Drop Tanks... Back From the Dead?

[MasterGwydion]

I did mine as a station because I wasn’t sure there was enough time to get clear. This is the preferable method, I’m sure. I may make a robotic one later just for completeness.

How long does it take to get 100D away from station or ship dispensing the fuel. You should be able to calculate it and make your acceleration enough to clear that in 1 round. Therefore, there are no checks (as there are for drop tanks) as you are 100+D away from objects other than your ship.

 

[Terry Mixon]

Use the same method but shrink it down. Think of using it for specific trade routes, such as the Heirate Route. J-4, 50,000 tons of cargo per ship. Tobia, Fist, Cordan, Tech-World, Tyokh. Tobia to Tyokh in 4 weeks. 8 weeks round-trip. A while back we tried to figure out the amount of traffic on this route, and it mentioned that one company did the vast majority of the trade and was in the process of building new ships. TL-15 to get all of the reductions for M and J Drives as well as the Powerplant.

Go for it.

 

[MasterGwydion]

Go for it.

Don't want to get into a legal battle with MixCorp,

 

[Arkathan]

How long does it take to get 100D away from station or ship dispensing the fuel. You should be able to calculate it and make your acceleration enough to clear that in 1 round. Therefore, there are no checks (as there are for drop tanks) as you are 100+D away from objects other than your ship.

100D for my 90 meter long Orca, which is 2000 tons, is 9 km. So once you are 100D from the planet, not long.

 

[Sigtrygg]

The way to stop this getting into the canonical Spinward Marches is either to insist drop tanks are single use or to revisit the special jump capacitors that were required.

From the Gazelle we know the IN was building drop tank capable ships long before the technology was declassified for civilian use, which was only a couple of decades ago from the 1105 start date:

"L-Hyd drop ships have only been in service for the last dozen years in the interior, being made possible by recent advances in the field of capacitor
engineering, a joint press release explained." in service for a dozen years, but there would be lead time in building the special capacitors

"high capacity accumulator is installed (tech level 12; Cr500 000)." kept as a military secret is one explanation for the lack of civilian use up until now.

So insist civilian ships that want to use jump stations or drop tanks or oilers must have the special capacitors refitted.

The Imperial core sectors on the other hand should be awash with jump stations, drop tanks, oilers etc. they have been using them routinely for over a decade.

That is what makes the core sectors different to the frontier regions like the Marches.

 

[Terry Mixon]

How long does it take to get 100D away from station or ship dispensing the fuel. You should be able to calculate it and make your acceleration enough to clear that in 1 round. Therefore, there are no checks (as there are for drop tanks) as you are 100+D away from objects other than your ship.

I meant I wasn’t sure a movable drop tank could get clear. I’ve made the assumption that the fueling must happen in a six-minute space combat round, but the part after that (according to the Starship Operator’s Manual) is a lot faster faster than a sophont can react.

Once the power is flowing through the drive/shunt system, hydrogen is pumped by the jump field subsystem on the hull of the ship, expanding it out to a large bubble if employing a bubble-configuration drive, or a conformal jump field if using a jump grid – see Jump Field, starting on page 90. The majority of fuel designated for a jump is used during this process to create the jump bubble. Many compare this to children blowing bubbles from soapy water, making the external view of jump initiation fascinating to watch. The crew can only observe the bubble forming from the limited view inside the ship.


The jump will not start until the jump field is completely formed. Outside observers will only see the field engulf the ship then seemingly pop, making the ship and everything else inside the field disappear, like the universe’s largest stage magic trick. From the crew’s point of view, once the field fully forms and blocks out the outside universe, the ship is in jumpspace until the field dissolves at the end of the jump.


Creation and inflation of the jump field is an extremely rapid process, happening faster than any sophont can react to. Only computers have a chance of performing all the steps in time. As such, jump entry is impossible without Jump Control software, which performs safety checks such as making sure there is enough fuel before attempting to begin. Without disabling these checks, attempting to jump without enough fuel causes the computer to display an error message.

 

[MasterGwydion]

I meant I wasn’t sure a movable drop tank could get clear. I’ve made the assumption that the fueling must happen in a six-minute space combat round, but the part after that (according to the Starship Operator’s Manual) is a lot faster faster than a sophont can react.

So, double your UNREP capacity so that it happen in a half of a round and then you get a half of a round of thrust.

 

[MasterGwydion]

The way to stop this getting into the canonical Spinward Marches is either to insist drop tanks are single use or to revisit the special jump capacitors that were required.

From the Gazelle we know the IN was building drop tank capable ships long before the technology was declassified for civilian use, which was only a couple of decades ago from the 1105 start date:

"L-Hyd drop ships have only been in service for the last dozen years in the interior, being made possible by recent advances in the field of capacitor
engineering, a joint press release explained." in service for a dozen years, but there would be lead time in building the special capacitors

"high capacity accumulator is installed (tech level 12; Cr500 000)." kept as a military secret is one explanation for the lack of civilian use up until now.

So insist civilian ships that want to use jump stations or drop tanks or oilers must have the special capacitors refitted.

The Imperial core sectors on the other hand should be awash with jump stations, drop tanks, oilers etc. they have been using them routinely for over a decade.

That is what makes the core sectors different to the frontier regions like the Marches.

Didn't those special capacitors allow a delay between pumping the fuel into the jumpdrive and starting the actual jump?

 

[Terry Mixon]

So, double your UNREP capacity so that it happen in a half of a round and then you get a half of a round of thrust.

I hear you, but the SOM makes that last part an extremely small fraction of that six minutes. I’m still not convinced you could add enough movement speed to change anything. Maybe make it Thrust 9 and add in reaction thrusters?

Nah, it’s written so that the fuel delivery can take that time but once the fuel is deployed, the time interval to jump is very, very short. In my Traveller universe, I’d have to say it wouldn’t work.

 

[Terry Mixon]

Didn't those special capacitors allow a delay between pumping the fuel into the jumpdrive and starting the actual jump?

*listens intently*

 

[Arkathan]

Didn't those special capacitors allow a delay between pumping the fuel into the jumpdrive and starting the actual jump?

That was under the system that did not use hydrogen to expand a jump bubble.

 

[MasterGwydion]

100D for my 90 meter long Orca, which is 2000 tons, is 9 km. So once you are 100D from the planet, not long.

If you make it a cube it is only 30 meters long and therefore only needs 3km of separation. You need 0.375Gs of acceleration to get far enough away in 3 minutes.

 

[MasterGwydion]

That was under the system that did not use hydrogen to expand a jump bubble.

So, use the lanthanum grid system. As far as I am aware, both are still in use in charted space. The Jump Bubble system seems to be in far more use than the lanthanum grid system though.

 

[Sigtrygg]

The SOM is... misleading. Go back to the source:

MgT JTAS 2

"Energy Storage Nodes - Once power is generated, it must be stored until the instant of jump*. Capacitors or large fast discharge batteries fit this requirement."

"When the jump drive is activated, a large store of fuel is fed through the ship’s power plant to create the energy necessary for the jump drive**. In the interests of rapid energy generation, the power plant does not work at full efficiency, and some of the fuel is lost in carrying off fusion byproducts, and in cooling the system. At the end of a very brief period (less than a few minutes)***, the jump drive capacitors have been charged to capacity. Under computer control, the energy is then fed into appropriate sections of the jump drive and jump begins."

* energy for the jump is held in the capacitors
**fuel is fed through the power plant really quickly to charge the capacitors - this is where the drop tank fuel is used.
*** and right there is the time you have got to get clear - a few minutes, few usually means three or more so somewhere between 3 and 6 minutes.

 

[Sigtrygg]

That was under the system that did not use hydrogen to expand a jump bubble.

You don;t need a jump bubble expanded with hydrogen, the collector make this contradictory. The hydrogen filled bubble causes more problems than it fixes, it should have been removed from MgT years ago.

 

[MasterGwydion]

The SOM is... misleading. Go back to the source:

MgT JTAS 2

"Energy Storage Nodes - Once power is generated, it must be stored until the instant of jump*. Capacitors or large fast discharge batteries fit this requirement."

"When the jump drive is activated, a large store of fuel is fed through the ship’s power plant to create the energy necessary for the jump drive**. In the interests of rapid energy generation, the power plant does not work at full efficiency, and some of the fuel is lost in carrying off fusion byproducts, and in cooling the system. At the end of a very brief period (less than a few minutes)***, the jump drive capacitors have been charged to capacity. Under computer control, the energy is then fed into appropriate sections of the jump drive and jump begins."

* energy for the jump is held in the capacitors
**fuel is fed through the power plant really quickly to charge the capacitors - this is where the drop tank fuel is used.
*** and right there is the time you have got to get clear - a few minutes, few usually means three or more so somewhere between 3 and 6 minutes.

Yeah. I was actually using your previous post as the justification for "maybe it works". lol

 

[Arkathan]

You don;t need a jump bubble expanded with hydrogen, the collector make this contradictory. The hydrogen filled bubble causes more problems than it fixes, it should have been removed from MgT years ago.

Right. As you quoted earlier, the improved capacitors that allowed a delay of engaging the jump, so that the drop tanks can get clear, did not operate under a system that filled a bubble with hydrogen.

 

[Arkathan]

If you make it a cube it is only 30 meters long and therefore only needs 3km of separation. You need 0.375Gs of acceleration to get far enough away in 3 minutes.

Even better.

 

[Sigtrygg]

MegaTraveller SOM introduced the jump bubble term, but they used it as a bubble of normal space maintained by the jump cable network in the hull.
(because DGP got virtually everything they did with ships wrong they even decided lanthanum was in this hull cable network, despite what was actually written about lanthanum coils in the inner workings of the jump drive)

T4 authors of the FF&S2 disaster introduced the hydrogen from the surge tanks being used in the normal space bubble.

MgT authors for some reason went all in and decided a hydrogen filled jump bubble is necessary despite:

reprinting MWM's article that never mentions a hydrogen filled bubble

having collectors being able to enable jump with no hydrogen required

Get rid of the hydrogen filled bubble.

 

[Terry Mixon]

The SOM is... misleading. Go back to the source:

MgT JTAS 2

"Energy Storage Nodes - Once power is generated, it must be stored until the instant of jump*. Capacitors or large fast discharge batteries fit this requirement."

"When the jump drive is activated, a large store of fuel is fed through the ship’s power plant to create the energy necessary for the jump drive**. In the interests of rapid energy generation, the power plant does not work at full efficiency, and some of the fuel is lost in carrying off fusion byproducts, and in cooling the system. At the end of a very brief period (less than a few minutes)***, the jump drive capacitors have been charged to capacity. Under computer control, the energy is then fed into appropriate sections of the jump drive and jump begins."

* energy for the jump is held in the capacitors
**fuel is fed through the power plant really quickly to charge the capacitors - this is where the drop tank fuel is used.
*** and right there is the time you have got to get clear - a few minutes, few usually means three or more so somewhere between 3 and 6 minutes.

Thanks for the clarification. It sounds like @Arkathan’s method (and what I would have preferred anyway) should be the way to go.