General Hypothetical: Detonating your reactor.

[kilemall]

A bit of research shows my EP to damage calculation above is the equivalent of setting off a mk 81bomb in the engineering compartmet - scout ship go boom.

Mark 81 bomb - Wikipedia

en.wikipedia.org

Now if you fully charge the jump capacitors and then release that energy explosively you get 36 EPs released instantly - a 1.6kt equivalent explosion.

My understanding was that the jump capacitor was equivalent to two turns of charging up- in other words in the case of scout ships 4 EP.

A more realistic destroy the ship scenario are using the capacitors on board the Kininur class.

And plenty of reason to do so given the black hole generator, the AI, and maybe intel about some of the missions they likely do ( in retrospect it looks more like a spec ops platform).

 

[Condottiere]

You could overclock the manoeuvre drive, and deliberately let it blow, though I think the rockets would be a better candidate.

 

[mike wightman]

My understanding was that the jump capacitor was equivalent to two turns of charging up- in other words in the case of scout ships 4 EP.

I prefer to just look up the rules rather than go by my misunderstanding and fading memory.

The jump drive of the scout contains capacitors equal to 0.005 x hull displacement x jump number.

0.005 x100 x 2 = 1

Each capacitor ton holds 36 EP. So to detonate you have to overload...

 

[kilemall]

I prefer to just look up the rules rather than go by my misunderstanding and fading memory.

The jump drive of the scout contains capacitors equal to 0.005 x hull displacement x jump number.

0.005 x100 x 2 = 1

Each capacitor ton holds 36 EP. So to detonate you have to overload...

That doesn’t make sense, it literally can’t load that capacitor in less then 18 turns.

You may be right re RAW, but that’s a helluva capacity. Not to mention that’s a big percentage of the j-drive itself.

 

[Grav_Moped]

Correct, but does explain the ship explodes critical affect.

<pedant>
"effect"
</pedant>

That doesn’t make sense, it literally can’t load that capacitor in less then 18 turns.

You may be right re RAW, but that’s a helluva capacity. Not to mention that’s a big percentage of the j-drive itself.

It can, if you posit that the jump drive also burns fuel (rather than just running the power plant at a surge rate) and turns some of it into electrical energy for the capacitors.

 

[mike wightman]

Nope, I meant affect - what effect does the critical explosion of a ship in HG of LBB2 combat have on another ship...

 

[mike wightman]

Again, I prefer to read what's been written rather than jump to wrong conclusions after forty two years - let's take a look at MWM's jump article in JTAS 24 which is repeated in MgT JTAS 1.2:
" 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."

Now for the fun bit (or rather the bit I made up) - the reason that LBB2 letter drives can do this is they have their own integral fusion reactor (hence the size difference with LBB5 jump drives), while a HG drive can use the ships fusion power plant.

Because the scout is a LBB2 design rather than a HG design it is woefully underpowered for a (para)military ship. It needs at least another 3 EP for a triple laser turret (which a LBB2 scout can manage), plus another 2EP for agility IMHO

 

[mike wightman]

You could overclock the manoeuvre drive, and deliberately let it blow, though I think the rockets would be a better candidate.

Really? Do you have a canon source that hints at this?

 

[Condottiere]

There's always the potential for damage, you just tweak it to be catastrophic.

 

[Condottiere]

If you don't have scuttling charges like the Enterprise, nor a convenient gravity well nearby.

Black globe rules point to the capacitors being the most vulnerable to overloading; since it's edition specific, and since I don't see any limitations in Mongoose Second, you have the batteries just transfer one hundred and one percent energy capacity direct to the jump capacitors, which default to two hundred and fifty percent, plus fifty power points, of energy requirement of maximum potential jump capability.

 

[whartung]

Again, I prefer to read what's been written rather than jump to wrong conclusions after forty two years

Yea see, that tells me that the drive is run from the capacitors, not from the power plant, which makes me wonder why we jump through all these hoops when, apparently, all we need to do is charge the capacitors.

The unstated thing I can come up with is that the capacitors actually leak rapidly, which is why they can't simply be charged from the power plant like anything else, just over a longer period of time. (Or from solar panels, fission reactors, ponies on treadmills, etc.)

Simply, the due to their high energy, capacity, bandwidth etc. they simply can't hold a charge long enough to suit a slower charging system.

Imagine a big tank with a large hole at the top, and a smaller hole at the bottom. You can't plug the smaller hole, so you need to pour in enough water to overwhelm it and then, when it's full, simply, the entire bottom drops out and all the water is flushed at once.

 

[Grav_Moped]

IMO/IMTU the issue is that the Jump Drive's integral "hot-but-inefficient" reactor is also somewhat unpredictable in its output. They're designed to not quite top off the capacitors, with the remainder supplied by the main power plant (which can be very precisely controlled). One could have the Jump Drive provide all the power, but there's a good chance that the capacitors would either end up undercharged (no Jump) or overcharged (boom).

In theory, it should be possible to make a highly-tuned Jump Drive that doesn't need a power plant to initiate Jump* (see the canon XBoat), but there are sound engineering reasons this is seldom done in practice.

------------
*LBB2 '77 and MgT don't require a power plant to maintain the jump field while in jump space; LBB2 '81 and LBB5 apparently do, based on fuel consumption rates.

 

[Condottiere]

Initially, once alternative power sources were introduced, the reason was that starship fusion reactors could be, would be, overclocked to provide the requisite energy that a transition requires, which a fission reactor couldn't do.

 

[Spinward Flow]

Think of it this way.

The jump capacitors are normally kept at a minimum baseline level of charge (below EP=1 but not EP=0). This baseline charge level is to keep the capacitors from "seizing" and needing to be replaced due to a loss of maximum capacity.

The LBB5.80 EP requirements are essentially the "preheat the tesla car battery before fast charging" phase of the preparation to jump. You're basically "conditioning" the capacitors to "flush" them in order to be ready to accept massively overclocked power input that will then be needed for FAST output in order to jump. Without this step, all kinds of unpredictable (and unfortunate) engineering effects could potentially happen, so the safety procedure is to "preheat" the jump capacitors prior to initiating jump. The capacitors need a specific quantity of energy input over a specific span of time.

A 100 ton starship with a J2 drive will have 1 ton of jump capacitors in its jump drive capable of storing 36 EP maximum.
In order to initiate a J2, the 100 ton starship will need to expend a minimum of 4 EP from its power plant to the task over 2 combat rounds (if it can do so in 1 combat round, it jumps at the end of the 1 round). So a PP2 drive in the ship would produce 2 EP per combat turn, allowing it to generate the 4 EP needed over 2 combat turns to jump (assuming no other EP consuming systems are in use during that time). In the case of a Scout/Courier, this effectively means the ship must go Agility=0 for 2 turns in order to muster the necessary precondition energy density in the jump capacitors in order to jump.

So if 4EP are dumped into the jump capacitors to initiate a jump, and they have a maximum capacity of 36 EP ... presumably the remaining 32 EP of capacity are "needed" to complete the jump (and produce the jump flash). That's 16x the normal output of 2 EP per combat round from the power plant.

Scale those assumptions up/down for hull sizes and jump numbers.



Personally speaking, I like the idea of "pre-heat to prepare for the controlled power cascade" that makes jump drives work the way they do. The jump capacitors help "condition" the power input/output to help smooth the flow from the crazy overclock of the power plant needed to initiate jump without destroying yourself.

"I can't change the laws of physics. I've got to have 30 minutes!"

 

[kilemall]

<pedant>
"effect"
</pedant>

It can, if you posit that the jump drive also burns fuel (rather than just running the power plant at a surge rate) and turns some of it into electrical energy for the capacitors.

If you have that capability, the logical engineering choice would be to have spinal weapons get their own jump drive charge plant sans jump capability and sized to not jump, just enough to generate the EP for spinals.

You’d have finite shots, but could fire them off quickly and get the tonnage difference out of a lot less main power plant.

 

[Condottiere]

I considered that, but as I interpret the rules, the only way to discharge the charge from the jump capacitors is through a functional power plant or the jump drive.

And for the power plant, it's in lieu of generating power, not in addition to it.

 

[Grav_Moped]

If you have that capability, the logical engineering choice would be to have spinal weapons get their own jump drive charge plant sans jump capability and sized to not jump, just enough to generate the EP for spinals.

You’d have finite shots, but could fire them off quickly and get the tonnage difference out of a lot less main power plant.

It's also a lot less efficient.

16EP for each 10Td of fuel burned in/for one turn, plus the "power plant" (partial jump drive) tonnage. For a single turn, it beats TL-15 power plants.

Or, to put it another way, for each increment of Pn-16, you burn 10% of the ship's tonnage in fuel per turn (Pn-32 is 20%/turn, etc.)

 

[kilemall]

It's also a lot less efficient.

16EP for each 10Td of fuel burned in/for one turn, plus the "power plant" (partial jump drive) tonnage. For a single turn, it beats TL-15 power plants.

Or, to put it another way, for each increment of Pn-16, you burn 10% of the ship's tonnage in fuel per turn (Pn-32 is 20%/turn, etc.)

Can you step me through the 16EP per 10 ton calc? I gather you are assuming 4EP for the two turns of Power Plant to jump.

I haven’t rigorously calced this, but my sense is even with the above assumptions you end up ahead of the game for a few shots. For instance let’s say we are talking an 800 EP spinal. 500 tons of fuel per shot, vs power plant capacity to generate conventionally.

That is 800 tons of power plant at TL15. But that’s not the whole story, fuel for the plant is 800 tons. So actually two shots figuring in the partial jump drive tonnage.

The lower tech levels work out as more shots due to the multiplier space cost. 2400 tons for TL13-14, 3200 for TL9-12. TL8- is moot given no jump drive to modify.

Should probably add in the conventional jump drive feed from the main power plant, in which case the TL15 case is looking more unviable.

In extremis one could burn the jump fuel to get more shots, but not really the sort of thing to count on.

It’s the sort of kludge that looks more attractive at TL12 then higher, and presumes combat for the ship will be resolved in a few turns.

What attracted me to the concept was possibly double firing, but that would need more conventional plant to do and more importantly how often can the incredibly intense power generation be done multiple times? We’re told it’s pushing jump drives to jump again in a few hours, pouring a full load through every 20 minutes may be a big ask.

 

[kilemall]

I considered that, but as I interpret the rules, the only way to discharge the charge from the jump capacitors is through a functional power plant or the jump drive.

And for the power plant, it's in lieu of generating power, not in addition to it.

It’s a specialized modification where the main power plant feeds the spinal jump plant, and it’s capacitors are dedicated to that spinal use circuit alone.

I’m judging this from the black globe capacitor discharge rules, which makes it clear that the power plant has a power distributor limit set to the plant’s rated capacity. So any such system using a ‘jump surge’ source has to be separate from the main power feeds.

 

[Grav_Moped]

Can you step me through the 16EP per 10 ton calc? I gather you are assuming 4EP for the two turns of Power Plant to jump.

Sure.

Jump caps hold 36EP per ton, and you get 1/2 ton per Jn per 100Td "free" with your Jump drive in High Guard, so 18EP per Jn per 100Td, and presuably the jump drive uses all of it.

Jump also requires 2EP per 100Td per Jn (per HG) to initiate, which can be delivered in either 1 or 2 turns. Since the jump requires the entire capacitor load, and the power plant provides 2EP of the 18EP the capacitors hold (per 100Td per Jn), the rest (16EP) has to come from the Jump Drive's fast-burn reactor.

The 10 tons is the fuel burn per 100Td per Jn.

Basically, it's describing doing a jump fuel burn and sending the energy output into the ship's power distribution system instead of whatever creates the jump field and opens the hole into jumpspace.

I have no idea how much of the Jump Drive is comprised of the "fast burn reactor" and how much is "everything else". It's not the 1/2%Td that's the jump caps, at least.