What X-Boat travels in your universe?

[Grav_Moped]

Yes you can and no they don't, not if you refine the formula for the fractional drives

There's nothing to refine. The formula generates impossible results at 100 "tons of thrust", and unlikely results below 150. This means you need an entirely different formula for lower values, though that formula should probably produce similar results at 200.

Hence the analysis of the smallcraft in LBB2 81 to get some sense of what may be the fractional drive formula.

Not a bad place to start.
Comparing the paired Ship's Boat/Slow Boat and Pinnace/Slow Pinnace would be quite informative, as would comparing a Shuttle with a 3G, 100Td ship using a maneuver drive generated by the LBB2 formula (which would be valid since it's above the 200 threshold).

Consensus can rarely be reached with such a fractured fan base and inconsistent and often contradictory rules, which have often been revised in the past without the benefit of the forty years of analysis we have since given them.

Yup, but there is fun to be had in dissecting the LBB info and making stuff up - that's what the game originally encouraged

Indeed.

This is another example of unintended consequence of a revision.
77 smallcraft have limited endurance thanks to the fuel use rate, then comes 81 with the flat 4 weeks of operation but at only a fraction of the ship power plant fuel requirement to break things. The CT LBB2 power plant fuel formula for ships has never made sense.

Oh, it makes sense as a game mechanic. As a description of in-universe engineering constraints, it absolutely doesn't.

I think this warrants a new thread: LBB 2 Drives in Small Craft? (and LBB2 PP Fuel Rules)

 

[Straybow]

Grav_Moped, you are assuming linear extrapolation, which is not the only means available. One could use a spline which has nonzero value at 100 dT for 1 G, or an optically corrected nonlinear approximation (i.e., "that looks good to me").

But then somebody says, "No, :nonono: you're doing it wrong."

 

[Grav_Moped]

Grav_Moped, you are assuming linear extrapolation, which is not the only means available. One could use a spline which has nonzero value at 100 dT for 1 G, or an optically corrected nonlinear approximation (i.e., "that looks good to me").

But then somebody says, "No, :nonono: you're doing it wrong."

Of course I'm assuming linear extrapolation -- it's a linear function.

My point is that the formula as it exists doesn't address the characteristics of maneuver drives smaller than 1Td/200 "tons thrust" very well, yielding increasingly implausible results below .75Td/150 "tons thrust," and literally impossible results below 0Td/100 "tons thrust". It's like expecting Newtonian physics to predict what happens inside the singularity of a black hole -- you need a different framework.

If you want to describe them, you need a different formula that applies to drives in that smaller power/size range.

Ideally, for maneuver drives in the range of the LBB2 drive table (200G-tons and up), that formula would yield lower performance and/or higher cost, but match exactly at 1Td/200 (Size A). Otherwise, scaled up small craft drives would replace LBB2 maneuver drives.

The OTU official answer is to use HG drives with their percentage-based tonnage and 1Td minimum size (or later rule sets). I don't like it all that much, but it's consistent and I understand why they did it that way.

I'd say that drives from the LBB2 drive table can be used (and started a thread on it) with the fuel consumption rates they'd have in a 100Td hull, but allowing them to idle down to at least Pn-1 (in 100Td) when not accelerating at over 1G. I might even consider letting them idle down to Pn-1 in the hull they're in, or the Pn-1 burn rate from High Guard.

 

[mike wightman]

It's only a linear function because that is how you are choosing to express it - express it using a different equation...

 

[Grav_Moped]

It's only a linear function because that is how you are choosing to express it - express it using a different equation...

Tthe functions that describe (in this case) the characteristics (size, cost) of maneuver drives are in fact linear with exceptions for the TL15 drives -- W through Z -- and one minor rounding-up exception for the Size J drive in a 2000Td hull.

But you definitely get the idea: You have to do something different to calculate drive characteristics below Size A.

There's nothing wrong with this!

The part where it can start breaking things is that LBB2 maneuver drives always get better as they get smaller, within the range covered by the drive table. That is, the output per ton increases, and below 1Td this increases exponentially.

One way to mitigate this (and it may not be the best one, it's just an idea) is to use fractions of a Size B or C drive rather than of a Size A drive. This results in output per ton that's never better than that of a Size A drive, which keeps scaled-up small craft drives from replacing Size A or B maneuver drives in 100Td+ ships.

In other words, Size A is as small as you can make a starship maneuver drive, but it can be used in smaller hulls and produce up to 200G-tons effect (a Size B will produce 400G-tons; Size C, 600.).

If you want less output than 200G-tons, you can either de-rate a Size A drive (basically, setting a 1 ton minimum size -- and maybe cost, that's a separate choice) or scale down a Size B (or C) drive.

If you want output in the range of 200G-tons and up, you can use the drive table formula "(tons of thrust desired/100)-1 = Drive Td". (This enables fractional drive sizes above Size A, desirable for, say, a 50-ton cutter with 5G or 6G performance instead of 4G)


On the other hand, the LBB2 power plant formula does work below 200 "Pn-tons" (minimum size is 3Td plus a little bit, and the numbers get weird close to 3Td).

 

[Proneutron]

J4, M2 X-boat SRD

This is what plies the Republic's "Mail" routes IMTU

 

[Straybow]

I have no idea what "ELB" is.

 

[mike wightman]

Emergency Low Berth?

 

[BRover]

How I handled the small drive problem: LBB2 Jump Drives are 5t x letter + 5t; Power is 3t x letter +1t; Man Drive is 2t x letter -1t. It's that "-1ton" that is the problem for drives under A.

So I took one ton from the Jump drive and added it to the Man drive. No other changes. Now J Drive is 5t x letter + 4t, and M Drive is 2t x letter. Which makes it (pretty much) linear in output--and easy to extrapolate.

 

[Proneutron]

Emergency Low Berth?

Right. The common abbreviation for a long time. Plus the tonnage and price is a dead give away to those who have designed ship for a while. It even comes up on a google search [traveller rpg "elb"]

 

[Grav_Moped]

Right. The common abbreviation for a long time. Plus the tonnage and price is a dead give away to those who have designed ship for a while. It even comes up on a google search [traveller rpg "elb"]

You don't need an emergency low berth, a standard half-ton one will do. The difference between the two is that the emergency one has a capacity of four persons, who share the same survival roll. Not suitable for paying passengers.

 

[Grav_Moped]

How I handled the small drive problem: LBB2 Jump Drives are 5t x letter + 5t; Power is 3t x letter +1t; Man Drive is 2t x letter -1t. It's that "-1ton" that is the problem for drives under A.

So I took one ton from the Jump drive and added it to the Man drive. No other changes. Now J Drive is 5t x letter + 4t, and M Drive is 2t x letter. Which makes it (pretty much) linear in output--and easy to extrapolate.

That's a plausible answer, and sort of fits with the LBB5 paradigm.

 

[Proneutron]

You don't need an emergency low berth, a standard half-ton one will do. The difference between the two is that the emergency one has a capacity of four persons, who share the same survival roll. Not suitable for paying passengers.

Not IMTU. ELBs are for Emergencies and require zero training to use and can be operated by the person being "frozen" whereas normal LBs require training and cannot be used by a lone person to "freeze" themselves but a trained person must activate once the person is inside and hooked up. Plus it is possible to have 2 people in this ship...

 

[ManOfGrey]

A step back in time...

So, what types of X-Boats do you have in your universe?

Perhaps it's ironic that I ran across this thread today. I've been recently looking at the starships as they are presented in T4, which I consider to be circa Milieu 0. In Milieu 0, Sylea/Core "only" has a Tech Level of 12, not 15. In that case, Jump-4 capable ships haven't been invented yet, so therefore the classic X-Boat from Traders and Gunboats hasn't been invented yet, either. Which, I would think, would place the bulk of interstellar communications upon the shoulders of the humble Scout/Courier.

Interestingly, the Tech Level-12 Scout/Courier as presented in T4, (unlike its Tech Level-15 counterpart,) is not armed, and probably cannot be, since it has no turrets, (or "hardpoints.")

I certainly believe those couple of interesting little facts might be exploited into any number of fun scenarios for player characters to enjoy.

 

[AnotherDilbert]

Interestingly, the Tech Level-12 Scout/Courier as presented in T4, (unlike its Tech Level-15 counterpart,) is not armed, and probably cannot be, since it has no turrets, (or "hardpoints.")

Turret sockets can easily be retrofitted, see FF&S p13. There are no "hardpoints" to specify.

 

[Straybow]

Right. The common abbreviation for a long time. Plus the tonnage and price is a dead give away to those who have designed ship for a while. It even comes up on a google search [traveller rpg "elb"]

I use DuckDuckGo to stick it to the man, doesn't catch "ELB"
Also searched Spacecraft Design – Traveller SRD
and Equipment – Traveller SRD


meh

 

[Proneutron]

I use DuckDuckGo to stick it to the man, doesn't catch "ELB"
[/URL]


meh

Yes DDG doesn't have as an extensive search index as Google. I used to use it for the same reason but that deficiency made it problematic.

 

[Straybow]

Hmmm, I don't see why all ELBs have to be the same size. If you have a market for one-man ELBs in thousands of X-boats, they'd get made. In general, I think low berths are about twice as big as they should be.

½ dT would be roughly 4' x 8' x 8'. That could probably hold four people if we go by the way camping tents are measured ~16 ft² per person. Even with allowance for very large individuals, ¼ dT at 4' x 4' x 8' should be enough for the occupant and a whole lot of equipment (at least 1' x 4' x 8').

Granted that an ELB needs a fully independent and indefinite power supply instead of the small back up power that a cryoberth would normally have. If that takes ¼ dT and we have ¾ dT left for people, it could probably fit six people in it with proper hook-ups and all. A two-body ELB might be ½ dT.

 

[Grav_Moped]

It's not just backup power, it's also life support. Granted, not much is needed, but it has to maintain constant pressure and temperature.

 

[Proneutron]

Hmmm, I don't see why all ELBs have to be the same size. If you have a market for one-man ELBs in thousands of X-boats, they'd get made. In general, I think low berths are about twice as big as they should be.

½ dT would be roughly 4' x 8' x 8'. That could probably hold four people if we go by the way camping tents are measured ~16 ft² per person. Even with allowance for very large individuals, ¼ dT at 4' x 4' x 8' should be enough for the occupant and a whole lot of equipment (at least 1' x 4' x 8').

Granted that an ELB needs a fully independent and indefinite power supply instead of the small back up power that a cryoberth would normally have. If that takes ¼ dT and we have ¾ dT left for people, it could probably fit six people in it with proper hook-ups and all. A two-body ELB might be ½ dT.

True. Especially is a gov spec was made for what you designed to be purchased for hundreds of ships.