High Guard 3

[robject]

As an experiment, I retrofitted MegaTraveller's power plant rules to High Guard values. I also scaled them to be more starship-friendly, but I lost some data in the process -- because the original volumes were minimum sizes. I tossed that out with very little regret.

I also, in the name of non-gearheadedness, ruthlessly reduced most numbers to one (or at most two) significant digits. So the numbers are not exact. But they might be close enough.

Finally, it seems that the EP scale is off, perhaps by a factor of 100. Can anyone make a suggestion?


</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">TL Desc EP Mass Cr Tons t/hr
-- --------------- ---- ------- -------- -------- -------
5 IC 7 27 27k 0.01 0.8
6 IIC 5 14 27k 0.001 0.3
6 Nuclear Fission 3 22 270k 1 0.005
7 Gas Turbine 16 27 140k 0.01 1.0
8 MHD Turbine 10 14 140k 0.001 0.5
9 Fusion 3 5 270k 1 0.004
10 Fusion 14 28 1.4m 1 0.02
11 Fusion 25 50 2.7m 1 0.04
12 Fusion 100 220 1.1m 1 0.2
13 Fusion 250 250 1.8m 1 0.5
14 Fusion 400 400 2.7m 1 0.7
15 Fusion 900 300 3.0m 1 1.4
16 Fusion 1200 170 3.4m 1 1.7
17 Antimatter 8 0.1 8400 0.01 4
18 Antimatter 15 0.07 6800 0.001 7
19 Antimatter 70 0.1 14k 0.001 34
20 Antimatter 200 0.04 6800 0.0001 100
21 Antimatter 350 0.01 3400 0.00001 170

* Antimatter fuel consumption is in years, not hours.</pre>[/QUOTE]

 

[The Oz]

I'm still working through the numbers myself, but I can say that I've always thought the MT fuel consumption of fission reactors was way too high.

Does anyone know if any errata was ever published about that? I'd think that fission reactors would have their fuel consumption rated in kl/year (like antimatter plants) not in kl/hour.

 

[The Oz]

I'm still working through the numbers myself, but I can say that I've always thought the MT fuel consumption of fission reactors was way too high.

Does anyone know if any errata was ever published about that? I'd think that fission reactors would have their fuel consumption rated in kl/year (like antimatter plants) not in kl/hour.

 

[aramis]

The Official conversion (Striker AND MT) is 250 MW/EP
It is not a direct statement, but all the 1 EP HG weapons draw 250 MW, and the 2 EP weapons all draw 500MW.

 

[aramis]

The Official conversion (Striker AND MT) is 250 MW/EP
It is not a direct statement, but all the 1 EP HG weapons draw 250 MW, and the 2 EP weapons all draw 500MW.

 

[The Oz]

Well, I'm not going to try to work the numbers out for all of them, but I have wondered myself about trying to use fission powerplants with High Guard designs, so here's what I get for them.

In MT, 1 kl of TL6 fission plant gets you 1MW output. You also get an x2 output modifier for large-scale (greater than 50 kl volume) fission plants. So to generate 250MW (which equals 1 EP in High Guard) you need 125 units of fission plant, which take up 125 kl, or 9.26 dtons (at 13.5 kl per dton). This compares poorly to HG powerplants that even at their lowest TL require only 4 dtons per EP.

Then there's the fuel. Any HG powerplant needs 1 dton of fuel per EP per month of operation. MT says that fission plants need 0.002 kl of fuel per hour per 1 kl of powerplant. So running a 250MW plant (of 125kl volume) requires 0.25 kl/hour fuel, or put another way, 1 dton of fissionables will provide 250MW of power for 54 hours, or over 2 days. So getting 30 days endurance will require about 15 dtons of fuel, according to MT. This really looks bad.

I used to run nuclear reactors for the US Navy. I can tell you that fission plants do not burn up their fuel so fast. FFS gives fuel consumption for fission reactors in kl/year, which is much better. A FFS TL8 fission plant uses 0.1kl fuel/year/kl of reactor. I'm using the fuel consumption stats for the FFS TL-8 plant because it gives 1MW output per kl plant, just like the MT TL-6 plant. Using this fuel consumption, a 250MW fission plant needs 12.5kl/year of fissionables for fuel. That's close enough to 1 dton volume (13.5kl) to just go ahead and say that 1 dton of fuel gives one year endurance for 1 EP of fission plant.

So, an example.

A factor-2 powerplant for a jump-2, 2-G, 200-ton far trader at TL 11 would take up 12 dtons and require 4 dtons fuel for one month's operation. The powerplant generates 4 EP. The powerplant costs MCr36. The fuel tank is free.

A 4 EP fission plant takes up 37.04 dtons (a little more than 3 times as much) but 4 dtons of fissionable fuel would run that power plant for a year. The powerplant costs MCr50 plus MCr4.05 for the 4dtons of fuel.

That powerplant endurance is enough to make you wonder what a TL15 fission plant might be capable of. I would not let it generate the power per kiloliter of a fusion plant, but if the size came down a little (to around twice the size of a fusion plant of that TL) and the fuel endurance went up some more (say, to twice as much) you might find fission plants to be very useful for some applications.

It also makes me wonder if you could run a jump drive off a fission plant. I would say "No" for right now, since that would be a major change in how TRAVELLER ships are designed (no 10% of ship volume per jump number in jump fuel???) but if you were starting a new campaign with your own setting and wanted things to be different, this would do it.

 

[The Oz]

Well, I'm not going to try to work the numbers out for all of them, but I have wondered myself about trying to use fission powerplants with High Guard designs, so here's what I get for them.

In MT, 1 kl of TL6 fission plant gets you 1MW output. You also get an x2 output modifier for large-scale (greater than 50 kl volume) fission plants. So to generate 250MW (which equals 1 EP in High Guard) you need 125 units of fission plant, which take up 125 kl, or 9.26 dtons (at 13.5 kl per dton). This compares poorly to HG powerplants that even at their lowest TL require only 4 dtons per EP.

Then there's the fuel. Any HG powerplant needs 1 dton of fuel per EP per month of operation. MT says that fission plants need 0.002 kl of fuel per hour per 1 kl of powerplant. So running a 250MW plant (of 125kl volume) requires 0.25 kl/hour fuel, or put another way, 1 dton of fissionables will provide 250MW of power for 54 hours, or over 2 days. So getting 30 days endurance will require about 15 dtons of fuel, according to MT. This really looks bad.

I used to run nuclear reactors for the US Navy. I can tell you that fission plants do not burn up their fuel so fast. FFS gives fuel consumption for fission reactors in kl/year, which is much better. A FFS TL8 fission plant uses 0.1kl fuel/year/kl of reactor. I'm using the fuel consumption stats for the FFS TL-8 plant because it gives 1MW output per kl plant, just like the MT TL-6 plant. Using this fuel consumption, a 250MW fission plant needs 12.5kl/year of fissionables for fuel. That's close enough to 1 dton volume (13.5kl) to just go ahead and say that 1 dton of fuel gives one year endurance for 1 EP of fission plant.

So, an example.

A factor-2 powerplant for a jump-2, 2-G, 200-ton far trader at TL 11 would take up 12 dtons and require 4 dtons fuel for one month's operation. The powerplant generates 4 EP. The powerplant costs MCr36. The fuel tank is free.

A 4 EP fission plant takes up 37.04 dtons (a little more than 3 times as much) but 4 dtons of fissionable fuel would run that power plant for a year. The powerplant costs MCr50 plus MCr4.05 for the 4dtons of fuel.

That powerplant endurance is enough to make you wonder what a TL15 fission plant might be capable of. I would not let it generate the power per kiloliter of a fusion plant, but if the size came down a little (to around twice the size of a fusion plant of that TL) and the fuel endurance went up some more (say, to twice as much) you might find fission plants to be very useful for some applications.

It also makes me wonder if you could run a jump drive off a fission plant. I would say "No" for right now, since that would be a major change in how TRAVELLER ships are designed (no 10% of ship volume per jump number in jump fuel???) but if you were starting a new campaign with your own setting and wanted things to be different, this would do it.

 

[The Oz]

Here's my numbers for the rest of the MT powerplants in HG terms.

MEGATRAVELLER POWERPLANTS IN HIGH GUARD TERMS

What I've done here is to use the MT stats to calculate the size in dtons (13.5 kiloliters) of a 1 Energy Point (250MW) powerplant. I have also calculated the fuel consumption of that plant. For nuclear fission plants I used a fuel consumption figure from FFS of 0.100 kiloliters per year, which I feel is more accurate. The fuel per month figure is based on 720 hours in one month of 30 days. I used the scale efficiency modifers for all plants.
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Plant type Dtons/1 EP Fuel/hr Fuel/month
(dtons) (dtons)
Internal
Combustion 51.3 1.5 1080

Improved IC 30.9 0.77 554.4

Gas Turbine 20.6 0.82 590.4

MHD Turbine 15.4 0.54 388.8

Fission 9.3 ---- ---- 0.93 dtons/year

TL9-12 fusion 3.1 0.009 6.48

TL13-14 fusion 2.1 0.01 7.2

TL 15 fusion 1.03 0.009 6.48</pre>[/QUOTE]For comparison here are the equivalent powerplant figures from High Guard
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Plant type Dtons/1 EP Fuel/hr Fuel/month
(dtons) (dtons)

TL7-8 ????? 4 0.001 1

TL9-12 fusion 3 0.001 1

TL13-14 fusion 2 0.001 1

TL 15 fusion 1 0.001 1</pre>[/QUOTE]I'm not sure what type the HG TL7-8 powerplants are; fusion plants are not available until TL9.

They got the size of the fusion plants just about right; MT fusion reactors are just about the same size as HG plants. HG plants use a lot less fuel, however.

The HG TL7-8 plant is an anomaly; it's not as big as a fission plant, it uses fuel like a fusion plant but fusion isn't available at those TLs.

 

[The Oz]

Here's my numbers for the rest of the MT powerplants in HG terms.

MEGATRAVELLER POWERPLANTS IN HIGH GUARD TERMS

What I've done here is to use the MT stats to calculate the size in dtons (13.5 kiloliters) of a 1 Energy Point (250MW) powerplant. I have also calculated the fuel consumption of that plant. For nuclear fission plants I used a fuel consumption figure from FFS of 0.100 kiloliters per year, which I feel is more accurate. The fuel per month figure is based on 720 hours in one month of 30 days. I used the scale efficiency modifers for all plants.
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Plant type Dtons/1 EP Fuel/hr Fuel/month
(dtons) (dtons)
Internal
Combustion 51.3 1.5 1080

Improved IC 30.9 0.77 554.4

Gas Turbine 20.6 0.82 590.4

MHD Turbine 15.4 0.54 388.8

Fission 9.3 ---- ---- 0.93 dtons/year

TL9-12 fusion 3.1 0.009 6.48

TL13-14 fusion 2.1 0.01 7.2

TL 15 fusion 1.03 0.009 6.48</pre>[/QUOTE]For comparison here are the equivalent powerplant figures from High Guard
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Plant type Dtons/1 EP Fuel/hr Fuel/month
(dtons) (dtons)

TL7-8 ????? 4 0.001 1

TL9-12 fusion 3 0.001 1

TL13-14 fusion 2 0.001 1

TL 15 fusion 1 0.001 1</pre>[/QUOTE]I'm not sure what type the HG TL7-8 powerplants are; fusion plants are not available until TL9.

They got the size of the fusion plants just about right; MT fusion reactors are just about the same size as HG plants. HG plants use a lot less fuel, however.

The HG TL7-8 plant is an anomaly; it's not as big as a fission plant, it uses fuel like a fusion plant but fusion isn't available at those TLs.

 

[PVernon]

Did you know that over on the CT-Starship yahoo group someone did a MT to HG convertion. It is a folder in the files area labled "MT to HG".

 

[PVernon]

Did you know that over on the CT-Starship yahoo group someone did a MT to HG convertion. It is a folder in the files area labled "MT to HG".

 

[The Oz]

No, I didn't. I'll have to check their numbers out.

Thanks.

<<added later>>

I have checked those files out on the YahooGroups page and while it's good work, it does not cover what we're discussing here, which is converting the MT powerplants to HG terms.

I do like the idea of factor-A bay weapons, though.

 

[The Oz]

No, I didn't. I'll have to check their numbers out.

Thanks.

<<added later>>

I have checked those files out on the YahooGroups page and while it's good work, it does not cover what we're discussing here, which is converting the MT powerplants to HG terms.

I do like the idea of factor-A bay weapons, though.

 

[The Oz]

I have now developed HG-style and LBB#2-style powerplant tables for fission plants, including suggested TL improvements in fisson plants.

You would use this table just like the regular powerplant table in High Guard. Decide on the powerplant number (Pn) needed, multiply that times the percentage given at the TL of your ship, and you get the percentage of your ship needed for a Pn-factor powerplant.

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Fission Power Plant Table (percentage/factor-based)

Percent --------TL---------
times 7-9 10-12 13+
Pn 10% 6% 3%</pre>[/QUOTE]Cost is MCr1.35/dton. Fuel for 1 year of continuous full-power operation (good for 10 years of normal operation, I would suggest) costs 1MCr per EP produced. Fuel volume is included in the powerplant volume.

This second table is used if you want to go the other way, by deciding on how many EPs you need and then building a powerplant just that size. It will not create a strict HG ship design, and you would have to take the number of EPs generated and work the EP calculation in HG backwards to find an equivalent Pn-factor.

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Fission Power Plant Table (EP-based)
TL dtons/EP Cost/EP (MCr)
7-9 10 13.5
10-12 6 8.1
13+ 3 4.05</pre>[/QUOTE]Fuel for 1 year of continuous full-power operation (good for 10 years of normal operation, I would suggest) costs 1MCr per EP produced. Fuel volume is included in the powerplant volume.

I have also created a Book 2 table for fission power plants. I based this on my TL13+ fission plant values since they seemed to fit best with the other Book 2 drive values. I have rounded off costs to keep the math simple.
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Book 2 Fission Power Plants
Rating Mass Cost Fuel Cost
A 12 16 2
B 24 32 4
C 36 48 6
D 48 64 8
E 60 80 10
F 72 96 12
G 84 112 14
H 96 128 16
J 108 144 18
K 120 160 20
L 132 176 22
M 144 192 24
N 156 208 26
P 168 224 28
Q 180 240 30
R 192 256 32
S 204 272 34
T 216 288 36
U 228 304 38
V 240 320 40
W 252 336 42/50
X 264 352 44/60
Y 276 368 46/80
Z 288 384 48/120</pre>[/QUOTE]The costs are in MCr. Fuel cost is also equal to the EPs generated (for HG purposes). The values after the slash for the W to Z plants is the EPs they should be generating from their performance on the Book 2 drive tables. One "fill-up" of fuel should last the drive for 10 years of normal operation, I would suggest. Fuel volume is included in the powerplant volume.

If you want to be completely consistent with MT/FFS fission reactor fuel consumption, one "fill-up" of fuel should only last 1 year, whether in HG or Book 2. I think 10 years per "fill-up" is more accurate, at least for civilian ships. Military ships (which tend to run around using up power) might get only 5 years out of one "fill-up."

I have reconsidered and I would allow these powerplants to run a jump drive, without any need for hydrogen jump fuel. I've done the economics and it's not as favorable as you'd think; in fact, it's often worse. These powerplants do save you a lot of tonnage in jump fuel, but you pay for it with powerplants that are much larger and more expensive up front (from their larger size; they are cheaper per ton). A low-performance freighter built with a fission drive seems to cost 30-50% more than a fusion-powered ship, and only gains about 20-40% more cargo space. High-performance ships (like the Subsizided Liner) do better. A Type M with a fission plant gains 132 tons of payload although it does cost about MCr100 more.

It's the military who would like these powerplants, and they'd like them a lot, especially for starships (SDBs and battleriders don't gain from these powerplants, actually). A 50,000 dton, J-3, 6-G cruiser at TL-15 with a factor-10 fission plant gains 10,000 dtons to use for extra weapons or defenses. Higher factor powerplants would gain you less, but that's still a lot of tonnage. Fission-powered starships could be near equals in combat of fusion-powered battleriders. Add in the fact that fission-powered ships would not need to refuel every time they jump and would be free from the peril of the SDB-infested gas giant and fission-powered warships look pretty nice.

I don't think I would add fission plants to a campaign already under way, but I might just include these in a universe of my own creation.

 

[The Oz]

I have now developed HG-style and LBB#2-style powerplant tables for fission plants, including suggested TL improvements in fisson plants.

You would use this table just like the regular powerplant table in High Guard. Decide on the powerplant number (Pn) needed, multiply that times the percentage given at the TL of your ship, and you get the percentage of your ship needed for a Pn-factor powerplant.

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Fission Power Plant Table (percentage/factor-based)

Percent --------TL---------
times 7-9 10-12 13+
Pn 10% 6% 3%</pre>[/QUOTE]Cost is MCr1.35/dton. Fuel for 1 year of continuous full-power operation (good for 10 years of normal operation, I would suggest) costs 1MCr per EP produced. Fuel volume is included in the powerplant volume.

This second table is used if you want to go the other way, by deciding on how many EPs you need and then building a powerplant just that size. It will not create a strict HG ship design, and you would have to take the number of EPs generated and work the EP calculation in HG backwards to find an equivalent Pn-factor.

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Fission Power Plant Table (EP-based)
TL dtons/EP Cost/EP (MCr)
7-9 10 13.5
10-12 6 8.1
13+ 3 4.05</pre>[/QUOTE]Fuel for 1 year of continuous full-power operation (good for 10 years of normal operation, I would suggest) costs 1MCr per EP produced. Fuel volume is included in the powerplant volume.

I have also created a Book 2 table for fission power plants. I based this on my TL13+ fission plant values since they seemed to fit best with the other Book 2 drive values. I have rounded off costs to keep the math simple.
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Book 2 Fission Power Plants
Rating Mass Cost Fuel Cost
A 12 16 2
B 24 32 4
C 36 48 6
D 48 64 8
E 60 80 10
F 72 96 12
G 84 112 14
H 96 128 16
J 108 144 18
K 120 160 20
L 132 176 22
M 144 192 24
N 156 208 26
P 168 224 28
Q 180 240 30
R 192 256 32
S 204 272 34
T 216 288 36
U 228 304 38
V 240 320 40
W 252 336 42/50
X 264 352 44/60
Y 276 368 46/80
Z 288 384 48/120</pre>[/QUOTE]The costs are in MCr. Fuel cost is also equal to the EPs generated (for HG purposes). The values after the slash for the W to Z plants is the EPs they should be generating from their performance on the Book 2 drive tables. One "fill-up" of fuel should last the drive for 10 years of normal operation, I would suggest. Fuel volume is included in the powerplant volume.

If you want to be completely consistent with MT/FFS fission reactor fuel consumption, one "fill-up" of fuel should only last 1 year, whether in HG or Book 2. I think 10 years per "fill-up" is more accurate, at least for civilian ships. Military ships (which tend to run around using up power) might get only 5 years out of one "fill-up."

I have reconsidered and I would allow these powerplants to run a jump drive, without any need for hydrogen jump fuel. I've done the economics and it's not as favorable as you'd think; in fact, it's often worse. These powerplants do save you a lot of tonnage in jump fuel, but you pay for it with powerplants that are much larger and more expensive up front (from their larger size; they are cheaper per ton). A low-performance freighter built with a fission drive seems to cost 30-50% more than a fusion-powered ship, and only gains about 20-40% more cargo space. High-performance ships (like the Subsizided Liner) do better. A Type M with a fission plant gains 132 tons of payload although it does cost about MCr100 more.

It's the military who would like these powerplants, and they'd like them a lot, especially for starships (SDBs and battleriders don't gain from these powerplants, actually). A 50,000 dton, J-3, 6-G cruiser at TL-15 with a factor-10 fission plant gains 10,000 dtons to use for extra weapons or defenses. Higher factor powerplants would gain you less, but that's still a lot of tonnage. Fission-powered starships could be near equals in combat of fusion-powered battleriders. Add in the fact that fission-powered ships would not need to refuel every time they jump and would be free from the peril of the SDB-infested gas giant and fission-powered warships look pretty nice.

I don't think I would add fission plants to a campaign already under way, but I might just include these in a universe of my own creation.

 

[aramis]

Oz:

One problem. MT PP's only work out right at 14KL/Dton...

Sadly, one of MT's little ironies... Since MT and TNE use the smae rates EXCEPT for fuel, TNE's FF&S is the better choice, as is 14KL/Td. (Which, it happens, is the CT rate, too.)

 

[aramis]

Oz:

One problem. MT PP's only work out right at 14KL/Dton...

Sadly, one of MT's little ironies... Since MT and TNE use the smae rates EXCEPT for fuel, TNE's FF&S is the better choice, as is 14KL/Td. (Which, it happens, is the CT rate, too.)

 

[The Oz]

It wouldn't really change things that much, anyway.

Fission plants are interesting but not economical for merchants or other ships that have to pay their way. Only governments can afford their upfront costs.

 

[The Oz]

It wouldn't really change things that much, anyway.

Fission plants are interesting but not economical for merchants or other ships that have to pay their way. Only governments can afford their upfront costs.

 

[mike wightman]

How about the secondhand and reconditioned market (something that has always been sadly lacking from Traveller, IMHO)

Regarding the endurance of fission plants, according to a Discovery program a Trident submarine could run for 20 years on its fuel load. I don't know how true this is, or at what rate of output (why are Traveller military power plants run at full output/fuel use all of the time?)
Great work Oz, by the way