Realistic and strategic mod: modelling

[Jadel]

OK, I wanted to get that up just in case my browser died before I was finished.

Crew size.
This is constrained by a couple of factors.
*Large crews are a strain on resources. living space supplies and "wiggle room" all take up volume that could otherwise be used for more useful tasks.
*Crew are expensive and hard to replace.
*Crews that are too small will tend to "step on each others toes" over time.
*We will need a crew wherever independence of action is required.
*Computers are expensive but take up very little space, don't grouse or cause trouble.

Vessels escorting other warships don't need crews, but it may be useful to keep a small bridge and quarters onboard.
Vessels operating independently will need crews large enough to cover any manpower tasks that they encounter while away from base.
Fleets will have large crews, but only on command vessels.

Parasite clamp:
This is a clamp installed on an FTL capable vessel to allow it to carry a drone escort that has no FTL drive of it's own. Once in the target system the escort is released to operate independently.
Drone escorts are typically frigate or destroyer sized. They have no bridge and are designed to be repaired and serviced from outside the hull.


Vessel size:

Fighter
Crew: 1-2
Mass: 5-50 tons
Length: 5 - 40 M

Gunboat:
Crew: 2-4
Mass: 50-150 tons
Length: 40-70 M

Frigate / Destroyer:
Crew: None - 40
Mass: 1,000 - 4,000 tons
Length: 150 - 250 M

Cruiser
Crew: 10 - 300
Mass: 12,000 - 20,000 tons
Length: 200 - 400 M
Note: while cruisers can be run independently, this is not done in practice. When part of a fleet a cruiser will operate independently with it's own retinue of support craft.

Command (Heavy) Cruiser
Crew: 100 - 300
Mass: 15,000 - 30,000 tons
Length: 400 - 600 m
Note: Carries a flag bridge specifically designed for running a battle.

Battleship
Crew: 100-300
Mass: 30,000 - 80,000 tons
Length: 500 - 1000 M

Notes:
These figures are somewhat lighter than comparable wet navy vessels. I'm assuming that due to advanced material design they are somewhat lighter than there modern counterparts.
Battleships tend to be not as useful as might be thought. Although they are powerful units they are far too precious to risk. As such the decisive battles tend to be faught by smaller craft.

[Jadel]

More on drones.

To be reasonably useful I envisage drones as being semi-independent. They should be capable of plotting courses and intercepts without human intervention. The human input comes in decision making. What craft to intercept and attack, which sensor traces to investigate etc. As such light speed lag is not as important a factor as first might be thought, still drones should not be operated too far from there home craft.
Drones can be handed off from one craft to another if the appropriate codes are known. for this reason these codes are set within an fleet or other operational group and are not sent over open communication channels.
All communication is done over laser links using strong encryption.
Most drones are small, 1-5 M long, and massing 1 - 10 tons. the exception being nuclear and type III sensor drones both of which are about twice the size.


Gun drones
typically have fixed direct fire weaponry, turrets while not unknown add too much weight for normal use.

Light: short ranged gun, little armour, no stealth, no sensors, very maneouvorable, really cheap. Typically used by pirates, police forces or to distract defenses to give an opening for more capable craft.

Combat: Better though still short ranged weaponry, light armour, enough stealthing to fuzz sensors, short range (optical?) sensor suite. Standard combat drone, able to shrug off light hits and dodge heavier weapons. This still has a very limited lifespan at short range.

Stealth: Carries one shot very heavy weapon. excellent stealthing, slow, unmaneuverable. Depending on type this may carry a railgun or a bomb pumped x-ray laser. used to sneak up on an unwary opponent.

Heavy: Long range direct fire weapon, moderate stealth, moderate speed and maneuverability. Acts like a sniper or artillery unit. fires from long range and changes position after each shot.

Recon drones.
Used to find and locate targets for other ships and drones to prosecute.

Type I: very small (10cm cube) carries a camera, laser communicator and a simple passive sensor. can change orientation with flywheels but no thrusters to change direction. Literally fired out of the mouth of a cannon and considered very expendable.

Type II: about the size and configuration of a light gun drone, though with a smaller engine. Carry a more sophisticated sensor suite and come in either active or passive models. Higher end models are stealthed.

Type III: Basically a starship level suite packed in to a fighter hull. Definately *not* expendable. Very rare, very expensive and very capable.

Kamikaze:
essentially command guided missiles flown from a remote location. Come in three basic types.

Stealth: as the gun drone, but with an explosive warhead.

Nuclear: Nuclear warheads are not trusted to automated systems, therefore all nuclear missiles are command guided. Typically large, fast and well armoured with a yeild in the megaton range.

Kinetic: Small, with a very large engine and with either an armoured prow or a "grapeshot" made up of steel ball bearings spread by an explosive charge. Used to ram ships at high velocity.

[pincushionman]

I'm going to have to argue that the ships will be heavier than their marine counterparts.

Let's look at a couple of real ships first: Compare the Seawolf (submarine, 353x40 ft, 9137 ton, 116 aboard) with the Valdez (frigate, 437x47 ft, 4167 tons, 275 aboard). As you can see, the submarine, while being significantly smaller and carrying less than half the crew, weighs more than twice as much as the frigate.

Much of this weight comes from the fact that the hull of the submarine is pressurized, as will be the hull of any space vessel. A marine surface ship's deck doesn't need to be enlcosed, and the hull doesn't even need to be completely watertight; a bilge pump can make up for that. A spaceship needs to be competely enclosed, airtight, and pressurized, and while the hull of the spaceship may be in tension (high pressure inside, low out) rather than the submarine's compression (low inside pressure, high out), the hull weight is still going to be pretty significant.

If you want any kind of maneuverability at all, you're going to be dealing with pretty significant forces applied to the spaceframe of the ship, directed in six degrees of freedom, more than any marine vessel could ever withstand, and most of the force on a ship is directed down or up. The load-bearing structure of the spaceship will have to be relatively large and thick as well, to prevent structural members from buckling under the stress applied by the engines.

And engines -- the engines on the spaceship will have to power not only the thrusters, but the energy weapons and the shield systems as well, so it will probably be a larger percentage of the ship's mass than the same powerplant on a marine vessel. And if your powerplant will produce gamma rays (I don't know if anyone has talked about antimatter or not) you will need an ungodly amount of radiation shielding.

As for "advanced materials," don't count on too much in that department. Materials engineers have become very good at making the elastic properties of various metal alloys, but we can't do very much to change the yield or ultimate strength of metals - and in the kind of applications we're talking about here, that's the kind of strength that counts. And don't just say "well, this will be hundreds of years from now, so we can count on good advances," we've ALREADY been doing this for thousands of years.

Oh, you can use composites, but you lose out big in several areas:

Composites cost a lot more than metal. Not only are the raw materials more costly to procure and the production methods are too, the material itself has to be engineered for a particular application.

Composites don't do well in thermal or electrical conductivity. Hit a steel plate with a laser, you'll spread heat around quite a bit. Enough energy and you will get a clean hole or cut; the composite material will just burn. You CAN NOT use them for engine components, and engines are usually the heaviest items on an aircraft, reactors are easily the largest components on a ship.

When a metal part is damaged, you can usually bang out the dents or weld metal in to the correct shape and nearly the same strength as before. If a composite part is damaged, it won't dent, it will usually fracture, so you have to either replace the part or patch it. Composite patches aren't near as strong as the original part, and since composite parts are made to do the job of sevaral metal parts and their associated fasteners (i.e. the whole wing spar is one piece - if you don't do that, you achieve no real weight savings at all) cost for replacement goes up big time. And you need special tools and facilities to properly work with composites. With metal you need hammers, wrenches, screwdrivers, and maybe arc welders and plasma cutters. Those are small, easy to come by, and easy to use.

Composites also disintegrate under ultraviolet radiation. Lots of that in space.

Of course I can't see the future, but I believe any starship is going to end up being heavier than a marine vessel of comparable size and crew. That is the opinion of the structural engineer.

-pincushionman

[Jadel]

Of course I can't see the future, but I believe any starship is going to end up being heavier than a marine vessel of comparable size and crew. That is the opinion of the structural engineer.

Fair enough. I'm electronic myself, so this is definately your field. Can you come up with some better figures?

[pincushionman]

I'll see what I can do, but I'd need to know what kind of maneuvers the ships would be expected to do and what kind of powerplants you're going to use. It may take a while for me to get around to it, but I'm going to ballpark it at roughly twice the mass (compared to a ship of the same length), but I think you can get away with 1.5x the mass and I'd believe it. Unless the ship is a lot wider than it is tall.

-pincushionman

[Jadel]

This is what I'm thinking of for power generation and propulsion.

reactor types:

Early
Fission (Gas cooled pebble bed?)
Inertial confinement Fusion. (tokamaks are probably not power dense enough)

Standard
Advanced Inertial confinement (small enough for fighters)
He3 fuel

Advanced
Zero point energy


Propulsion:

Early
Chemical, hydrogen and oxygen for small craft
Thermal (vaporization of working fluid) with hydrogen for large.
Stutterwarp available on large craft

Standard
Thermal with hydrogen or water as propellent standard on all craft
Stutterwarp available on all craft

Advanced
Thermal for small craft.
Photon rection drive for large (no reaction mass required)

[DiGuru]

FlyingAce, your designs are great! Could you make a whole range of ships?

But I think you should think some more about the functions of the parts. And you should flip the cones, as they are supposed to be rocket engines.

But I think you are doing great, keep up the good work! When you are done with a whole fleet, you will probably want to redo your first designs, as you learned a lot, but (except for the cones), they are great as they are.

[DiGuru]

Jadel, I completely agree with your designations and classes. But I think it might be interesting to discuss acceleration versus nimbleness.

I agree, that only large ships (cruisers and upwards, probably destroyers as well) should have fast drives. But even if we only look at Newton, large ships will be a lot faster than small ones. Missiles will have a hard time closing in on large ships that run away.

But small ships have less inertia. They are more nimble. Fire a missile at a ship with a small vector away from you, and the missile can overtake it.

But there is no way for a small missile/fighter/ship to have the power plant and reaction mass (or whatever we need) to out-accelerate a large ship over time!

And don't fret about small ships like fighters. Small ships (missiles, fighters and whatever) are all drones, per definition, and expendable. There is no other way to do it if we want things to be more or less probable anyway.

[DiGuru]

pincushionman, great analysis!

I completely agree, I don't think that material science and engineering will advance very fast in the near future. We will probably do things better and there are some interesting ways to strenghten materials actively, by applying magnetic fields and such, but I don't see them protecting a whole spaceship.

Can you come up with some basic rules? That would be great!

[Jadel]

And don't fret about small ships like fighters. Small ships (missiles, fighters and whatever) are all drones, per definition, and expendable. There is no other way to do it if we want things to be more or less probable anyway.

At this stage I'm beginning to think that the smallest manned craft will be about 100m long and about 1500 tons, nothing smaller can carry the required armour and point defences. the designation Corvette has a nice ring to it.

[Jadel]

Warning Major fluff text zone ahead!








Name: Progress
Class: Light Cruiser (modular)
Tech Level: Early

Length:225m
Empty tonnage: 3700 tons
Fuel: 6300 tons
All up: 16300 tons
Engines: 3 x Lloyd Haskins 2200 series thermal fusion
Isp: 5000
Max Accell: 0.75 g
DeltaV: 18000 m/s
FTL Drive: Class 2 Stutterwarp generator, max 0.5c insystem.
Crew accomodations: 24 with carousel
Cargo: 300 tons internal. External clamp stressed to 6000 tons.
Complement: four repair drones.

The Progress class was the first modular design, able to carry an interchangable cargo container on a large clamp it was hailed as being a major advance. The flexibilty to reconfigure a craft from colony transport to freighter and carry entire prefabricated modules, combined with her engines - over twice as efficient as the earlier fission models - was seen as an revolution that would open up the universe to further colonisation.
Most people overlooked the fact that the Progress was grossly overpowered for a simple transport. Comments about it's heavy structure and apparent armour were brushed off with comments about robustness and service life, but the real secrets were hidden under hatches and removable panels, the progress was the first spacecraft in the hundred years of the human diaspora designed to hunt.

Notes:
The Progress has major balance problems, it's engines are very inefficient by modern standards and the large fuel tanks are mounted above the thrust line. The flight control computer is supposed to compensate by throttling the engines as required, but in practice the class was restricted to approximately 0.55g.
Control runs and interfaces for four point defence turrets were installed in the first six off the production line. From number seven on, no attempt at concealment was made and all weaponry was installed during construction.
The standard weapons module for the progress massed four thousand tons, and carried 120 X-Laser drones, and four 20 Megaton ground bombardment munitions, all conventionally powered.
The Fusion generators burn a mixture of deuterium and tritium resulting in the engine spaces being notably radioctive. As such all repairs and refurbishment is done by waldoes and drones.

OK, thoughts?

[DiGuru]

Super!!!

Great job, jarel! It sure inspires me to learn how to put some of my own designs into Wings!

Btw. What were you planning with the fast drives? How about limiting us to anything under C for the moment?

[DiGuru]

And don't fret about small ships like fighters. Small ships (missiles, fighters and whatever) are all drones, per definition, and expendable. There is no other way to do it if we want things to be more or less probable anyway.

At this stage I'm beginning to think that the smallest manned craft will be about 100m long and about 1500 tons, nothing smaller can carry the required armour and point defences. the designation Corvette has a nice ring to it.

Yes, a Corvette sounds very nice and promising. How would you do one?

[Ratbert_CP]

Just because I like to stir the pot...

Has anyone here played with gyroscopes?

Extrapolate that to a multi-ton spinning flywheel, and tell me what your manuverability will be like.

I *knew* reading "Bio of a Space Tyrant" would pay off some day...

[DiGuru]

Just because I like to stir the pot...

Has anyone here played with gyroscopes?

Extrapolate that to a multi-ton spinning flywheel, and tell me what your manuverability will be like.

I *knew* reading "Bio of a Space Tyrant" would pay off some day...

MKruer beat you to it to suggest two, counter-rotating ones.

But you are right. How would you design one?

[Ratbert_CP]

Just because I like to stir the pot...

Has anyone here played with gyroscopes?

Extrapolate that to a multi-ton spinning flywheel, and tell me what your manuverability will be like.

I *knew* reading "Bio of a Space Tyrant" would pay off some day...

MKruer beat you to it to suggest two, counter-rotating ones.

But you are right. How would you design one?

Hmmm... I would think that two, counter-rotating rings might counter out the natural precession(?) of the ships mass about an axis, but wouldn't you still be fighting some massive rotational inertia if you tried to turn? Also, wouldn't it work better to have about three rings, all rotating at 90 degrees to each other? I'm not an engineer, but I would think you might need something odd like that...

Also note that a spinning ship like that would provide one heck of a stable firing platform...

[DiGuru]

Just because I like to stir the pot...

Has anyone here played with gyroscopes?

Extrapolate that to a multi-ton spinning flywheel, and tell me what your manuverability will be like.

I *knew* reading "Bio of a Space Tyrant" would pay off some day...

MKruer beat you to it to suggest two, counter-rotating ones.

But you are right. How would you design one?

Hmmm... I would think that two, counter-rotating rings might counter out the natural precession(?) of the ships mass about an axis, but wouldn't you still be fighting some massive rotational inertia if you tried to turn? Also, wouldn't it work better to have about three rings, all rotating at 90 degrees to each other? I'm not an engineer, but I would think you might need something odd like that...

Also note that a spinning ship like that would provide one heck of a stable firing platform...

Yes. It would be really stable. And that would be very good. As it is very hard to hit a target about a lightsecond (300.000 kilometer) away.

And we can emulate the third axis by firing the enginges to compensate. That would probably be better for a spaceship than three interlocking rings at 90 degrees.

[Jadel]

Easy cheat, spin the rings down when you want to maneuver, they are too exposed anyway.
With counter rotating rings precession would still occur, but the reaction forces would tend to cancel each other out - at this point, you hope that your hull structure wsn't built by the lowest bidder.....

[Ratbert_CP]

Easy cheat, spin the rings down when you want to maneuver, they are too exposed anyway.
With counter rotating rings precession would still occur, but the reaction forces would tend to cancel each other out - at this point, you hope that your hull structure wsn't built by the lowest bidder.....

This is actually what (Piers) Anthony was theorizing in Bio of a Space Tyrant. His premise was that the ship would normally be spinning it's rings, but during combat, it would spin them down to maneuver. Then you have the trade-off of spinning them back up for stability, or leaving them still for agility...

The energy you bleed off from the spin-down can be captured to either re-spin the rings or for whatever other nefarious purposes you might envision.

[FlyingAce]

as for the cones, if they're rocket engines, why are they cones? shouldn't they be cylinders?

EDIT: aah I see what u mean. they are cylinders with one end circle scaled

[Jadel]

If you are referring to my model further up the thread, It should be pointed out that my artistic skills are somewhat lacking.
I have a Newer model that solves some of the gripes I have with this one, I'll post it a bit later.

edit: spelling looks bad too

[Jadel]

Name: Prometheus
Class: Heavy Cruiser (modular)
Tech Level: Early

Length:350m
Empty tonnage: 9,000 tons
Fuel:18,000 tons
All up: 40,000 tons

Engines: 4 x Lloyd Haskins 2200 series thermal fusion
Isp: 5000
Max Accell: 0.5 g
DeltaV: 30,000 m/s
Crew accomodations: 24 with carousel
Passengers: 24 with carousel
Cargo: 800 tons internal, four external clamps each stressed to 6000 tons.
Complement: four repair drones.

An attempt to fix some of the problems with the earlier Progress class the Prometheus was far more succesful than it's predecessors. It solved many of the mass distribution problems with the earlier design while retaining it's advantages in modularity over more classical layouts. As with the previous design it mainly utilised as a lightly armoured transport, but control runs and auxiliary systems were installed during construction to make it easy to convert to a warship should the need arise.

Going front to back, the sections are:
Crew area, systems and life support and important cargo.
Crew carousel
Passenger carousel
Cargo area - between one and four cargo pods can be installed in external clamps Delta V figures are calculated for a total of 12,000 tons of cargo.
Fuel tankage
Engine section

As with the previous design, the engine section is "hot" hence the seperation between that and the inhabted areas further forward.

[DiGuru]

Now, *THAT* is what I want to travel the solar system.

Drool....

EDIT: But I really want the front to be nothing but armor, I don't want my life support systems up there! Could you change the description? And make me one?

[FlyingAce]

who can I send my models to?

[DiGuru]

who can I send my models to?

Yes, good question. Who will stand up to incorporate them? We need someone to show them to us in Vega Strike, downloadable.