Book 2 Small Craft Design

[far-trader]

Ah well, in my continuing negative frame of mind (apologies in advance) I have to disagree with the whole premise...

Originally posted by robject:
Reverse engineering the Book 2 small craft, I find a couple of interesting things going on.

First, crew accomodations are all in the form of two couches, for a total of 1 ton. There is no bridge.

That has not been my experience. I found the designs pretty much doable with HG ed2. Some have bridges, some just computers and couches, iirc. My notes are a mess and I am in the middle of spring cleaning so I can't lay hands on them. Hey it's still spring in the southern hemisphere, so what if I live in the northern one

Originally posted by robject:
Second, fuel is 1% of thrust, with a minimum of 1 ton.

Curious. I always thought fuel in CT was a function of powerplant size not thrust. I found it works, again with HG ed2. Some of the designs are low tech and some are high tech, most are mid tech, iirc.

Originally posted by robject:
Third, I found some things that are most likely either errors or fudges (a rose by another name). More importantly, one particular variance (and perhaps two) is probably explained as being a TL effect.

Hey, not fair, I actually have to agree with this observation

The errors I've noted in doing the HG versions seem to be the same as you notice.

Or possibly being due to the small craft being designed with an early draft of HG, something even pre HG ed1.

Anyway, I'll leave it at that and go spread my gloom to other cheery threads

 

[far-trader]

Ah well, in my continuing negative frame of mind (apologies in advance) I have to disagree with the whole premise...

Originally posted by robject:
Reverse engineering the Book 2 small craft, I find a couple of interesting things going on.

First, crew accomodations are all in the form of two couches, for a total of 1 ton. There is no bridge.

That has not been my experience. I found the designs pretty much doable with HG ed2. Some have bridges, some just computers and couches, iirc. My notes are a mess and I am in the middle of spring cleaning so I can't lay hands on them. Hey it's still spring in the southern hemisphere, so what if I live in the northern one

Originally posted by robject:
Second, fuel is 1% of thrust, with a minimum of 1 ton.

Curious. I always thought fuel in CT was a function of powerplant size not thrust. I found it works, again with HG ed2. Some of the designs are low tech and some are high tech, most are mid tech, iirc.

Originally posted by robject:
Third, I found some things that are most likely either errors or fudges (a rose by another name). More importantly, one particular variance (and perhaps two) is probably explained as being a TL effect.

Hey, not fair, I actually have to agree with this observation

The errors I've noted in doing the HG versions seem to be the same as you notice.

Or possibly being due to the small craft being designed with an early draft of HG, something even pre HG ed1.

Anyway, I'll leave it at that and go spread my gloom to other cheery threads

 

[Takei]

I'm afraid I have to agree with Dan. I reverse engineered the Traveller Book small craft and found them to be almost completely accurate (tonnage wise) using High Guard 2nd ed.
My findings are that they are all TL9 designs with a 4-ton small craft bridge (apart from the fighter, which has no bridge, but a single couch and a Model/1 computer).

Small Craft-Excess Space(TB/Me)-Cost (TB/me)
Launch-13/13-14/5.76
Ship's Boat-13.7/13.7-16/18.24
Slow Boat-19.9/19.9-15/10.68
Pinnace-22.4/22.4-20/21.28
Slow Pinnace-31.6/30.6-18/11.52
Modular Cutter-2.5/2.5-28/19.36
Shuttle-71/72-33/34.58
Fighter-1/3-18/7.58

The designs seem to be most out as far as cost goes.

 

[Takei]

I'm afraid I have to agree with Dan. I reverse engineered the Traveller Book small craft and found them to be almost completely accurate (tonnage wise) using High Guard 2nd ed.
My findings are that they are all TL9 designs with a 4-ton small craft bridge (apart from the fighter, which has no bridge, but a single couch and a Model/1 computer).

Small Craft-Excess Space(TB/Me)-Cost (TB/me)
Launch-13/13-14/5.76
Ship's Boat-13.7/13.7-16/18.24
Slow Boat-19.9/19.9-15/10.68
Pinnace-22.4/22.4-20/21.28
Slow Pinnace-31.6/30.6-18/11.52
Modular Cutter-2.5/2.5-28/19.36
Shuttle-71/72-33/34.58
Fighter-1/3-18/7.58

The designs seem to be most out as far as cost goes.

 

[far-trader]

But now, based on Sigg's post elsewhere I wonder if what you're after robject is making them work to the formulae for Book 2 maneuver drives? That is an entirely different idea. One I've never tried. Before HG if I wanted my own (different) small craft I fudged by simple division or addition of the ones in Book 2

It wasn't perfect, but close enough and dead easy.

 

[far-trader]

But now, based on Sigg's post elsewhere I wonder if what you're after robject is making them work to the formulae for Book 2 maneuver drives? That is an entirely different idea. One I've never tried. Before HG if I wanted my own (different) small craft I fudged by simple division or addition of the ones in Book 2

It wasn't perfect, but close enough and dead easy.

 

[robject]

I tried that, too. Since power plants can be very, very small, even assuming a lower M-drive bound of 1 ton, the results are much different than using a "combo drive": they're smaller and more expensive.

 

[robject]

I tried that, too. Since power plants can be very, very small, even assuming a lower M-drive bound of 1 ton, the results are much different than using a "combo drive": they're smaller and more expensive.

 

[aramis]

Rob, et al:

The combo drives are reaction mass throwers...
the lletter drives are gravitic tech, and use the nearest well as a reaction mass.

 

[aramis]

Rob, et al:

The combo drives are reaction mass throwers...
the lletter drives are gravitic tech, and use the nearest well as a reaction mass.

 

[robject]

That's a good handwave...

 

[robject]

That's a good handwave...

 

[far-trader]

Originally posted by Aramis:
Rob, et al:

The combo drives are reaction mass throwers...
the lletter drives are gravitic tech, and use the nearest well as a reaction mass.

But the small craft drives use 1/10th the fuel of the letter drives? So where is the reaction mass?

Or did you mean (as I once handwaved) that the letter drives are reaction drives (with most of the power fuel as reaction mass) and therefore they are good for well outside strong gravity wells (like interplanetary space, trips to 100d, and such). While the small craft drives are anti-grav and need no reaction mass (so the fuel is just for power) but are however limited to operating near a strong gravity well, typically to orbit though possibly as far as 10d at much reduced performance.

 

[far-trader]

Originally posted by Aramis:
Rob, et al:

The combo drives are reaction mass throwers...
the lletter drives are gravitic tech, and use the nearest well as a reaction mass.

But the small craft drives use 1/10th the fuel of the letter drives? So where is the reaction mass?

Or did you mean (as I once handwaved) that the letter drives are reaction drives (with most of the power fuel as reaction mass) and therefore they are good for well outside strong gravity wells (like interplanetary space, trips to 100d, and such). While the small craft drives are anti-grav and need no reaction mass (so the fuel is just for power) but are however limited to operating near a strong gravity well, typically to orbit though possibly as far as 10d at much reduced performance.

 

[robject]

Also useful handwaving material.

But I suspect the small craft drives are just little power plant + m-drive combo units.

 

[robject]

Also useful handwaving material.

But I suspect the small craft drives are just little power plant + m-drive combo units.

 

[far-trader]

Yes but (for example) a 100ton letter drive C power plant and maneuver will get you 4 weeks of 6gees for 60tons of fuel while the same small craft tonnage (3 1/3 Ship's Boats equal 100ton hull) will get you 4 weeks of 6gees for just 6tons of fuel. It's always seemed obvious to me the difference implied reaction mass in the requirement for letter drives. Of course you also have to handwave some reason that the reaction mass is based on the performance and not the hull, something like a field effect that negates hull mass for reaction effects as long as your drive is suited to the hull for performance. Besides, it's large ships and starships that need to go interplanetary and small craft will usually operate in or near a gravity well.

And then came High Guard

and everybody has anti-grav thrusters that work anywhere and sip fuel. No more reaction drives.

 

[far-trader]

Yes but (for example) a 100ton letter drive C power plant and maneuver will get you 4 weeks of 6gees for 60tons of fuel while the same small craft tonnage (3 1/3 Ship's Boats equal 100ton hull) will get you 4 weeks of 6gees for just 6tons of fuel. It's always seemed obvious to me the difference implied reaction mass in the requirement for letter drives. Of course you also have to handwave some reason that the reaction mass is based on the performance and not the hull, something like a field effect that negates hull mass for reaction effects as long as your drive is suited to the hull for performance. Besides, it's large ships and starships that need to go interplanetary and small craft will usually operate in or near a gravity well.

And then came High Guard

and everybody has anti-grav thrusters that work anywhere and sip fuel. No more reaction drives.

 

[parmasson]

ome reason that the reaction mass is based on the performance and not the hull, something like a field effect that negates hull mass for reaction effects as long as your drive is suited to the hull for performance. Besides, it's large ships and starships that need to go interplanetary and small craft will usually operate in or near a gravity well.

Pha . . .that much is obvious. (he says with a scoff ) that is why maneuver drive performance is rated on displacement not mass. The damper/AG and thruster system work in perfect concert to produce high sustained acceleration and incredible speeds. The small combo drive system simply cannot sustain the proper effect above 95 tons. The field becomes unstable and the thrust effect very inefficient. At 95 tons and above the small craft drives are very efficient, unfortunately it is a matter of M drive physics. A similar problem occurs with letter drives in hulls above 5000 tons.

You cannot change the laws of physics.

 

[parmasson]

ome reason that the reaction mass is based on the performance and not the hull, something like a field effect that negates hull mass for reaction effects as long as your drive is suited to the hull for performance. Besides, it's large ships and starships that need to go interplanetary and small craft will usually operate in or near a gravity well.

Pha . . .that much is obvious. (he says with a scoff ) that is why maneuver drive performance is rated on displacement not mass. The damper/AG and thruster system work in perfect concert to produce high sustained acceleration and incredible speeds. The small combo drive system simply cannot sustain the proper effect above 95 tons. The field becomes unstable and the thrust effect very inefficient. At 95 tons and above the small craft drives are very efficient, unfortunately it is a matter of M drive physics. A similar problem occurs with letter drives in hulls above 5000 tons.

You cannot change the laws of physics.