drag in space [Archive] - .com.unity Forums

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oleg

February 9th, 2003, 04:27 AM

Well, vacuum is not exactly an emty space. If we have a spacecraft moving at sublight velocity, it can encounter some resistance even at very low concentration of particles in space. Does anybody know the website that can provide an estimate ? I'm just thinking that though most SE shipsets are sleek and aerodynamic for purely aesthetics reasons, there might be some sense in such design ?

Slick

February 9th, 2003, 05:02 AM

Here are some good ones (used a google search for "atoms per cubic meter"):

http://www.hq.nasa.gov/office/pao/History/EP-177/ch4-6.html

http://hypertextbook.com/facts/2000/ChristinaCheng.shtml

http://hypertextbook.com/facts/2000/DaWeiCai.shtml

Slick.

couslee

February 9th, 2003, 05:04 AM

WHEW!
I was afraid this thread was going to talk about some hairy ship wearing a dress.

primitive

February 9th, 2003, 05:37 AM

Ain't gonna happen.
High heels, big wigs, and short dresses is not advisable in Zero-G conditions. http://forum.shrapnelgames.com/images/icons/icon10.gif

Sorry Oleg.
Can't help.

Fyron

February 9th, 2003, 06:53 AM

There is not enough mass in space to cause enough drag to make aerodynamic designs any better than non-aerodynamic designs.

Taz-in-Space

February 9th, 2003, 07:08 AM

How about in a nebula??

Fyron

February 9th, 2003, 07:09 AM

Real nebulae are nothing like nebulae you see in Star Trek, B5, SW, etc. I am fairly certain that the gasses and such are spread out really thin, and would not create much more drag than normal space.

Gryphin

February 9th, 2003, 07:40 AM

Fyron, I'm very happy to hear that. My Tessalates are safe even if they are not esthetic. Hmm, Guess i beter get them zipped and up loaded. < Phew >

[ February 09, 2003, 05:41: Message edited by: Gryphin ]

Fyron

February 9th, 2003, 09:07 AM

It does cause a (barely) measureable drag, but it is something like a fraction of a percent decrease in speed, so it does not have very much of an effect overall, esp. with the speed of engines in SE4. http://forum.shrapnelgames.com/images/icons/icon7.gif

capnq

February 9th, 2003, 09:04 PM

A while back in Discover magazine, I read an article which said that even "dark" nebulae that appear opaque are better vacuums than can be created here on Earth.

Shadowstar

February 9th, 2003, 10:47 PM

Well, there is the whole thing about having ships that just look nice. After all, just because you can build a flying rock doesn't mean it'll look like a million bucks (unless it's a flying gold nugget -- space casinos anyone?).

And, of course, space isn't empty. There are planets out there, and chances are, if you can travel to other stars, you're also gonna wanna check out the planets along the way. Designing a ship that can function in the atmosphere of a planet is important in that case. So even if you don't need to be aerodynamic all the time, chances are you'll need to be aerodynamic some of the time.

Of course, you could also go the way of having two different kinds of spacecraft; one for space and another for air and space, but that could end up more expensive as you'd then have to build two ships instead of just one, and one of the ships (probably the space-only ship) would have to be able to carry and launch the other one.

Then there's the whole discussion of designing ships that can function in very different atmospheres than Earth's. For instance, a planet with gravity half that of Earth, or a planet with air that's twice as thick, or a planet with a very thin atmosphere (low cieling), or one with high surface winds, etc. The aerodynamics on these planets would be very different, and ships would have to be designed to function in as many different environments as possible to be useful. And many planets have different atmospheric gasses, what then? How much will that anti-corrosive plating weigh? How does heat-shielding effect your aerodynamics? And so on...

It's good that these questions can be answered in the present, using aerodynamics simulations, so that we are prepared for the future.

[ February 09, 2003, 20:49: Message edited by: Shadowstar ]

Baron Munchausen

February 9th, 2003, 11:23 PM

Originally posted by Imperator Fyron:
It does cause a (barely) measureable drag, but it is something like a fraction of a percent decrease in speed, so it does not have very much of an effect overall, esp. with the speed of engines in SE4. http://forum.shrapnelgames.com/images/icons/icon7.gif Actually, it would increase with greater speed. Our spacecraft barely notice the drag because they are so slow. Get up to several percent of the speed of light and the solar wind will start to have a noticable effect on your ship.

I seem to recall that someone somewhere (NASA?) calculated what the temperature effects of 'ambient' matter on interstellar travel would be and figured out that ships could not go more than about .75 light speed without some new materials that could handle the heat buildup from friction, just like jets experience today. That's in interstellar space, not here in the much denser solar wind...

So as far as travel in 'normal' space is concerned, aerodynamic ships make perfect sense. http://forum.shrapnelgames.com/images/icons/icon7.gif In hyperspace/subspace/jumpspace/ whateverspace all bets are off.

[ February 09, 2003, 21:25: Message edited by: Baron Munchausen ]

F Te antKe

February 9th, 2003, 11:23 PM

Then again, this is Science Fiction game and we can use a ship set just because it looks cool us.
I believe the applicable word is, "Grok".
The ability to recognize that something does not make sense but to accept it anyway.
Shadowstar I think we agree or at least partially.
Gryphin’s Tessellates are an interesting and to me attractive ship set. I can see how many would not like them.
Gryphin? How about it? Will you be uploading it?
I promise I won’t use my stiletto on them.
That brings up an idea. I should make a stiletto shaped set.

Fyron

February 10th, 2003, 12:45 AM

Ships in SE4 do not go anywhere near the speed of light, so we don't have to worry about that. http://forum.shrapnelgames.com/images/icons/icon7.gif

couslee

February 10th, 2003, 02:55 AM

Originally posted by primitive:
Ain't gonna happen.
High heels, big wigs, and short dresses is not advisable in Zero-G conditions. http://forum.shrapnelgames.com/images/icons/icon10.gif Might make a funny ship-set. Have your ships so repulsive, that everyone feels the need to eradicate you just on the basis of aesthetics. And talk about a role play race..... lmao

Puke

February 10th, 2003, 07:15 AM

i expected this thread to be about male ships in dresses.

oleg

February 10th, 2003, 04:52 PM

Originally posted by Imperator Fyron:
Ships in SE4 do not go anywhere near the speed of light, so we don't have to worry about that. http://forum.shrapnelgames.com/images/icons/icon7.gif But what kind of enviroment do you encounter when traveling through the wormhole ? http://forum.shrapnelgames.com/images/icons/confused.gif
It is conciavable that "compressed space" or something can create some need for sleeky ships.

Based on data found in links, thanks Slick http://forum.shrapnelgames.com/images/icons/icon7.gif , I estimated that ship traveling at 0.3c between Sun and Alpha Centauri will get about 2kW per meter^2. Enough to start glowing red...

Aloofi

February 10th, 2003, 05:39 PM

Originally posted by Imperator Fyron:
Ships in SE4 do not go anywhere near the speed of light, so we don't have to worry about that. http://forum.shrapnelgames.com/images/icons/icon7.gif Exactly what i thought. In SE4 a ship needs 2 turns to go from the system's star to the the Warp point outside the system, which in our solar system would be over 4 Light Hours, and every turn in SE4 its about 40 days (36.8?) so the speed of the ships would be aroung 625 Km/sec. http://forum.shrapnelgames.com/images/icons/shock.gif
Wow, I thought they would be faster than that! http://forum.shrapnelgames.com/images/icons/icon10.gif

oleg

February 10th, 2003, 05:56 PM

Originally posted by Aloofim:
<blockquote>quote:<hr />Originally posted by Imperator Fyron:
Ships in SE4 do not go anywhere near the speed of light, so we don't have to worry about that. http://forum.shrapnelgames.com/images/icons/icon7.gif Exactly what i thought. In SE4 a ship needs 2 turns to go from the system's star to the the Warp point outside the system, which in our solar system would be over 4 Light Hours, and every turn in SE4 its about 40 days (36.8?) so the speed of the ships would be aroung 625 Km/sec. http://forum.shrapnelgames.com/images/icons/shock.gif
Wow, I thought they would be faster than that! http://forum.shrapnelgames.com/images/icons/icon10.gif <hr /></blockquote>But first they must accelerate to that speed, right ? That means to make the trip in time, the peak velocity would be much higher than apparent _average_ velocity.

Aloofi

February 10th, 2003, 06:47 PM

Originally posted by oleg:
But first they must accelerate to that speed, right ? That means to make the trip in time, the peak velocity would be much higher than apparent _average_ velocity.[/QB]There is a big diference between 625 Km/sec and 300 000 Km/sec.......
Ships in SE4 are traveling at 1/480s of light's speed. http://forum.shrapnelgames.com/images/icons/icon10.gif

Fyron

February 11th, 2003, 12:09 AM

Originally posted by Aloofim:
<blockquote>quote:<hr />Originally posted by Imperator Fyron:
Ships in SE4 do not go anywhere near the speed of light, so we don't have to worry about that. http://forum.shrapnelgames.com/images/icons/icon7.gif Exactly what i thought. In SE4 a ship needs 2 turns to go from the system's star to the the Warp point outside the system, which in our solar system would be over 4 Light Hours, and every turn in SE4 its about 40 days (36.8?) so the speed of the ships would be aroung 625 Km/sec. http://forum.shrapnelgames.com/images/icons/shock.gif
Wow, I thought they would be faster than that! http://forum.shrapnelgames.com/images/icons/icon10.gif <hr /></blockquote>One month in SE4 is exactly 30 days. Watch the movement replay log some time. http://forum.shrapnelgames.com/images/icons/icon12.gif

couslee

February 11th, 2003, 01:18 AM

Yes, but now we have the new "conceptual math". The answer can be wrong, but the question gets marked as correct if the student shows he "has the concept"

http://forum.shrapnelgames.com/images/smilies/rolleyes.gif

30 days, 36.8 days, I knew what he was getting at. http://forum.shrapnelgames.com/images/icons/icon10.gif lol

Fyron

February 11th, 2003, 02:43 AM

The exact answer isn't very important, really. That can be found with a calculator quite easily.

Andr�s

February 11th, 2003, 05:33 AM

SE4 standard years have 10 months * 30 days = 300 days
Obviously they are based on the orbital period of Malfadoris Proper (homeworld of the Malfadorian) and on the insignificant Terran homeworld.

[ February 11, 2003, 03:34: Message edited by: Andr&eacutes Lescano ]

Aloofi

February 11th, 2003, 04:49 PM

Originally posted by oleg:
Another argument: tanks have sloped armour not because of the air drag but because of a chance to reflect shells. Surely, it would be a nice bonus if your ship can ricochet lasers or DUC shells ! http://forum.shrapnelgames.com/images/icons/icon7.gif [/QB]Dam, I thought the sloped armour in tanks were for the air drag..........

Aloofi

February 11th, 2003, 05:19 PM

Originally posted by oleg:
You are completely wrong. The SE speed of light has been estimated before :

According to these canon opuses, on average SE ships move at 1-3 % c. It is also mean that maximum ship speed can be even higher. For example, we can assume that combat speed, which is twice faster than "strategic" speed is in fact the max. speed. Then it can be as high as 0.05c !

[/QB]Redoing my numbers:
Year=300 days (10Months of 30 days)

Crossing a system in two turns (60 days)

2000 Km/sec or 0.66% of c, not 3%

.

dogscoff

February 11th, 2003, 05:31 PM

Redoing my numbers:
Year=300 days (10Months of 30 days)

Crossing a system in two turns (60 days)

2000 Km/sec or 0.66% of c, not 3%
This is just the average speed though - there ought to be accelleration and decelleration factored into that (even though SE4 ships can change direction completely mid-journey without any apparent need to slow down).

Stone Mill

February 12th, 2003, 12:34 AM

I hate to bust into a discussion where I clearly don't belong, but...

To Wong Foo, Thanks for
Everything! Julie Newmar

http://forum.shrapnelgames.com/images/icons/icon10.gif http://forum.shrapnelgames.com/images/icons/tongue.gif Couldn't resist.

oleg

February 12th, 2003, 12:39 AM

Originally posted by Aloofim:
<blockquote>quote:<hr />Originally posted by oleg:
Another argument: tanks have sloped armour not because of the air drag but because of a chance to reflect shells. Surely, it would be a nice bonus if your ship can ricochet lasers or DUC shells ! http://forum.shrapnelgames.com/images/icons/icon7.gif Dam, I thought the sloped armour in tanks were for the air drag..........[/QB]<hr /></blockquote>Well, some Lotuses and Lamboardginy(sp.) do look like a very pressed down tanks http://forum.shrapnelgames.com/images/icons/icon7.gif

[ September 04, 2003, 23:53: Message edited by: oleg ]

oleg

February 12th, 2003, 02:26 AM

Originally posted by Aloofim:
<blockquote>quote:<hr />Originally posted by oleg:
But first they must accelerate to that speed, right ? That means to make the trip in time, the peak velocity would be much higher than apparent _average_ velocity.There is a big diference between 625 Km/sec and 300 000 Km/sec.......
Ships in SE4 are traveling at 1/480s of light's speed. http://forum.shrapnelgames.com/images/icons/icon10.gif [/QB]<hr /></blockquote>You are completely wrong. The SE speed of light has been estimated before :
http://www.shrapnelgames.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=23;t=008034#000003

and here:

http://www.shrapnelgames.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=23;t=007281;p=4

According to these canon opuses, on average SE ships move at 1-3 % c. It is also mean that maximum ship speed can be even higher. For example, we can assume that combat speed, which is twice faster than "strategic" speed is in fact the max. speed. Then it can be as high as 0.05c !
Now, the battle usually takes place around planet.
Obviously, matter density between Earth and Moon is much higher than between Sun and Epsilon Eridani.Now I'm pretty convinced that at max. battle speed SE warships can easily get a measurable resistance. Hence, sleek and aerodynamic ships should get an advantage !

Another argument: tanks have sloped armour not because of the air drag but because of a chance to reflect shells. Surely, it would be a nice bonus if your ship can ricochet lasers or DUC shells ! http://forum.shrapnelgames.com/images/icons/icon7.gif

Aloofi

February 13th, 2003, 04:48 PM

One thing its clear, combat turns are definitively not days. I mean, a ship can only fire its guns once a day? and needs 3 days to reload its CSM launching tubes?
And how come you can fight with the same ships several times in the same sector during the same game turn using the full 30 combat turns?
So I belive a combat turn its less than an hour, probably a minute. Yes, a 30 minutes space combat make sense, and firing Meson BLasters every minute, and reloading the CSM in 3 minutes.
Now, that brings up of course that the combat map its not exactly a sector from the main map, but just the fraction from the sector where the 2 fleets meet.
About planet size, you have to assume that its been scale up for easy recognition on the map.
Now it all make sense...... http://forum.shrapnelgames.com/images/icons/icon10.gif http://forum.shrapnelgames.com/images/icons/tongue.gif

Suicide Junkie

February 13th, 2003, 05:01 PM

This is just the average speed though - there ought to be accelleration and decelleration factored into that (even though SE4 ships can change direction completely mid-journey without any apparent need to slow down).If you take the ships a undergoing constant acceleration, you'd have the peak speed being twice the average speed.

However, problems start as soon as you include acceleration, since SE4 movement does not model acceleration at all.