81 replies to this topic

[Kaleb Graff]

The problem is that unless you can match accelerations and velocities while directly ahead of them, they aren't going to stay in the exhaust stream for long.

[Sûlherokhh]

Regarding a) the original question and b) imposed speed limits:

A general combat speed limit makes sense. Even though you can accelerate a ship to unlimited velocities using a thrust-drive (well, unlimited in regards to a frame of ship-to-ship combat), It doesn't make sense to do so at all, unless trying to flee or follow a fleeing ship. If you accelerate a ship for 10 seconds using full thrust, you are going to need 10 more seconds of full thrust to make a significant vector change. So, to preserve mobility and combat efficiency, a ship's maximum thrust effectively limits it's maximum combat velocity (whatever the vector) in a proportional manner. When adding the versatile (and fuel- as well as exaust-mass-efficient) repulsor generators it becomes glaringly apparent which of the two will be the dominant propulsion mechanism, the thrust-drive merely providing support as well as a means to disengage the battle altogether, by more or less pushing the constraints imposed by the limits of repulsor technology.

[feld]

But it logically follows from Saxton's argument that they could. IF the rockets really are that powerful. If the ships use repulsor as their primary means of travel in a gravity well, then they don't need rockets that powerful and the problem goes away.

Also note his little commentary below the comparison chart that states that the Sun is a relatively slow reactor overall. So really, the thrusters emitting more power than the Sun isn't exactly too unreasonable.

Well...Saxton also mentions getting rid of the waste heat in that part. It's not the power so much as the power density that is unreasonable. That's power divided by the volume of the reactor. The Sun is...well...the size of a star. 10^31 kg and 100,000s of miles across, etc etc. The size of an ISD or SSD engine/reactor complex (i.e. probably hundred of millions of kg and maybe a few hundred meters long) is obviously many orders of magnitude smaller, so the power density (the number that tells you if the device will melt or not) is many orders of magnitude larger.

It's a challenge to cool chemical rockets today. And it'll be even harder to cool the fusion engines that they have on the drawing boards. So that's what I was thinking about.

Even still, the folks in SW have forcefields, they could probably use ridiculously powerful particle/ray shielding inside the engine to protect it.

[Pred the Penguin]

The sure don't shield the reactors - Episode 1

I wonder, while a typical engine is too unwieldy to use in combat, is there anything designed around that idea?

Edited by Pred the Penguin, 27 January 2009 - 02:03 PM.

[Ghostrider]

Actually, a lot of people were killed when the Lusankya took off, just that the book probably failed to mentioned it (been a while since I read it). It's probably in The Essential Chronology.

I thought the book did indicate - I remember onlookers being horrified as the main engines kicked in.
I distinctly remember 3 separate causes of death:
1. the guns shooting the buildings above Lusyanka as it broke free.
2. the main drive kicking in, presumably converting several square miles of urban dwellings to plasma.
3. the repuslorlift cradle being discarded, which then dropped on a different area of coruscant, killing yet more innocents.

What scared Wedge even more though was the thought of how many millions were killed when it was hidden to ensure it stayed hidden!

[Tropical Bob]

Actually, a lot of people were killed when the Lusankya took off, just that the book probably failed to mentioned it (been a while since I read it). It's probably in The Essential Chronology.

I thought the book did indicate - I remember onlookers being horrified as the main engines kicked in.
I distinctly remember 3 separate causes of death:
1. the guns shooting the buildings above Lusyanka as it broke free.
2. the main drive kicking in, presumably converting several square miles of urban dwellings to plasma.
3. the repuslorlift cradle being discarded, which then dropped on a different area of coruscant, killing yet more innocents.

What scared Wedge even more though was the thought of how many millions were killed when it was hidden to ensure it stayed hidden!

As it lifted off, it fired its weaponry and ignited its thrusters, apparently devastating around 100 square kilometers.

The weapons, shortly after take-off, then turned against a skyhook. As soon as that was destroyed, the Lusankya began to attack the planetary shielding. When it got through those, it engaged a Golan.

The repulsorlift cradle was jettisoned shortly after escaping from the shield perimeter. From the way it's worded, I believe that it was used as a shield between the Golan and the Lusankya. That would mean that it was above the planetary shields, and would either be destroyed by the Golan, or fall into the shields.

Wedge thought of two scenarios (Suffice to say he liked the first better):
A) Palpatine used the Force to make all the witnesses forget, or completely ignore, the burial.
B) All the witnesses were killed.

Whatever happened with the burial and subsequent rise of the Lusankya, we can be sure that more than just millions per scenario would be killed. Because it's not just 100 square kilometers: it would be a few hundred cubic kilometers. After doing a bit of math, I got about 8 billion (I think?). That's probably a better estimate of the deaths.

Edited by Tropical Bob, 28 January 2009 - 08:44 PM.

[Pred the Penguin]

What was Coruscant's population then?

[Tropical Bob]

What was Coruscant's population then?

The only official census that we have states one trillion permanent residents right at the end of the Clone Wars, but the real population at the time could have been three times that many. Then Traitor apparently states the same number, which is a good 49 years later. Instead, I got the volume from using Mexico City vs. the general height for the world's tallest buildings (500-ish meters) as a base for my math (Which I admit could have come out wrong).

I suppose if we use the official post-CW census as the lower limit, and the theoretical triple of that as the upper limit, we'll get something different. Though that's coming out at something like 212,465-637,395 casualties. Which isn't anywhere near what even the book claims during the escape.

I think that several hundred cubic kilometers on the most populated city in the galaxy would hold more than a few hundred thousand or a few million.

Edited by Tropical Bob, 29 January 2009 - 09:21 AM.

[Pred the Penguin]

I remember reading something about how all of Coruscant's skyscrapers are at least a kilometer up.
And also there should be less people near the poles.

[Tropical Bob]

I remember reading something about how all of Coruscant's skyscrapers are at least a kilometer up.
And also there should be less people near the poles.

All of them are a few kilometers I believe. Or at least most of them will be.

Not entirely true...There's going to be a significant lack of climate effects near the poles, and for people to be kilometers up without feeling any effects of low temperatures, then I doubt the poles will be too much different. Especially after all the "global warming" effects that Coruscant will have gone through. Not to mention that the wonders of futuristic technology will likely promise cheap household heating and air conditioning for all.

[Kaleb Graff]

But Coruscant's poles have to be heated by orbital mirrors, making it unlikely that global warming was significant enough to make them habitable.

[Kitkun]

I thought the mirrors were just for light. There's also bound to be many species and people that prefer cooler temperatures.

[feld]

I thought the mirrors were just for light. There's also bound to be many species and people that prefer cooler temperatures.

With available power in the GFFA, I imagine that each of the Coruscanti buildings could have very different environments. Possibly even atmospheres. The locations Incredible Cross Sections cutaway of the Senate building gives some idea of the art of the possible...

[Kaleb Graff]

I remember reading that the polar areas would be uninhabitable for humans without the mirrors, or at least very unpleasant.

Edited by Kaleb Graff, 30 January 2009 - 10:10 PM.

[Pred the Penguin]

Heck. If you could live kilometers up in the air, I bet you could live anywhere. Besides you can live on Coruscant without even walking outside, so I bet the mirrors are for something else.

I remember there still being ice in the poles, people even go skiing there. O_o


Anyways, we're getting really off-topic...

[Pellean]

The sure don't shield the reactors - Episode 1

I wonder, while a typical engine is too unwieldy to use in combat, is there anything designed around that idea?

Starfighters' use of maneuvering jets seem to indicate that they use thrusters as their main source of propulsion. Presumably they have much lower mass relative to their engine output than capital ships do, allowing them to accelerate and turn more effectively.

[Phoenix Rising]

Tangent: Check out this discussion (actually the one after, BB Code doesn't like the ellipses) on hypermatter that's buried on Wookieepedia. It's a pretty interesting read if you can ignore the typical Internet flaming.

I'm a little on the edge with that discussion. A Wizards of the Coast guy came in and said that Saxton's calculations from the movies should be disregarded, and that a magical solution to the figures should be taken instead (The bit about the virtual mass). It also regards a lot about fuel cells, which might or might not be canon for a lot of things.

I think the main point is that we know ships don't incinerate atmospheres with their engine wash, so it can't be explained by modern physics alone. Crunching the numbers is useful to get a better understanding of how things operate, but IMO, numbers alone can't contradict how the galaxy works - and engines just aren't aft-mounted superweapons in SW.

[Tropical Bob]

I know that flying closely through an Imperial-class Star Destroyer's engine wash in Rogue Squadron II means a pretty quick death.

I can't imagine anything being able to apply enough force to move things that big not having adverse effects on atmosphere...

...Unless they use particles that don't interact with normal matter (Somehow)...Things like tachyons, dark matter, etc. Going off of hypermatter's description on Wookiepedia...Perhaps not all of the energy is utilized by the reactor, and when its still in realspace, the remnants of hypermatter is used to accelerate the ship right before the hypermatter re-enters hyperspace. Then we would have a very limited particle wash range from the engine.

Edited by Tropical Bob, 06 February 2009 - 07:09 AM.

[feld]

I can't imagine anything being able to apply enough force to move things that big not having adverse effects on atmosphere...

Well...repulsors quite visibly hold up things...and repulsor tanks can run characters over without hurting them (EP1:TPM)...so they clearly are "action at a distance". It's hard to see how they could do this and not have HUGE tidal forces induced somewhere between the repulsorlift and the planet...but...well...I like the repulsors-as-propulsion better because it gives me a nice handwavium box to stick all the otherwise crazy stuff the ships can do into.

r/
feld

[Tropical Bob]

I can't imagine anything being able to apply enough force to move things that big not having adverse effects on atmosphere...

Well...repulsors quite visibly hold up things...and repulsor tanks can run characters over without hurting them (EP1:TPM)...so they clearly are "action at a distance". It's hard to see how they could do this and not have HUGE tidal forces induced somewhere between the repulsorlift and the planet...but...well...I like the repulsors-as-propulsion better because it gives me a nice handwavium box to stick all the otherwise crazy stuff the ships can do into.

r/
feld

Ah, sorry. I meant that post as a response to PR's statement:

I think the main point is that we know ships don't incinerate atmospheres with their engine wash, so it can't be explained by modern physics alone. Crunching the numbers is useful to get a better understanding of how things operate, but IMO, numbers alone can't contradict how the galaxy works - and engines just aren't aft-mounted superweapons in SW.