Compact KF drives were not the hurtle the IS had with Warships?

[Daryk]

To get plasma up to a significant fraction of c, electricity absolutely has to be involved.  Heck, even just pointing it in a direction involves electricity (and lots of it).

[Maingunnery]

To get plasma up to a significant fraction of c, electricity absolutely has to be involved.  Heck, even just pointing it in a direction involves electricity (and lots of it).

If I wanted fast plasma, I would just open up the magnetic bottle of the reactors towards the aft and make sure that the reactor makes the plasma as hot enough as possible. It would take a bit more electricity for some extra magnetic fields, but that is hardly anything compared to the thrust.

If you mostly rely on electricity then you are going to have massive conversion losses.

[Takiro]

More useful than no warship at all.

And why no one thought of it is certainly a mystery.  There's plenty that you can cram into a 100,000 ton warship that can't be installed in DropShips...

Ooh, sounds like a design challenge waiting to happen.

Sorry to come to this thread so late or too early. I designed the Vanguard class Corvette based on the Behemoth back in February of 2010. Know I posted it but can't find it here, probably lost in the great board crash of 2011, so I will post it again now. Basically it was an alternate FedCom testbed which began research and development after the War of 3039. Also it ties in on another discussion I am having on TAG (or Tharkad Aerospace Group) as I call them.

All reposted now -
https://bg.battletech.com/forums/index.php?topic=63136.0

My fluff is obviously for an alternate setting as if you want to canonize it I would have more ComStar and Great House espionage efforts to derail construction which would have kept it from launching before the Clan invasion when resources and the start of the Invincible Project (aka the Fox) would have discontinued the Vanguard. Please note that existing vessels while flawed could still have served as valuable training ships for rebuilding InnerSphere warship crews.

[Liam's Ghost]

The physical mechanism of which thrust is gained is different then that of electricity. To have WarShip levels of electric power one should have the high capacity energy conversion
See it like having a heat source and using it to heat up a green house, it can be done directly using circulating heat or converting the heat to electricity and back again (with the associated conversion losses). Using reactor plasma for thrust is very direct, but to get electricity will require some conversion.

And yet, still doesn't explain why two drives operating on the same principles and able to produce the same amount of thrust would have different abilities to generate electricty.

[Maingunnery]

And yet, still doesn't explain why two drives operating on the same principles and able to produce the same amount of thrust would have different abilities to generate electricty.

Why bother assuming that the drive technologies are completely the same?
For example: Piston and turbine engines can both produce torque and use fossil fuels, but they aren't the same. 

[Daryk]

Bending fluff to inconsistent rules is inferior to bending rules to consistent fluff.  Above the quantum scale in the real world, consistency is the rule.

[Liam's Ghost]

Why bother assuming that the drive technologies are completely the same?
For example: Piston and turbine engines can both produce torque and use fossil fuels, but they aren't the same.

Why assume they aren't? The fluff indicates the transit drives of all large craft operate on the same principles (which is explained in strategic operations). The universal technology advancement table in Interstellar Operations doesn't even differentiate between dropship and warship transit drives. It's all just "maneuvering/station keeping drive components".

Clearly the difference is scale, not technology, and when you get to Behemoth sized ships, purely arbitrary.

Really, it's the Behemoth's fault for being so big.

[Maingunnery]

Why assume they aren't? The fluff indicates the transit drives of all large craft operate on the same principles (which is explained in strategic operations). The universal technology advancement table in Interstellar Operations doesn't even differentiate between dropship and warship transit drives. It's all just "maneuvering/station keeping drive components".

Clearly the difference is scale, not technology, and when you get to Behemoth sized ships, purely arbitrary.

Really, it's the Behemoth's fault for being so big.

Because both rules (weight, fuel efficiency, number of integrated HS) and fluff (no DS with capital energy weapons) present different performances.
As both Turbines and Piston engines might be abstracted as ICE engines in BT, they are different technologies in RL.

[Liam's Ghost]

Because both rules (weight, fuel efficiency, number of integrated HS) and fluff (no DS with capital energy weapons) present different performances.
As both Turbines and Piston engines might be abstracted as ICE engines in BT, they are different technologies in RL.

And yet the fluff says the dropship and warship engines operate on exactly the same principles. Unlike your piston engine and turbine, which don't. They're all fusion rockets that primarily function by firing an insanely fast stream of fusion byproduct out the back. Any differences are a factor of size, not design. Every vessel capable of strategic movement (heat expansion mode in the fluff) shoots fused helium out the tailpipe for thrust. Vessels in tactical mode (standard movement) use a combination of fusion byproduct and unfused hydrogen reaction mass, with the fraction of reaction mass increasing as the size of the drive decreases. Larger craft use almost no reaction mass and derive their thrust almost entirely from fusion byproducts, the smallest example given, light aerofighters, rely entirely on unfused hydrogen.

It's the same principle, producing the same thrust output. It's silly to assume it's somehow different when it's exactly the same and has no reason to be different. There are any number of reasons why dropships wouldn't be allowed capital weapons (power distribution, structural concerns, the fact that almost every dropship in existence is so much smaller than a warship that it's entirely reasonable that they couldn't produce the power output to support capital weapons).

Handwaving "It's different because reasons" is still just handwaving to cover up that the disconnect is a bug in the construction rules, not a feature. Almost every other dropship sorta works under these rules because they're small enough that the gaps in the rules isn't visible. The Behemoth is just too damn big.

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[Jellico]

Bending fluff to inconsistent rules is inferior to bending rules to consistent fluff.  Above the quantum scale in the real world, consistency is the rule.

And both are slaves to Gameplay.

[Liam's Ghost]

My understanding is that the scale gap between DropShips, and downward in tonnage, and JumpShips and WarShips is entirely due to the size of JumpDrives, JumpSails and batteries and energy conversion and transfer equipment. Otherwise, jump capable ships would scale through all the sizes through all types of spacecraft.

Transit drives (anything other than a Jump Drive) operate on fusion thrusters for all scale of spacecraft, from the huge triple nozzle WarShips , through single engine fighters, to nimble, multi-nozzle fusion powered VTOLs.

Ergo, it may be that the main reason that DropShip sizes don't scale upward smoothly to classic WarShip size is that JumpShips can only have so many Docking Collars.

Anything you build that cannot attach to a Docking Collar is NEVER going to leave that star system.

While it may be that you can build ships to any scale on the standard fusion thruster, it probably isn't the case, economically, to build any DropShip that could not be fit onto a standard Docking Collar, (or two). Thus, over the centuries, tooling and construction equipment would probably be optimized to assemble DropShips at the scale this requires. Otherwise, any specialized size over that will have to be built within it's destination system, requiring all the shipyard and support facilities that implies.

Don't misunderstand, I'm in no way advocating that dropships should get bigger. The current construction rules can't accommodate it (and I don't mean they don't allow it, I mean that if they did they'd break), and even if we had a rulesystem that could build a non jumping, warship sized ship without it coming out horribly broken, I wouldn't advocate it, because it's all kinds of pointless. Even the Behemoth isn't all that practical. It needs two docking collars, can't enter the atmosphere (a real problem when you don't have the infrastructure onsite to quickly unload it), and it does all that to carry twice the cargo of a Mammoth, which has literally none of its limitations. Two mammoths have a higher startup cost, but long term, they'll make all that up in flexibility.

The limitation on dropship size is a good thing.

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[Maingunnery]

And yet the fluff says the dropship and warship engines operate on exactly the same principles. Unlike your piston engine and turbine, which don't. They're all fusion rockets that primarily function by firing an insanely fast stream of fusion byproduct out the back.

Don't forget the abstraction in BT. For BT, both Piston and Turbine engines are abstracted into ICE engines. Which is quite understandable, as they can use the same fuels, operate on the same basic principles (They're all combustion engines that primarily create rotary movement from fossil fuel combustion byproduct.), but do rely on different technologies/alloys. A factory that makes one type can't quickly switched over to producing the other.

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[Liam's Ghost]

Don't forget the abstraction in BT. For BT, both Piston and Turbine engines are abstracted into ICE engines. Which is quite understandable, as they can use the same fuels, operate on the same basic principles (They're all combustion engines that primarily create rotary movement from fossil fuel combustion byproduct.), but do rely on different technologies/alloys. A factory that makes one type can't quickly switched over to producing the other.

The abstraction is rules, not fluff. I don't know how many different ways I can say that the fluff says they operate the same way.

[Maingunnery]

The abstraction is rules, not fluff.

The fluff doesn't go into detail, it is abstracted.
We have multiple points where there are differences, and that is to be expected as both have to meet different requirements.

Someone might be able to mount an DS engine on a WS frame, but that will have side-effects.

[Chaotic,Blues]

Here's my theory on the subject, with two points I have noticed.

1 Both warships, and dropships use similar (but different) fusion drive technology.
2 Given what we know about capital weapons, aside from their shear mass, there is no reason a dropship couldn't use a Naval AC, or PPC.  Any ship over 50k should be able to mount these weapons without any known problems.

My theory is that dropships use Duterium based fusion drives.  Warships on the other hand use Helium 3 based drives.  What we suspect of Helium 3 based fusion, is they (might) have better power to weight rations, and require far less shielding then Duterium based. 

If everyone (out side of the wobbies, and the Com Star) assumes the drives are using the same fusion that dropships use, then the drives they create may not be able to power naval weapons effectively. 

This however, fall short when talking about naval ACs.  As I can't think of a logical reason why a large dropship can't be equipped with them as well as Capital missiles.  Also I'm assuming that fuel is just propellant, and not needed to actually run the power plant of the either craft in question.