2300 starship power plants and other issues

[Murph]

I have a real issue with fuel cells being used to power a starship. I just don't see the power being available to develop and maintain FTL speeds.

Also the same goes for MHD turbines. What about exhaust gasses, heat generation, and size of the turbine(s)?

Fission and fusion seem to be the only viable (other than antimatter), that can potentially generate enough energy to activate the ships drive.

Anyone more versed in the physics of the thing care to comment?

 

[Erik Boielle]

The whole stutterwarp thing is more than enough of a plot device that you can say it runs on a warm cup of tea and a fairy cake with nothing to say your wrong other than personal preference.

From what I've seen of vaguely science based ftl schemes, manipulation of enough energy to tow all of the planets of the solar system around with gay abandon would appear indicated, so to my mind a piddling 150 mw fusion plant also seems a little wussy.

Do whatever you like, man.

I like the idea of conventional submarines in space, YMMV.

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Actually, I was kinda thinking of replacing the tantalum coil thingy with a quantum black hole, just cause I like the idea of dragging those things around, and relying on magic black holes seems better than relying on magic crystals, ifn you take my meaning.

 

[Colin]

2300 breaks the known laws of physics rather handily with the stutterwarp drive. Once you accept that, though, everything else flows from there. Basically, in the game, stutterwarp works, at these power levels. Therefore, a fuel cell or MHD turbine is sufficient to power it.
Realistic? Only if you accept the stutterwarp. If you don't, the whole thing goes out the window anyway. If you do, then your set. If you would prefer, IY23U, to have all ships powered by fusion or fission plants, then do so. Myself, I like the idea of a PC ship where they don't have to have a large enginering crew of nuclear engineers. (Of course, if they did, I could have a safety technician by the name of H. Simpson. But I digress.)

Thanks.

Colin

 

[aramis]

Any plant which involves waste gasses wan operate simply by choking down the exhaust path such that the exterior vaccum doesn't draw it fast enough to prevent combustion. No problem there.

MHD Turbines and Fuel Cells easily CAN be used for spacecraft. Just remember, tho, that the fuel is 8x the mass of fuel for an air breather of same output.

The Power levels are not terribly far out of whack... except for energy requirements for the stutterwarp.

I've always assumed that SW draws some energy from a dimensional interphase at a microscopic level...

 

[BMonnery]

Originally posted by Murph:
I have a real issue with fuel cells being used to power a starship. I just don't see the power being available to develop and maintain FTL speeds.

Also the same goes for MHD turbines. What about exhaust gasses, heat generation, and size of the turbine(s)?

Fission and fusion seem to be the only viable (other than antimatter), that can potentially generate enough energy to activate the ships drive.

Anyone more versed in the physics of the thing care to comment?

Compare the power outputs of IRL wet navy ships to 2300 and Traveller ships. A Suffren class Cruiser produces more power than USS Nimitz ( http://www.geocities.com/littlegreenmen.geo/MW.htm ).

This is perhaps more realistic, as getting rid of waste heat is a real problem. Even with the entire hull radiating, a Kennedy needs to be about 1000 degrees C or so to dump that puny 150MW. Traveller type ships with GW outputs would IRL quickly vapourise themselves as spacecraft can only radiate heat away, there is no medium for convection or conduction.

2300 MHD plants are quite oversized (as are plants in general) but remember, the "power plant" also covers the maneuver drive systems, cooling systems and a plethora of other abstracts. Using some common sense (i.e. allowing the drive to be throttled back without penalty) and using solar panels, MHD powered ships can achieve reasonable endurance, although they'll never be fast. See below for an example of a small MHD warship based on an SSK which be reasonable mount 4-6 month patrols.

As for how much energy is required to drive stutterwarps, it's one of the great unknowns. IRL physics has only just provided a "real" explantion as to why tantalum can be used only in drives and what the effects of going further than 7.7ly are (and the fact that only 1 part in 8,300 of tantalum is useful for drive engines).

Bryn

British Leander Class Patrol Cruiser (Frigate)

The Leander is the current “Frigate” type vessel operated by the RSN, and has replaced most other classes in the RSN inventory. It’s British designation is “Patrol Cruiser”, a statement of function rather than size, the British designate the larger “Destroyers” as “Fleet Cruisers”, while “Missile Cruisers” are designated as “Fleet Battle Ships”. The PC is a scaled down, conventionally powered version of the Fleet Cruiser. It’s role is to act independently of the Battleline, providing support and defence for non-combat elements, and patrolling independently.

In many ways, PC’s have an advantage over FC’s as they do not have fusion cores, and so can reduce their emissions by throttling back the turbines, and producing less waste heat. While cruising, it is normal to run the plant at ¼ power (1MW), lowering signature and providing for extended patrol times. While insystem often the turbine will be shut down, and the vessel will run on solar, with an extremely low effective radiated signature (-3). In battle, the Turbines are deployed to full power, and the stutterwarp and lasers both powered up. Like many small warships, the Leander has a power shortfall, and the lasers and active scanners cannot be run simultaneously, however, since the active array is for long range detection between 10 spacials, and the lasers provide close protection only out to one special, this is not a real problem.

Close protection is provided by 2 modern laser turrets, backed up by a Gallowglas launcher. Offensive power is provided by 4 Longbow missiles, with provision for carrying an external pack in time of war with another 4 missiles. Detection is provided by a full long range military suite, giving some early warning of hostiles and a fairly modern tactical suite, although slightly behind the larger fleet cruisers and battle ships.

The hull is armoured to modern standards and is a basic cylinder 12m across and 25m long. It also has a external landing pad/ magnetic sling capable of embarking a spaceplane, drone or fighter, although there are no maintenance facilities onboard.

Typically, vessels of this type need to call in to refuel every 16 weeks, which limits their patrol times but since most fusion vessels will call in as frequently, this is not a problem. Usually they will rendezvous with a tanker and take on fuel and supplies. Like most ships, she carries no spares for the ordnance (it is a waste not having them in the launcher if needed) and she carries only a small supply of missiles so after contact with the enemy, she must withdraw to rearm.

Proposed in light of the Kafer War is a 13 Million per unit refit, involving upgrading the stutterwarp and passive array, but the increase in fighting potential will be minimal, and this has not been adopted.

Design Date: 2283
First Example Laid Down: 2283
First Example Completed: 2284
Fleets in Service: Britain, Canada
Number in Service: 18 in RSN service, one commissioning every year

Streamlining: As Spaceplane

Performance
Warp efficiency: 1.76 (1.40 in cruise mode)
Power Plant: 4 MW MHD Turbines with thrusters
Fuel: 800 tons (8 weeks cruising, 4 weeks high speed cruising, 2 weeks combat)
Range: 7.7 light years
Endurance:
Mass: 1,507 tons
Cargo Capacity: Negligible
Crew: 40 (14 Bridge, 8 TAC, 6 Engineering, 8 troops, 4 stewards, 2 medical); Passengers: none
Comfort: 0;
Emergency Power: 1 week
Total Life Support: 40 for 180 days
Cost: MLv30.93 without ordnance (including multiple TC and paying for streamlining and workstations)

Ship Status Sheet
Move: 4
Screens: 0
Radiated Signature: 1(4) (-2(1) while cruising)
Radial Reflected: 3
Lateral Reflected: 4
Target Computers: +2;
Radial Profile: -2
Lateral Profile: -1
Armour: 4
Hull hits: 20/10/5 (80 by CSC)
Power Plant Hits: 16/4
Active: 10
Passive: 10
Other: 2MW Solar Array

Weapons
2 x1+1 lasers in masked turrets (1238, 4567)
1 Gallowglas close defence launcher (6 shots, 5x1 warhead)

Ordnance Load
4 Longbow missiles in single bays

Sensors and Electronics:
Phased Active-10
Spherical Passive-10
Navigation Radar
DSS
Gravitational
2 Fire Control Radars (TTAs)

Crew Hits:
Bridge: Captain, Navigator, Helm, 2 Communications, 2 Computer
TAC: 2 Fire Control, 4 Remote Pilot, Active Operator, Passive Operator

Damage Control: 18 (3 Engineers, 7 Unused Bridge Crew and 8 Marines)

Notes

I’ve tried to produce the best small combatant I could given the limitations. I was inspired by thinking of her as an SSK to the Fleet Cruisers SSN, and maybe Oberon is a better name. A smaller version was considered, using a 1MW NM drive instead of the 2MW OM drive, but there was a drop in performance, an increase in cost and no real benefits (better profiles for example). FWIW, the mass of missiles is roughly the same mass as the total weapons load of a Trafalgar SSN…

(14 Bridge, 8 TAC, 6 Engineering, 8 troops, 4 stewards, 2 medical);

 

[Erik Boielle]

>>This is perhaps more realistic, as getting rid of waste heat is a real problem. Even with the entire hull radiating, a Kennedy needs to be about 1000 degrees C or so to dump that puny 150MW. Traveller type ships with GW outputs would IRL quickly vaporise themselves as spacecraft can only radiate heat away, there is no medium for convection or conduction.<<

You are well within your rights to say that all of that is just dissipated back in to the zero point energy of the universe through the stutterwarp though.

If you like the combat system better that way.

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Seen this?

http://dark.unitz.ca/~nemtos/theory.htm

That there kennedy merely* needs a couple of 40 meter square 1000k radiators. And the emitted energy goes up with the cube of temperature, or something like that, so if you can run hotter you need less area.

Although getting your waste heat concentrated and up to 5000K and conducted out to the carbon radiators is apparently a challenge.

I keep thinking that directional radiation is the way ahead for stealth ships. Thats what EMM does, I guess, but I'm not sure how easy it is.

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And that fully expends my knowledge gained by reading 'The Bluffers Guide to Heat Management in High Powered Spacecraft'

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One of the nicer images I've heard for TS is some droplet radiators

http://www.engr.psu.edu/antimatter/Papers/ICAN.pdf

made out of smart materials (materials incorporating little, er, machines that allow it to change shape) so the masts can bend as a ship rotates or changes direction, so the ship can turn without spilling any coolant.

Although thinking about it, I guess you could spin the drive and leave the radiators alone, since a stutterwarp ship doesn't need to realign them, not actually moving or anything.

*I highly recommend Transhuman Space for the opportunity to say things like 'a mere 7 terawatts'

 

[BMonnery]

Originally posted by Erik Boielle:
>>This is perhaps more realistic, as getting rid of waste heat is a real problem. Even with the entire hull radiating, a Kennedy needs to be about 1000 degrees C or so to dump that puny 150MW. Traveller type ships with GW outputs would IRL quickly vaporise themselves as spacecraft can only radiate heat away, there is no medium for convection or conduction.<<

You are well within your rights to say that all of that is just dissipated back in to the zero point energy of the universe through the stutterwarp though.

If you like the combat system better that way.

-----------

Seen this?

http://dark.unitz.ca/~nemtos/theory.htm

That there kennedy merely* needs a couple of 40 meter square 1000k radiators. And the emitted energy goes up with the cube of temperature, or something like that, so if you can run hotter you need less area.

Although getting your waste heat concentrated and up to 5000K and conducted out to the carbon radiators is apparently a challenge.

I keep thinking that directional radiation is the way ahead for stealth ships. Thats what EMM does, I guess, but I'm not sure how easy it is.

-----------

And that fully expends my knowledge gained by reading 'The Bluffers Guide to Heat Management in High Powered Spacecraft'

-----------

One of the nicer images I've heard for TS is some droplet radiators

http://www.engr.psu.edu/antimatter/Papers/ICAN.pdf

made out of smart materials (materials incorporating little, er, machines that allow it to change shape) so the masts can bend as a ship rotates or changes direction, so the ship can turn without spilling any coolant.

Although thinking about it, I guess you could spin the drive and leave the radiators alone, since a stutterwarp ship doesn't need to realign them, not actually moving or anything.

*I highly recommend Transhuman Space for the opportunity to say things like 'a mere 7 terawatts'

E = 5.67x10^-12 x A x T^4 (Stefan-Boltzman Law)

Where E is radiated energy in watts, A is area is square cm, and T is temp.

So, is we allow 1,800 square meters (the advanced masking area), or 1.8x10^7 cm2, 150 MW or 1.5x10^8 watts and rearrange

T^4 = 1.5x10^8/ (5.67x10^-12 * 1.8x10^7)

T = 1,101 Kelvin (828 Celcius)

This assumes an exceptionally efficient fusion plant and relays (50%) and that all the used energy is the stutterwarp goes elsewhere (probably a cloud of excited hydrogen). It also assumes space is absolute zero (it's about 3K ISTR in deep space, more closer to suns).

The Kennedy will thus radiate upto:

2.897x10^6/T (Weins Displacement Law)
= 0.54 nm

ISTR Some of the big THS ships should radiate X-Rays or the like. They aren't truely feasible. Trying to explain 2300AD 150MW fusers is hard enough without having square km radiator panels....

Bryn

 

[Anthony]

For regular power plant radiators and waste heat elimination, THS radiator wings emit around 100 kW/m^2, for a temperature under 1200K. This pretty much assumes that most of the waste heat for the drive is eliminated in a way other than through the radiator wings, however.

THS ship performance may be on the edge of possible, though it's at least an order of magnitude higher power density than is particularly plausible.

 

[Erik Boielle]

Originally posted by Anthony:
For regular power plant radiators and waste heat elimination, THS radiator wings emit around 100 kW/m^2, for a temperature under 1200K. This pretty much assumes that most of the waste heat for the drive is eliminated in a way other than through the radiator wings, however.

THS ship performance may be on the edge of possible, though it's at least an order of magnitude higher power density than is particularly plausible.

The favorite theory, I understand, is that the cage thingy at the back is made of graphite and operating at 3500K, from which, with a few guesses you can guess how far the superconducting magnetic nozzle needs to be from the, er, ignition point so it radiates at the same rate it takes in.

So the big wings dump energy from other souces.

So you should get these massive glowing cages like 50' in diameter for pretty small drives.

Course, theres a small star in the middle of them, so you can't see them, at least when the drive is operating, but anyway.

But the likly one or two order of magnitude mark up on accelerations just isn't talked about.

On pain of torture.

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Someone was talking about getting whole G's worth of acceleration out of seriously honking big solar sails made out of seriously advanced nanofabricated materials the other day.

Disturbing, I thought.

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So the question you need to ask yourself is, do you like your ships hot?

I feel that since you are adding a stutterwarp to move your ships, a little bit of twiddling with it to make sure they can hide is so useful for story purposes that the oppertunity should not be missed.

I have vague impressions that hiding a ship at 1000K is pretty impossible to hide in something as small as a solar system, and thats no damn fun.

So, to my mind, the stutterwarp, remarkably, operates at near absolute zero, even when surrounding a big assed fusion plant and having vast ammounts of pressure applied to them by the Busman/Halibut/Phiggins array.

Must be the magic crystals.

 

[Anthony]

Actually, without a reaction drive, and at the speeds of stutterwarp ships, hiding may be tactically relevant. A 1 megawatt source, at 1 AU, has an apparent magnitude of about 25, and given that it is likely to be spread across multiple pixels and thus make signal integration very difficult, is probably not detectable at those ranges. Reliable detection ranges are probably on the order of 1-10 light-seconds * sqrt(megawatts).

 

[Erik Boielle]

A mere 36,000,000 kilometers for a kennedy?

Well thats alright then

 

[BMonnery]

Originally posted by Anthony:
Actually, without a reaction drive, and at the speeds of stutterwarp ships, hiding may be tactically relevant. A 1 megawatt source, at 1 AU, has an apparent magnitude of about 25, and given that it is likely to be spread across multiple pixels and thus make signal integration very difficult, is probably not detectable at those ranges. Reliable detection ranges are probably on the order of 1-10 light-seconds * sqrt(megawatts).

Although the survey sensors confuse the issue, the combat system is clear. "Black Globe" Range (i.e. you can tell there's a contact) is 30 hexes, which is 1 light minute using the classic scale (the scale is broken, I use the classic scale but up turn length to 20 mins to fit Trav stuff, Kevin Clark truncates the hex to 0.1ls).

For the Kennedy, that would fit 5xsqrt(MW), assuming the very high 50% efficency again.

My personal take on operations given these restraints is here: http://www.geocities.com/Area51/9292/2300/BG2k3.htm

I know some people (Kevin Clark) have the Grav Scanner as an "all seeing eye", and that any vessel entering a system is instantly tracked, but this removes an finesse IMHO.

Bryn