Idea for Change to Book 2 Designs

[Spinward Flow]

If I had my notes handy, I could work out the point below which the combination would put out less than 1EP.

I'm not sure we're doing the same thing here.

In my example, the drives are fixed for tonnage and cost (so a drive-A is a drive-A regardless of what you install it into) ... it's just the performance that changes (as demonstrated above). The flipside to that is that a power plant-A drive will ALWAYS produce 2 EP, while a power plant-B will ALWAYS produce 4 EP (and so on and so forth up to power plant-Z producing 48 EP). Whether or not a small craft actually USES all of that EP output is a different question ... at which point power down rules can come into play.

So a 30 ton Ship's Boat with a 6G maneuver drive (drive-A) will need 1.8 EP to achieve Agility=6 (because 30/100*6=1.8).
A power plant-A standard drive will produce (up to) 2 EP ... however, absent weapons and computer, only up to 1.8 EP are required for Agility 6 maneuvering. This then means that the power plant could be "powered down" to deliver only 1.8 EP (90% of max power) full time as a matter of routine operating procedure and thus only require 1.8 tons of fuel per 28 days because of 1.8 EP required to maneuver at full agility.

The point being that you can always "use less power" than a power plant is capable of generating.
Using "more power" than a power plant is capable of generating (temporarily) is a matter of Emergency Agility ... which presumably cannot be used "forever" but LBB5.80 places no real restrictions on the use of Emergency Agility (other than disabling offensive capability in favor of a "purely defensive" posture for the combat round).

If you want to create (house) rules for how long Emergency Agility can be used for, I would recommend pirating borrowing from the LBB2 rules for use of the Double Fire program. Roll 1+ on the first round that Emergency Agility is used to avoid a breakdown ... +1 DM per round that Emergency Agility has been used previously, -1 DM per round that Emergency Agility was not used previously (minimum 0 DM). That way, you can use Emergency Agility "for a while" when you need to, but you can't use it indefinitely because it does place a strain on the drive systems to sustain.

 

[Grav_Moped]

I'm not sure we're doing the same thing here

We aren't.

You're extrapolating what Size A Drives do in hulls under 100Td. I'm extrapolating drives smaller than Size A, so you can make the 20Td 1G Launch (as one example).

Continuing my point above, a LBB2 power plant of 2.5Td produces 1EP (the formula is 1.5Td per EP + 1Td). If the m-drive is scaled linearly (it won't, but let's say it does), half of a Size A m-drive (0.5Td) uses that 1EP. So, only (combined small-craft) drives of 3Td and larger have a 1EP output; any smaller and they do not produce any (available) EP because the power plant component would be too small.

3Td works out to 120 G-Tons (4g in a 30Td hull) in that it's 60% the size of Size A drives with 200 G-Tons output.

If you need extra EP in a small craft, add a separate power plant, or just go with a Size A one from the start. (Need to sort out how big the m-drive actually would be in that case -- this is just working out the principles involved).

 

[Spinward Flow]

I'm extrapolating drives smaller than Size A

Okay, that is going in the other direction of scaling the drive (down) rather than scaling the performance (up).

Continuing my point above, a LBB2 power plant of 2.5Td produces 1EP (the formula is 1.5Td per EP + 1Td). If the m-drive is scaled linearly (it won't, but let's say it does), half of a Size A m-drive (0.5Td) uses that 1EP.

The problem with scaling "in that direction" is that the drives are no longer standard (the whole point of the LBB2 drive paradigm) ... instead, they're CUSTOM (which is the province of LBB5.80).

My perspective is that the drives are NOT scalable in terms of tonnage and cost.
There is no "1/2 drive-A" like you're providing here.

(Need to sort out how big the m-drive actually would be in that case -- this is just working out the principles involved).

You're going to run into a problem detailed in LBB5.80, p34.

No maneuver drive or power plant may be less than one ton; when a computation produces a drive of less than one ton, use a value of one ton

From my perspective, that's TWO strikes against the notion of a "1/2 maneuver-A drive" like you're exploring, since (full size) maneuver-A drives are 1 ton to start with.

Just because you can mathematically "convince" yourself the option is there (by formula), doesn't necessarily mean that is actually IS there.

It's the same reason why even though the quadratic equation will give you 2 answers for the values you plug into it, you still have to PROOF both answers you get out of the equation as valid ... because sometimes the quadratic equation will give you answers that "don't work" when you try to use them. Just one of those fun little bits of algebra where a formula can help you arrive at the WRONG conclusion with confidence!

 

[Grav_Moped]

Okay, that is going in the other direction of scaling the drive (down) rather than scaling the performance (up).

The problem with scaling "in that direction" is that the drives are no longer standard (the whole point of the LBB2 drive paradigm) ... instead, they're CUSTOM (which is the province of LBB5.80).

My perspective is that the drives are NOT scalable in terms of tonnage and cost.
There is no "1/2 drive-A" like you're providing here.

You're going to run into a problem detailed in LBB5.80, p34.

From my perspective, that's TWO strikes against the notion of a "1/2 maneuver-A drive" like you're exploring, since (full size) maneuver-A drives are 1 ton to start with.

Just because you can mathematically "convince" yourself the option is there (by formula), doesn't necessarily mean that is actually IS there.

It's the same reason why even though the quadratic equation will give you 2 answers for the values you plug into it, you still have to PROOF both answers you get out of the equation as valid ... because sometimes the quadratic equation will give you answers that "don't work" when you try to use them. Just one of those fun little bits of algebra where a formula can help you arrive at the WRONG conclusion with confidence!

I'm working toward small craft drives that are consistent with LBB2, rather than abandoning it entirely for LBB5. The problem with keeping to the Standard Letter Drives is that they do not scale down far enough (cannot be used to construct the Lifeboat and Fighter). Keep the formulas but not the letters, and they can, mostly.

Fuel is a separate issue (LBB2'77 had a very implausible system, then '81 made it completely unworkable in small craft).

 

[infojunky]

Is stressing or emphasizing EP really that worthwhile in a set of mechanics that doesn’t even worry about the mass of the vessel being moved under gravitic drives.

If gravity is “the the curtature of spacetime, caused by the uneven distribution of mass, and causing masses to move along geodesic lines”, then the mass of a ship could be important. Unless, of course, the mechanism of the drive use undiscovered physical phenomena that rely on volume, in which case EP can be a thing again. Magic beans I think someone wrote.
So either way, we just shouldn’t sweat it too much. : ]

In that the extra volume require to power weapons gives insight into the difference between civilian and military craft.

 

[infojunky]

Ok, to point out a rules treatment of smallcraft, the hit location in Book2 is Drives as a unitary whole. As such I have tended to postulate that smaller drives exist, hence the existence of the slow variations of the common smallcraft. Well actually I include subsets of the standard drives notably the sub-A level of drives which gives a 1 performance in 100 ton hulls.

With that I use Steve Osmanski's Smallcraft design rules, which are kinda fusion of Book2 and Book5.

 

[Spinward Flow]

(cannot be used to construct the Lifeboat and Fighter).

I would argue that those are the "exceptions that prove the rule" in that those two ought to be built using LBB5.80 custom drives instead of LBB2.81 standard drives (because the standard drives are "too powerful" for the performance profiles of the Lifeboat and Fighter). That's primarily a function of the fact that the Lifeboat and the Fighter "break the paradigm" (too much) for LBB2.81 standard drives to make sense as is given the details of maneuver/power plant-A drives.

And yes, the power plant fuel rules for LBB2.77/81 are ... sub-optimal.

 

[Grav_Moped]

Ok, to point out a rules treatment of smallcraft, the hit location in Book2 is Drives as a unitary whole. As such I have tended to postulate that smaller drives exist, hence the existence of the slow variations of the common smallcraft.

Feels like another carry-over from '77, kept for backwards compatibility (and because it didn't really need fixing).

 

[Spinward Flow]

Feels like another carry-over from '77, kept for backwards compatibility (and because it didn't really need fixing).

Exactly.

 

[infojunky]

Feels like another carry-over from '77, kept for backwards compatibility (and because it didn't really need fixing).

Ok, the '77 edition smallcraft are mostly their own paradigm. If you look at the '79 edition of Book5 there is another one.

 

[Grav_Moped]

Ok, the '77 edition smallcraft are mostly their own paradigm.

They were mostly (pinnace, cutter, and ship's boat -- that one slightly rounded down) using Size A drives while being allowed to have less than 10Td fuel per Pn.

 

[Grav_Moped]

The problem with scaling "in that direction" is that the drives are no longer standard (the whole point of the LBB2 drive paradigm) ... instead, they're CUSTOM (which is the province of LBB5.80).

Custom vs. non-custom isn't the point. The point is that they're two different -- and in places mutually inconsistent -- systems. LBB2 power plant outputs are not affected by TL, and drive tonnages are a percentage plus (or minus) a fixed constant value. LBB5 power plant outputs are affected by TL, and drive tonnages are a flat percentage with no constant value summed in. And then there's the relative drive size issue. And fuel of course, but I haven't really gotten there yet.

You could have standard drives using LBB5's formulas. They wouldn't work -- mathematically -- quite the same way, but you could have them. The fact that they don't work that way mathematically might be the (in-universe) reason why there isn't such standardization in drives built using LBB5.

My perspective is that the drives are NOT scalable in terms of tonnage and cost.

And I'm taking the other angle on it: the LBB2 Standard Drives are point cases of the underlying drive engineering. The only reason there aren't (for example)"A.5" drives that would yield a rating of 3 in a 100Td hull is not that they're impossible to build, but that nobody bothers to build them. This makes sustainment logistics for such drives impractical -- so nobody bothers to build them.

That is, the Standard Drives are "standard" because those sizes are what everyone has settled on producing, not because there's anything special about those sizes from an engineering standpoint.

Scaling down below 200 rating-tons only gets weird for maneuver drives.
If the idea of bundling the M-drive in with the power plant for linear scaling doesn't sit well, one can borrow HG's 1Td minimum drive idea to resolve it -- just scale the cost by output as with the rest of LBB2. (A 20Td Lifeboat's 1G drive is the same 1Td as that of a 200Td Type A Free Trader, but at 1/10 the cost.)

 

[Grav_Moped]

From my perspective, that's TWO strikes against the notion of a "1/2 maneuver-A drive" like you're exploring, since (full size) maneuver-A drives are 1 ton to start with.

You assume LBB5 limits apply to LBB2-derived drives. They can! (I even suggest it, above.) But they don't have to.

The point of the "half a Size A Maneuver Drive" there was to establish just how small a "combined drive" could be while still including a power plant that generated 1EP. It wasn't to establish the size of the actual "maneuver drive part of the drives". As I said, you aren't supposed to think about it too hard.

 

[daryen]

I made a "sub-A" set of drives. (Despite being a "half-A" drive set, it isn't exactly half because I maintained the forumlas used in the tables as much as I could.) This would give the 100 ton hull the chance for J1M1P1 ratings, but also be used in small ships. But, I never really finished it off. I thought of using a 1/4, 1/2, and 3/4 set of sub-A drives, but it is really just pointless. The single "sub-A" drive works good enough if I ever wanted to publish something with it.

 

[daryen]

Just for fun, here's the WIP of what I did. The "!" represents the .25 entry; "@" represents the .5 entry; the "#" represents the .75 entry. I used the implied formulas as before (where A = 1, B = 2, C = 3, etc.) but I used .25, .5, and .75 instead. Note that the implied formula for maneuver drive tonnage doesn't work with a number under 1, so I just arbitrarily assigned the sizes shown.


(On the performance table, please feel free to ignore anything about 6. Cepheus allows numbers higher than 6, so I was allowing numbers up to 10(A).)

Using this means that 50 tons and bigger boats are using A and B (or even C) drives to get better performance, and the tiny drives only really matter for boats smaller than 40 tons. In all honesty, you can get away with just using the .5 size (@ in the charts above) and hand-wave the rest.

 

[infojunky]

I made a "sub-A" set of drives. (Despite being a "half-A" drive set, it isn't exactly half because I maintained the forumlas used in the tables as much as I could.) This would give the 100 ton hull the chance for J1M1P1 ratings, but also be used in small ships. But, I never really finished it off. I thought of using a 1/4, 1/2, and 3/4 set of sub-A drives, but it is really just pointless. The single "sub-A" drive works good enough if I ever wanted to publish something with it.

Ok, I play with drives often. One change I have made is to increase the base volume of Manuver to 3 tons. Reasoning the bulk of the table uses increment of 2 tons per letter code.

Note this gives each drive a baseline overhead of required tonnage plus whatever the cost per increment is...

• Jump is 5 tons plus 5 tons per letter
• Maneuver is 1 ton plus 2 tons per letter
• Power is 1 ton plus 3 tons per letter

Now for the subA drive that would give you 4.5 tons though I tend to treat smallcraft drives as unitary installations as such I round down to the nearest whole number... as such a smallcraft subA is 4 tons. While the same installation in a full sized would be 4.5 tons.

Though in another school of thought Smallcraft drives could be half sized in that they need to land for any work to be done on the installed drives.

 

[infojunky]

They were mostly (pinnace, cutter, and ship's boat -- that one slightly rounded down) using Size A drives while being allowed to have less than 10Td fuel per Pn.

Sorry it was kinda half assed answer, the common smallcraft are all based on the A drive, the shuttle and life boat both don't. Now fighter came latter in the 1st edition of Book5.

 

[BackworldTraveller]

You could look at this another way. Drive manufacturers build standard drives in big factories and get economies of scale. The others have to be built individually similar to hand-crafting research and development engines. Those shipyards like to install standard sized elements.

The only problem is that the "standard" drives can be split across multiple drive rooms (e.g. Lab Ship, Far Trader, Even Scouts) - so standard isn't so standard! But the idea sort of works. Those major factories are going to be important in the sector, and remarkably few and not-too far between

 

[Condottiere]

Assuming Alphabet Drives are canon, there probably has to be some Bureau of Standards that sets them, and does certification.

 

[Spinward Flow]

The only problem is that the "standard" drives can be split across multiple drive rooms (e.g. Lab Ship, Far Trader, Even Scouts) - so standard isn't so standard!

Depends on how (exclusively) wedded you are to Fluff Text™ ...

This is one of those "there's more than one way to skin a cat" kinds of deals.
A standard drive-E needs to have a standard performance/cost profile ... but it doesn't necessarily have a single form factor.

So a standard drive that delivers code: 1 in a 1000 ton hull (which is the standard-E drive) ... you can have different executions of the engineering details that all yield comparable outputs. The analog in aerospace aviation would be single motor, dual motor, tri motor, quad motor ... and so on. For OUR purposes (as gamers) that # of motors lies "below the layer" that determines the performance of standard drives you see on the table in LBB2.77/81.

So you can have "different drive room layouts" (twin drive, tri drive, quad drive, etc.) all of which functionally all equate to being standard-E drives.



For anyone familiar with the past glories of Dream Pod 9 and their Silhouette game system for vehicle design used in Heavy Gear and Jovian Chronicles, the approach is one where it's the PERFORMANCE that is being described by the stats ... and the nuts 'n' bolts engineering details "just do it" by whatever means the Fluff Text™ supplies (which can vary widely).

In this way you can have the exact same STATS for a ship class, but the actual "lived in" details of the ship class manufactured by different shipyards do not have to be perfectly identical in all respects.

So a ship class constructed by (say...) General Products could be a dual motor standard-E drive, while the same ship class constructed by (say...) LSP could be a quad motor standard-E drive. Both ships use "standard-E drives" ... but the Fluff Text™ execution of those "standard-E drives" is different (dual motor vs quad motor) while the stat performance of the two constructs is exactly the same (for our gaming purposes).