BattleTech - The Board Game of Armored Combat
BattleTech Game Systems => Ground Combat => Topic started by: YingJanshi on 03 July 2012, 18:16:06
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Ok so I'm starting to really like using Fuel-Cell engines on combat vees, but I'm wondering if any home grown militia units would use them on a reasonably well off planet?
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By and large, not on military units. While they were technically offered and available, per TacOps, the militaries preferred to stick to ICEs. I'm not aware of any canon vehicles of that era that use them, for instance, although that doesn't completely preclude their use. They only really became popular during the Jihad. Fluff in one unit writeup or another mentioned reliability issues, as well.
During the Succession Wars, keep in mind that combat vehicle fuel cells are going to be very rare and have less military infrastructure to support and repair them than a fusion engine would. Any militia using one would be effectively dealing with a prototype design using a prototype engine. Maybe a prototype of a well-proven technology since they were used in IndustrialMechs for centuries, but a prototype nonetheless.
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Fuel Cells are mostly a development of the post-3050 era. Out of character, they were really only introduced with Tech Manual (or Combat Equipment Guide) in the 2000s, and thus most BT publications didn't address them. Working backwards, for some reason they weren't popular in published designs - ICEs dominated.
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Sort of like rockets really.
I am increasingly tempted to allow massive switch overs, especially since I have grown increasingly more aware of the main deficiencies of the fuel cell system. You get an operation range, you blow up on engine hits, you pretty much stop using energy weapons, and you aren't actually gaining a great deal, but their are some advantages, and in an age when fusion is for the king of the battlefield, the switch to a more "advanced" drive system seems to work really.
Besides, using them means less clean up after a battle!
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Well, fuel cells are clearly superior to ICEs, and the only thing really keeping them in check are fluff reasons. Even their supposedly lower operational range (unlikely to come up often at the playing table) is to some extent a myth -- fuel cell engines are actually more fuel efficient than internal combustion, they just carry a smaller fuel supply with them by default.
(Using the factors given by the TacOps fractional accounting rules for simplicity's sake, fuel cell engines weigh 60% of their ICE equivalent while getting 75% of their range...and the same ratio holds true for their fuel tanks, where investing 10% of the engine's weight adds its base range again. Not using fractional accounting complicates this somewhat with rounding errors, but the basic principle still holds.)
So, really, if the fluff wasn't holding them back, there'd be no reason not to upgrade every single ICE-powered vehicle in existence to fuel cells straight away.
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A minor problem with fuel cells is that they are three times as expensive as ICE's, which puts them at a price point where they are compared not with ICE's but with SFE's. There, the weight saved by less shielding must be balanced against the nine free tons of heat sinks. But for militia vehicles on a well off planet, where energy weapons are limited to a single small laser, FC powered vehicles are a clear way to signal wealth, without needing lots of fusion techs.
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A minor problem with fuel cells is that they are three times as expensive as ICE's, which puts them at a price point where they are compared not with ICE's but with SFE's. There, the weight saved by less shielding must be balanced against the nine free tons of heat sinks. But for militia vehicles on a well off planet, where energy weapons are limited to a single small laser, FC powered vehicles are a clear way to signal wealth, without needing lots of fusion techs.
As I said, fluff reasons. It's not like C-bill costs have an actual game effect unless one practically drags them kicking and screaming into the game, after all. :)
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A minor problem with fuel cells is that they are three times as expensive as ICE's, which puts them at a price point where they are compared not with ICE's but with SFE's. There, the weight saved by less shielding must be balanced against the nine free tons of heat sinks. But for militia vehicles on a well off planet, where energy weapons are limited to a single small laser, FC powered vehicles are a clear way to signal wealth, without needing lots of fusion techs.
Where (and how) are you getting those fuel usage figures from? Last time I did the math FCE paid 90% the cost an ICE did for a given operational range (FCE 1.5% per 500km Vs. ICE 1% per 500km, FCE is 60% weight of ICE so 1.5 *0.6 equal 0.9 or 90%)
If your using energy weapons an SFE is better, but for designs like the Vedette or Demolisher? Because they don't use energy weapons the SFE isn't better
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Where (and how) are you getting those fuel usage figures from? Last time I did the math FCE paid 90% the cost an ICE did for a given operational range (FCE 1.5% per 500km Vs. ICE 1% per 500km, FCE is 60% weight of ICE so 1.5 *0.6 equal 0.9 or 90%)
If your using energy weapons an SFE is better, but for designs like the Vedette or Demolisher? Because they don't use energy weapons the SFE isn't better
I was not talking about fuel usage, at all. I was simply referring to the engine cost formula. SFE's are 5000 times a function of rating and vehicle mass, ICE's are 1250 times the same function, and FCE's are 3750 times the same function, so, for a given rating, FCE's are three times the cost of an ICE and 75% of the cost of an SFE. While not quite as bad as mechs, where everything after the engine and gyro is nearly free, you could be able to get two slightly less effective ICE vehicles for the same price as FCE vehicle.
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How much do crew's cost?
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Depending on the vee a FCE offers a lot more than a slightly more efficient vehicle. A standard Bulldog gets an extra 10 tons to add to its payload. An LRM Bulldog gets 9 tons. So does a Demolisher. Allowing a Demolisher to boost armor by 50% and double its ammo capacity seems more than a slight improvement. An Ontos adds 13 tons to its payload when switching to an FCE. And the price tag increase I get is not quite so severe as suggested. Including the extra weapons and armor you can add the increased price tag has been generally 50% - 60% higher.
So in many cases (not all) you get 2 much more efficient FCE vehicles for the price of 3 ICE vehicles.
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I was not talking about fuel usage, at all. I was simply referring to the engine cost formula. SFE's are 5000 times a function of rating and vehicle mass, ICE's are 1250 times the same function, and FCE's are 3750 times the same function, so, for a given rating, FCE's are three times the cost of an ICE and 75% of the cost of an SFE. While not quite as bad as mechs, where everything after the engine and gyro is nearly free, you could be able to get two slightly less effective ICE vehicles for the same price as FCE vehicle.
Sorry rlbell looks like I quoted the wrong person
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Post SW I like to use Fuel Cells. During SW you want to stick with what is already out there, so ICE would be the better decision.