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Curtis Saxton wrote:Each SPHA-T cannon exceeds the size and the instantaneous firepower of all the guns on an Accalamator transport ship. This is unsurprising, since the Acclamator is simply a well-protected military barge with some secondary capability for surface bombardment, and not a true combat warship. The Acclamators that landed on Geonosis could not hope to shoot through the shields protecting Trade Federation core ships, but the combined, maximum firepower of several SPHA-T guns could overcome these shields (one target at a time). If a SPHA-T were integrated into the body of a star frigate, destroyer or larger vessel (with adequate, dedicated power feeds) then it would compare with the heavy turbolaser turret of a star destroyer.

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The maximum continuous heat disposal by the shields of a Trade Federation core ship is rated as 6×1023 W. The maximum reactor output of an Accalamator-class military transport is 2×1023 W. Thus the maximum continously sustainable firepower of an Acclamator is less than a third of what the core ship can shrug off. In a one-on-one test of guns against shields, the core ship would not suffer any unsustainable accumulation in its shields' internal heat-sinks.

In the Battle of Geonosis it was therefore unfeasible for Acclamators to attack core ships directly. Furthermore, it was tactically impossible to settle close to the Separatist landing fields, and any inter-ship fire would have been attenuated and scattered by the Geonosians' theatre shields over the intervening tens of kilometres. Rather, the Acclamators would deploy their lumbering, pre-charged SPHA-T artillery to crawl across the open battlefield and concentrate on the enemy ships and fortifications from more advantageous positions.

Approximately five SPHA-T guns were able to penetrate the shields and cut into a single launching core ship. If the core ships were fully shielded (as a sane and cowardly Neimoidian captain must command when evacuating an invasion zone), then we infer a lower limit on the output of an individual SPHA-T. By this reckoning, each gun yielded an instantaneous maximum firepower of around ~1.2×1023 W. However this rate was only sustainable for a little over a second before the SPHA-Ts were exhausted. This implies that the gun's reactor initially carries, and eventually annihilates, the equivalent of around a million tons of fuel. This much mass-energy, in whatever exotic form it takes, must contribute significantly to the effective weight of the walker.

Waste heat from inflicted damage ought to have generated incredible explosion events, complete with fireballs and overpressure.

The Original Nex wrote:

Waste heat from inflicted damage ought to have generated incredible explosion events, complete with fireballs and overpressure.

Doesn't Saxton cover this in the very article you quoted?

The SPHA-T, seen in action on Geonosis, is a turbolaser cannon. The SPHA-T is essentially a line-of-sight gun: it can shoot anything that it can see. It fires massless beams that are essentially the same as the fire from turbolasers, laser cannons and blasters. The beam itself is an invisible form of energy that propagates at the speed of light. The bright light emission, which appears to drift at distinctly subluminal speeds, is a byproduct of the decay of some patches of the beam into ordinary photons. Its apparently slow propagation is essentially a strobe effect upon more rapid fluctuations within the beam, as seen by the [virtual] movie camera. Air has a high degree of transparency to this turbolaser beam (like blaster energy generally) but solid matter does not. The beam passes harmlessly through air with little collateral heating, but dumps intense power within the first opaque material that it meets. Indeed at its highest intensity, the beam may melt a thin column all the way through its target.

Crossroads Inc. wrote:Does he explain why, if these are essentially big TurboLaser,s that they have a 'Dish' and shoot a 'Beam' instead of a Mega Blaster Bolt?

Illuminatus Primus wrote: This implies that the Core Ships were fully shielded and the SPHA-Ts were overcoming them with raw firepower. How does this reconcile with observation in the film? Waste heat from inflicted damage ought to have generated incredible explosion events, complete with fireballs and overpressure.

Robert Walper wrote:

Illuminatus Primus wrote: This implies that the Core Ships were fully shielded and the SPHA-Ts were overcoming them with raw firepower. How does this reconcile with observation in the film? Waste heat from inflicted damage ought to have generated incredible explosion events, complete with fireballs and overpressure.

This concept is precisely what I was wondering in this thread as well.

Illuminatus Primus wrote:

Robert Walper wrote: This concept is precisely what I was wondering in this thread as well.

That's hardly as problematic: we've observed shield "bleedthrough" where only a fraction of the energy makes it through the shield, and to boot these weapons appear to be of the point-defense variety.

We have a postulated yield and shield dissipation quantity here. Its hard to get around that.

Waste heat from inflicted damage ought to have generated incredible explosion events, complete with fireballs and overpressure.

Robert Walper wrote:Even a tiny fraction of the firepower Wars ships are capable of should be making kiloton/megaton effects which is not seen...and if these are point defense guns as you suggest with yields looking no more powerful than WW2 battleship guns, how could they possible be expected to damage said craft?

Illuminatus Primus wrote:

Robert Walper wrote:Even a tiny fraction of the firepower Wars ships are capable of should be making kiloton/megaton effects which is not seen...and if these are point defense guns as you suggest with yields looking no more powerful than WW2 battleship guns, how could they possible be expected to damage said craft?

I just said bleedthrough - an option here but not there, because continuous beam weapons once penetrated have obviously penetrated fully. I also noted that it was whatever energy penetrated through both armor and shield, as opposed to whatever waste energy absorbed anywhere which is reradiated into the atmosphere around. And most importantly, the matter of yield. The SPHA-T according to Saxton has more firepower than a 200 gigaton Acclamator battery. A point defense weapon may have firepower anywhere from low kiloton range to low megaton range. Its much more understandable to see how such fire bledthrough shield and armor might be decidably underwhelming. However, I will admit the observed effect is a little alarmingly weak, but I find it a lot less distressing than the seeming self-contradiction with the SPHA-T shooting down the Coreships scene.

Hardy wrote:The possibility of a "Mysterious Chain Reaction" beam does seem somewhat tempting in this case. It nicely explains the lack of recoil, lack of atmospheric heating, and accounts for the size of the vehicle. Unfortunately, a mechanism for said MCR can't be defined.

Shroom Man 777 wrote: Giant super phasers?

Me likes!

phongn wrote:I thought the Core Ships would have been projecting a theatre shield to stop the Republican vessels from simply razing their droid armies in the field with orbital bombardment; thus the SPHA-Ts would have an unimpeded shot at the TF ships.

Meest wrote:I thought waste heat from shields was released as neutrinos, that can explain some of the effects especially if the armour is still working and the heat is still being absorbed and retransmitted till complete heat sink failure.

Connor MacLeod wrote:AFAIK there's no errors regarding the SPHA-T entry. The beam is supposed to be at maximum power in order to allow it to penetrate the Trade Federation core-ship's hull. The idea seems to be that the SPHA-T beam is transparent to atmosphere, so very little energy is "bled" off into the surrounding atmosphere (the AT-AT guns in TESB are the most directly comparable example. One might refer to the hoth Ion cannon too, but that's less of a direct comparsion.)

Recoil was addressed either by the tractor/repulsor "anchoring" mechanisms, and/or the neutrino "recoil damping" mechanism he mentioned.

Illuminatus Primus wrote:I'm talking about waste heat from neutronium impregnated materials being melted, deformed, and vaporized - matter which will probably have enormous heat content - being dropped into the atmosphere. There's no way that essentially 100% of the energy of the beam is all going to be perfectly absorbed by the hull and innards with virtually no waste from the site of impact and absorption into the atmosphere.

Illuminatus Primus wrote: I'm talking about waste heat from neutronium impregnated materials being melted, deformed, and vaporized - matter which will probably have enormous heat content - being dropped into the atmosphere.

There's no way that essentially 100% of the energy of the beam is all going to be perfectly absorbed by the hull and innards with virtually no waste from the site of impact and absorption into the atmosphere.