General traveller questions.

[Lexx]

I had a couple minor questions for traveller, some centering around the tech side.


Basically, I want to know if I understand the 'power slice' issue. As I seem to get it now, a power slice in a system means it has it's own, self-contained mini fusion plant dedicated to running it at a minimal level, thus a turret with lasers has enough self-contained fusion power to run the lasers at a RoF of 1/60. Is this correct?

I would make sense to decentralize power to vital systems so that the loss of the main reactor would not mean the ship was totally powerless, and that essential systems like weapons would still have power.

Also, in an emergency a competent engineer could tap the power slices to power systems that were needed, like comms.

I was also wondering about the grav tanks in traveller. As I seem to get it now, they can basically fly like air/space craft. Can they enter atmosphere from orbit it deployed from a ship? Can they achieve orbit or even travel thru space?

Ground forces says they can fly but rarely do because airborne targets are uncovered and vulnerable. What is the extant of a traveller grav tanks flight ability? Orbital, suborbital or what?

I note there are fighterplanes in traveller, so I assume that the grav tanks cannot fufill the role of a true fighter air/space craft, so I'm trying to ascertain their limits and why people still need fighters if tanks can fly.

I'm not a traveller grognard yet, but I am working on it and regret not getting in on traveller's ground floor when I had the chance. Any input from grognards is appreciated.

[jeff37923]

I'm a little unclear on the power slices myself, so I'll pass on that but I can give what I know on the grav vehicles.

Grav vehicles can function out to 10 planetary diameters before their lifters become unusable. IMTU, grav vehicles are the 'anything' craft out to that point and my grav tanks tend to by very streamlined so that they can engage in combat at Mach+ speeds. Makes for a very interesting battlefield.

[thrash]

Originally Posted by Lexx

Basically, I want to know if I understand the 'power slice' issue. As I seem to get it now, a power slice in a system means it has it's own, self-contained mini fusion plant dedicated to running it at a minimal level, thus a turret with lasers has enough self-contained fusion power to run the lasers at a RoF of 1/60. Is this correct?

No. You have to realize that the "modules" in the modular ship design system are an accounting fiction -- a way of simplifying the bookkeeping associated with designing a ship, for the designer. They have no existance in context. The design system is modular; the ships themselves are not.

"Power slices" were an attempt to remove one variable (power) from the list that a designer has to control (the others are mass, volume, cost, and function), and reduce the number of interations required in the design process. Instead of saying, "the 1.21 Gigawatt heavy laser uses 2.5 GW of input power," and then require the designer to adjust the size of his power plant (and thus mass, volume, cost, etc.) every time he changes his weapons loadout, the "slice" of additional power plant capacity required to support each weapon module was included in its design.

It was a reasonable enough idea that didn't work out so well in practice. In particular, you wind up with the strange circumstance that adding and subtracting weapons after launching -- which turrets and bays are supposed to allow one to do -- "magically" adjusts the size of the ship's power plant to fit. Power slices also result in a power plant that is sized to run every system on the ship simultaneously, which is not only wasteful (jump drives and maneuver drives are never needed at the same time) but short-circuits all sorts of dramatic decision-making.

By the time GURPS Space was revised for its third edition, it was clear to all that "power slices" weren't working out as intended, and the modular ship design system in that book supports separate power plants and accounting for power requirements independently. One intermediate position would have been to include power slices along with turret or bay mounts, rather than with the weapons' modules, but that would have required rating both weapons and mounts for their power requirements and ultimately leads back to separate power accounting.

It would make sense to decentralize power to vital systems so that the loss of the main reactor would not mean the ship was totally powerless, and that essential systems like weapons would still have power.

It might, but Traveller starships don't behave this way: a hit that knocks out the power plant also takes all the weapons and drive systems offline. Moreover, to have a distinct power plant in GURPS Vehicles (from which GT's design system ultimately derives), you must have a power plant "core." In the modular design system, these are only included in Engineering modules -- so you have only as many separate power plants as you have Engineering modules. There's nothing to prevent you from having more than one, however, and in fact I recommend that all naval vessels have at least three.

This is covered in some detail in GT: Starships, pp. 14-16.

I was also wondering about the grav tanks in traveller. As I seem to get it now, they can basically fly like air/space craft. Can they enter atmosphere from orbit it deployed from a ship? Can they achieve orbit or even travel thru space?

Any vehicle equipped with contragravity and reactionless thrusters can eventually reach orbit. The main problem with grav tanks is that they are designed for offensive firepower and self-defense, not aerodynamics. In classic Traveller, grav vehicles could reach orbit in one hour per 1,000 miles of planetary diameter, or land from orbit in a similar length of time. In GURPS, most unstreamlined vehicles (like grav tanks) are limited to a maximum airspeed of 600 mph in atmosphere, which imposes a similar restriction.

I note there are fighterplanes in traveller, so I assume that the grav tanks cannot fufill the role of a true fighter air/space craft, so I'm trying to ascertain their limits and why people still need fighters if tanks can fly.

Different designs, optimized for different missions. Fighters emphasize speed and aerodynamic maneuverability over firepower and armor; tanks are the reverse. At high enough tech levels, the designs start to merge into one vehicle (generally called a "gunship"), with different missions dictating different tactics, instead.

This was originally covered in Book 4, Mercenary, pp. 46-47 (available in The Classic Books reprint from FFE); a GURPS Traveller version was included in GT: Star Mercs, pp. 56-60.

[mcv]

I see Traveller grav tanks as a combination of two kinds of modern "cavalry": the tank and the helicopter gunship. A tank is heavily armoured, powerful, but limited in its maneuverability. A helicopter has very light armour, powerful weapons, and is fast and maneuverable. A grav tank is heavily armoured, has powerful weapons, but is at least as maneuverable as a helicopter.

I think the grav tank designs look a bit to much like tanks, though. An oversized, rotorless helicopter sounds more appropriate, perhaps.


mcv.

[tsykoduk]

One of the best scenes in any traveller game that I ran:

Our band of intrepid heros were in the process of running from the law on a CTL 4 planet - they stole a prop-driven aircraft from a local concern and took off. The impys took notice, and next thing there is an Intrepid crusing next to the plane, gun swiveled around to cover them, and they are being ordered to 'pull over'.

On Topic: It really depends on the forces and the tactical situation that you are in. The great thing about a grav tank is that it is very mobile, and very powerful. If you are in a high threat enviroment, then you stay hull down, or NOE and engage at short range. If you need to sprint you can. In a low threat enviroment, you can use the tank as highly mobile strike unit.

[Lexx]

Originally Posted by thrash

No. You have to realize that the "modules" in the modular ship design system are an accounting fiction -- a way of simplifying the bookkeeping associated with designing a ship, for the designer. They have no existance in context. The design system is modular; the ships themselves are not.

"Power slices" were an attempt to remove one variable (power) from the list that a designer has to control (the others are mass, volume, cost, and function), and reduce the number of interations required in the design process. Instead of saying, "the 1.21 Gigawatt heavy laser uses 2.5 GW of input power," and then require the designer to adjust the size of his power plant (and thus mass, volume, cost, etc.) every time he changes his weapons loadout, the "slice" of additional power plant capacity required to support each weapon module was included in its design.

It was a reasonable enough idea that didn't work out so well in practice. In particular, you wind up with the strange circumstance that adding and subtracting weapons after launching -- which turrets and bays are supposed to allow one to do -- "magically" adjusts the size of the ship's power plant to fit. Power slices also result in a power plant that is sized to run every system on the ship simultaneously, which is not only wasteful (jump drives and maneuver drives are never needed at the same time) but short-circuits all sorts of dramatic decision-making.

By the time GURPS Space was revised for its third edition, it was clear to all that "power slices" weren't working out as intended, and the modular ship design system in that book supports separate power plants and accounting for power requirements independently. One intermediate position would have been to include power slices along with turret or bay mounts, rather than with the weapons' modules, but that would have required rating both weapons and mounts for their power requirements and ultimately leads back to separate power accounting.


It might, but Traveller starships don't behave this way: a hit that knocks out the power plant also takes all the weapons and drive systems offline. Moreover, to have a distinct power plant in GURPS Vehicles (from which GT's design system ultimately derives), you must have a power plant "core." In the modular design system, these are only included in Engineering modules -- so you have only as many separate power plants as you have Engineering modules. There's nothing to prevent you from having more than one, however, and in fact I recommend that all naval vessels have at least three.

This is covered in some detail in GT: Starships, pp. 14-16.


This was originally covered in Book 4, Mercenary, pp. 46-47 (available in The Classic Books reprint from FFE); a GURPS Traveller version was included in GT: Star Mercs, pp. 56-60.

I have GT starships and it still has power slices. That's what made me ask about it.

In a way, if susion power units are small, like say footlocker sized, it'd make sense that a laser might come with one. And as I said, starships still talks about power slices.

As to jump and manuever drives, I thought most ships in traveller used an energy bank to store up power for a jump so the main power unit didn't have to put it all out at once.