Post by deltav on Feb 21, 2017 4:06:34 GMT
Edit: Here is a quick and dirty guide to the science behind COADE, particularly regarding railguns which before 1.10,
violated the laws of science.
childrenofadeadearth.boards.net/post/15217/thread
.
This is supposed to be one place that gathers the multiple info from questions science noobs like me had understanding the basics of science relating
to COADE all in one place. It will focus on raliguns for now as that gave me the most trouble. But more will be added by request.
Please whomever is a little rusty or maybe just learning about the science behind COADE and esp how it applies
in COADE, please check it out, and either comment or message me with your suggestions or ideas. Thanks
The rest of my early attempts to understand Railgun Physics remain unaltered below.
Much of this was very based on misconceptions, so click the link above for the "right" way to look at the science with explanations.
---------------------------------------------------------------------------------------------------------------------------------------------------------------
At great risk, I address something that I've been pondering...
One the largest debates on COADE Board is regarding to what degree Railguns in COADE follow the laws of physics.
And it is often heard that this or that stock railgun, or custom railgun is "broken".
Mostly that has focused on using this chart...
Weapon Check
and this formula...
Kinetic Energy / Second = 1/2 * Projectile Mass * (Muzzle Velocity)² / Time between shots.
Here is an example Used on our stock 3mm Railgun.
0.200 MW 3mm Railgun
0.0025kg projectile
5060 km/s velocity
53.62 ms reload
W = J/s = 0.5 * 0.0025 kg * (5060 m/s)² / (0.05362s) = 596,876.16 Joules per second = 0.596 MW input needed.
So this stock railgun would be "broken" because the output in watts is more than the input.
But if the rate of fire per second is slowed down, say to 175 ms per shot, then the railgun would be fine.
The clear place of contention is the rate of fire, not the velocity nor mass of the round.
^^If you don't feel like reading what follows, please skip to the conclusion at the bottom.^^
^^If you happen to not agree or don't quite get what I am trying to say, please take the time to read the whole thing and watch the video before you comment.^^
But that got me thinking, why are we calculating energy per second instead of energy per shot? And why would
faster shots have anything to do with how much power was fed to the rails, since the loader is separate?
Let me explain my thinking, but first please watch this short video...
Imagine you are standing in front of one of those lampshaded lamps like everyone's Grandparents had in their houses
growing up with the little turny switch. The lamp is plugged in the wall, but switched off.
The lamp is the coilgun, the switch is the round, and the loader is your finger.
1. Before the round enters, the railgun is already powered, like the lamp plugged in the wall, but not switched on.
Since the circuit is broken, nothing happens.
But as soon as the round #1 touches the rails, it completes the circuit and the railgun "flashes", and round #1 shoots
out the barrel.
The split second the round #1 leaves the railgun, the circuit is broken and the railgun shuts off just like if
you turned off that same light switch again, but left it plugged into the outlet.
No round (switch) put in the railgun, no circuit, and only one switch can be in this simple circuit at
once.
2. If you put round #2 in (turn the lamp switch), you get another "flash" like a light bulb and round #2 shoots out, but
as soon as that round #2 leaves out, the railgun shuts off again. The railgun switches off between shots because
the circuit is broken by round #2 leaving the railgun, so each shot gets its own 0.200 MW.
3. So we know from this that the "rail power" 0.200 MW we are using for our calculations can only act on that one
round/armature that is completing the circuit of that railgun at a time.
And you will never have more than one round in the railgun at once, or one round would "short circuit" the other
and they would collide inside your railgun.
4. So as fast as you can load rounds into the railgun (flip that lamp switch), the railgun will fire provided the barrel or
round does not melt or blow up from the pressure and you don't put more than one round in the rail gun at once.
So why are we bringing shots per second into the mix?
The rail power (plug of lamp), and the loader power (your finger) are separate.
More power fed to the rails (more power to the lamp plug) will send a round further and faster perhaps, but never
results in a greater rate of fire per second (faster finger motion), because the rails can only fire one round at a time.
So I submit that the number we need to be looking at to see if railguns are broken is not the Joules per second, but
the Joules per shot since the power of the rail gun doesn't act on seconds, but on shots can exhausts all its energy,
in this case 0.200 MW on round #1, and then shuts off, until the next shot comes along.
Then the railgun uses all of 0.200 MW on round #2, and so on.
We saw that number briefly before we divided it at the last step.
It is 32,004.5 J per shot and we already know that number is 100% physics compliant.
Conclusion....
Each shot gets its own 0.200 MW as only one round is being fired at a time.
We must look at energy per shot to find out if our railguns obey physics or not, not energy per second.
As long as we have power going to the railgun (the lamp plug is in the wall), we can keep shooting and shooting as
rounds can be loaded (the finger can flick the switch) as long as there is no double loading.
The switch is the round itself, and the "finger" moving the switch is the loader, which is powered separately.
For the 0.200 MW 3mm Railgun, the loader uses 0.001 MW.
This isn't over...
It might be an argument that no loader can feed 1 g rounds into a railgun
in 53.62 ms repeatedly without breaking anything and for only 0.001 MW.
But that is separate discussion, and maybe we should have it, but that is entirely different discussion.
In that case the discussion is about round loading tech, not physics.
Thanks to everyone and anyone who answered my questions and send me the info I used in this post.
Without your ideas/ formulas to give me a place to start, I would starting from scratch and wouldn't
have half an idea what was going on.
Thanks.
violated the laws of science.
childrenofadeadearth.boards.net/post/15217/thread
.
This is supposed to be one place that gathers the multiple info from questions science noobs like me had understanding the basics of science relating
to COADE all in one place. It will focus on raliguns for now as that gave me the most trouble. But more will be added by request.
Please whomever is a little rusty or maybe just learning about the science behind COADE and esp how it applies
in COADE, please check it out, and either comment or message me with your suggestions or ideas. Thanks
The rest of my early attempts to understand Railgun Physics remain unaltered below.
Much of this was very based on misconceptions, so click the link above for the "right" way to look at the science with explanations.
---------------------------------------------------------------------------------------------------------------------------------------------------------------
At great risk, I address something that I've been pondering...
One the largest debates on COADE Board is regarding to what degree Railguns in COADE follow the laws of physics.
And it is often heard that this or that stock railgun, or custom railgun is "broken".
Mostly that has focused on using this chart...
Weapon Check
and this formula...
Kinetic Energy / Second = 1/2 * Projectile Mass * (Muzzle Velocity)² / Time between shots.
Here is an example Used on our stock 3mm Railgun.
0.200 MW 3mm Railgun
0.0025kg projectile
5060 km/s velocity
53.62 ms reload
W = J/s = 0.5 * 0.0025 kg * (5060 m/s)² / (0.05362s) = 596,876.16 Joules per second = 0.596 MW input needed.
So this stock railgun would be "broken" because the output in watts is more than the input.
But if the rate of fire per second is slowed down, say to 175 ms per shot, then the railgun would be fine.
The clear place of contention is the rate of fire, not the velocity nor mass of the round.
^^If you don't feel like reading what follows, please skip to the conclusion at the bottom.^^
^^If you happen to not agree or don't quite get what I am trying to say, please take the time to read the whole thing and watch the video before you comment.^^
But that got me thinking, why are we calculating energy per second instead of energy per shot? And why would
faster shots have anything to do with how much power was fed to the rails, since the loader is separate?
Let me explain my thinking, but first please watch this short video...
Imagine you are standing in front of one of those lampshaded lamps like everyone's Grandparents had in their houses
growing up with the little turny switch. The lamp is plugged in the wall, but switched off.
The lamp is the coilgun, the switch is the round, and the loader is your finger.
1. Before the round enters, the railgun is already powered, like the lamp plugged in the wall, but not switched on.
Since the circuit is broken, nothing happens.
But as soon as the round #1 touches the rails, it completes the circuit and the railgun "flashes", and round #1 shoots
out the barrel.
The split second the round #1 leaves the railgun, the circuit is broken and the railgun shuts off just like if
you turned off that same light switch again, but left it plugged into the outlet.
No round (switch) put in the railgun, no circuit, and only one switch can be in this simple circuit at
once.
2. If you put round #2 in (turn the lamp switch), you get another "flash" like a light bulb and round #2 shoots out, but
as soon as that round #2 leaves out, the railgun shuts off again. The railgun switches off between shots because
the circuit is broken by round #2 leaving the railgun, so each shot gets its own 0.200 MW.
3. So we know from this that the "rail power" 0.200 MW we are using for our calculations can only act on that one
round/armature that is completing the circuit of that railgun at a time.
And you will never have more than one round in the railgun at once, or one round would "short circuit" the other
and they would collide inside your railgun.
4. So as fast as you can load rounds into the railgun (flip that lamp switch), the railgun will fire provided the barrel or
round does not melt or blow up from the pressure and you don't put more than one round in the rail gun at once.
So why are we bringing shots per second into the mix?
The rail power (plug of lamp), and the loader power (your finger) are separate.
More power fed to the rails (more power to the lamp plug) will send a round further and faster perhaps, but never
results in a greater rate of fire per second (faster finger motion), because the rails can only fire one round at a time.
So I submit that the number we need to be looking at to see if railguns are broken is not the Joules per second, but
the Joules per shot since the power of the rail gun doesn't act on seconds, but on shots can exhausts all its energy,
in this case 0.200 MW on round #1, and then shuts off, until the next shot comes along.
Then the railgun uses all of 0.200 MW on round #2, and so on.
We saw that number briefly before we divided it at the last step.
It is 32,004.5 J per shot and we already know that number is 100% physics compliant.
Conclusion....
Each shot gets its own 0.200 MW as only one round is being fired at a time.
We must look at energy per shot to find out if our railguns obey physics or not, not energy per second.
As long as we have power going to the railgun (the lamp plug is in the wall), we can keep shooting and shooting as
rounds can be loaded (the finger can flick the switch) as long as there is no double loading.
The switch is the round itself, and the "finger" moving the switch is the loader, which is powered separately.
For the 0.200 MW 3mm Railgun, the loader uses 0.001 MW.
This isn't over...
It might be an argument that no loader can feed 1 g rounds into a railgun
in 53.62 ms repeatedly without breaking anything and for only 0.001 MW.
But that is separate discussion, and maybe we should have it, but that is entirely different discussion.
In that case the discussion is about round loading tech, not physics.
Thanks to everyone and anyone who answered my questions and send me the info I used in this post.
Without your ideas/ formulas to give me a place to start, I would starting from scratch and wouldn't
have half an idea what was going on.
Thanks.