Maximum Total Speeds

Bob McDob

Bob McDob

Better Health Through Less Flavor
Yeah, I hope this make sense ...

Although speeds in space should be unlimited, we get a definate impression that they are, in many ways, and that when capships open scoops it reverses things entirely. Take the Gilgamesh, for example. 10,000 tonnes, its maximum velocity is normally 250KPS. However, open the scoops and within a half hour (ignoring End Run's confusing and tenuous grasp of physics) it accelerates to over 10,000 KPS.

On the other hand, the Rapier, at around 14 tonnes (using the Hellcat as a baseline, since no set mass exists for the Rapier and they seem to be contemporaries), and you're barreling along at a comfortable 450 KPS, nearly twice the speed as the Gilgamesh. Yet with scoops open, the Rapier can certainly accelerate faster than the Gilgamesh - according to Fleet Action if I'm not mistaken, 3000 KPS in a few minutes - yet that speed is vastly slower.

My question is, what makes it tick? What relationship between mass, acceleration, and speed exists here? I have something of a stake in this, since I'm playing around with a Homeworld mod (not a WC one specifically, but one that models things like this) and I'm curious as to what relationship can be taken from this. If anyone can work out some sort of formula that, based on this, gives even a rough estimation, I'd be grateful for it.

Thanks.
 
I'm not really sure about the question...

In vacuum with thrust only, certainly the normal functions apply, with the thrust of the engine overcoming the inertia of the ship to accelerate its speed, and with the scoops open I guess some kind of retarding field is produced which causes a sort of magnetic induction and slows the ship down.

You can find all of these formulae in a physics 101 book. However, nowhere does it say how powerful Confed engines are or how strong the magnetic field is. So it's not really useful.
 
Incidentally, you have to remember two things:

1) In End Run, they CLOSED the scoops to achieve, by burning most all of their fuel, 10,000kps, which is only logical given that if you were coasting about at 450kps all the time, you'd take forever to get between jump points in a system, instead of a few hours.

2) Those speeds are relative measures, as compared to some body (the carrier, a nearby planet, your target). There are no absolute measures for speed, since this depends on a fixed distance and something to measure it against... which ends up being your carrier, most of the time.
 
Also keep in mind that with the scoops closed you dont have any reaction mass coming in - so you might only have enough particles stored to get your Rapier up to 3000kps relative to what you were doing and even then you might have cut vastly into your afterburner fuel. Larger ships would have to shift far more mass but they would have both larger tanks and more powerful engines, so each gram of fuel burned would have much more energy imparted to it.
 
I always assigned WC physics to the "suspend disbelief" category (if the jump points are out around Neptune, it'll take quite a long time to travel between two points even at an appreciable fraction of the speed of light, and who wants to sit in a CAP for weeks?), but the idea of Bussard ram scoops is somewhat consistent. Most of these points have already been raised, but I'll collect them with the physical explanations (IAAP).

First, ram scoops have a "drag" effect which makes accelerating to arbitrary velocities impossible (once the scoop drag = thrust generated, you're stuck at that speed, just like with an airplane). In fact, I think the calculations show that ram scoops won't work, because the thrust generated would never be able to overcome the drag of the scoop. However, let's suspend disbelief on that point, too. After all, there might be a technological fix to make collection more efficient. Incidentally, Forstchen also uses the scoops to explain why WC fighters are so manueverable (in a vacuum, a fighter probably couldn't generate enough thrust quickly enough to make tight turns--however, with scoops, the interstellar hydrogen provides something to redirect/reflect your velocity without additional energy, just like an airplane).

Second, if you eliminate (close--not open, as the original post said) the scoops, the drag effect is eliminated, and you can continue to accelerate. However, there's another limitation here... you only have a fixed amount of fuel. Think of it this way: if your engines generate X amount of thrust, they will burn a constant Y amount of fuel. Since you don't have infinite fuel, you can't accelerate to arbitrary velocities, even ignoring relativistic effects. This is the idea behind specific impulse and the rocket equation, and it's why you can't just build an arbitrarily large chemical rocket and expect it to hit light speed... you need different engine technology like ion, nuclear, or antimatter drives.

Third, velocities are measured relative to something. This is probably the least important point, but consider it... right now, you're going around the sun at something like 67,000 mph, yet you're probably sitting still in your seat. It depends on where you measure from.

One reason why ships in WC keep to a fixed speed (besides gameplay) given in the novels is to maintain the fuel levels... once you start to accelerate to a high velocity, you're going really fast, but you're also extremely predictable, since you can't manuever much as you've run out of fuel. Better to keep the speeds down in preparation for tactical manuevers. Also, fuel is probably used up in the jump process, I would imagine. At least they did for the Broadswords in WC2, I don't know if that holds true into the future, since we don't seem to need it in Privateer.

Some points for comparison: a space shuttle zips around the Earth at something like 18,000 mph, which is about 8 kps. A 450 kps ship (not even counting afterburners) can go about 55 times as fast, but that still doesn't seem all that impressive. And the fastest manmade objects ever, the Helios space probes, hit about 150,000 mph, which is about 67 kps, which makes that 450 kps ship only about 7 times faster than what we've already achieved with mere chemical propulsion.
 
I'd like to add a little something:
Even though the speed measurement can be only relative, I find them to be highly incongruent to our perception on the game, i.e., you approach a kilrathi fighter doing 450KpS, he's doing 400KpS, which means you and the kat have the relative speed of 850KpS. A human pilot shouldn't be able to see him zip past so fast. Even in a modern day atmospheric fighter dogfight, the contestants are moving so fast in relation to one another that you must relly strongly in your radar to know what's going.

Of course, if the game was to be realistic in this aspect, it would be boring like hell. But I think thay made a mistake by calling the speed measurement "Kilometers per Second", they should've used something more abstract...

What do you think?
 
It's for gameplay reasons. You wouldn't be able to hit anything at even three or four kilometres per second. 500kps is just what the Hud tells you. Ingame they move about the same speed as FreeSpace fighters, but the WC speed gauge has some sort of multiplier(the value is 0.13) So 65m/s are 500m/s in WC (they replaced m/s with kps to give the feeling of higher speeds).

And kps doesn't mean "kilometers per second" but klicks per second, I don't think a click is defined anywhere, and in WC a click happens to be 0.13m. ;)
 
I'm fairly certain that in the real world, people use "klicks" as a shorthand for "kilometers" and sometimes "kilometers per second" or "kilometers per hour", and not as some arbitrary unit like miles per hour or something. And I've certainly never heard it defined as some arbitrary number like 0.13m. :) Incidentally, if you look at the little nav pointer distance counter thing, the way the number of meters spin down does seem to support a km/s interpretation. On the other hand, a real kps interpretation should mean you should shoot past the Midway in something like 2 ms when you're flying bow to stern, which from what I recall, isn't the case. I suppose another explanation is that the Midway is like 1000x longer, but I recall someone else trying this interpretation before, and I didn't like it then, and I don't like it now. :)

Personally, I prefer having the gauge read "kps" even if it's totally wrong. Other explanations just smack of apologism to me. I'm more willing to suspend my disbelief about how fast 500 kps (since I've never experienced it anyway, and would only notice if I gave it some thought) than to tell myself "it's not really km/s, it's really some arbitrary future unit!". I know the "megalights" in the X-Wing games always bugged the heck out of me, especially since they used km in the movie (remember the Death Star trench run?). Especially since the speeds didn't seem to match what the distance gauge read (I once flew across the length of various ships to try and get a feel for what a MGLT translated to).

Incidentally, while I think it's probably true that you wouldn't be able to hit something with guns at anything approaching the speeds WC ships are supposed to be zooming around at, I doubt that it would seem too "fast". Keep in mind that (1) it's space (it's always been pretty hard to convey real speed--and size in space fighter games, ever notice how a 30m enemy fighter looks shorter, and capships never seem as big as they should be?--simply because of the lack of reference... I think adding superhigh detailed textures to cap ships would help), and (2) if you've ever driven down the freeway or looked out the window while flying in an airplane (I suppose the best example would be if you had ever been in a fighter cockpit, but that's pretty rare), you'll notice that after the initial acceleration, you mind tends to adapt and things don't seem as "fast" anymore. Basically, you just look farther on, and the distance doesn't tick by quite as fast.

Assuming you could see a Kilrathi fighter from huge distances, a head-on approach, even at 850 kps, wouldn't seem particularly fast until you got right up close and zoomed past each other. I've heard that the enemy planes in fighter combat hardly seem to move, and then suddenly they're a lot closer and moving a lot faster than you thought.
 
Do keep in mind that because a term is used in WC as well as RL doesn't mean that the terms are used the same way. Basing WC knowledge on real life terminology is, at best, mental masturbation. :p
 
That would be a neat point to make, Death, if Claw Marks didn't specificly mention that a klick is a term used to mean kilometer.

Source
 
Woot!

Regardless, though, as a personal matter, it kinda interferes with my ability to enjoy a game if I worry about whether or not 1 kps = 1 kps. It's easier for me to just assume it is, and not worry about the nitty gritty. Probably why I don't enjoy alternate history as much as science fiction... despite how unlikely it might seem, at least there's a distinct possibility that in 2665, humanity may indeed be locked in a bitter struggle with a felinoid race known as the Kilrathi. Ya never know. :)
 
GeeBot said:
despite how unlikely it might seem, at least there's a distinct possibility that in 2665, humanity may indeed be locked in a bitter struggle with a felinoid race known as the Kilrathi. Ya never know. :)
Click to expand...

I'd rather not, thank you :\
 
Hasn't there been quite a few discussion about the relative aspect of the speeds used being mps in combat situations instead of kps?

C-ya
 
Klicks are Kilometers, and the entire world, apart from the US, UK and probabably the Commonwealth, use meters for everything. Actually, even the military and scientific people in these exceptions mentioned above use the metrical system too. Miles, inches and other related measurement units are just ancient, arbitrary and senseless...
 
Err, I doubt that they use inches all around the world for pipes. Heck, they even use metric for screws and stuff, and if there's one thing you wouldn't want to be incompatible, it'd probably be screws. The measurements are often similar, but they're never exact conversions.

I'm pretty sure folks in the UK and Commonwealth also use metric. The only people who really use the English system are the Americans. Go figure. Actually, I suppose some old geezers who predate the metric system probably use it, too.

In my personal opinion, metric (and the SI system in particular) is very useful for scientific computations, since the units mix and match properly in the formulas without too much thought.

However, the imperial system has one advantage over the metric system: the measurements have some sort of human proportion. A yard corresponds somewhat to the length of an arm, a foot about the length of a (very big) foot, an inch about the length of a digit of a finger.

While the correspondances are obviously non-exact, it's often easier to think about lengths in various imperial units than as 170 cm or 200 mm. While metric units are convenient for calculations, human beings sometimes have trouble imagining lengthy decimals. You rarely hear people talk about how something is 5.36 feet long, but it's common to talk about how something is 1.85 meters long.
 
I don't know if all navies use knots and if air forces still use feet. It seems like most armies have converted to metric, anyway (calibers in mm: 9mm pistols, 120mm tank cannons; distances seem to be given in meters/kilometers; etc.).

A good reason to use knots is that 60 nautical miles = 1 degree of latitude (degrees of longitude don't correspond to any sort of constant distance). In other words, 1 nm = 1 minute of latitude. So knots are a good way to correspond ship speed with navigational charts (if you're moving at 30 knots due east, you'll know that you should be about 1 degree farther east after 2 hours of travel). A nautical mile is a bit longer than a statute mile, which is what's used on land.

I don't know about the feet question; perhaps it's simply a matter of tradition (most civilian airplanes in the US still use feet on their various gauges). However, I'm pretty sure that metric nations use metric on their gauges, and perhaps even the US Air Force does (it'd help to coordinate with NATO).

Generally, the US military is better about migrating to new systems than the civilian sector; after all, the military is, by design, a top-down bureaucracy with strict discipline.
 
I'm pretty sure folks in the UK and Commonwealth also use metric. The only people who really use the English system are the Americans. Go figure. Actually, I suppose some old geezers who predate the metric system probably use it, too.
Click to expand...
Considering that the origins of the metric system date back to the French revolution, these geezers must be really old indeed.

BTW, I lived my whole life with the metric system, and I have no problem thinking about things in metric terms. After all, the several differente measurements (meters, liters, degrees celsius etc.) make lots of sense, can be subdivided or multiplied very easily, and relate to each other without any hassle.

Exemple, 0°Celsius is the temperature in which water freezes, and 100° is the one when it boils (considering the atmospheric pressure at sea level). And 1 liter of water weights abou 1 kilo.
 
Yeah, the idea of some 250 year old pre-metric geezer was supposed to be incredibly amusing. I guess you had to be there. :)

Anyway, if the metric system makes so much sense, why don't we have metric time (besides counting everything in seconds)? They tried it, but it never stuck, because people find existing time systems easier to divide into convenient fractions. Similarly with angle measures; almost nobody uses gradians today, not even the French.

And about that liter; the liter is a cubic decimeter, and the SI unit is the kilogram, with a mass equivalent to a cubic decimeter of water. Surely, if we're being purely scientific here, a cubic meter and the megagram would have made better base units. As a practical matter, though, both quantities are unwieldly for everyday use (personally, the choice for volume/mass units never bothered me much; I never use the volume units in scientific computations, just convert everything to cubic meters; and the only time mass and volume interact is with density computations, where the density is generally given).

As for the "naturalness" of various metric units, this is mainly convenient to scientists. For example, temperature ranges that most people encounter don't really fall conveniently on the Celsius scale (one of the things that always gets me about the Celsius system is that there's a big difference between it being 25 and 28 outside, and yet it's only a difference of 3 degrees). One could also argue that the Kelvin scale is better, even though that makes 0 degrees Celsius something like 293 K (I believe kelvins are, in fact, the SI unit for temperatures).

Also, the meter was initially defined as something like 1 millionth (or 10 millionth, or something, I don't recall) of the length of the meridian passing through Paris, but this isn't precise (as is the problem of keeping accurate solar time); eventually, the meter had to be redefined in terms of the speed of light and the frequency of cesium atoms.

Still, it all boils down to what you're used to. Given that, though, I still think that the metric system "naturalness" derives from its compatibility with computation in base 10, and not really with what size unit is most convenient.

I really do like the metric system, especially when solving physics problems, and wouldn't mind if the US converted to metric tomorrow (like everybody else already has), but I what I'm trying to say is that I think the metric system's reputation for being natural is overblown. :) Sometimes, decimalized units aren't the most convenient scale for measurements; one size doesn't fit all (I guess that's my engineering perspective kicking in). It's a highly rational system, though, so I guess if you've gotta choose just one way to go, it's the only way to go.
 
You must log in or register to reply here.
Back
Top