About a Star Destroyer main power output rerouted to guns...

[Mr. Oragahn]

As it was claimed in one of the prequels' ICS, that as a true warship, a Venator could have its entire power output (teratons per second) directly to guns.
But then why are the power cores and thrusters so huge if such little barrels as found on turbolaser turrets could handle just as much power?
Most of the main power core, itself being so large that it partially protrudes beneath an ISD, would be used for mere motion purposes.
With observed accelerations of such ships, relatively adequate tonnage figures and a rough idea of the fuel that's used, we could get a good idea of the energy that's generated there.

When you think of it, it's totally insane. Back then, Saxton claimed that the vast majority of starships in SW could easily apply accelerations in the thousands of g.
Since it was claimed that the power plant's output could be channeled to the gun batteries (and therefore "turbo" compressed), not only an ISD would be thrown sideways every time such a turret would fire, but we'd also have to assume that the entire gun assembly and its moorings could perfectly withstand the insane sudden stress while on the same hand big honking conical thrusters are actually needed to properly handle and exploit the super heated ejecta.

Perhaps I'm missing something here?
Well, of course, they conveniently claimed that the guns fired lasers, which dramatically reduced concerns regarding momentum... to some degree. Remember Wong's entire calculation about the Millennium Falcon being jolted by a multi-megaton level shot hitting at a plunging yet quite open angle?
With teratons, we're talking about shots millions of times greater than the figure Wong's extracted from his calculation. Of course and ISD is ought to be millions of times heavier than the good old piece of junk, but that simply means you might expect an equally impressive recoil applied to an ISD, nothing like the almost unnoticeable recoil shown in movies.

Leaving this madness on the side road, I have a simple question for you guys.

Wouldn't there be a rule-of-thumb method to use here, by the way, to gauge the output of guns if they indeed were capable of tapping directly into the main power core's output, by comparing bore size versus some main thruster's aperture, using both minimum and maximum diameters?
There would be a lot of assumptions going along this train of thought, including the zero loss of power, but that might work.
Or perhaps this has already been done before?

[2046]

In the strange, peculiar land of Greater Saxtonia where the folks are well-dressed and have their own unique versions of Star Wars quite distinct from those Lucas made, I believe the prevailing theory of hypermatter requires that the ship be capable of adjusting its mass as desired. As such, they could drop proverbial anchor when firing.

Of course, conservation of momentum would suggest that velocity should then change, but I presume they have compensation of some kind.

After all, in Greater Saxtonia, compensation is the national obsession. Some might even suggest they overdo it.

[359]

I don't think a using thruster force versus recoil is a valid way to determine weapon outputs. These are mainly energy weapons after all.

Unlike modern (or not so modern) kinetic projectile weapons where most of the energy is stored in the kinetic motion of the projectile energy weapons store their energy in the composition of the projectile.

For example, a grenade can explode with about one megajoule worth of energy. But were I to throw one I would only experience around 33 joules (1/2 * 0.39 kg * (13 m/s)^2) worth of recoil. This is because the grenade stores its energy chemically which makes the recoil totally disproportionate to the explosion energy. Same thing with laser pointers and atom bombs. Since blaster bolts seem to be more thermal/explosive weapons than kinetic projectiles the same idea applies to them.

[Pheonix]

This is something I've considered before. The engines are a lot bigger than the guns. Probably thousands of times larger. But of-course, the drives aren't just massive turbolasers, so 1:1 scaling would probably be unrealistic. Turbolasers would have to handle a lot more power within a much smaller area if ships could pump all of their reactor output into their guns. If the turbolasers were thousands or millions of times less powerful than what the multi-thousand g engines ought to be, then they'd be handling megatons of firepower, consistent with some interpretations of asteroid superheating from lighter guns and town vaporization, though perhaps inconsistent with others.

The new films might just give us something explicit ;)
Technical extrapolation can be sound, but it's not how the writers go about determining firepower, or much else really.

[Pheonix]

359, recoil does become an issue even with massless beams if they are sufficiently powerful. Teratons and petatons can get pretty stressful. Unless you are suggesting they fire sub-sonic bolts of anti-matter or some such?

Deriving energy from momentum in sci fi for massless beams, is not something I'm a big fan of. Because far too frequently, we end up with multi-gigajoule beams which chuck people through the air, without vaporizing them (or doing much else). In space and with the Falcon it seemed reasonable technically, until you make comparisons to stuff that happens on the ground and elsewhere in Star Wars, and pretty much everywhere else too.

[359]

Yes, if you do throw enough light one direction you will get noticeable recoil, but that's because of radiation pressure and not the kinetic motion of a projectile. Same thing with my grenade example, you would experience significant recoil if you were to throw it fast enough or if it were significantly heavier. Although for different reasons than radiation pressure.

But in the case of turbolasers, we do not know the mass of the projectile and it is most definitely not traveling fast, so we should not expect significant recoil. For clarity, I am modeling them as more a "plasma" bolt rather than a particle weapon because they behave far more like one. But yes, similar to a sub-sonic bolt of anti-matter or whatever, the actual material doesn't really matter too much, no pun intended scratch that, it was intended.

[Mr. Oragahn]

I don't think a using thruster force versus recoil is a valid way to determine weapon outputs. These are mainly energy weapons after all.

Unlike modern (or not so modern) kinetic projectile weapons where most of the energy is stored in the kinetic motion of the projectile energy weapons store their energy in the composition of the projectile.

For example, a grenade can explode with about one megajoule worth of energy. But were I to throw one I would only experience around 33 joules (1/2 * 0.39 kg * (13 m/s)^2) worth of recoil. This is because the grenade stores its energy chemically which makes the recoil totally disproportionate to the explosion energy. Same thing with laser pointers and atom bombs. Since blaster bolts seem to be more thermal/explosive weapons than kinetic projectiles the same idea applies to them.

I'm a proponent of the explosive-plasma projectile idea, and the flak is sufficiently documented in the novelizations to consider this a fact by now. This means the weapons create a projectile on the go, and perhaps turbo-charge a jacketed pack of plasma with a laser. Still, I wouldn't obsess too much over the laser term, as we've seen where it took the saxtonians and wongites (yes, such is their names!). The recoil is much more a problem in Saxton's model but I don't want to waste time on a defunct and troublesome idea.

More to the point, we sort of know where most of the power is generated, when know how the ship is shaped and we have a rough idea of the size of certain components. Things are big because they need to be after all.
What makes things more complex is IF weapons are directly powered by the main core (or perhaps smaller but still enormous auxiliary plants), how is the energy carried?
After all, our current fission power plants can, for example, output 1 GW of power but the entirety of it is carried through a rather small amount of not too big cables, linking said plant to the power grid.
Somehow, we shouldn't focus too much on the size of theoretical power conduits, as the information is near totally absent and in Star Wars, the technology is advanced enough so we could safely consider them to be able to carry more per certain forms of conduits, with the same cross sectional areas, than we do today with our thick cables (and as I said, we already do carry a lot in fact).

[Mr. Oragahn]

359, recoil does become an issue even with massless beams if they are sufficiently powerful. Teratons and petatons can get pretty stressful. Unless you are suggesting they fire sub-sonic bolts of anti-matter or some such?

Deriving energy from momentum in sci fi for massless beams, is not something I'm a big fan of. Because far too frequently, we end up with multi-gigajoule beams which chuck people through the air, without vaporizing them (or doing much else). In space and with the Falcon it seemed reasonable technically, until you make comparisons to stuff that happens on the ground and elsewhere in Star Wars, and pretty much everywhere else too.

Well back then, Wong never bothered to explain why his calculations based on a pure light model ignored the fact that bolts didn't cover the distances at c.
That, Saxton tried to do it with his spinning tubes of light. But it made zero tactical sense so they had to find a reason and based on some really minuscule amount of evidence, they claimed that photons beams were traveling down corridors of *something* that could be redirected; somehow providing a locking feature to beam weapons.
A very absurd notion considering that with particles moving at c, you wouldn't need to follow a target because aside from super mega ranges never observed in SW, the moment you'd press the button, the beam would immediately connect with the target.

[Mike DiCenso]

Well back then, Wong never bothered to explain why his calculations based on a pure light model ignored the fact that bolts didn't cover the distances at c.

I recall that Wong did the calcs in response to people who were noting that if Star Wars turbolaser were actual L.A.S.E.Rs, they wouldn't be able to penetrate Star Trek ships' navigational deflector shields. So he did them to show that if the turbolasers were L.A.S.E.Rs, then rocking the Falcon like that would prove they were very powerful weapons in the 32,000 TW range given photons mass less nature.

It has since been twisted into what we see now, that the momentum transfer is proof, regardless, of high Star Wars firepower. So Saxton, Wong, Young, etc all went on to find excuses to justify sticking with that estimate is hardly surprising.
-Mike

[Praeothmin]

Yeah but I showed the same thing could apply to ST photorps, as in ST VI:TUC, a photorp rocked a 120 meter long Bird of Prey the same way, imparting angular momentum to it...

All in all, I believe it came around 25 Gtons...

[Mike DiCenso]

That would be a good example, except that the opposition could simply say that the rocking motion of the BoP was due to the direct impact of the torpedo against the hull, rather than the explosions themselves.

Two better examples would be the indirect torpedo detonations seen in TNG's "Preemptive Strike" used to chase off the Maquis raiders, and Star Trek II: The Wrath of Khan where the Enterprise's very near miss with phasers causes the Reliant to rock instantly 20 meters to port.
-Mike

[Praeothmin]

For the momentum to be imparted by the impact of the torpedo itself, it would have to be infinitly dense and massive, and would have imparted some sort of noticeable recoil upon the firing ship...

[Mike DiCenso]

I'm sure that the opposition would just say in that case that KE does not come from the E-1701's launcher, but the accelerating torpedo's own propulsion, which is why we don't see a noticeable recoil from the ship itself. The rocking motion, they will also say, is the result of the BoP's still working mass lightening system, making the Klingon ship infinitely lighter than it otherwise would be. This despite the fact that we often see Trek ships move with real mass, such as the E-D's saucer section crash in "Generations", or the E-E colliding with the Scimitar in "Nemesis", and or the Alt-prise scraping a chunk of debris in Star Trek 2009.

See with them it's always brute force and raw power for Star Wars and for Trek or anyone else it's magic tech that causes massive damage through low-power and chain-reactions, etc.
-Mike

[Praeothmin]

It's just that these arguments fail against any kind of scrutiny or logic...

[Jedi Master Spock]

If you fire a massless beam, you're basically minimizing the ratio of momentum per unit energy.

The higher-end Saxtonite model of an ISD is about 1e25 watts; if you fired that out the front end as lasers, you'd have (1e25 J)/(3e8 m/s) ~ 3e16 N of force. If your ship masses 30 million tons, or 3e10 kg, that would be about a million m/s^2 acceleration, or about 100,000 g.

OTOH, if you were firing them as sublight projectiles whose energy is mostly in terms of some sort of thermal content (explosive plasma packets) then momentum is completely decoupled from energy content.

If you're talking about the sort of yields actually discussed in Wong's botched momentum calculations based on the Falcon, however, we're talking about orders of magnitude less. Wong's actual claim in that calculation was that the instantaneous output of a turbolaser is "over 215,000 TW," i.e., in the close vicinity of 2e17 watts. That's 50 million times less. (And not a sustained power level.) At that level, there isn't really a recoil problem.

This is one of the problems the Saxtonites had; lots of them produced "lower limits" without realizing that those "lower limits" were not only not actually lower limits, but also typically bounds to within an order of magnitude for that model of the technology. Saxton himself, I think, had a vague idea of the recoil problem, but was (A) assuming that Star Wars ships were supermassive and (B) assumed the existence of neutrino-based recoil compensators (without carefully considering the problems involved there).