LLB:2 Drives, LBB:3 Tech Levels and High Guard Jump Drive

[ddamant]

I found a slight anomaly between LBB:2, LBB:3 and High Guard, specifically concerning Jump Drives.

High Guard indicates Jump 1 is available at TL9, J2 at TL11, J3 at TL12, J4 at TL13, J5 at TL14 and J6 at TL15.
LBB:3 indicates at which TL certain drives become available, with letters A-D coming in at TL9, E-H at TL10, J-K at TL11 and so forth.
LBB:2 has a 100 ton Scout ship with Jump A-Drive (achieving Jump 2), which by the book would be available at TL9. Indeed if we go by the drive table then 100 ton scouts can achieve Jump 6 at Tech Level 9 with a Jump C-Drive.

So, my question is: has anyone attempted to tie the three books together regarding Jump Drive TL availability and the LBB:2 Starship drives table? If I was too take all three books into account then 100 ton scouts would not be possible to build until we reach TL11 (when J2 becomes available). At TL 9 when Jump Drives are introduced only ships between 200 and 800 tons could be built (since only Drives A-D are available and J1 is the limit). We can assume that engines are not miniaturized enough for 100 ton hulls or large enough for bigger hulls to enter jump space.

I realize that Jump Drive distance and Tech Level are not correlated in the original 3 books. I am just curious if anyone has noticed this and what they did about it.

 

[MThompson016]

An easy way to square the circle is to make it a computer limitation. The programs to control a J-drive for distances greater than those in High Guard are due to the problems of hyperspace physics and computation.

The programmers don't have the theoretical knowledge to run a J-drive beyond the mentioned distance.

 

[infojunky]

Well, High Guard says both systems are valid... Book 2 uses book 2 and High Guard uses High Guard.

Is that a problem?

Note there is the larger question of what Ship combat rules you are using. As well the of what sort of game are you running.

 

[Grav_Moped]

Jump range and TL are not directly correlated in LBB2, aside from the computer TL requirements (only matters at TL9, no J4 because Mod/4 computer is TL10). The limit is range by hull size, and how big a drive and its fuel can be crammed into a hull.

IMTU I posit that LBB2 describes/enables exceptions to the TL requirements for Jn, if you have the appropriate computer. That is, if everything fits and you're using LBB2 components and fuel requirements, you get the LBB2 performance. For anything other than that, you're limited to what HG allows.

This is not true for the initial discovery of Jump capability for each Jn. Until your civilization has figured out that higher Jump numbers are possible, you're limited to what HG allows.

In other words:
TL 9: J1 any size, and J2-3 possible for 100-200Td (note: constraint is computer, drives can be J4)
TL 10: J1 any size, and J4 possible 100-400Td, J3 100-600Td, J2 up to 800Td
TL 11: J2 any size, and J4 possible for 100-400Td, J3 100-600Td
TL 12: J3 any size, and J6 possible for 400Td, J5 200-400Td, J4 100-600Td
TL 13: J4 any size, and J6 possible for 400Td, J5 200-600Td
TL 14: J5 any size, and J6 possible for 400-600Td
TL 15: J6 any size, but you still can’t get J6 into a 100Td hull (HG rules let you build J6, approx. 130Td).

Some notes:
Td = Tons Displacement
- J4 in a 100Td hull is an XBoat (there's room for the drives, fuel, controls, and pilot and nothing else, not even a maneuver drive or any more fuel than needed to keep the power plant running at Pn 6 for the duration of Jump). J6 in a 400Td hull is pretty much the same concept.
- Use of drop tanks (TL 12+) changes this significantly. You may choose to only allow drop tanks with drives/ships built under HG rules, or use "strict" drop tank rules (drop tanks must be retained through Jump rather than being jettisoned immediately before Jump).

 

[AnotherDilbert]

Custom-built drives must be produced and installed while observing restrictions as to tech level and interior space. It is possible to include standard drives (at standard prices) from Book 2 if they will otherwise meet the ship's requirements; such drives use fuel as indicated by the formulas in Book 2.

Note that custom (HG) drives must obey the TL limitations, standard (LBB2) drives do not.

LBB2 drives are mass-produced standard drives with standard connectors, installable by any shipyard in the Imperium.

I would not allow TL15 drives (V+) in a TL14 setting, such as the Zhodani Consulate or the Solomani Confederation.

 

[Brandon C]

Note that custom (HG) drives must obey the TL limitations, standard (LBB2) drives do not.

... Why?

I've seen a lot of pretzel logic in this thread trying to say two incompatible things are true.

Sorry, pick one and change the other to fix it. Personally, I would ignore the TL limits on drive size and go with the TL limits on drive performance.

 

[vegas]

My preferred solution is to allow Bk2 jump drives and disregard the TL restrictions in HG (for other than HG-designed drives). My explanation is that these represent different architectures of achieving jump (my technobable is that Bk2 is "two-stage, integrated" architecture while HG is a "discrete" architecture.)

 

[AnotherDilbert]

... Why?

Custom-built drives must be produced and installed while observing restrictions as to tech level and interior space. It is possible to include standard drives (at standard prices) from Book 2 if they will otherwise meet the ship's requirements; such drives use fuel as indicated by the formulas in Book 2.

Custom drives observe the TL limits.
Standard (LBB2) drives apparently does not.

 

[Brandon C]

Custom drives observe the TL limits.
Standard (LBB2) drives apparently does not.

It can be argued that Book 5 supersedes Book 2/3 if it is used.

I find it makes much more sense to limit technology by performance, not size, at a given TL. While I have a soft spot for Books 1-3, I have no problem dropping or changing rules from them if they don't make sense.

 

[AnotherDilbert]

It can be argued that Book 5 supersedes Book 2/3 if it is used.

I find it makes much more sense to limit technology by performance, not size, at a given TL.

I quite agree, but the passage I have quoted twice seems to disagree...

 

[infojunky]

It can be argued that Book 5 supersedes Book 2/3 if it is used.

Yes, and by that argument book 2 designs are still valid as per book 5...

The question still comes down to how do you want to treat jump drives, there rest is superficial. Also consider the actual number of high jump ships you can actually create with book 2.

Also one should note that High Guard lumps TL 9 through 12 into one broad category for a lot of things, thus the incremental validity of those tech level are suspect when it comes to this topic.

 

[Keklas Rekobah]

In another thread (I forget which one) someone (I forget who) came up with the idea that LBB2 j-drives have more governors, feedback loops, and other “protective” systems because they’re designed for the average civilian to operate without constant monitoring and adjustment; while the LBB6 j-drives are intended for military operations where performance is slightly more of a consideration than safety of the engineering team, and there is always someone on watch to keep things going. Military j-drives must also sync up more accurately with other vessels than civilian j-drives.

 

[mike wightman]

LBB2/3 drive paradigm is different in more ways than TL to HG drive paradigm.
Despite HG claiming compatibility it is just grandfathering and superficial similarity.

CT builds a different universe to a HG universe, and there are even differences between CT editions. Under 77 LBB2/3 jump 6 is possible at TL9 (with drop tanks), under 81 CT the jump is limited by computer model/TL.

 

[vegas]

@Mike,

Yes, but...

At least for maneuver and jump, B2 and HG work out close enough to the same, provided that the J rating equals or is greater than the M rating. It turns out that the vast majority of canon Bk2 designs have that feature (the most important exception being the patrol cruiser)

 

[mike wightman]

Like I said - superficial similarity when taken as a package deal.

Under LBB2 the jump drive is big, the m-drive is small; under HG this is reversed.

Make a jump 2 maneuver 2 ship under either system and they are similar enough in performance, but there are cost differences.

Then there is the difference in power plant and power plant fuel formulae...

People have tried for years to reconcile the irreconcilable - they are different paradigms . Pick one, or use them both by having a fudge about the letter drives being what a TL15 culture can make at lower TLs (which is how I have done it).

Whatever works for the universe you wish to describe.

Alternatively just use a more modern set of rules that don't have the dichotomy.

By the time MT was released there was no letter drive, the OTU was described using the HG TL paradigm of discovering higher jump numbers with advancing TL. MgT, T20, GT, T5 all have only one drive paradigm (MgT1e went back to letter drives but their drive formulae in HG1e was based on the letter drive progression rather than the CT-HG contradiction.

A universe where high jump numbers are possible at low TLs thanks to the letter drives is interesting for an exploration based campaign.

 

[AnotherDilbert]

CT builds a different universe to a HG universe, and there are even differences between CT editions. Under 77 LBB2/3 jump 6 is possible at TL9 (with drop tanks), under 81 CT the jump is limited by computer model/TL.

LBB2 and LBB5 are both CT?
Drop Tanks are only LBB5, not LBB2?

 

[mike wightman]

LBB2 and LBB5 are both CT?

Yes, they are both CT.
Superficially they are very similar, in fact they are very different paradigms.
TL progression for drives, size of drives, cost of drives, ship size limitations, combat resolution.

Drop Tanks are only LBB5, not LBB2?

I said if...
if you port stuff from HG into your LBB2 ship universe you can get ships like the Gazelle.
(edit note - a jump 6 x boat is doable under 77 LBB2 but requires the x-boat no power plant fudge, even without that fudge you can get a 200t ship with jump 6 and md/pp1 at TL9; there is one final fudge in that the TL of drives A-F is not listed in LBB3 )

The jump governor first made an appearance in HG79 and then became a standard feature of drives for HG80 and the revised 81 LBB2 (so standard it was never mentioned again, it just became a feature of how jump drives use their fuel).

 

[BlackBat242]

Another way of looking at things is that the TL limit in B5 is intended for a ref creating new civilizations - this is where the TL determines what J-capability can be achieved.

B2 is for a long-established civilization - where high-tech things (j-drives) have been re-engineered so they can be manufactured and repaired by lower TL companies & facilities - which is why B2 J-drives are so large compared to B5.

A B5 drive has been built at at least the proper TL - thus all components are smaller, etc. The B2 drive has likely been manufactured a couple of TLs lower that what it was developed at, thus the components are larger etc.


As an example, you could build a cell-phone with the capabilities of a modern phone using TTL chips etc (late 1970s tech) instead of "large-scale compact chips" (1990s & later tech), but it would be the size of a briefcase, and operate a bit "slowly". This despite cell-phone technology having been developed in the 1980s.

 

[Grav_Moped]

The reason HG maneuver drives are large is to force design trade-offs when building combat vessels. In LBB2, this was accomplished with the power plant fuel requirements in the smaller ships that PCs have access to. HG's imposition of power requirements for energy weapons (and reduction of fuel requirements) meant that almost any combat ship would have a power plant big enough to run a 6G drive if only in Emergency Agility mode, and if you simply scaled up LBB2's formulas, plenty of room to fit the drive in. Thus, maneuver drives had to be enlarged to make high-G designs harder to build.

On the other hand, a Jump Drive doesn't affect combat capability aside from being a means of escape or an energy sink for a Black Globe. And its big "cost" is the fuel requirement. Therefore, its space requirements could be reduced without changing the design process significantly -- and meanwhile, this would allow ships with similar "engine room size" to LBB2 ships so pre-existing canon deck plans could be grandfathered in without major changes.

That's the out-of-universe explanation. In-universe? There isn't one, really. We're left to come up with our own.

Mine is the aeronautical axiom that you can make a brick fly if you give it a big enough engine (as with the F-104 fighter jet). IMTU, this only works with the LBB2 standard drives, and "how big" is limited by TL as per LBB3. Otherwise, you have to know how to build just the right drive to get the desired Jn, and that knowledge is a function of TL. Doing it that way gives you the HG drive size requirements.

That said, I concur with BlackBat242 that the HG TL limitations apply to civilizations developing a particular Jump level for the first time. That's probably a function of not knowing how to control such Jumps (that is, the constraint is the ability to write the Jump-n and requisite Generate computer programs).

This paradigm allows for technologically mature civilizations to have high-Jn couriers/express boats that can be maintained at lower-TL starports.

Something that doesn't get mentioned much, though, is the other side of the engine bay: under LBB2, a 6G, 2000Td ship uses a TL15 size Z drive; if it can get by with just the Size Z powerplant (no energy weapons or can tolerate reduced agility to fire them) the MD+PP+fuel comprise 9% of the ship and cost 288MCr. The HG equivalent (at TL-15) with fuel is 26% of the ship and costs 377MCr. However, 2000Td is the largest hull that can have a drive rating of 6 (any drive) under LBB2 rules, so there's an upper limit to this loophole.

 

[ddamant]

I think, at least for me personally I found the answer to my problem. It lies in Travaller 5. Now yes that game is a mess. However, it has slick rules for Ship Drives and Power systems.

T5 uses the same letter codes as LBB2 but incorporates Tech level limitations and advantages based on when a piece of technology is either discovered or being tested. Want Fusion Plants at TL 7 vs TL9? Sure. But they will cost a fortune, be much bigger and their efficiency (power generation) and fuel consumption will be terrible.

This system integrates the Drive Size by TL, Jump Drive by TL and generally solves my initial problem.