Fuel needed

[Daddicus]

On page 297, in the top table, it says that fuel costs for maneuver drive (with a power plant) is "included in operations". Does that mean the ship doesn't have to allocate any fuel storage beyond what the jump drive uses?

If so, what's the justification? Is it that all those consoles each hold a few gallons of fuel, and they add up to enough over time to run the ship?

 

[The Pakkrat]

It says it's included in the Operations. So look down in the Operations for the Power Plant. Maneuver Drives use very little fuel and that is lumped in with the ship's Operations consumption each time increment. I hit that road bump too.

-Pakkrat

 

[Daddicus]

It says it's included in the Operations. So look down in the Operations for the Power Plant. Maneuver Drives use very little fuel and that is lumped in with the ship's Operations consumption each time increment. I hit that road bump too.

-Pakkrat

I agree that that's how it reads. But, earlier, it says to calculate the fuel needs for power, maneuver, and jump drives. But, that table on 297 has power and maneuver crossing each other.

It just seems confusing.

 

[Timerover51]

It says it's included in the Operations. So look down in the Operations for the Power Plant. Maneuver Drives use very little fuel and that is lumped in with the ship's Operations consumption each time increment. I hit that road bump too.

-Pakkrat

Why would maneuver drives use little fuel? You are changing the velocity of a large amount of mass, and that takes a lot of energy. Simply maintaining ship power should take a limited amount of energy.

One cubic meter of heavy water would supply all the energy the average ship up to roughly 5,000 dTons should need for a year for ship's power.

Changing the velocity vector on 1,000 plus tons of mass, now that takes energy.

 

[jcrocker]

I agree, I'd like to know the answer for that question as well.

 

[David Johansen]

It's a gravitic reactionless drive so it doesn't use reaction mass or a related expenditure of energy.

The premise of Traveller is that efficient fusion drives, anti gravity, reactionless engines, and hyperspace jump drives make space travel relatively cheap and simple.

Something it will never be using realistic constraints or squinting at the standard model until it gets blurry.

Even then, Traveller is somewhat rigorous with vector movement in space and space suits and so forth. It's space opera but it's space opera without the giant planet sized gun that eats stars or star systems within visual range of each other.

The original game had the simple relationship of 1 power plant unit to 1 maneuver unit to 1 jump unit (requiring 10% of the ships volume per jump number) with the volume scaling up with the size of the vessel. It really just relates to the needs of the game much like the much maligned Battle Tech weapon ranges. Warhammer 40k ranges get some slack as there isn't really a defined ground scale. But even so it's just a matter of what plays well on the table top not real physics.

It's not really to my tastes but it is Traveller. TNE tried to inject some realism and we know how that went.

I loved Fire Fusion and Steel and I really wish SJG would get GURPS Vehicle Design out for 4th edition. (yes I have all of the Spaceships pdfs but it's just not the same)

 

[OjnoTheRed]

The standard Traveller MDrive is reactionless and hence fuel is 'lumped in with operations'. But there are realspace maneuver drives included in the starship design sequence that do directly consume fuel - Rocket and HEPlaR. So it's a fine distinction that for most T5 starship designs is completely ignored because, basically, MDrives need a Power Plant but not direct fuel.

 

[aramis]

On page 297, in the top table, it says that fuel costs for maneuver drive (with a power plant) is "included in operations". Does that mean the ship doesn't have to allocate any fuel storage beyond what the jump drive uses?

If so, what's the justification? Is it that all those consoles each hold a few gallons of fuel, and they add up to enough over time to run the ship?

As others have noted, apparently since about 1980, Marc et al have considered maneuver drives to be gravitic in nature.

It only became explicit in 1987.

Gravitic maneuver drives require no fuel, only a PP.

Noting that science fiction maneuver drives come in about 4 varieties...

1. Gravitic field generation (Dean Drive)
2. Gravity Well interaction/Spacetime crawlers
3. Gravity nullification (Contragravity)
4. Gravitic repulsion (Star Wars "repulsorlift") - only provides lift.

Traveller Thruster Plates are the second type; they are explicit in MT, T4, GT, and T5.
TNE & T4 have contragrav...

Since T4, Thruster Plates have had cut-off points. I don't recall the exact levels.

T5 Gravitic drives do not work in jump space.

 

[mike wightman]

Frank Chadwick didn't - that's one reason why TNE went back to reaction drives.

MgT now includes both, and 3I fighters, SDBS and battle riders are likely to have both reactionless drives and a reaction drive for very high g ratings.

T5 allows reaction drives to change a ship's vector in jump space.

 

[Daddicus]

Thanks for all the info, guys!

 

[Selandia]

Why would maneuver drives use little fuel? You are changing the velocity of a large amount of mass, and that takes a lot of energy. Simply maintaining ship power should take a limited amount of energy.

One cubic meter of heavy water would supply all the energy the average ship up to roughly 5,000 dTons should need for a year for ship's power.

Changing the velocity vector on 1,000 plus tons of mass, now that takes energy.

If you think this is a problem, consider that the design system does not differentiate between mass and volume. A 5,000 dtonner hauler with 4,000 of empty cargo space is handling ( speed et all) like a fully loaded one... without regard for the density of the cargo ...

As long as we have fun...

Selandia