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Question, was/is/will there be any diagrams, drawings or whateer of a fusion engine with its various, variants? Occured to me the books talk a lot about 'The light fusion engine is.. etc, the XL engine is.. etc' and about armor shielding around it, but what Is the fusion core made of, acellrator rings and coils, boxes.. what?

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Aha.. ok that can work with. becuase ive been staring at TDB and BMR and MT for.. almost a week non stop and some things have hit me about general construction fromsensors to skeleton and engines itself a way to redesign and still be within the general BT rules some things; is why i asked wanted to have a general idea of what the 'core looked like, tanks. heh

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i'm very doubtfull that tokamaks could be scaled down to such small sizes.

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i wasn't aware FASA wanted the engines to use simple hydrogen as fuel. Looks like they didn't do much research about it. but well, it's fiction and demanding to much realism and depth of detail is asked to much.

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btw, was there any reasoning or try to explain why the fusion engines are suposed to explode?

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A good question. This was discussed at length in a multitude of BT books.

The older MaxTech provided game rules on the engine explosions. However, in those rules is an interesting statement to the effect of, "Fusion engine explosions are physically impossible, but since they're fun and appear in the fiction, here's the rules."

The CBT:Companion has the current, most detailed description of the explosions (though no rules). The Companion's writing about fusion engine explosions is one of those cases where the writers were constrained by canon produced by the novel writers. The CBT:Companion writers damn well knew the engine explosions should not happen and, yes, were referencing current fusion research websites, but since explosions had been written into the game so often, the writers had to come up with some explanations.

Fortunately, the writers were able to do some quick calculations on latent heat and the basic gas laws, which provided a suitable explanation for 99% of fusion engine explosions. While the hydrogen in a fusion engine is below a milligram at operating temperature, the operating temperature is so high that when the engine is punctured and ambient air rushes in to fill the vacuum chamber, the air is flash-heated to several thousand degrees. Naturally, it expands. Vigorously. And at those temperatures with flash vaporized reactor lining entrained in the air, it creates quite a light show. Since it takes enormous damage to puncture the reactor, this sort of "explosion" tends to occur at about the same time the battlemech is falling apart. This leads to the over-used BT fiction cliche about a lambent ball of fire bursting out of the battlemech. It's not a real explosion. (And note that the hydrogen-oxygen combustion reaction plays no role in the event.)

The much rarer form of fusion engine explosion involves an intact reactor, a ballsy and stupid mechwarrior, and (again) latent heat in the plasma. Now, normally, the dead mass of the reactor vessel is enough to soak the latent heat of plasma in a complete containment failure. As was stated in 1986 in the BT 2nd edition rule book, and as was stated in the 2004ish CBT:Companion, this will frag key components of the reactor, but you won't have an explosion. However, the reactor shielding and vessel is not a model of thermal conductivity.

That leads to the deliberate "Stackpole" explosion, so named for the novelist that popularized it and caused so many headaches for the folks trying to write realistic descriptions of 'mech fusion reactors. In the Stackpole, a mechwarrior "floors the gas pedal" on his reactor, running up its power output as high as possible so the plasma is holding as much heat as possible, then kills the magnetic containment system as fast as possible (often by lobotomizing the engine control computers in the cockpit). The plasma expands, hits the reactor wall, and starts flash-cooling.

Given enough TIME, the total amount of heat left in the plasma would only leave the exterior of the reactor scorching to the touch (basic heat capacity calculations again), but there isn't time. At a couple bajillion degrees (bajillion is a very technical term used in fusion engineering to describe plasma temperatures ), the plasma ions will all very quickly collide with the reactor walls, giving them a chance to quickly dump their heat into the cold metal and ceramic. Again, these aren't very thermally conductive materials, so they can't move the heat quickly. What happens is that the innermost liner evaporates, spiking reactor pressures way beyond their design limits. (And, again, hydrogen-oxygen reactions play no part in the explosion.)

In short, you get a very high tech boiler explosion out of the deal.

Really, given a chance, the writers wouldn't even allow those explosions, but some novelists got away with it and didn't have a fact checking overview, so now BT is stuck with exploding fusion engines.

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but MHD in general is the physics branch that applies to tokamaks (all the problems the fusion people have are MHD and material problems, the fusion itself ain't so difficult) so mentioning MHD doesn't necesarily mean MHD generators.

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theres also never anything mentioned about radiation protection when maintaining the engines.

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Really, given a chance, the writers wouldn't even allow those explosions, but some novelists got away with it and didn't have a fact checking overview, so now BT is stuck with exploding fusion engines.

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However, handling of low level to intermediate level wastes, mostly in form of fine dusts does conflict quite a bit with open fiel repairs. that's things that need to be done in underprezurized buildings, with lot of care, to prevent incorporation of radioactive dusts.

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Actually it's an interesting problem, everything that's ever writen becomes part of the universe, and can't be undone. so if some writers go on a fantastic rampage it takes a lot of handwaving from more tech oriented people to get a consistent universe with similar laws of nature as ours.

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Actually it's an interesting problem, everything that's ever writen becomes part of the universe, and can't be undone. so if some writers go on a fantastic rampage it takes a lot of handwaving from more tech oriented people to get a consistent universe with similar laws of nature as ours.

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*cough*aliens*cough*

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YEah i never really understood the fusion engines in BT either. you can have a 10-rated fusion engine that fits under your 87' honda's hood? And it can power a bunch of lasers and whatnot?

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You can power lasers with a little dynamo hooked up to an exercise bike, it'll just take quite a while to charge up their capacitors.

And note even a 10-rated ICE can charge lasers in one turn with the aid of a power amplifier.

There's several estimates running around about the energy output of BT lasers. At the high end, it is fairly impressive for small engines to power lasers.

However, at the lower value of 12.5 megajoules, you'd need an engine with a few thousand kilowatts (or horsepower) of power output to charge a laser for one shot per turn. While that sounds impressive, there are gas turbines today that deliver 6000 horsepower for less than 500kg. Asking a fusion reactor to deliver several thousand horsepower shouldn't be a problem.

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As for it exploding....

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The CBT:Companion has the current, most detailed description of the explosions (though no rules).

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