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Re: GCS Vs 12" Cannons
Posted: Tue Feb 17, 2009 5:59 am
by Coalition
m52nickerson wrote:I used KE=0.5mv2 that gave the joules, the Watts joules divided by the time of impact, which is the time it took the torpedo to travel its length.
Drat, I forgot about that 1/2. Sorry.
m52nickerson wrote:Mass lightening will reduce the energy needed to be put into the torp, but it will also reduce the damage delivered. I.e. if you make the torp 1% of its original mass, it only takes 1% of the original the energy input, but it also only does 1% of the original weapons damage. It works both ways. KE does not let you get more energy out than what you put in.
I understand that, but even a 1kg object traveling at 0.25c would generated exawatts of power on impact.
Completely true. Of course then I'd get into arguing that you should measure impact in terms of Joules and Watts. High Joules are good for damage, unless it takes too long. High Watts are good for damage, if it can be maintained. Given the length of a photorp (1-2 meter IIRC), those ExaWatts will only last 1/75,000,000 of a second to 2/75,000,000 of a second.
As another example of high Wattage/low Joules, would be the protons impacting in the Supercollider. From
here the speed is roughly .000001% less than that of light. Given the estimated mass (1.67
-27 kg) and dividing by the estimated width of a proton (~10
-15 meters) you get a roughly 22 TW per proton (I am assuming the proton is decelerated to a full stop in its length).
But I am getting off the original topic of GCS vs cannons, am arguing too much, and should probably stop.
Re: GCS Vs 12" Cannons
Posted: Tue Feb 17, 2009 7:49 am
by Captain Seafort
Coalition wrote:Completely true. Of course then I'd get into arguing that you should measure impact in terms of Joules and Watts. High Joules are good for damage, unless it takes too long. High Watts are good for damage, if it can be maintained. Given the length of a photorp (1-2 meter IIRC), those ExaWatts will only last 1/75,000,000 of a second to 2/75,000,000 of a second.
It depends on what's the key factor in knocking down a ship's shields. The fact that Worf gave the power of the impact rather than it's energy suggests that that's what's important. If we follow the theory that it's actually the momentum of the impact rather than its energy that really does the damge (given the evidence of various ships holding off TW of other forms of energy) then it would be the impulse.
But I am getting off the original topic of GCS vs cannons, am arguing too much, and should probably stop.
This entire thread is an off-topic tangent from another. If it goes down yet another tanget it'll simply be split off again to make finding the various debates easier. No big deal.
Re: GCS Vs 12" Cannons
Posted: Fri Feb 20, 2009 12:55 am
by SteveK
The biggest problem that I have with shield strength of 400 gigawatts is that it would render high speeds insanely dangerous.
KE = mc^2 (1 / (1-v^2/c^2) -1 )
(This looks quite different from what we're used to, but I can demonstrate [if requested] that at v <<<c this expression reduces to 1/2 mv^2)
If we make the assumption that any energy on the shields is transfered over a full second (such that joules = watts) then we can solve for the minimum mass needed to collapse the shields at .25c as follows:
m = 400 x 10^9 j / (c^2 * (1 / (1-v^2/c^2) -1 ) )
m = 1.35 x 10^-4 kg
or about 1/10th of a gram! If I adjust the previous approximation and assume the energy is transfered over 1/1000th of a second (which is still quite high given the velocity of the Enterprise) then 1.35 x 10^-4 grams would be sufficient to collapse the shields of the Enterprise.
If the shields were really that fragile, then the Enterprise would face mortal peril everytime it hit a tiny speck of dust. It never would have surivived the trip to Jupiter.
Re: GCS Vs 12" Cannons
Posted: Fri Feb 20, 2009 1:25 am
by Mikey
As I understand it (though this may be based on some assumptions along with backstage or canon info,) that's why the navigational deflectors are both so hugely important and somewhat different in principle to defensive shields. While this perhaps seems to exaggerate the issue, certainly to an extent it holds with common sense that hitting something, even something fairly minute, at relativistic speed can be catastrophic.
Re: GCS Vs 12" Cannons
Posted: Fri Feb 20, 2009 7:24 am
by Captain Seafort
That might be the difference between combat and navigational shields - the former are optimised to be effective against radiated energy (since that's what everyone seems to use as weapons in some form or other) while the latter are optimised to be effective against physical impacts (of course they're clearly somewhat effective against directed energy weapons as well, as Riker expected them to be effective against small lasers in "The Outrageous Okona"). The question is why they don't use these two systems as twin energy/particle shields in combat a la Star Wars.
Re: GCS Vs 12" Cannons
Posted: Fri Feb 20, 2009 7:34 am
by Lazar
I'm wondering how the Bussard ramscoops would work in relation to the deflector.
Re: GCS Vs 12" Cannons
Posted: Fri Feb 20, 2009 4:07 pm
by Mikey
Lazar wrote:I'm wondering how the Bussard ramscoops would work in relation to the deflector.
I always envisioned the collectors/scoops as a completely tangible, mechanical system.
Re: GCS Vs 12" Cannons
Posted: Fri Feb 20, 2009 4:10 pm
by Lazar
Mikey wrote:I always envisioned the collectors/scoops as a completely tangible, mechanical system.
Would the deflector be able to let hydrogen particles through, without any damage to the ship? Would it employ selective deflection or variably shaped fields, or would hydrogen particles not be worth deflecting in the first place?
Re: GCS Vs 12" Cannons
Posted: Fri Feb 20, 2009 4:12 pm
by Mikey
I can't see hydrogen doing much damage if it did get through. You're talking about one proton and one electron. If a hydrogen atom did get through, there's still only a small chance it would actually impact against one of the atoms comprising the material of the ship.
Re: GCS Vs 12" Cannons
Posted: Sun Feb 22, 2009 12:05 am
by Coalition
Lazar wrote:Would the deflector be able to let hydrogen particles through, without any damage to the ship? Would it employ selective deflection or variably shaped fields, or would hydrogen particles not be worth deflecting in the first place?
I'd see the two systems working together. The Navigational Deflector wants to keep stuff from hitting the ship where it will hurt. The Collector is designed to handle particles coming in. So the Deflector just shunts aside stuff from the front of the ship towards the Bussard Collectors, and the Collectors only grab the hydrogen from that stream (in addition to the rest of the volume wher it grabs hydrogen).
As far as physical impact from hydrogen you are correct. However that darn electron cloud will still try to repel the electron cloud of the ship's hull material, causing slow damage. I think I ran the numbers for the Wattage of a hydrogen atom hitting earlier in this topic. That was nearly c though, so at 1/4 c, it would be 1/16 that value, or about 1 TW.
The time frame for the impact is ~4 times longer, so only 250 GW. It only has 75 picoJoules of energy though (1/2 mv²).
Re: GCS Vs 12" Cannons
Posted: Tue Feb 24, 2009 10:30 pm
by Deepcrush
Did this ever get finished out? I was gone for a while.
Re: GCS Vs 12" Cannons
Posted: Wed Feb 25, 2009 2:41 pm
by m52nickerson
Not really, it got to a point of opening so many questions that I think many lost interest. It became more work then fun.
Re: GCS Vs 12" Cannons
Posted: Wed Feb 25, 2009 3:25 pm
by Thorin
I'm pretty sure we came to the conclusion that the gigawatt range figure in Survivors is not equivilent to the strength of the shields and is not the total energy incoming - as from the fact that 500 GW is the power of the NX's phasers. Somehow I doubt that one shot of the NX's phasers could take down the shields of the most advanced ship 200 years from the future.
PS I've not read the thread, sorry if it's already come up!
Re: GCS Vs 12" Cannons
Posted: Wed Feb 25, 2009 7:09 pm
by Captain Seafort
Thorin wrote:PS I've not read the thread, sorry if it's already come up!
Once, somewhere in the depths of the thread. No-one's suggesting that 400GW of any type of energy would have the same effect, but that it was the fact that it was KE that caused the problem.
Re: GCS Vs 12" Cannons
Posted: Wed Feb 25, 2009 7:15 pm
by Deepcrush
So KE is the key to wrecking the shields. Maybe thats why those Spacial Charges did so much hurt to Voy.