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Enterprise-D center of mass
Posted: 2004-03-09 11:00pm
by The Silence and I
Something I noticed about Booby Trap at the end while piloting the Enterprise out of the field with two thrusters: the thrusters only controlled lateral movement--left and right, but were mounted midway on the "neck" between the saucer and the engineering hull. This is interesting as it apparently represents the horizontal location of the ship's center of mass! Perhaps those nacelles aren't as light-weight as they look? Maybie antimatter is stored at high densities (yeah the Tech. manual says otherwise but...who cares

)? With such a placement the ship should have developed very significant rotation, but it was rock stable. Anyone have thoughts?
Re: Enterprise-D center of mass
Posted: 2004-03-09 11:34pm
by Lancer
The Silence and I wrote:Something I noticed about Booby Trap at the end while piloting the Enterprise out of the field with two thrusters: the thrusters only controlled lateral movement--left and right, but were mounted midway on the "neck" between the saucer and the engineering hull. This is interesting as it apparently represents the horizontal location of the ship's center of mass! Perhaps those nacelles aren't as light-weight as they look? Maybie antimatter is stored at high densities (yeah the Tech. manual says otherwise but...who cares

)? With such a placement the ship should have developed very significant rotation, but it was rock stable. Anyone have thoughts?
Trek fucking the laws of physics once again. That or impulse can selectively decrease mass throughout an object.
Posted: 2004-03-09 11:43pm
by Major Diarrhia
I always thought nacelles are made from super dense meterial and would therefore be very heavy.
Posted: 2004-03-10 12:50am
by RedImperator
For what it's worth, the TNG tech manual stated that the warp coils were the single heaviest components in the entire ship.
Posted: 2004-03-10 01:18am
by Jason von Evil
Major Diarrhia wrote:I always thought nacelles are made from super dense meterial and would therefore be very heavy.
Yet the Bozeman tapping one of the E-D's nacelles causes the entire ship to blow up.

Posted: 2004-03-10 01:31am
by Thag
Aya wrote:Major Diarrhia wrote:I always thought nacelles are made from super dense meterial and would therefore be very heavy.
Yet the Bozeman tapping one of the E-D's nacelles causes the entire ship to blow up.

Actually, it made the warp core blow up, but who's counting?
The warp coils themselves would be the only things that could be that dense. The episode with the guy jumping into the nacelle's plasma stream to kill himself made it look like that, except for the coils, most of the nacelle is hollow.
Posted: 2004-03-10 01:07pm
by Enola Straight
Each coil is actually a pair of C's... a split donut.
Each split pair of a GCS measures 21*43 meters, massing 34,375 metric tons.
Posted: 2004-03-10 03:14pm
by Major Diarrhia
Aya wrote:Major Diarrhia wrote:I always thought nacelles are made from super dense meterial and would therefore be very heavy.
Yet the Bozeman tapping one of the E-D's nacelles causes the entire ship to blow up.

I used to think that was cool untill a few years ago.

Posted: 2004-03-10 04:29pm
by Isolder74
I never did like that episode. The only thing I did like was the uniforms on the Bozeman
Posted: 2004-03-10 04:44pm
by StarshipTitanic
Isolder74 wrote:I never did like that episode. The only thing I did like was the uniforms on the Bozeman
I thought Capt. Fraiser did pretty well.
Posted: 2004-03-10 05:48pm
by Jason von Evil
StarshipTitanic wrote:Isolder74 wrote:I never did like that episode. The only thing I did like was the uniforms on the Bozeman
I thought Capt. Fraiser did pretty well.
And you know his dad was sitting in the ready room in a shabby recliner.

Posted: 2004-03-11 12:02am
by The Silence and I
So would this indicate nacelles are very very massive, despite being mostly hollow, instead of a high fuel density?
-Thank you for all your replies.
Posted: 2004-03-11 03:29am
by Sarevok
Isolder74 wrote:I never did like that episode. The only thing I did like was the uniforms on the Bozeman
It was a pretty good episode actualy. Time loops were properly used in that episode.
Posted: 2004-03-11 05:24am
by Uraniun235
It was a godawfully dull episode.
Posted: 2004-03-11 05:29am
by Spanky The Dolphin
Indeed. It got old fast watching the same stuff happen like four times in a row. Some parts were a bit interesting--no wait, I'm confusing it with that one Worf episode. Yes, it was boring.
Posted: 2004-03-11 12:43pm
by Crazedwraith
evilcat4000 wrote:Isolder74 wrote:I never did like that episode. The only thing I did like was the uniforms on the Bozeman
It was a pretty good episode actualy. Time loops were properly used in that episode.
no. The only time i've seen time loops ued properly was SG1's Window of Opportunity"
Posted: 2004-03-11 12:44pm
by airBiscuit
The Silence and I wrote:So would this indicate nacelles are very very massive, despite being mostly hollow, instead of a high fuel density?
-Thank you for all your replies.
They're hollow only so far as there is a gap inside of the warp field coils for the plasma stream to shoot through. The fuel involved in the M/AM to plasma conversion is located in the secondary hull in the form of a deuterium slush tank, and not in the nacelles. The nacelles are mainly coils, and according to the TNG tech manual, they are made of a very dense alloy material that has the special property of warp field induction. (paraphrasing there, not quoting).
Also note that it makes sense from a maneuvering standpoint to have the center of gravity be as close as possible to the center of length and width of the ship. This way the pivot occurs not at the front of the ship or the back of the ship, but at the center. This is probably a good thing from a rotational inertia standpoint.
Posted: 2004-03-11 12:51pm
by Darth Wong
Of course, the minute the saucer comes off, the CoG shifts severely. Unless you assume the saucer's mass is insignificant relative to the rest of the ship, which seems absurd.
Posted: 2004-03-11 03:33pm
by Thag
Darth Wong wrote:Of course, the minute the saucer comes off, the CoG shifts severely. Unless you assume the saucer's mass is insignificant relative to the rest of the ship, which seems absurd.
In this situation, wouldn't the thruster packs on the backs of the nacelles be enough to offset the shift? Instead of having one set in the middle of the ship, you have one set at each end.
Posted: 2004-03-11 07:27pm
by Howedar
Darth Wong wrote:Of course, the minute the saucer comes off, the CoG shifts severely. Unless you assume the saucer's mass is insignificant relative to the rest of the ship, which seems absurd.
Or if the center of mass of the saucer is roughly in line with the center of mass of the stardrive. At least from the front, I doubt if the fore-aft CG location is much of a big deal usually.
Posted: 2004-03-11 11:41pm
by The Silence and I
Darth Wong wrote:Of course, the minute the saucer comes off, the CoG shifts severely. Unless you assume the saucer's mass is insignificant relative to the rest of the ship, which seems absurd.
Hmm, well there are three impulse engines, and the CoG of the completed ship is between them. This means all three impulse engines are needed to provide balanced thrust, remove the saucer and the CoG will move downwards, perhaps right to the stardrive impulse engine.

Posted: 2004-03-12 01:08pm
by Thag
Not quite. The only times we saw the saucer units operating during TNG's run was when the saucer was separated. The rest of the time, only the stardrive unit was lit.
Posted: 2004-03-12 05:33pm
by Einhander Sn0m4n
And therein lies one of my worst pet peeves about ship design: Starship Engines' combined Thrust Axes _NOT_ going through (or anywhere near in some cases) the CoG! *GACK* I fucking hate that! I can understand warp nacelles being somewhat off the CoG since they essentially don't use newtonian thrust, but there's no excuse with any kind of rocket engine (like the fusion rockets commonly referred to as 'impulse')!
Posted: 2004-03-12 06:52pm
by airBiscuit
I believe that the TNG Tech Manual states the Impulse Drives generate a weak subspace field to lessen the relativistic and inertial aspects of the ship. You 'lighten' it in real-space so that you get better acceleration from the ion thrusters. Not being in the Center of Gravity is probably not a problem, since the subspace geometry can be modified to compensate for this. You'd have an artificial center of gravity maintained from the shaped millicochrane field.
This is speculation, of course.
Posted: 2004-03-12 07:13pm
by Howedar
Thag wrote:Not quite. The only times we saw the saucer units operating during TNG's run was when the saucer was separated. The rest of the time, only the stardrive unit was lit.
However, in DS9 Galaxies usually ran on all three impulse engines.