Jump fuel requirements

[Spartan159]

I was looking at MT jump fuel requirements, which appear at first glance, to be 5% of hull per Jump number plus 5%, vs other versions at 10% of hull per jump number.

I am curious, does anyone use the MT rate outside of MT? What kind of impact does it have? More payload and/or faster jump ranges more common? With the advent of higher drive ratings, the MT formula would allow a reasonable Jump 9 design with 50% of the Hull being fuel.

I am thinking of using the MT formula in MgT but have not decided yet.

 

[aramis]

I was looking at MT jump fuel requirements, which appear at first glance, to be 5% of hull per Jump number plus 5%, vs other versions at 10% of hull per jump number.

I am curious, does anyone use the MT rate outside of MT? What kind of impact does it have? More payload and/or faster jump ranges more common? With the advent of higher drive ratings, the MT formula would allow a reasonable Jump 9 design with 50% of the Hull being fuel.

I am thinking of using the MT formula in MgT but have not decided yet.

TNE and MT use 5 x Jump Drive size for full range jump, which USUALLY is also 5*(1+Jn)%, but might not always.

 

[McPerth]

I am curious, does anyone use the MT rate outside of MT? What kind of impact does it have? More payload and/or faster jump ranges more common? With the advent of higher drive ratings, the MT formula would allow a reasonable Jump 9 design with 50% of the Hull being fuel.

In MT, the maximum jump is 6, so no J9 ship would be allowed (of course, that may vary acording the ersion you use), but with 50% of the tonnage as fuel, you can easily build a ship with J4 and capacity for two consecutive jumps. This, off course, would make the rift not so important a barrier, and the Islands not such an isolated cluster, just to give you an example of the consequences...

 

[AnotherDilbert]

IIRC the reduced jump fuel requirement in MT was intended to balance the very high power plant fuel requirement. The ships did not carry less fuel.

MgT has rather small pp fuel requirements, reducing jump fuel too would be a bit much. As McPerth points out it would break the 3I setting a little.

 

[McPerth]

The ships did not carry less fuel.

That was not always true.

While it was the intent (as you say), as in MT the JD was fully indepenent from the Power Plant, if you didn't overload your PP you could have a high jump ship carrying quite less fuel than in other versions.

This was rarely true for military ships, but for merchants, that don't need high maneuver nor to devote too much power to weaponry, it was. It also lead to the diferent endurance for PPs in combat/non combat days by runing your PP at the minimal output needed for non combat systems.

 

[GypsyComet]

Initial MT designs did not address variable loads on the powerplant, so the fuel allocations are huge. Military ships, paradoxically, don't care all that much unless they are also very high jump. Merchants need cargo space, though, and the weapons load ends up having a huge effect on cargo because just one laser can add enough fuel need to knock a design from profitable to hard-scrabble.

Then the art of variable power loads was revealed in Challenge, and everything changed.

 

[aramis]

IIRC the reduced jump fuel requirement in MT was intended to balance the very high power plant fuel requirement. The ships did not carry less fuel.

MgT has rather small pp fuel requirements, reducing jump fuel too would be a bit much. As McPerth points out it would break the 3I setting a little.

MT, you didn't need PP to match JDrive...

... it's perfectly reasonable to make a 2J4 MT design.

 

[Carlobrand]

There was at least one instance - Starship Operator's Manual - of a ship being described as entering and passing through jump space while the rest of the ship's systems were on batteries due to power plant damage. Little more than basic life support, environment and controls, I'd guess. That one has some very interesting potential ramifications, at least for MT.

 

[aramis]

There was at least one instance - Starship Operator's Manual - of a ship being described as entering and passing through jump space while the rest of the ship's systems were on batteries due to power plant damage. Little more than basic life support, environment and controls, I'd guess. That one has some very interesting potential ramifications, at least for MT.

In MT, the Jdrive itself only operates for 20 minutes a jump... the grid, however...

 

[Spartan159]

I'm rampantly stealing from every version of Traveller I can lay my grubby paws on FYI, which is why I was curious if anyone had used the fuel rates outside of an MT setting. I need to look at rift crossings a bit more I suppose, I had been thinking of ships having more payload rather than being able to double jumping. Merchants would be more interested in cargo/passenger space, and military ships would be faced with double jump capable "raiders" vs single jump battlewagons.

 

[AnotherDilbert]

In CT a Book5 Scout needs 22 dT fuel.
In MgT2 a Scout needs ~21 dT fuel.
In MT a Scout needs ~27 dT fuel.
In MT a Scout with reduced PP fuel needs ~20 dT fuel.

I call it roughly the same for normal ships.

But yes, it is of course much easier to optimise for jump range in MT. In a quick estimate we can make ships with 2 × J-6, obviously not possible in most editions.

 

[McPerth]

In CT a Book5 Scout needs 22 dT fuel.
In MgT2 a Scout needs ~21 dT fuel.
In MT a Scout needs ~27 dT fuel.
In MT a Scout with reduced PP fuel needs ~20 dT fuel.

I call it roughly the same for normal ships.

But yes, it is of course much easier to optimise for jump range in MT. In a quick estimate we can make ships with 2 × J-6, obviously not possible in most editions.

A CT (or MgT) J5 ship needs 50% volume jump fuel (plus maintaining a PP capable of a rating of 5).
A MT J5 ship needs 30% volume as jump fuel, while not needing to maintain a large PP.
A MT J5 with capability for 2 successive jumps needs 60% of volume for jump fuel (same as a CT J6 ship only able to make one jump), and still does not need a large PP.
A MT ship with J6 and capacity for 2 successive jumps would need 70% of its volumen for fuel. I guess this can be done (never tried it), if needed, with not much payload. It would probably be a specialized (Courier or scout) ship, but if able to scout at 6 parsecs (with fuel enough for return trip), it can be quite useful, and as Courier, there are no more rifts.

It's at high J capacity where the diference is really felt, but can really be significative

 

[Spartan159]

A CT (or MgT) J5 ship needs 50% volume jump fuel (plus maintaining a PP capable of a rating of 5).
A MT J5 ship needs 30% volume as jump fuel, while not needing to maintain a large PP.
A MT J5 with capability for 2 successive jumps needs 60% of volume for jump fuel (same as a CT J6 ship only able to make one jump), and still does not need a large PP.
A MT ship with J6 and capacity for 2 successive jumps would need 70% of its volumen for fuel. I guess this can be done (never tried it), if needed, with not much payload. It would probably be a specialized (Courier or scout) ship, but if able to scout at 6 parsecs (with fuel enough for return trip), it can be quite useful, and as Courier, there are no more rifts.

It's at high J capacity where the diference is really felt, but can really be significative

... Ninja'ed ... LOL I was typing much the same thing.

 

[aramis]

It's not practical to build a 2J6 ship in MT (77%)... But 2J5 (66%)is. 3J3 is, too (64).

 

[AnotherDilbert]

It's at high J capacity where the diference is really felt, but can really be significative

Certainly.

A prime example is Fleet Tenders, they will generally be max jump in MT. That means Imperial fleets will move at J-6, and Zho fleets move at J-5, significantly changing the terrain in the FFW. As I said the 3I setting breaks a little.

It would be worse in MgT2 where reduced jump fuel would not be balanced by increased anything.

 

[Carlobrand]

It's not practical to build a 2J6 ship in MT (77%)...

Not practical but possible. It's a great muckin' fuel tank with drives and a wee bit of space for the crew. At 100 dTons it actually looks very much like an express boat - but what an express boat!

 

[AnotherDilbert]

It's not practical to build a 2J6 ship in MT (77%)... But 2J5 (66%)is. 3J3 is, too (64).

Not practical but possible. It's a great muckin' fuel tank with drives and a wee bit of space for the crew. At 100 dTons it actually looks very much like an express boat - but what an express boat!

Quite possible, works down to 200 dT. Very little payload.

TL 15                                                        6▮908       337,6            
Civilian 0                                         0         5▮519       270,1         321      9▮854
                #       Desired        UCP    Vol m³    Mass tonne    Cost MCr    Power MW    Control  
                                        
Hull                      1▮000      1▮000    13▮500           310         1,4            
Config        Box             4          4         0          1,00        0,60            
Streamlining  Streamlined    SL         SL                                1,50            
Armour Type               TL 15          G                    0,14        1,00            
Armour                        0         40                   33,00       33,00            
Hull Total                                    13▮500         1▮432       40,10 
                                        
Power, Fusion   1        150 m³     Ag=0,3       150           300       30,00      -2 700      4▮500    
Solar (HabZone) 1        116 m²                    1             1        0,23         - 9         35    

Jump Drive      1          6 Pc       6 Pc       945         1▮890      210,00                 31▮500    
Manœuver Drive  1           1 G        1 G       270           700       14,00       1▮400      2▮100    
                                        
Fuel, Jump      2          6 Pc                9▮450           662                
Fuel, Power           10,0 days                  324            23                
                                        
Scoops          1               2▮700 m³/h                                1,01            
Purif           1          24 h                  236           473       17,72           6        
                                        
Computer        3           m/0        m/1         6             2        1,20           0    -50▮300    
Control        20       Holographic Linked         1             0        0,04           0        -30    
Add-on         10       Heads-up HoloDisplay      10             5        0,20           1     -2▮000    
Large add-on    2       Large Holodisplay          4             2        0,10           1     -3▮000    

Commo, Radio    3       Radio       System         0             0        0,45           0         68    
    Maser       2       Maser       System         0             0        0,36           0         54    
    Meson       0       5: System     None                        
                                        
Sensors,Passive 2       Interstellar               0             0        0,64           0         96    
    EMS Active  2       Far Orbit                  0             0        1,20           0        180    
    EMS Jammer  0       Far Orbit                                
    Densitromet 2       LoPen    250 m             1             0        0,41           0         62    
    Neutrino Se 2       10 kW                      0             0        0,22           0         33    
                                        
                                        
Stateroom      19                              1▮026            76        7,60           0        

AirLocks        1                                  3             0        0,01           0          1    
LifeSupp, Basic 1   13▮500 m³  Env,AGrav,InComp  338           608       10,26         959      1▮539    
LifeSupp, Full  1    3▮726 m³  Bas+Ext Life-Sup   30            30        1,86          11        279    
                                        
Cargo                                52 dT       705           705                

                                        
                                        
                       High    Mid    Low                
        Passangers        0    0    0                      Damage Points        
                                                   Hull      900/2▮250    
                                                   PP         10/20    
        Crew                19                     MD         18/36    
                                                   JD         63/126    
            Command          2                        
            Bridge           6                        
            Flight           0            Loaded Mass      6▮908 tonnes    
            Gunnery          0            Unloaded Mass    5▮519 tonnes    
            Engineering     10                        
            Maintenance      1                        
            Steward          0            Nominal Price      337,607 MCr    
            Medic            0            Architect's Fee      3,376 MCr    
                                          Standard Price     270,085 MCr    
            Troops           0

 

[whartung]

In CT a Book5 Scout needs 22 dT fuel.
In MgT2 a Scout needs ~21 dT fuel.
In MT a Scout needs ~27 dT fuel.
In MT a Scout with reduced PP fuel needs ~20 dT fuel.

For trivia, the TL15 Scout in TNE has over 50 dT of fuel. 15 dT for jump, the rest is combination reaction mass and power plant fuel. The plant uses ~1dT of fuel per year, so it's mostly reaction mass.

The TL-10 Free Trader has 70 dT of fuel, 20dT is Jump Fuel. It has 54dT of cargo space.

 

[AnotherDilbert]

At 100 dTons it actually looks very much like an express boat - but what an express boat!

Yes, it took some squeezing to get it to 100 dT. Almost Scout-like with 1 G, 2 staterooms and 3 dT cargo.

TL 15                                                             707        36,7        
Military 1                                            0           594        29,4          13      1 602
                      #    Desired        UCP    Vol m³    Mass tonne    Cost MCr    Power MW    Control
                                    
Hull                           100        100    1 350             40         0,1        
Config              Box          4          4        0           1,00        0,60        
Streamlining     Streamlined    SL         SL                                1,50        
Armour Type                  TL 15          G                    0,14        1,00        
Armour                           0         40                   33,00       33,00        
Hull Total                                       1 350            185        3,98        
                                                                        
Power, Fusion         1      14 m³     Ag=0,1       14             28        2,80       - 252        420
Solar (HabZone)       1      37 m²                   0              0        0,07         - 3         11

Jump Drive            1       6 Pc       6 Pc       95            189       21,00                  3 150
Manœuver Drive        1        1 G        1 G       27             70        1,40         140        210
                                    
Fuel, Jump            2       6 Pc                 945             66            
Fuel, Power              10,0 days                  30              2            
                                    
Scoops                1              270 m³/h                                0,10        
Purif                 1       24 h                  40             47        1,77           1    
                                    
Computer              3        m/0     m/0bis        2              0        0,39           0     -6 045
Control               3      Holographic Linked      0              0        0,01           0         -5
    Add-on            3      Heads-up HoloDisplay    3              2        0,06           0       -600
    Large add-on      0      Large Holodisplay                    

Commo, Radio          2      Radio     System        0              0        0,30           0         45
    Maser             2      Maser     System        0              0        0,36           0         54
    Meson             0      System      None                    
                                    
Sensors, Passive      2        Interstellar          0              0        0,64           0         96
    EMS Active        2        Far Orbit             0              0        1,20           0        180
    EMS Jammer        0        Far Orbit                            
    Densitrometer     2        LoPen    250 m        1              0        0,41           0         62
    Neutrino Sensor   2        10 kW                 0              0        0,22           0         33
                                    
                                    
Stateroom             2                            108              8        0,80           0    

AirLocks              1                              3              0        0,01           0          1
LifeSupport, Basic    1   1 350 m³ Env,AGrav,InComp 34             61        1,03          96        154
LifeSupport, Full     1     375 m³ Bas+Ext Life-Sup  3              3        0,19           1         28
                                    
Cargo                                    3 dT       45             45            
                                    
                                    
                                    
                                   High    Mid    Low            
        Passangers                   0      0      0                   Damage Points    
                                                                Hull       90/225
                                                                PP          1/2
        Crew                  3                                 MD          2/4
                                                                JD          7/14
            Command           0                    
            Bridge            2                    
            Flight            0                        Loaded Mass      707 tonnes
            Gunnery           0                        Unloaded Mass    594 tonnes
            Engineering       1                    
            Maintenance       0                    
            Steward           0                        Nominal Price     36,731 MCr
            Medic             0                        Architect's Fee    0,367 MCr
                                                       Standard Price    29,385 MCr

 

[AnotherDilbert]

For trivia, the TL15 Scout in TNE has over 50 dT of fuel. 15 dT for jump, the rest is combination reaction mass and power plant fuel. The plant uses ~1dT of fuel per year, so it's mostly reaction mass.

The TL-10 Free Trader has 70 dT of fuel, 20dT is Jump Fuel. It has 54dT of cargo space.

20 - 30 hours reaction mass is probably a bit much for a civilian design. 5 - 10 hours is enough? That would result in a lot more payload, at the cost of a few hours more transit time to 100d.

How many Gturns does a warship need?