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Bren
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 Posted: Thu Sep 15, 2011 5:07 pm Post subject: |
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| Fallon Kell wrote: | | At the distance I use for a space unit, ISDs and VSDs are too slow in comparison to their size to get out of the way in a round or two. |
ISDs and VSDs move less than 1 unit per round? That seems a bit slow - almost stationary actually. How slow is a stock light freighter? |
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Fallon Kell
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| Posted: Thu Sep 15, 2011 8:30 pm Post subject: |
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| Bren wrote: | | Fallon Kell wrote: | | At the distance I use for a space unit, ISDs and VSDs are too slow in comparison to their size to get out of the way in a round or two. |
ISDs and VSDs move less than 1 unit per round? That seems a bit slow - almost stationary actually. How slow is a stock light freighter? |
I posted adjusted version of my rules.
I'm using a 100m space unit, so an ISD is 16 space units long, and a VSD is 9. At full acceleration, they would both pass out of the space they had occupied sometime in the second turn.
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Bren
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| Posted: Fri Sep 16, 2011 12:08 pm Post subject: |
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| Fallon Kell wrote: | | I'm using a 100m space unit, so an ISD is 16 space units long, and a VSD is 9. At full acceleration, they would both pass out of the space they had occupied sometime in the second turn. |
OK. So then you must be assuming an initial velocity for the SD that is either 0 or is along the same vector as the incoming shot. Otherwise the initial velocity would allow the SD to get out of the way faster. |
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atgxtg
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| Posted: Fri Sep 16, 2011 1:32 pm Post subject: |
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| Fallon Kell wrote: |
I'm using a 100m space unit, so an ISD is 16 space units long, and a VSD is 9. At full acceleration, they would both pass out of the space they had occupied sometime in the second turn. |
That means than an ISD is moving about 576kph (358mph).
That is considerable slower than what we have ships moving at today. And it is too slow to obit a planet.
By extrapolation, an ISD in obit would be moving at around 50,000 times it ACC (16G?) and would be vitually impossible to maneuver byyour newonian rules. |
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Fallon Kell
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| Posted: Fri Sep 16, 2011 3:33 pm Post subject: |
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| atgxtg wrote: | | Fallon Kell wrote: |
I'm using a 100m space unit, so an ISD is 16 space units long, and a VSD is 9. At full acceleration, they would both pass out of the space they had occupied sometime in the second turn. |
That means than an ISD is moving about 576kph (358mph).
That is considerable slower than what we have ships moving at today. And it is too slow to obit a planet.
By extrapolation, an ISD in obit would be moving at around 50,000 times it ACC (16G?) and would be vitually impossible to maneuver byyour newonian rules. |
Uhh... most ships top out near 40 knots, not 358 mph. Anyways, that's after 1 turn of acceleration, isn't it? About 72 miles per second per second?
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Bren
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| Posted: Fri Sep 16, 2011 4:37 pm Post subject: |
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| Fallon Kell wrote: | | Uhh... most ships top out near 40 knots, not 358 mph. Anyways, that's after 1 turn of acceleration, isn't it? About 72 miles per second per second? |
 Weren't we discussing Newtonian motion of space ships? If we are discussing wet navy vessels you really need to include rules to account for drag in the water.  |
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Fallon Kell
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| Posted: Fri Sep 16, 2011 5:23 pm Post subject: |
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| Bren wrote: | | Fallon Kell wrote: | | Uhh... most ships top out near 40 knots, not 358 mph. Anyways, that's after 1 turn of acceleration, isn't it? About 72 miles per second per second? |
Weren't we discussing Newtonian motion of space ships? If we are discussing wet navy vessels you really need to include rules to account for drag in the water. |
He said "ships". I had already posted and driven off to a job interview before I realized he meant spaceships. Regardless, 358 mph every 5 seconds is pretty good acceleration for something the size of a small mountain, isn't it?
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Bren
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| Posted: Fri Sep 16, 2011 6:32 pm Post subject: |
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| Fallon Kell wrote: | | Regardless, 358 mph every 5 seconds is pretty good acceleration for something the size of a small mountain, isn't it? |
Not really, 358 mph is roughly the speed of a fast propeller plane from WWII not a spaceship. That spaceship is traveling at about 1/2 mile per 5 second round. At that rate it will take that space ship nearly a month to travel from the Earth to the Moon. That doesn't align with starfighters being able to travel from the Rebel Base on Yavin's moon to reach the Death Star before it rounded Yavin.
Technical nitpick: 358mph is a speed not an acceleration. |
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atgxtg
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| Posted: Wed Sep 21, 2011 2:18 pm Post subject: |
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| Fallon Kell wrote: | | [] . Regardless, 358 mph every 5 seconds is pretty good acceleration for something the size of a small mountain, isn't it? |
No, it isn't. The reason why big sea-going ships accelerate so slowly is partly due to the fact they are are moving through water, which is about 800 times as dense as air, and provides greater resistance.
Also, the 358mph is the velocity after 5 seconds, not the acceleration. It is also incoorect (  ).
If an ISD is 1600m long, and it takes about two turns at full acceleration to vacate the spot there were just at, the ISD must move 1600m in 6 to 10 seconds. Since D=1/2at^2, acceleration must be something between 32m/s and 88.88 m/s , or from 3.2G to 9.1G.
That's assuming the ISD began at a dead stop.
As V=at, the ISD must be moving somewhere between 320 m/s (1152kph/716mph) and 533.28 m/s (1920kph/1193mph). Considerably better than 576kph/358mph, but still too slow for ships to maintain an orbit, according to Newtonian physics.
Spacecraft in orbit move at many times their acceleration (for example a Space Shuttle Orbiter has an acceleration of less than 1G, but orbits the Earth at around 8000 meters per second.
If you want Star Wars spacecraft to stick to Newtonian physics you are either going to have to up the scale to something closer to the offical ratings, or be more lenient with the difficulties for moving at multiples of ACC.
Or just assume that contragav is preventing the Star Wars ships from being pulled out of orbt and into nearby planets.But then you'd have to explain why "primitive" spacecraft are outrunning the Star Wars ships. |
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Fallon Kell
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| Posted: Wed Sep 21, 2011 3:15 pm Post subject: |
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[quote="atgxtg"] | Fallon Kell wrote: |
As V=at, the ISD must be moving somewhere between 320 m/s (1152kph/716mph) and 533.28 m/s (1920kph/1193mph). Considerably better than 576kph/358mph, but still too slow for ships to maintain an orbit, according to Newtonian physics.
Spacecraft in orbit move at many times their acceleration (for example a Space Shuttle Orbiter has an acceleration of less than 1G, but orbits the Earth at around 8000 meters per second.
If you want Star Wars spacecraft to stick to Newtonian physics you are either going to have to up the scale to something closer to the offical ratings, or be more lenient with the difficulties for moving at multiples of ACC.
Or just assume that contragav is preventing the Star Wars ships from being pulled out of orbt and into nearby planets.But then you'd have to explain why "primitive" spacecraft are outrunning the Star Wars ships. |
Star Wars ships, at least in combat, don't seem to orbit in the movies. They appear to stand stationary off a planet with little or no motion relative to the center of said planet. Whether this is the work of repulsorlifts or something else, I don't know, but it seems they don't have to orbit if they don't want to.
"Primitive" spacecraft generally move faster than Star Wars craft because they have to, and because they've been accelerating at full power for close to an hour, while the Star Wars craft have generally been accelerating for less than a minute.
Also, since it's impossible to determine an absolute velocity in space, I treat all motion as relative to an imaginary battlefield, which can itself be in orbit. Under that system, a Star Destroyer moving at a total of 9,000 meters per second in the same direction as a battlefield moving at 8,000 meters per second would only have about 3 levels of speed penalties, rather than the 28 levels for a stationary battle field.
The imaginary battlefield would primarily be used to determine difficulty to avoid asteroids and satellites things like that, and thus remain stationary relative to these un-powered objects. It could also follow one big capital ship under attack from starfighters, or a Super Star Destroyer being attacked by waves of capital ships.
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atgxtg
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| Posted: Wed Sep 21, 2011 6:12 pm Post subject: |
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| Fallon Kell wrote: | | [Star Wars ships, at least in combat, don't seem to orbit in the movies. They appear to stand stationary off a planet with little or no motion relative to the center of said planet. Whether this is the work of repulsorlifts or something else, I don't know, but it seems they don't have to orbit if they don't want to. |
Yup. That seems to be the case. But it is obviously non-Newtonian. The most likely answer is that they can negate the pull of gravity and thus don't have to worry about falling back to the planet.
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"Primitive" spacecraft generally move faster than Star Wars craft because they have to |
Quite true.
| Quote: | | , and because they've been accelerating at full power for close to an hour, while the Star Wars craft have generally been accelerating for less than a minute. |
Not true, but I can understand the slip up. Primitive Spacecraft don7t have enough fuel to accelerate for "close to an hour". They only have enough fuel to accelerate for several minutes. The trick with the space shuttle orbiter is that it uses booster rockets and an exrernal fuel tank to achieve up to 3Gs acceleration for part of the trip, and then it ditches the bosters and external tank. The orbiter iself has barely enough fuel to maneuver back into the atmosphere.
But the ramifications of that, according to your rules is that the Space Shuttle Orbiter would not be able to land, since the difficulty for it to maneuver would be in the thousands. Basically, it's a rock. Realistically, it can maneuver, but the change would be minor compared to it's velocity.
[/quote]
Also, since it's impossible to determine an absolute velocity in space, I treat all motion as relative to an imaginary battlefield, which can itself be in orbit. Under that system, a Star Destroyer moving at a total of 9,000 meters per second in the same direction as a battlefield moving at 8,000 meters per second would only have about 3 levels of speed penalties, rather than the 28 levels for a stationary battle field.[/quote]
Better. That was something I was PMing someone about a few weeks back, and I7m all for it. That way you can have ships match speed with a primitvve craft and just treat a primitive shuttle as a unmoving object.
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The imaginary battlefield would primarily be used to determine difficulty to avoid asteroids and satellites things like that, and thus remain stationary relative to these un-powered objects. It could also follow one big capital ship under attack from starfighters, or a Super Star Destroyer being attacked by waves of capital ships. |
Works reasonably good as long as ships stay in the same orbital path. A fight that strayed into a differernt orbit could be in for a nasty surprise, when something comes zipping by at thousands of kph. |
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Fallon Kell
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| Posted: Wed Sep 21, 2011 7:10 pm Post subject: |
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| atgxtg wrote: |
Not true, but I can understand the slip up. Primitive Spacecraft don7t have enough fuel to accelerate for "close to an hour". They only have enough fuel to accelerate for several minutes. The trick with the space shuttle orbiter is that it uses booster rockets and an exrernal fuel tank to achieve up to 3Gs acceleration for part of the trip, and then it ditches the bosters and external tank. The orbiter iself has barely enough fuel to maneuver back into the atmosphere.
But the ramifications of that, according to your rules is that the Space Shuttle Orbiter would not be able to land, since the difficulty for it to maneuver would be in the thousands. Basically, it's a rock. Realistically, it can maneuver, but the change would be minor compared to it's velocity. |
As I understand it, it took upwards of 40 minutes for a Saturn V to leave Earth orbit. I was using the Saturn V since it's role is closer to that of Star Wars ships.
Regardless, the are generally moving faster than I have Star Wars ships moving because they have been accelerating much longer. Several minutes is still much longer than, say 4 combat turns.
Also, the real orbiter would not likely have anything to avoid, but would have real trouble getting out of the way in time if there was something like an alien spacecraft standing stationary above the planet. This is an example of exactly what you're talking about below.
| atgxtg wrote: |
Works reasonably good as long as ships stay in the same orbital path. A fight that strayed into a differernt orbit could be in for a nasty surprise, when something comes zipping by at thousands of kph. |
As far as landing goes, the orbiter does slow some before directly interacting with anything outside of it's own frame of reference, or imaginary battlefield, if you will. Then it enters the atmosphere, where it continues to slow, eventually reaching low enough speeds to maneuver safely.
If someone tried to make a right angle turn in the Orbiter during reentry, the ship would probably crash or burn up. Maybe even explode or something, depending on the stage of reentry and the exact maneuver attempted.
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atgxtg
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| Posted: Thu Sep 22, 2011 10:39 am Post subject: |
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| Fallon Kell wrote: |
As I understand it, it took upwards of 40 minutes for a Saturn V to leave Earth orbit. I was using the Saturn V since it's role is closer to that of Star Wars ships. |
But it wasn't firing it's thrusters all that time. It took only a couple of mnutes to burn up most of the Saturn's fuel and put the craft into orbit. The reason for the lo ng time to break orbit is that the command module would use it's maneuveri ng thrusters to make a minor coruse adjustment, and then the ship would "coast" out of orbit and towards the Moon.
The big factor with real spacecraft is that it takes about 90%+ of thier fuel to put them into orbit, and they do most of thier "flying" unpowered.
You can even work it out yourself using the time of burn and accleration. A Saturn V has an accleration of 5-6Gs (about 50m/s) so it doesn't take long to get into orbit.
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Regardless, the are generally moving faster than I have Star Wars ships moving because they have been accelerating much longer. Several minutes is still much longer than, say 4 combat turns. |
Yup.
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Also, the real orbiter would not likely have anything to avoid, but would have real trouble getting out of the way in time if there was something like an alien spacecraft standing stationary above the planet. |
It could apply thrust to alter it's trajectory and avoid a threat, but ANY Star Wars spacecraft could kick in it's thrusters and eventually catch up. Just how fast that would take depends on how how you rate thier accleration. With your ratings it would take minutes, while with teh "official" ratings it would take seconds. Either way, the shuttle would be in big trouble. The only real difference would be how much time they would have to send off a message.
[quoute]
As far as landing goes, the orbiter does slow some before directly interacting with anything outside of it's own frame of reference, or imaginary battlefield, if you will. Then it enters the atmosphere, where it continues to slow, eventually reaching low enough speeds to maneuver safely.[/quote]
Yes, but it can't do that with your Newtonian rules. Any coruse correction would be at ultra-high difficulty. Now if you are "zero-ing out" movment for the "battlefield" then there isn't a problem.
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If someone tried to make a right angle turn in the Orbiter during reentry, the ship would probably crash or burn up. Maybe even explode or something, depending on the stage of reentry and the exact maneuver attempted. |
A right angle turn at high speed would rip the orbiter apart. The same holds true for slower moving fighter aircraft. What real vechiles have to do is to make more gradual turns over time. Or go slower.
How about you allow ships to take extra time for a maneuver? Each addtional turn spent could halve the speed difficulty modifier. Thay way an archaic starship could maneuver, but not very well in comparsion to Star Wars ships. |
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vanir
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| Posted: Sat Nov 12, 2011 10:08 am Post subject: |
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You'll have to forgive the fact that my technical understanding of the subject material is extremely limited by education level (mid high school but I read a lot and have pilot training which is like doing a uni course), however wouldn't interception be a little difficult when you don't believe in gravity wells and length contraction?
I mean it's a problem just with planes, use newtonian math and you'll be a few km out of place when enemy fighters roll up.
I read a great period description of Newtonian gravity once, written in the 19th century some time, essentially the core belief is that objects have a will of motion.
This is the marked difference from Relativity which states that space is curved rather, and objects have no idea what they're doing.
Newton was brilliant, often correct, but it was his religion. He made a personal mythology of math, and at least one conclusion was utterly erroneous.
Does this come into play at all here?
Like I said, I dunno much about the learned aspect of all this. Just second hand conceptualisations in science-media.
(fyi atgxtg, dude you're freaking me out with your smarts, man  ) |
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atgxtg
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| Posted: Sun Nov 13, 2011 3:55 pm Post subject: |
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Vanir,
I think by Newtonian Motion most of us are reffering to the Newtonian Physics that are used for most physics problems. Stuff like F=ma, or V=1/2 at^2, or G=mr^2 Stuff that is reasonably accurate for most things. For our purposes (gaming), it probably doesn't matter why gravity works the way it doees. although your descripion of Newtonian gravity does bear an uncanny resemblance to the Force. The Force has a will and binds the galaxy together. Maybe Newton is right and Einstien is wrong in the Star Wars Universe. It would explain a lot.
You seem to have a decent grasp of the basics, and I doubt there are many astrophysicicist on these forums to check out math and theories.
As far as interception goes. It can be a big problem, but it might not be. It depends on what the fule situation is, how much time the ships have to break, and if the intercepting ship needs to match speeds and vector. Not to mention detection.
In the real world ships need to use fuel to change their speed and heading, both to speed up and slow down. So ships would be limited by how much fuel they can afford to use. There are some neat tricks to consume fuel using planets and other gravity wells, but they take more time, and wouldn't be of much use in Star Wars. In the end this kind of limits all space encounters. if both want to fight, then they would have to keep realtively similar speeds and vectors. Otherwise youd either have a running chase, or some sort of starfing run as the ships passed each other (or a ramming situation).
In Fallons rules, as well as in real life, a major drawback to high velocity is that it restricts maneuverability. A ship that has been acclerating at full power for ten minutes is generally going to take at least ten minutes to come toa stop. |
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