.0008 seconds of flight time as the upper boundary, but it gets really silly.
If you assume 99% of c for the projectile, you're looking at a mass of 8.6437277081851349276334261731994e-8 kg (or 0.000000086 kg (or 0.000003 ounces.))
It's the other way around : the more the projectile approaches the speed of light, the bigger its mass.
This man speaks the truth. That's why you can never break the speed of light using conventional thrust - your mass approaches infinity, thus the force required to accelerate any faster also approaches infinity (time dilation plays a role there too)
That being said, a fart traveling at 82% the speed of light still won't do much damage - high-energy particles travelling near that speed smash into the earth every second in far greater quantities. And I'm pretty sure even armour-tanked ships in Eve have shields that can withstand that.
Also, it may already have been said, but railguns don't just use capacitor juice to launch...they're constantly drawing a significant amount of power (over 2 gigawatts is nothing to sniff at; that's the output of some nuclear power plants). I highly doubt that much energy is being used to make the thing turn and track. In zero gee, in a vacuum. Yah. |

stoicfaux
259
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Posted - 2011.10.05 04:18:00 -
[20] - Quote
Cipher Jones wrote:Plasma has very little mass. The description of railgun rounds says a "shell of titanium" contains the "lead plasma" and the shell is launched directly. So the mass also includes the (tiny) titanium case.
ThisIsntMyMain wrote:
The server clock tick is 1 second so lets assume a travel time of 1 second for the maximum range - not 0.1 seconds - so v = 250,000 m/sec
That produces a more realistic mass of ~1,200kg, however, a one second flight time is a long time against a fast maneuvering target, such as a ship moving at several hundred to a thousand plus meters per second. Even with good predictive targeting computers, it would be hard to hit something that can be several hundred to several thousand meters away by the time the shell arrives a second later.
Good point in regards to the server heartbeat, but it might be more accurate to say that the server processes all the messages once a second, but the messages are still processed in time order thus allowing sub-second times. Meaning, if you shoot at 3.5 seconds, the server will consider the target's location as of 3.5 seconds instead of at 4.0 seconds for determining range/falloff. Or not. We would need a Dev to attest to the specific details.
Quote:The activation cost of a 425mm railgun is 30 GJoules ... So if the railgun is 100% efficient and accelerates the round with 30 GJoules
Nope, 30GJ is nowhere near 100% efficient. 30 GJ is for an unskilled, unbonused railgun. In the best case that I could come up with, namely skills V, 6% gun-cap implants, gun-cap rigs, officer gun, and lead ammo, you can fire a 425mm railgun with a mere 3.807 GJ of energy. Taking efficiency/laws_of_thermodynamics into consideration means that the projectile gets even smaller.
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stoicfaux
259
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Posted - 2011.10.05 04:31:00 -
[21] - Quote
Jiska Ensa wrote:Hugo Junkers wrote:
It's the other way around : the more the projectile approaches the speed of light, the bigger its mass.
This man speaks the truth. That's why you can never break the speed of light using conventional thrust - your mass approaches infinity, thus the force required to accelerate any faster also approaches infinity (time dilation plays a role there too) I'm not a physicist and I'll leave accounting for relativity up to an expert. My point was that if you increase the speed from 83% of c to 99% of c, then you still have only 3.807 GJ with which to accelerate the projectile which would imply reduced projectile mass in the Newtonian model.
Quote:Also, it may already have been said, but railguns don't just use capacitor juice to launch...they're constantly drawing a significant amount of power (over 2 gigawatts is nothing to sniff at; that's the output of some nuclear power plants). I highly doubt that much energy is being used to make the thing turn and track. In zero gee, in a vacuum. Yah. If you include the 2344MW used by the turret and a firing rate of once per 4.7 seconds (5x Faction MagStabs,) that adds 1.1 GJ of energy to our 3.807 GJ of cap energy. You still wind up with a projectile massing 0.001568kg (or 0.055 grams) as an upper bound, which is still significantly less dense than 0.05m^ of methane gas.
|

Headerman
Quovis Shadow of xXDEATHXx
144
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Posted - 2011.10.05 04:34:00 -
[22] - Quote
0ld School wrote:Headerman wrote:Pro tip: rail guns use a 'shoe' to fit over the sabot to accellerate it. the 'shoe' then falls away from the sabot after firing. The 'shoe' is a great conductor of electricity, allowing the railgun to work. From evelopedia: Quote: The weapon commonly referred to as a 'Railgun' does not utilize rails within the barrel of the gun that the charge slides on - mounting lugs are not visible on images of the charges.
Pointless. Its a made up game about made-up spaceships using made-up technologies. Further attempts to use maths/real logic will be met with contradicting quotes from a made-up wiki.
OK. I should have said A railgun uses....  [img]http://i53.tinypic.com/bebnf8.jpg[/img] |

Killwitch
The Riot Formation Get Off My Lawn
0
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Posted - 2011.10.05 10:01:00 -
[23] - Quote
hey guys where did you all go to school? |

Vicker Lahn'se
STRAG3S THE UNTHINKABLES
0
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Posted - 2011.10.05 20:35:00 -
[24] - Quote
Killwitch wrote:hey guys where did you all go to school?
I'm going to guess various community colleges.
First, you can't just make up some number for the flight time and then strut about as if you've done some kind of rigorous mathematical proof.
Second, you make a false assumption by claiming that all of the energy to launch the projectile comes from your capacitor, or even your capacitor plus power grid. When you fire your hunting rifle at your neighbor's yapping dog, the energy to launch that bullet doesn't come from the rifle's battery. It comes from the chemical energy of the gunpowder which is contained in each individual round. Hybrid rounds in Eve could easily contain some form of stored energy in each individual round. It doesn't even need to be chemical energy like gunpowder. You could very easily claim that each individual round has its own nuclear fission (or fusion) device to propel the round. It would be entirely plausible to say that there is a one time use thermonuclear device that sends a sudden electrical surge to the electronics that power the magnetic accelerators.
Third, you don't need a car sized projectile to deal damage if you're launching it with 10GJ of kinetic energy. It doesn't matter if you hit something with a train that has 10GJ of kinetic energy or if you hit it with a grain of sand having 10GJ of kinetic energy. You're still hitting it with 10GJ of kinetic energy. In today's warfare, it's actually better to have smaller projectiles rather than larger projectiles if the two projectiles in question are going to have the same kinetic energy. Smaller projectiles focus their energy on a much smaller area, resulting in more armor piercing force.
The combination of your assumption based reasoning and your fixation with fart gas leads me to believe that perhaps you have your head up your ass. |

Dr Offensive
Republic University Minmatar Republic
8
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Posted - 2011.10.05 20:55:00 -
[25] - Quote
Is this debate still going on, jeesus christ
OK how about this, Gandalf and the Emperor off Star Wars have a threesome with that tart off of the Matrix (spit roast).
Then a light sabre falls end over end right through the bed (on its way to the center of the planet)
Who would survive? |

Serene Repose
Perkone Caldari State
6
|
Posted - 2011.10.05 21:18:00 -
[26] - Quote
I liked the part where the thing went into the thing then came screaming out the other thing into the thing that...what was the middle part?
Smokestack lightnin' shinin' just like gold. |

stoicfaux
265
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Posted - 2011.10.05 21:26:00 -
[27] - Quote
Vicker Lahn'se wrote: First, you can't just make up some number for the flight time and then strut about as if you've done some kind of rigorous mathematical proof.
I agree that 0.1 seconds was arbitrary. However, the numbers go beyond silly if you assume shorter time units or even instant hits.
Quote:Second, you make a false assumption by claiming that all of the energy to launch the projectile comes from your capacitor, or even your capacitor plus power grid. It's not a false assumption, for the simple reason that nowhere is it stated that hybrid ammo contains an energy pack to assist in firing. An imprudent or dubious assumption would be a better phrasing, methinks.
Quote:You could very easily claim that each individual round has its own nuclear fission (or fusion) device to propel the round.
It would be entirely plausible to say that there is a one time use thermonuclear device that sends a sudden electrical surge to the electronics that power the magnetic accelerators.
If you used a fission/fusion device to propel the round, then it would no longer be a railgun.
Railgun ammo containing a power source plus the warhead would make sense, if it was described anywhere in Eve, game-wise or in the fiction. There's also another big problem with the idea:
Let's extrapolate by looking at a Cap Booster 25. A Cap Booster 25 provides 25 GJ of energy with 3kg of mass in 1m^3 volume. Unfortunately, the volume of a large railgun round is merely 0.05m^3. Thus it's not far fetched to assume that Eve technology cannot create a large hybrid round that provides a significant amount of additional energy to power the shot.
Quote:Third, you don't need a car sized projectile to deal damage if you're launching it with 10GJ of kinetic energy. It doesn't matter if you hit something with a train that has 10GJ of kinetic energy or if you hit it with a grain of sand having 10GJ of kinetic energy. You're still hitting it with 10GJ of kinetic energy. It would matter if your teeny tiny itsy bitsy shell hits a whipple shield.
Other considerations: * what prevents the "lead plasma" from smashing against the titanium case during acceleration? * why would a railgun not have solid projectiles? * why does Lead ammo require less power than an anti-matter round? * why does the ammo type have such a drastic effect on range? * why use anything but anti-matter? * why can we fire through solid objects? * why are weapon ranges so short? * seriously, a shell full of lead plasma?
Quote:The combination of your assumption based reasoning and your fixation with fart gas leads me to believe that perhaps you have your head up your ass. No dear, it's called playing with numbers. Some people enjoy analyzing the pseudo-science behind sci-fiction games to see just how far off it is.
Tinfoil. It should be at the top of everyone's food pyramid.
|

Zey Nadar
Aliastra Gallente Federation
7
|
Posted - 2011.10.05 22:10:00 -
[28] - Quote
stoicfaux wrote:Cipher Jones wrote:Plasma has very little mass. The description of railgun rounds says a "shell of titanium" contains the "lead plasma" and the shell is launched directly. So the mass also includes the (tiny) titanium case.
In addition, when you turn a hunk of metal into plasma, the plasma has exact same mass, its just in different form..
Its like.. which weighs more, a pound of iron or a pound of feathers.. |

Jiska Ensa
School of Applied Knowledge Caldari State
3
|
Posted - 2011.10.05 22:25:00 -
[29] - Quote
It all seems to depend on the flight time. We don't know that information and we can't simply assume it's 0.1 seconds or whatever. Heck, if we even assumed it was 4.whatever seconds (the cycle time) that significantly increases the mass of the round.
Long story short, there's a lot of intelligent discussion going on but we simply don't have enough data to make a truely educated estimate :( |

Apollo Gabriel
Mercatoris Etherium Cartel
50
|
Posted - 2011.10.05 22:29:00 -
[30] - Quote
thank god the game doesn't use smellovision. |
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