Stutterwarp Minimum Speed

[rgrove0172]

What would you consider to be the minimum stutterwarp speed?

Lets say your ship finds itself a few kilometers from its destination. Using attitude thrusters this might take a while. On the other hand, can you engage the stutterwarp to make that short a trip? The description of stutterwarp travel indicates each jump of hundreds of meters and maybe thousands of jumps per second. Is this top speed? Could you "dial it down" to making only one jump? Shorten the jump distance to a few meters each?

Along a similar line of thought - just how manueverable is a stutterwarp inside the .1G threshold? Its said that it is less effecierent than conventional drives and barely maintains orbit, typically requiring some gravity field maneuvers to escape orbit, but with no stats on conventional drive performance its impossible to guage this. Hundreds of meters per hour, thousands? And while we are at it, what sort of delta V can the attitude thrusters generate? Obviously they wouldnt measure up to the regular neutonian thrusters out there, but again, with no data, its all guess work.

If a shuttle engaged your orbiting stutterwarp ship, how would they pair off? How would you present this in a game?

 

[shaunhilburn]

What would you consider to be the minimum stutterwarp speed?

Lets say your ship finds itself a few kilometers from its destination. Using attitude thrusters this might take a while. On the other hand, can you engage the stutterwarp to make that short a trip?

Sure.

The description of stutterwarp travel indicates each jump of hundreds of meters and maybe thousands of jumps per second. Is this top speed? Could you "dial it down" to making only one jump? Shorten the jump distance to a few meters each?

My take is that the tunnel length of 100+ meters is the maximum, it can be throttled down to nearly zero, and the cyclic rate as well. Pretty much any speed from zero to maximum.

Along a similar line of thought - just how manueverable is a stutterwarp inside the .1G threshold? Its said that it is less effecierent than conventional drives and barely maintains orbit, typically requiring some gravity field maneuvers to escape orbit, but with no stats on conventional drive performance its impossible to guage this. Hundreds of meters per hour, thousands?

The 1st edition rulebook only says that it's less than the *efficiency* of chemical rockets.

A strict technical interpretation of "efficiency" is fuel consumption. The figure of merit for chemical rockets is "specific impulse", the best current figure is 450 seconds. This interpretation means the vessel would consume huge amounts of fuel whilst wallowing in the deadzone.

I think the authors intent was that the device suffered another huge drop in warp efficiency, e.g. warp efficiency 1 drops from 20,000 km/s to, say 2 km/s

And while we are at it, what sort of delta V can the attitude thrusters generate?

The delta-v of reaction drives is limited only by the available propellant supply (until relativistic effects take hold). If attitude jets have access to the ships main fuel supply, they could generate quite a bit of delta-v. You'll need to use the rocket equation to calculate the delta-V, based on the ratio of ship+propellant mass pre-burn vs post-burn.

If a shuttle engaged your orbiting stutterwarp ship, how would they pair off? How would you present this in a game?

Re-calculate the warp efficiency of your vessel with the additional mass of the shuttle. The SW field extends for some distance beyond the ship's hull, as can be seen by the behavior of screen generators, it should easily encompass a docked shuttle.

 

[McPerth]

What would you consider to be the minimum stutterwarp speed?

Zero. Or better said, the vector it had without stutterwarp (but see below).

Lets say your ship finds itself a few kilometers from its destination. Using attitude thrusters this might take a while. On the other hand, can you engage the stutterwarp to make that short a trip? The description of stutterwarp travel indicates each jump of hundreds of meters and maybe thousands of jumps per second. Is this top speed? Could you "dial it down" to making only one jump? Shorten the jump distance to a few meters each?

IIRC I read somewhere (I guess in an article about stutterwarp on a challenge, but I don't remember for sure, nor what issue), the number of cycles (so tunneling) the stutterwarp makes is power dependent, and is because so that power available for stutterwarp determines the pseudo-sped of the ship.

If so, you could just give the stutterwarp the power for one tunneling, moving only less than some hundreds of metters (T2300, RM, page 20),or just one tunneling per second, or just some of them, to move the distance required (with the mínimum of those less than hundreds of metters).

Along a similar line of thought - just how manueverable is a stutterwarp inside the .1G threshold? Its said that it is less effecierent than conventional drives and barely maintains orbit, typically requiring some gravity field maneuvers to escape orbit, but with no stats on conventional drive performance its impossible to guage this. Hundreds of meters per hour, thousands?

Acording Traveller 2300 (the first edition, as is the one I have Access to), Referee's Manual, page 20:

Finally, when gravitation reaches some tenths of a G, the efficiency of the stutterwarp drops off once again, down to a point where the stutterwarp cannot overcome that gravitation and some other means of propulsion will be required.

So it seems that inside the 0.1 G threshold stutterwarp maeuverability is nil.

If a shuttle engaged your orbiting stutterwarp ship, how would they pair off? How would you present this in a game?

If the stutterwarp is active, no docking is posible for the shuttle. If it is off (or idle), it can dock and the stutterwarp efficiency must be recalculated, as Shaunhilburn says. See that to undock the shuttle, stutterwarp must also be off or iddle, and, when undocked, it will keep the original vector of the ship.

 

[rgrove0172]

Gosh, IM sorry guys, i wasnt very clear about the shuttle.

When I asked about them pairing off, I was referring to combat, maneuverability. Who would have the advantage, the crippled stutterwarp ship in .1G or the rocket-driven shuttle. Im just trying to assign some typical speeds to orbital engagements.

The Space Shuttle for example, orbited at about 28,000kph, but it wasnt having to maneuver, essentially on a straight and clear track. Would a stutterwarp vessel be orbiting at something like that velocity using only its attitude jets? What about other conventional traffic? A pursuing planetary defense space plane? I understand we would be talking Thrust and not Speed, but then whats a reasonable G factor to assign a vessel with no conventional thrusters? What about those with them?

 

[shaunhilburn]

Gosh, IM sorry guys, i wasnt very clear about the shuttle.

When I asked about them pairing off, I was referring to combat, maneuverability. Who would have the advantage, the crippled stutterwarp ship in .1G or the rocket-driven shuttle. Im just trying to assign some typical speeds to orbital engagements.

At orbital speeds, objects have a movement rating of 0 and are considered at "All Stop" with regard to 2300 space combat. There was a thread on this a while, and the consensus was that "All Stop" objects are subject to automatic hits.

The rationale being that targeting computers capable of engaging a high-speed stuttering vessel with x-in-10 odds of hitting are easily capable of automatic hits on "slow" non-stuttering Newtonian objects. One of my house rules for Star Cruiser:

Automatic hits: no roll necessary to hit
- stutterwarping objects with a movement rating of 0 (discharging or wallowing in a deadzone hex)
- objects without stutterwarp, regardless of speed
- objects in planetary orbit
- objects parked on an airless body
- stationary or "All Stop" objects (including submunitions)

According to Star Cruiser, your rocket-driven shuttle cannot be hit with beam weapons while it's down in the atmosphere, and it may have the upper hand by using ASAT weapons against orbiting spaceships.

The Space Shuttle for example, orbited at about 28,000kph, but it wasnt having to maneuver, essentially on a straight and clear track. Would a stutterwarp vessel be orbiting at something like that velocity using only its attitude jets? What about other conventional traffic? A pursuing planetary defense space plane?

To orbit at something like that velocity, it would be at that same altitude. I can't imagine a situation where a warp-driven vessel would venture down that low. They're completely out of their element there. The deadzone boundary is typically 5,000 - 20,000 km above the planet surface. At lower altitudes, a starship can be considered crippled (whether or not it actually is), and forfeits its main advantage over the exo-atmospheric interceptor.

I understand we would be talking Thrust and not Speed, but then whats a reasonable G factor to assign a vessel with no conventional thrusters? What about those with them?

No conventional thrusters: stutterwarp is inertia-less, there is no G factor you can give it. You turn it on and off you go - the "acceleration" is infinite, like the popular notion of a "flying saucer".

Conventional thrusters: F=ma and a=F/m, so acceleration = thrust/mass.
A 100-ton vessel with 200 "tonnes" of thrust (200,000 kgF) has an acceleration of 2G = 1,961,330 newtons / 100,000 kg = 19.61 m/s^2 = 2G
With a specific impulse of 450 seconds, a spacecraft will burn about 45 kg/sec for each KgF of thrust produced (not sure, I need to double-check).

 

[rgrove0172]

I was assuming the engagement would be with conventional weapons as the starship lasers and such couldnt function that close in, hense the importance of maneuverability.

For simplicity then, could one guage the relative 'maneuverability' of various craft by their max thrust - ignoring such factors as fuel etc. and looking strictly at their ability to alter their deltaV?

Sluggish as hell - .25G
Slow - 1G
Moderate - 2G
Fast - 3G
Extremely Fast - 4G

It would help visualize just how manueverable a particular ship would be in a non-stutterwarp situation and compare various vessels.

"A .5G capable shuttle is making for the space station 15,000km away while an attacking space plane with a 3G maximum is in pursuit. If the shuttle has a hope of getting there first they will have to have a good head start and hope that the hotrod fighter overshoots, gaining too much speed while closing to manuever once they get close." Skill rolls and the GMs description of the engagement will use the comparison of the ship's capabilities to generate the action.

 

[rgrove0172]

So it seems that inside the 0.1 G threshold stutterwarp maeuverability is nil.

I realize you said you didnt have the new MTr2300 book on hand but it has a different approach.

Page 266 "Ships at orbital speed must subtract the world's surface gravity from their warp efficiency rating and then multiply the new number by 10,000 to determine their speed in kilometers per hour."

It would appear that even with that ruling the verys sluggish stutterdrive or very strong gravity field could render a ship inert.

 

[McPerth]

So it seems that inside the 0.1 G threshold stutterwarp maeuverability is nil.

I realize you said you didnt have the new MTr2300 book on hand but it has a different approach.

It seems you botched with your quotes, as the phrase you quoted was mine, not Shaunilburn's .

I have not read MgT2300, so I talk about Traveller 2300 (2300 AD first edition), that is the one I have access to.

Page 266 "Ships at orbital speed must subtract the world's surface gravity from their warp efficiency rating and then multiply the new number by 10,000 to determine their speed in kilometers per hour."

It would appear that even with that ruling the verys sluggish stutterdrive or very strong gravity field could render a ship inert.

I undertood from one of your first posts that you wanted to play old fashioned 2300AD, not MgT2300. IMHO the rules you talk about here give too much maneouverabilty to stutterwarp ships in orbit.

With such maneuverability, Richmond would not have benefited from the caotic deorbit maneuvers of the Kafer fleet at Joi, as most of Kafer ships would have had warp efficiencies enough (kefer capital ship's warp efficiency goes form 1.8 to 2.8, and Joi gravity is, IIRC, about 1, so they could have maneovered quite easily to confront him.

 

[rgrove0172]

Grrr... sorry about the misquote... the poor moderator has already been gigging me for my screw ups!

I am playing classic 2300, but I browse through the new book for ideas and sometimes clarrifications. There is a lot of good stuff in there, much of it directly transferable (sensor upgrades and such) but occasionally there is a stark contradiction.

I tend to agree with you. I like the idea that the stutterwarp simply "peters out" within the wall, forcing the ship to not only maintain orbit by other means but also get fancy when trying to leave.

 

[shaunhilburn]

I was assuming the engagement would be with conventional weapons as the starship lasers and such couldnt function that close in, hense the importance of maneuverability.

For simplicity then, could one guage the relative 'maneuverability' of various craft by their max thrust - ignoring such factors as fuel etc. and looking strictly at their ability to alter their deltaV?

Sluggish as hell - .25G
Slow - 1G
Moderate - 2G
Fast - 3G
Extremely Fast - 4G

It would help visualize just how manueverable a particular ship would be in a non-stutterwarp situation and compare various vessels.

A 0.25G craft can reach the same speed as a 4G craft, it just takes 16x longer. As far as maneuverability, well... they're all pretty maneuverable. They can pivot, roll, fly backwards/belly-first, whatever. Acceleration doesn't translate to maneuverability. Spaceflight is pretty boring and spacecraft do very little maneuvering, unless you're running a cinematic campaign where spaceships fly around like aircraft. It's just one burn to change orbit inclination, one burn for a de-orbit into the atmosphere, two burns for de-orbit & lunar landing, two burns for a launch & orbit insertion, two burns (sometimes one) for a rendezvous/intercept. For the most part, one or two burns - pretty boring stuff.

 

[rgrove0172]

A 0.25G craft can reach the same speed as a 4G craft, it just takes 16x longer. As far as maneuverability, well... they're all pretty maneuverable. They can pivot, roll, fly backwards/belly-first, whatever. Acceleration doesn't translate to maneuverability.

Yes but to some extent acceleration does translate - as in the ability to reduce speed quickly, change vectors dramatically rather than casually, rapidly accelerate when the need arises and so on. Granted that .25G ship could reach the same speed as the 4G but once there they cant do much but continue blazing along whereas the 4G ship can decelerate faster, make a course change and cancel the current delta v etc.

No, Im not running a cinematic space dogfight and I invision the 'burn" mechanic just as you illustrate but some ships do it better than others and as a result gain an advantage when coming into and out of effective weapon ranges or maneuvering around obstacles etc. Enough so that I would think there should be a rating for it in game terms, even without a tactical mechanism to play it out. Vehicles have an abstract "Evade" value, why not give spacecraft a "Manuever" rating?

The Traveller Setting Book "Orbit" handles it pretty well (Using fuel consuming burns to alter engagement range) albiet a bit archaic for 2300 but where conventional drives are concerned, its not far off.

MT2300 kind of tries to fill the gap, which tells me Im not the only one that found it mysteriously missing from Classic 2300.

 

[shaunhilburn]

Enough so that I would think there should be a rating for it in game terms, even without a tactical mechanism to play it out. Vehicles have an abstract "Evade" value, why not give spacecraft a "Manuever" rating?

What would you be evading? Not beam weapons. Guns? Missiles?

For close quarters orbital combat, ordinary guns would do the trick. Muzzle velocities run from 0.6 to 1.6 km/s, so the reaction time to evade bullets/shells from several kilometers away is a handful of seconds - if the muzzle flashes are spotted in time. A small (one man) craft *might* be able to evade, but larger vehicles are just too sluggish from that sort of rapid response.

For close range missile combat, you could just use the homing/evasion ratings, but a spacecraft is nowhere near as agile as an aircraft; their evasion ratings would be much lower. It would be easier to destroy or jam inbound missiles than to evade them.

 

[rgrove0172]

The thread is moving in the direction of my Conventional Space Combat thread so Ill leave this here and pick it up there if need be.

I think the minimum Stutterwarp speed question has been sufficiently addressed. Thanks all!

 

[McPerth]

A 0.25G craft can reach the same speed as a 4G craft, it just takes 16x longer.

This would only be true in vaccum, but when inmersed in a fluid (and atmosphere is just that) there's a drag that depends on your craft's own speed (and how streamlined is it) and brakes it.

As it must overcome this negative acceleration to keep accelerating, and sure a 4 G craft can overcome more of it, it attain higher speeds than a 0.25 G one.

 

[rgrove0172]

I was referring to low orbit and beyond, space combat and maneuvering. The rules seem to cover atmosphereic, naval and ground combat ok.

 

[McPerth]

I was referring to low orbit and beyond, space combat and maneuvering. The rules seem to cover atmosphereic, naval and ground combat ok.

Even then, they will probably not reach the same speed, it will depend on their endurance. With no drag, and so no speed limit, the only limit would be its acceleration capacity, and, to reach the same speed, the 0.25 G craft would need to have 16 time the endurance of the 4 G one, as it will need, as Shaunhilburn says, 16 times the time to reach it. Of course, the 4 G craft can be quite far by then...

 

[rgrove0172]

More information we dont have like fuel consumption in the short term for conventional drives.

 

[BMonnery]

One of the books implies a minimum speed of warp eff. 0.15. This makes sense as otherwise a very small drive could very slowly move very large objects - like Vesta.

As to a single "jump" or tunneling event - it depends on what the drive is actually doing.

IMC the stutterwarp looks like a giant NMR machine (IRL I'm a chemist). I has a static coil and a spinning "screw". As the screw spins it's field and the static field of the coil align and at the moment of alignment there is the "jump", but the fields repulse each other in doing this.

Since I have a mechanical moving part rather than an electronic magic box such precision is impossible. Indeed the jump is variable and IMC the jump lengths fall on a Boltzman distribution which is why shooting at warping ships is difficult.

 

[McPerth]

One of the books implies a minimum speed of warp eff. 0.15. This makes sense as otherwise a very small drive could very slowly move very large objects - like Vesta.

I guess you're talking about the mínimum stutterwarp maximum efficiency a ship needs to have, while, as I understand it, the post is about how much you can reduce the pseudo-speed of your stutterwarp ship.

In any case, what you say is quite interesting. Never though about it, but you're right, there must be a minimum efficiency to avoid too large bodies to be moved by stutterwarp too easily (and to explain why the Bayern burnt it sdrive instead of ).