Battle Riders

[Sigtrygg]

The 3I setting does it differently...

you can build a jump ship with no jump fuel tanks internally.

You use the drop tanks to power your power plant/jump drive (the MgT explanation of hydrogen filled jump bubbles is contra to every other version of Traveller ever).

[phavoc]

Here is the actual CT canon; you will find that in 1105 civilian shipping in the core sectors have been using drop tanks for a couple of decades in order to carry more passengers and or cargo per trip.

Aye, I said that up-thread. In CT the fuel was used to generate energy, then they were dropped, then the ship jumped. And drop tanks later were updated to survive the jump process once they reached a high enough TL in their construction.

These were created for TCS tournament play, which was always won by designs that gamed the system in a pure min/max fashion. The first two TCS games were won by a computer program coming up with the optimum designs, much to the consternation of the human players. And later on the rules were changed to stop so much gaming of the system.

Nobody has mentioned that nearly all of the classic designs are done without drop tanks. There is the Tukera lines mention about drop tanks. But that seems to be an outlier rather than the norm.

While the drop tank idea seems to work to an extent under CT, in MGT, with it's jump bubble being formed by the fuel in the drop tank, the mechanics are totally different, and thus they work against the safe implementation of it.

[baithammer]

The problem is the fuel in the tank could never be used fast enough to avoid having the mass / displacement of the tanks affecting the overall mass /displacement, you'd have to literally create a zero point in time in order to get that to work.

Further, Mgt HG 1ed had tanks with structure / hull but no mass or displacement which would've affected the mass /displacement calculations.

in MGT, with it's jump bubble being formed by the fuel in the drop tank, the mechanics are totally different, and thus they work against the safe implementation of it.

The singularity referred to would start rather small and with the amount of hydrogen required to expand the bubble its reasonable to assume the tank would have a chance of surviving ejection with the expansion of the bubble.

This makes more sense than a zero time between fuel dump and jump initiation.

Basically this closes a munchkin hole in the rules.

[AnotherDilbert]

These were created for TCS tournament play, ...

No, L-Hyd Tanks (Drop tanks) were available in HG'79, and used as early as JTAS4 in the Gazelle.

They also seem to be used commercially:

REGINA/REGINA (2314-A788899-A) 186-1106
A spokesman for Tukera Lines today announced indefinite suspension of high capacity commercial service to the Regina subsector pending outcome of the official investigation of the Trimkhana-Brilliance tragedy.
Less than a month ago, the 800-ton liner Trimkhana- Brilliance was lost with 217 lives due to a jump capacitor discharge immediately prior to jump. While all four survivors of the disaster are still under intensive medical care, interviews with the one surviving crew member indicate that the capacitor discharge may have been due to a delay in jump after full charging due to a failure of the port inboard L-Hyd drop tank to separate completely.
A Tukera Lines official press release stated that a team of company engineers would be “taking a long hard look at General Shipyard’s quality control standards.”
In the wake of the announcement of high-capacity service suspension, General shipyards common stock fell 34 points on the Regina exchange before exchange officials suspended trade. Oberlindes Lines stock closed up 5 ¾.

[AnotherDilbert]

Drop tanks works in MgT2 just as they have always done since CT:

Drop Tank
..., these are external fuel tanks that are jettisoned just as the ship enters jump space.

The Gazelle on p130 exemplifies how they can be used.

[AnotherDilbert]

To jump, a ship creates a bubble of hyperspace by means of injecting high-energy exotic particles into an artificial singularity.
The singularity is driven out of our universe, creating a tiny parallel universe which is then blown up like a balloon by injecting hydrogen into it. The jump bubble is folded around the ship, carrying it into the little pocket universe.

Nothing in this implies that all the jump fuel is used to inflate the jump bubble.

There is really no conflict with CT if just a fraction of the jump fuel is used.

[AnotherDilbert]

The problem is the fuel in the tank could never be used fast enough to avoid having the mass / displacement of the tanks affecting the overall mass /displacement, you'd have to literally create a zero point in time in order to get that to work.

Mass is not considered in the Traveller jump system. The displacement of energy stored in the jump capacitors is negligible.

Further, Mgt HG 1ed had tanks with structure / hull but no mass or displacement which would've affected the mass /displacement calculations.

No. Drop tanks worked just as usual in MgT1:

A ship’s M–Drive rating must be recalculated when carrying a drop tank. For example, a 200–ton ship with a 150–ton drop tank counts as being a 400–ton ship for the purposes of determining its effective M–Drive rating. Round the tank’s tonnage up to the nearest hull size. Drop tanks can also be used to store fuel for other purposes, such as reaction drive propellant.
The jump performance for the ship is calculated assuming that the drop tanks are not attached unless the jump is to be carried out without jettisoning the drop tanks. In this case, the jump performance should be calculated in a similar manner to the effective M–Drive rating.

[baithammer]

Nothing in this implies that all the jump fuel is used to inflate the jump bubble.

Considering the Jump Drive needs power which in most designs comes from a fission / fusion power plant that requires its own fuel ( One of the reasons I like the High Cap batteries, less fuel needed.), the jump drive also directly needs independent fuel to expand the bubble. ( Which is the jump drives fuel calculation and the jump drive doesn't have enough mass / displacement in order to buffer the fuel.)

And there has been changes between editions.

Mgt HG 1ed

Drop tanks are relatively fragile and if they are attached when the
ship is attacked, they are very vulnerable to fire. A drop tank has
one hull point and one structure point per 100 tons.

Mgt HG 2ed

In addition, drop tanks are automatically
destroyed once their ship has lost 10% of its Hull points.

Both of which hint that the tank should have its own mass /displacement outside of the carried fuel. ( This was the major flaw in the design.)

If we go with the correction, the drop tanks are still useful and are not broken in its use.

[h1ro]

My, my, isn't this thread going round in circles...

Maybe we should organise a tournament, BR vs J1 BR?

We would need to agree victory points and set it in a subsector or several subsectors.

Agree an initial budget for fleet construction and then see how it goes...

[Jeraa]

My, my, isn't this thread going round in circles...

Maybe we should organise a tournament, BR vs J1 BR?

We would need to agree victory points and set it in a subsector or several subsectors.

Agree an initial budget for fleet construction and then see how it goes...

Which would solve little as the actual argument going on now is about how drop tanks work with the jump drive.

[Sigtrygg]

Ships equipped with collector arrays, such as the Annic Nova, do not use hydrogen at all when they jump. So this whole idea of using hydrogen to inflate a jump bubble is just plain wrong.

Every previous version of Traveller, the definitive Jump Space article in JTAS 24 and T5 all agree that hydrogen is not used to form a jump bubble.

[baithammer]

The collector most likely is using the bussard scoop technique where it collects exotic particles, hydrogen and can generate a fusion reaction which would explain why it doesn't have hydrogen storage or fission/fusion rector. ( Also takes a week to build up enough to jump.)

Since we're dealing with mgt the hydrogen bubble is part of the package, of course there is nothing stopping you from enjoying different editions.

Was looking at CT-S09-fighting ships and saw it had doctrine shift for rider designs.

Initially used as main line forces during the start of the 4th Frontier Wars, after a few defeats moved the riders to strategic reserve where it was used to follow up conventional fleets. Also saw mention of J1 hybrid designs as well as up gunning the tender to a battleship in its own right. ( Mgt 2ed also gives us break away hulls which can be used to increase the individual rider while minimizing the tender size.)

[Jeraa]

Hydrogen bubbles are mentioned in T4 (Fire, Fusion, & Steel page 12). The majority of the fuel is used during the initial jump to create the jump tunnel, but some is used "to create a thin hydrogen atmosphere around the ship during jump, which helps to delay the collapse of the jump bubble."

Evidence of a previous edition having jump bubbles, but not using all of the hydrogen to form it. Since nothing in MgT 2e indicates that all of the hydrogen is used to form the bubble, you can easily assume that most is used during the jump itself while only a little of it is used to form the bubble. That fits with at least 1 of the previous editions and doesn't change anything in MgT.

As to the amount of hydrogen needed, that would depend in the bubble shape. T5 gives two forms. The default is a large sphere. But with added equipment, you can get a much smaller bubble that follows the form of the hull. (T5 makes no reference to what fills the bubble as far as I can see, just that they do exist. MT uses the smaller, hull-following bubble, but again no mention of anything inside it.)

[AnotherDilbert]

Both of which hint that the tank should have its own mass /displacement outside of the carried fuel. ( This was the major flaw in the design.)

I'm not sure I understand your point, but of course the tanks have volume and mass of their own. Note that the rules specify that they modify drive performance when attached, regardless of whether they are filled with fuel or not.

[AnotherDilbert]

Every previous version of Traveller, the definitive Jump Space article in JTAS 24 and T5 all agree that hydrogen is not used to form a jump bubble.

Not quite, they say nothing at all on the subject.

That does not imply that they agree with hydrogen inflated bubbles, but it might possibly be reconciled. If you see both explanations as incomplete, layman-terms explanations of the jump process they can very well be describing the same phenomena.

Neither description is very detailed.

T4 seems to be using an intermediary description, and may explain where MgT got the idea?

Hydrogen bubbles are mentioned in T4 (Fire, Fusion, & Steel page 12). The majority of the fuel is used during the initial jump to create the jump tunnel, but some is used "to create a thin hydrogen atmosphere around the ship during jump, which helps to delay the collapse of the jump bubble."

Thanks Jeraa, I have never delved into T4.

[ShawnDriscoll]

What I want to know is, how does the crew survive the creation of the bubble?

[AnotherDilbert]

Maybe we should organise a tournament, BR vs J1 BR?

We would need to agree victory points and set it in a subsector or several subsectors.

Unfortunately that would be a test of the contestants strategic skill more than the strengths of the fleets.

The concept of a J-1 BR is not purely tactical, so is difficult to test as a single variable in a lab-like environment.

[AnotherDilbert]

What I want to know is, how does the crew survive the creation of the bubble?

As far as I can see the bubble is not inflated through the ship, but beside the ship:

To jump, a ship creates a bubble of hyperspace by means of injecting high-energy exotic particles into an artificial singularity. The singularity is driven out of our universe, creating a tiny parallel universe which is then blown up like a balloon by injecting hydrogen into it. The jump bubble is folded around the ship, carrying it into the little pocket universe.

So first we create the bubble, then it is "folded" around the ship.

From ye olde JTAS article we also know:

Strong Hull: The hull of a starship must not only be constructed to withstand normal space; it also must withstand the rigors of jump space. Starship hulls contain as an integral part of their structure a network of wiring which maintains the jump field around the ship. Without this field, the natural physics of jump space would intrude into the ship interior.

[Sigtrygg]

Hydrogen bubbles are mentioned in T4 (Fire, Fusion, & Steel page 12). The majority of the fuel is used during the initial jump to create the jump tunnel, but some is used "to create a thin hydrogen atmosphere around the ship during jump, which helps to delay the collapse of the jump bubble."

Good spot, thanks for finding it. I sit corrected.
It doesn't alter the in setting fact that collector based jump drives do not use hydrogen.

Evidence of a previous edition having jump bubbles, but not using all of the hydrogen to form it. Since nothing in MgT 2e indicates that all of the hydrogen is used to form the bubble, you can easily assume that most is used during the jump itself while only a little of it is used to form the bubble. That fits with at least 1 of the previous editions and doesn't change anything in MgT.

This has come up many times over the years and I think it stems from DGP's MT SoM which mentions the jump drive maintaining a bubble of normal space within jump space, but doesn't mention filling it with anything.
The author of T4's FF&S may have had this in mind and added the fanon which is contradicted by collector technology and antimatter powered jump drives.

As to the amount of hydrogen needed, that would depend in the bubble shape. T5 gives two forms. The default is a large sphere. But with added equipment, you can get a much smaller bubble that follows the form of the hull. (T5 makes no reference to what fills the bubble as far as I can see, just that they do exist. MT uses the smaller, hull-following bubble, but again no mention of anything inside it.)

It is a bubble of our spacetime universe inside the jump dimension universe, it doesn't need to be filled with anything.

[ShawnDriscoll]

What I want to know is, how does the crew survive the creation of the bubble?

As far as I can see the bubble is not inflated through the ship, but beside the ship:

To jump, a ship creates a bubble of hyperspace by means of injecting high-energy exotic particles into an artificial singularity. The singularity is driven out of our universe, creating a tiny parallel universe which is then blown up like a balloon by injecting hydrogen into it. The jump bubble is folded around the ship, carrying it into the little pocket universe.

So first we create the bubble, then it is "folded" around the ship.

Ok. Magic then. The bubble just appears safely outside the ship. Nothing indicating any connection with the engine room inside the ship.