Designing a spaceship (detailing - pg 6)

A spaceship is a popular subject to model,so I decided to create a battleship. It won’t be a truly realistic design, as those build nowadays are boring, but a sci-fi one, but without any ultimate gadgets. I consider it “quarter-realistic”.

First of all, a basic environment and strategy description. I don’t think that the future space battles (if any will be) will resemble something seen by now. The space is insanely huge and the speeds at which anything flies in space are also very high. This makes the spacecrafts very expensive, because of high-end technology needed to produce them. Also, the ship itself is a weapon capable of destroying entire countries on planets. The terrible destruction power will make them similar to nuclear weapons, but many times stronger. So instead of dramatic battles like in movies, I think there won’t be almost any, or only against much weaker opponents.

Now to the ship itself. A huge, with mass of 70 000 tons monster is a good way to demonstrate the power of a country. Being 360m long and high (with radiators extended), mainly to store large amounts of propellant to enable her to get anywhere on solar system, she is one of the largest combat ships. The shape has evolved from Mothership from Homeworld 2, but now it far from original. With small cross section from front, which is also the only armoured part it is supposed to always face the enemy. Although it might not be possible to accelerate during this maneuver it is the best to position to defend because the of the small angle between the enemy and armour plates.

Powered by a fusion reactor with total output of about 400 GW (and efficiency about 80%, which is a bit too high) she is a threat, even unarmed. With armament of 20 missiles with multiple nuclear warheads, a big laser and few kinetic cannons in a main turret, she can easily defeat any opponent. For defence, there is a number of small lasers and effective space machineguns.

Carrying 32 000 tons of liquid hydrogen, she has maximum delta v of about 400 km/s, but to accelerate to this speed, about 10 months are needed. The exhaust velocity of 700 km/s means a good fuel economy.

The majority of crew are officers, because of high level of automation. The battleship doubles as command and flag ship.

Any comments or suggestions for improvement are welcome, as well as critics. Also discussion about possible space colonization, war and everything similar. I hope, I will start the actual model soon.

Here are two drafts how the ship looks:
http://img235.imageshack.us/img235/9493/dscf8758croprr3.th.jpg
http://img171.imageshack.us/img171/3176/dscf8761cropju8.th.jpg

I’m looking forward to see how this is going to come along :-b
great project ! and some nice drawings :smiley:
Are you making an animation or just a still ?

Looks a lot like this http://i181.photobucket.com/albums/x138/Vanaleto/warcruiser_sharlin.jpg

From Babylon 5 TV series (that one is just some version of it made by someone)

Yes, I check you on your mathematics. I figure it has a mass ratio of about 1.84, and a maximum delta V of 426 km/s or so. This checks with your “about 400 km/s”

Ten months (26,297,430 seconds) means it has an acceleration of around 0.015 m/s^2 (about a thousandth of a g). If the ship is 70,000 metric tons, this means the engines are cranking out about 1,050,000 newtons. Looks like three or four fusion engines to me.

Good work!

if you were going for a cartoony look on your sketches, good work…however, if you want it to be realistic, you should make it a little longer, add windows…ect

i love the stats…i wish all ships had stats so we could have like huge ship battles.

good luck with the model :smiley:
Blah

Thanks Nyrath for your website, it was the main source of information. Excelent one.
I think exact figures aren’t necessary, as it is basic design and this always differs from reality.

iliketosayblah:
I wasn’t going for cartoon, it was quickly done. Now I’m reworking the drawings to be more realistic, with more details. The design has yet passed trough several iterations and more will come. Also few schematics of inner structure and layout are done, again, working on newer.

I don’t think windows are realistic for spaceships. First, there is some radiation around Earth and some other planets (because of magnetic field they generate that protect the surface from space and sun’s radiation). Also having them in armour plates isn’t the best way to ensure best defence. Furthermore, the crew compartment will be about 2-8 from the surface to protect the crew from being burned, or fatally irradiated by close nuclear explosion and to have enough space for stopping kinetic projectiles and holes in pressurized compartments. But certainly, some windows are vital for looking at stars, planets and crew not go crazy from being locked inside for years.

Don’t know, but longer ship needs heavier construction and it is a bigger target, but there are other benefits. I like the shape it has now, in space the the body doesn’t need to be aerodynamic (longer bodies have lesser drag in some cases).

I have more figures (some have been mentioned already) for the interested:

  • exhaust velocity 700 km/s
  • 1200 g of propellant per second
  • 840 kN thrust
  • acceleration 0,012 m/s (fully loaded)
  • 70 000 t (full)
  • 32 000 t (propellant)
  • 8 000 t (crew + supplies + operational stuff, a.k.a. coolants, various gasses, spare parts + 2 shuttles)
  • 3 000 t (weapons)
  • 10 000 t (engines + reactor + radiation shielding)
  • 12 000 t (hull + machinery + equipment of ship)
  • 5 000 t (tanks, can be considered partly as hull)
  • 2 000 000 cubic m (upper limit for total volume, a very wild guess, better about 2/3 to 3/4 of this)
  • min 450 000 cubic m (liquid hydrogen + some more for boiled from cooling some parts)
  • 100 000 cubic m (crew compartment, they should have enough space + additional for supplies)There will be a gap between the outer and inner hull as a part of armour. The material considered by now are metals and composites for armour and main frame and composites for the rest of hull. Plastics can be used for the less stressed components.

But I also have some questions…
The reactor is fusion, so it needs quite some energy to start and to operate. So now, I think 400 GW isn’t too much, 300 GJ being the energy needed to push 1200 grams of propellant each second at 700 km/s. Plus, the amount to power the equipment, keep all the hydrogen liquid, and after combat to charge the supply of energy for weapons, and other minor things, one of which is the waste heat (although the waste heat from propulsion can be used to generate electricity in ordinary way using steam turbines). Do you think 400 GW is enough, with 75% of this flying out?

What system to use for attitude engines? Because years of maneuvering in space with ineffective engines would result in big fraction of fuel/propellant being burned for spinning around. Do you thing some pulse engines, where a little amount of hydrogen is pumped into a cavity and quickly heated into hot plasma using lasers is good one?

That’s all for now, thanks for help.

hmm…windows on a ship thousands of years into the future…yes…this point has been raised many times…

i guess at that point in time they are not going to use glass but a super radiation resistant, hard to break material.

I don’t know, but radiation resistant window is thick and heavy, although this depends of the radiation it has to stop. Also, there are some engineering, technical and economic difficulties with windows. You need to make them as hard as the surface around it, otherwise it is a weak point. Window doesn’t make sense if you can be 2 meters from it and it is small. It is surely cheaper to produce a single metallic plate, than produce it, cut a hole into it, make the frame, the window and assemble it together. Have you ever wondered why on aircraft the windows are so small and have almost the same shape and round corners (some are bigger, the new planes have larger windows)? Or why navy ships have also only few?

Although there might be some solution like making a material and change its transparency locally, which a nice thing, but again, there should be people near the window, not far away. And at what would you look, while travelling few months from Earth to Mars?

BTW, there aren’t any windows in my drawings. But some will be, not many. I have leaved big volume for the crew, there are possibilities for windows.

P.S. What do you mean by glass? Organic glass isn’t used so often, instead for more than 80 years other materials are used, e.g. cellon or plexi glass and surely many other exist.

i said they wernet going to use glass :slight_smile:

Rather then relying on materials to fend off radiation, wouldn’t it be much cooler to have a magnetic field generator to bend the radiation away from your ship? Sure, visually it’d be boring as hell, but in terms of practicalty it’d be much more effective.

i like the way you think sandrew

sounds good, i think it should be a little less height-wise. (z-axis)
only thing is acceleration is m/s² (metres per second squared ), m/s is speed :slight_smile:

hope that helped :slight_smile:

//charlie

i do think that grebles would be useful in this design, but nothing like the Millennium Falcon, just some in certain spots.

also, regarding windows, what about plasma windows. they exist now, but r very tiny. and for ur sheilds, cold plasma could work, though u wont get the armoured feel.

speaking of that, when i think of a heavy duty battleship, i think of something big, and intimidating. ur ship, imo, would be better as a sort of shuttle from a bigger ship.

When I read this, I knew what was picking my mind all the time: Dory, from Nemo!
I do really not want to offense your with this thought, but it was just something I recognized.

Other than that, I think it’s gonna be a great ship, most ships (as far as I’ve seen them) were pretty mechanical lately, your one looks a bit more smoothed. Good luck!

Thanks for responses.

Sandrew:
What magnetic field generator? OK, if I remove the radiation shielding and add this, will the mass change? And, what is more important, how much energy the field generator needs? Moreover, if the magnetic field is strong enough to repel radiation, how will the electronics work inside, in very strong field? Plus, heavy materials can ablate when lasers are fired at them, or deflect projectiles made of some non-magnetic material or tiny asteroids or space trash.

charliemcf:
Why it should have less height? you can consider this as width or span, only the length will the same always (well, as long as people think the engines are on the other side than the nose and the ship doesn’t move to side). Shortening one dimension will also shrink the volume, and there are very large tanks needed.

Thanks for correction, but it’s far more easier to write this on paper.

zbirdboy:
I’m afraid that ionized gasses heeds some energy to stay in place, and are highly reactive. Again, nobody will be close to any window, except some crewmembers.

svenniemannie:
At least one person that thinks the ship resembles a giant fish. When I first draw something like this, I immediately though of this one: http://en.wikipedia.org/wiki/Pterophyllum

About the style, I really like a smooth shell which have gaps in some areas to enable to see the mechanical fundamentals of the artificial object.

Well, I have some new drawings. If you are interested in the first designs, here are they:
http://img509.imageshack.us/img509/3289/dscf8763cropku4.th.jpg http://img341.imageshack.us/img341/2272/dscf8764cropds7.th.jpg http://img255.imageshack.us/img255/5995/dscf8765croptr9.th.jpg

And the newest are these:
http://img253.imageshack.us/img253/1545/dscf8766cropch9.th.jpg http://img404.imageshack.us/img404/9017/dscf8767cropjp0.th.jpg http://img214.imageshack.us/img214/1671/dscf8768croppx9.th.jpg
in the last, slice view, the red lines are the main structure.

So I’m awaiting your comments.

I’d suggest to stop calculating how long it would take to accelerate to 400 km/s and start modeling, especially since you

consider it “quarter-realistic”
.

btw, really nice design :smiley:

i totally agree with BonE, do less thinking and more building! :wink:

If I start modelling now, it would be just waste of time, because the shape changes. What is more important, as the base mesh will be subsurfed, I need to know where to place edgeloops to preserve smooth surface. Although inventing new things and refining the design on the fly is good method in some cases, sometimes it isn’t a good way to go (mainly the windows and other cut parts are most evil).

Though in reality, windows on spacecraft are highly over-rated. They are structural weak points on the hull, they let in radiation, and what exactly are you going to look at anyway? Black space?

TV and Movie SF aside, unless you are docking to another spacecraft, you will seldom approach another craft closer than several hundred kilometers. Even if you are engaged in ship-to-ship combat. You won’t be able to see the other ship without a telescope.