2010-02-05

Updates on the Main Page

I haven't mentioned them here yet, but they're there, including updates to the Overview, a new page on SW power technology, and more.

I'm probably going to update the Volumetrics page with the new Star Wars and new Google SketchUp data, then quit for awhile.  Been spending a lot of time on this, which is nice insofar as making up for a lot of lost time, but I don't want to get burned out.  And, it would be nice to get other things done.  :-)

Thanks for reading!

4 comments:

  1. The links in the page on SW power technology point to folders on your HDD. Other than that, great work! ;)

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  2. Gah. Thanks.

    I was trying a different way of doing things with Kompozer, and discovered that it is flaky, but still preferable to the old way.

    I'd had to check that link-URL-rewriting it does more than once, but apparently it changed them again and I didn't catch it. Thanks!

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  3. A couple quick notes on the SW reactor tech page.

    First, about keeping the liquid deuterium cool, just partially exposing the fuel tank to space wouldn't work so well. Space isn't actually cold, and a vacuum is a rather poor medium for heat transfer (that's why it's used as an insulating medium, like in some thermoses), because the only method for heat to transfer is by radiation, which is very poor compared to the transfer of heat through physical contact. Exposed to vacuum and in the shadow of a solid object, protecting one from the light of nearby stars, heat would eventually radiate away, yes, but it would not be a fairly quick process, and the tank would be just as likely to absorb heat if exposed to space (especially when that part of the hull is oriented towards a nearby star) as it would be to radiate it (especially at lower temperatures).

    Just a technical nit-pick, though, as SW ships obviously don't use super-cooled liquid deuterium as a fuel.


    My other point is about the PPM machine ideas. Nothing that I have seen in SW lore says that the repulsorlift tech negates the energy requirements of maneuvering in gravity; everything I have seen indicates that repulsorlift tech still requires energy to operate, it just provides a different source of propulsion that is better-suited to operating within a gravity field than just ion drives alone. Without repulsorlift tech, ships would be required to have massive engines oriented downward relative to their landing struts (or, more accurately, land with their engines oriented downward), to provide enough thrust to lift off. These engines would also have to constantly burn to push the ship out of the gravity well, creating traffic lane and landing area problems.

    Repulsorlit tech solves this problem by allowing ships to maneuver in a gravity well with only maneuvering thrusters or minimal main engine burns. Presumably, lifting a 40 megaton starship out of an ~Earth-massed gravity well would still require ~317 petajoules of usable energy expended, whether that energy was directed through the ion drives or the repulsorlifts.

    Using your figure of 90% engine efficiency, an ISD would need to channel 352 petajoules into its engines to lift off. Assuming a maximum of 75% power to engines, and your lower 400-TW ISD reactor output figure, an ISD could lift itself off the surface of the Earth in ~ 352,000 TJ / 400 TW * 0.75 = 1,173 seconds, or roughly 20 minutes at maximum output. Not too shabby considering that's like lifting over 425 fully-loaded CVN-65 USS Enterprises into orbit.


    Oh, and one other thing: Your Acclamator landing/take-off numbers don't really mean much, other than putting an absolute-maximum cap on the energy being expended through their ion engines at the time, which obviously wouldn't be much, as the ion engines were oriented laterally and the ships were lifting vertically - most of the 'thrust' had to have been coming from the repulsorlifts at the time, and since we have no direct measure for the energy directed through the ion drives, we have no real way of determining reactor output values from those numbers.

    We can get some idea of energy expenditure in the Palpatine incident by measuring the distance the ships moved straight up, and the time they took to move that distance, since we have an estimate of the ships' mass, and the planet appeared to be ~Earth-normal gravity. That should give us a good observed usable 'thrust' energy expended by the Venator.

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  4. First, about keeping the liquid deuterium cool, just partially exposing the fuel tank to space wouldn't work so well.

    Took me a minute to realize you were replying to a minor tangent off of one of the addendum points. I wasn't being completely serious there. After all, the vast majority of the sphere would still have a big hot ship around it.

    As for space being cold, interstellar space is about 3 degrees K, and I was talking about having something cooled to 20K. So if the ship interior was kept at a brisk 21K or so then that little bulb might keep the hydrogen cold enough for the most part. But even if that were so, in-system or orbital temperature would screw it up.

    I might end up removing that lest detractors get confused.

    Nothing that I have seen in SW lore says that the repulsorlift tech negates the energy requirements of maneuvering in gravity; everything I have seen indicates that repulsorlift tech still requires energy to operate, it just provides a different source of propulsion that is better-suited to operating within a gravity field than just ion drives alone.

    I don't think it requires no power . . . I just don't think it requires all of it. Just consider the energy benefit from nullifying gravity's pull on your ship, whether in the form of artificial mass reduction or some sort of gravity mirror effect or some semi-magic sci-fi substance they toss into the reactor or what-have-you. Departing from the atmosphere thus becomes, not an issue of fighting gravity, but a simple job of normal acceleration.

    In such a case, a thruster capable of giving a ship just one tenth of a gee could put it 600km up in those 1173 seconds of yours. If it was capable of 25m/s^2, it could climb to above 100km (roughly the definition of outer space, depending on who you talk to) in about 90 seconds.

    Now, I don't know how exactly antigravs operate. I rather doubt they completely nullify gravity, and I certainly don't think they're a perfect free lunch without any required energy input. And I do agree that even if they were simply more efficient or even just more user-friendly than rockets their use could be justified on that basis alone.

    However, in concert with the other details of antigravs and their use (e.g. leaving things floating for kicks), I don't think it safe to assume their power requirements.

    Oh, and one other thing: Your Acclamator landing/take-off numbers don't really mean much, other than putting an absolute-maximum cap on the energy being expended through their ion engines at the time

    They meant enough, and provided what I sought . . . as noted in the page, it isn't just the ion engines, but the whole heat output of the ship being considered. In most such cases of close, unprotected individuals we need not assume the reactors were at full power, and of course there are a lot of ways (real or sci-fi) a ship could deal with excess heat that might not involve simple radiation from the entire hull, but nonetheless it was a useful guide.

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