Loaded vs. Unloaded M-ratings

[Sigtrygg]

Irrelevant. CT doesn't even explain drives at all, so it's completely worthless as a source of information for this.

Yes it does - CT '77 edition m-drive burns fuel, 1st edition HG the m-drive is a fusion rocket.

Neither of these was overwritten until MT so by your understanding remain in force until DGP saddles us with the ridiculous thruster plate explanation in MT - which are TL11, what's the TL of MgT gravitic maneuver rives again?

In TNE the HEPlaR drive was standard but as I have already quoted, Thruster Plates are explained in detail in FF&S, so your argument can be dismissed.

Thruster plates in TNE are now an optional drive that doesn't exist in the OTU. The description of thrusters was lifted directly from MT. It was so naff thet it was changed in T4 and T5.

T4 changes the details, but it still isn't a "gravity well in front of a ship".

Very true. But consider this, read MgT High Guard, page 57 "A Gravitic drive is a smaller version of the drive plates used by larger spacecraft, and propels the craft using artificial gravity."

Sounds a bit different to the MT, TNE and T4 versions yes?

I give up. You're just refusing to understand what I'm saying, so there's no point in continuing this discussion.

I undertand perfectly - you are wrong.

You claim that explanations from other versions of the game based on different technological paradigms can be use to explain the MgT maneuver drive, but they can't.

All I want is for people to accept that the official explanation for MGT Thruster Plates is not "gravity well projected in front of a ship". MGT has no "official explanation". I think it makes a hell of a lot more sense to use previous explanations to fill the gap (which at least have some pretence of validity since it's the same bloody game setting) - if you don't, then fine - just stop pretending that an explanation that has been pulled out of thin air is any more valid.

I repeat my earlier quote from MgT HG:

A Gravitic drive is a smaller version of the drive plates used by larger spacecraft, and propels the craft using artificial gravity.

The only way artificial gravity can move a ship forward is if the ship is falling into an artificial gravity field.

 

[Ishmael]

Neither of these was overwritten until MT so by your understanding remain in force until DGP saddles us with the ridiculous thruster plate explanation in MT - which are TL11, what's the TL of MgT gravitic maneuver rives again?

High Guard 2nd edition redid the drives to use relatively little fuel and removed the rules concerning using the drive's exhaust as a weapon. This made it functionally the same as reactionless drives. In MT, grav units are tech-9. Thruster plates which are a combination grav-damper technologies are tech-11.

Very true. But consider this, read MgT High Guard, page 57 "A Gravitic drive is a smaller version of the drive plates used by larger spacecraft, and propels the craft using artificial gravity."

This sounds bery much like MT's grav units while acting very much like MT's thruster plates ( which are a combo of grav and damper technologies, so 'artificial gravity' could still be said to apply )

You claim that explanations from other versions of the game based on different technological paradigms can be use to explain the MgT maneuver drive, but they can't.

of course they can. Similar explanations to describe similar game effects.

The force accelerating the ship ( and everything in it )is F=mg which is the same as weight ( which is actually a force ). Note how mass is still involved? Or look at the classic gravity equation F = G*m1*m2/r^2.... oooh mass.
Just accept that mass is involved even if its couched in the terms of volumes at a constant density....
That'd also allow for the game's descriptions for reaction thrusters to be valid without changing anything or requiring accel = F/m to be undefined.

In these cases, the OP only has to define the various densities for his cargo or perhaps added armor, to get the performance changes he asked about.

The only way artificial gravity can move a ship forward is if the ship is falling into an artificial gravity field.

Not really. Consider quantum gravity and perhaps technologies that use interactions with exotic matter or exotic energy, for example.
This whole argument is about technobabble? bleh.

The rules describe game effects
The ref/players agree on descriptions of how those effects are achieved (technobabble).

 

[phavoc]

I didn't want to get in between any of the discussions relating to the technology behind thruster technology.

However, the point of the thread was adjusting the speed of a vessel that while loaded is capable of one G thrust, but when 90% of it's mass is gone, is the consensus that it would be capable of a six G thrust rating now?

 

[F33D]

I didn't want to get in between any of the discussions relating to the technology behind thruster technology.

However, the point of the thread was adjusting the speed of a vessel that while loaded is capable of one G thrust, but when 90% of it's mass is gone, is the consensus that it would be capable of a six G thrust rating now?

No. In MGT it doesn't change based on mass. See MRB & HG.

 

[Wil Mireu]

Yes it does - CT '77 edition m-drive burns fuel, 1st edition HG the m-drive is a fusion rocket.

Neither of these are valid anymore though - they were superseded by later editions of CT. The later version of HG (1980) says that "fuel consumption for M-Drives is inconsequential" (pg 17), and I can find no mention of it being able to be used as a fusion rocket. So they cannot be used as part of this argument. By the end of CT, there were no details for how M-Drives worked at all, beyond the fact that they used no fuel - that's as far as I can find anyway, it's hard to look through lots of books and PDFs with the info scattered all over the place.

Thruster plates in TNE are now an optional drive that doesn't exist in the OTU. The description of thrusters was lifted directly from MT. It was so naff thet it was changed in T4 and T5.

It doesn't matter that they're optional in TNE and it doesn't matter that you think it was "naff" - the explanation still stands and does not disagree with what came before.

Very true. But consider this, read MgT High Guard, page 57 "A Gravitic drive is a smaller version of the drive plates used by larger spacecraft, and propels the craft using artificial gravity."

Sounds a bit different to the MT, TNE and T4 versions yes?

A bit, but not enough to make a significant difference.

The communication problem here is twofold:

1) You are stubbornly refusing to acknowledge that "using artificial gravity" means anything other than "must be creating a gravity well in front of the ship that the ship then falls towards". It means nothing of the sort - it just means that gravitic technology is being used as the basis of the Thruster Plate. Gravitics is gravity manipulation. It doesn't necessarily involve "gravity wells" any more than spinning a spacestation to generate "artificial gravity" does.

2) I am working from the principle that "Any knowledge from Traveller canon fills gaps in later canon". You seem to be working from the principle of "Gaps remain unfilled unless the knowledge originates in the same edition". Which is fair enough in some cases, but when the current edition doesn't provide that knowledge then what are we expected to do? It seems that you think we should just assume that it's unknown, which I disagree with since there is an answer right there in previous editions that applies to the same situation.

You claim that explanations from other versions of the game based on different technological paradigms can be use to explain the MgT maneuver drive, but they can't.

And you haven't provided any evidence to back up that opinion at all.

CT cannot be used to support your case since its initial ideas were superseded by later editions that then didn't elaborate on the technology. But it's obvious that the designers had a change of heart about how they thought that M-Drives worked then.

MT introduced the ideas of Thruster Plates (they weren't introduced by DGP either - the description I quoted was from the Referee's Companion, which was a GDW product).

TNE continued to use that description, though Thruster Plates were presented as an alternate technology.

T4 actually used both HEPLaR (introduced in TNE) AND Thruster Plates, though it slightly modified the way the Thruster Plate technology worked. The problem with that though is that it was set over 1000 years before CT, MT, and TNE. So historically speaking should we be assuming that ships initially used HEPLaR and Thruster Plates, then abandoned HEPLaR by the CT era, then started using it again in TNE? (for added spanner in the works, GT Interstellar Wars - set a few thousand years before T4 - just uses "Reactionless Thrusters") That's a whole other can of worms though.

MGT says that M-Drives use "Drive Plates" (MGT HG pg 57) and are "gravitic" in origin (MGT HG pg 42). That agrees with MT, TNE, and T4.

I repeat my earlier quote from MgT HG:

A Gravitic drive is a smaller version of the drive plates used by larger spacecraft, and propels the craft using artificial gravity.
The only way artificial gravity can move a ship forward is if the ship is falling into an artificial gravity field.

And as I keep showing, that is an assumption on your part, and it is incorrect. "using artificial gravity" means "using the technology of artificial gravity (i.e. gravitics)" not literally using gravity as something to fall towards. Otherwise artificial gravity on a spaceship's decks means that you're literally creating gravity wells on every deck of the ship, which is ridiculous. It's a poor choice of words for them use, granted - but they are clearly referring to gravitic technology, not a literal gravity well.

For another thing, if a ship is supposedly falling towards a gravity well, then the drive plates should be on the front of the ship (so they can generate and project the field in the right direction) shouldn't they?

 

[Wil Mireu]

However, the point of the thread was adjusting the speed of a vessel that while loaded is capable of one G thrust, but when 90% of it's mass is gone, is the consensus that it would be capable of a six G thrust rating now?

The consensus is that it doesn't do that according to any of the rules.

Realistically speaking though, it should change the thrust rating though (since the mass of the ship is changing), but the rules don't account for mass of the ship changing. Chalk it down to Traveller being over-simplified for gameplay purposes.

What we're really arguing now is about the interpretation of how MGT drives actually work. Some people seem to have latched on to the erroneous idea that "artificial gravity" literally means "by creating gravity wells", which is not the case at all.

 

[F33D]

Some people seem to have latched on to the erroneous idea that "artificial gravity" literally means "by creating gravity wells", which is not the case at all.

ACTUALLY, it doesn't state how it is done. So, it is open to explaation. The only thing that is erroneous is your ego. I thought I explained that to you. Don't learn fast do you?

 

[Wil Mireu]

ACTUALLY, it doesn't state how it is done. So, it is open to explaation. The only thing that is erroneous is your ego. I thought I explained that to you. Don't learn fast do you?

Do you understand that AndrewW is a moderator here, and he's already asked people not to use personal attacks?

I would rather not see this thread locked because you are incapable of being civil.


As it stands, MGT states that the drive is gravitic and uses drive plates. I think you're stretching somewhat to insist that somehow this rules out the idea that they are the "Thruster Plates" described in previous editions, despite the fact that those are also gravitic and use 'drive plates' (and of course the fact that it's the same setting too).

And being "open to interpretation" doesn't mean that any explanation that people pull out of thin air - like the "gravity well" explanation - is the official one. Yes, the "Thruster Plate" explanation is also interpretation, but at least it's one that has evidence supporting it (which you refuse to acknowledge) - unlike the "gravity well" interpretation, which has no basis in any previous edition and certainly isn't specified as such in MGT either, and which stems from people incorrectly insisting that the phrase "using artificial gravity" cannot mean anything other than "creates a gravity well in front of the ship".

 

[Sigtrygg]

As it stands, MGT states that the drive is gravitic and uses drive plates. I think you're stretching somewhat to insist that somehow this rules out the idea that they are the "Thruster Plates" described in previous editions, despite the fact that those are also gravitic and use 'drive plates' (and of course the fact that it's the same setting too).

It states it uses artificial gravity and uses the term thruster plates. But the thruster plates of MgT are not the same as the MT or TNE ones - same name different pseudo-physics.

And being "open to interpretation" doesn't mean that any explanation that people pull out of thin air - like the "gravity well" explanation - is the official one. Yes, the "Thruster Plate" explanation is also interpretation, but at least it's one that has evidence supporting it (which you refuse to acknowledge) - unlike the "gravity well" interpretation, which has no basis in any previous edition and certainly isn't specified as such in MGT either, and which stems from people incorrectly insisting that the phrase "using artificial gravity" cannot mean anything other than "creates a gravity well in front of the ship".

MT an TNE explanation has been overwritten by T4 and T5.

 

[Sigtrygg]

I didn't want to get in between any of the discussions relating to the technology behind thruster technology.

However, the point of the thread was adjusting the speed of a vessel that while loaded is capable of one G thrust, but when 90% of it's mass is gone, is the consensus that it would be capable of a six G thrust rating now?

No, lowering the mass doesn't improve drive performance.

That said if you design a 100t ship with a 6g engine an then load it with 5x100t cargo modules or fuel tanks it moves at 1g.

Once those are delivered you drop back down to being a 100t, 6g ship again.

If you build a 600t ship with a 1g engine and a 500t cargo hold your rive performance is 1g regardless of a full cargo hold or an empty cargo hold.

If you want mass to affect m-drive performance you can do it with a bit of work. First you will have to work out the average mass of the unload ship.
Look at the ship design total for drives, electronics an other solid metal stuff - multiply by 70 to get the mass of the heavy stuff in the ship in metric tons.
Look at fuel tankage 1 ton of fuel has a mass of 1 ton so that is easy.
For all the staterooms and other air filled spaces the good news is every ship ton has a mass of 0.014 tons.

This will give a very rough idea of the mass of the unload ship and allow you to determine an unloaded m-drive rating.

Now you have to start keeping track of the density of whatever you are going to put in the cargo hold

 

[Sigtrygg]

The consensus is that it doesn't do that according to any of the rules.

Yup, completely agree.

Realistically speaking though, it should change the thrust rating though (since the mass of the ship is changing), but the rules don't account for mass of the ship changing. Chalk it down to Traveller being over-simplified for gameplay purposes.

Yup, if the maneuver drive is a reaction drive mass is a factor and should be taken into account, but (there's always a but) if the maneuver drive is generating a force field that moves the ship the mass of the ship is not a factor in the equations, so Traveller has handwaved magic reactionless thrusters that work on magic artificial gravity principles.

What we're really arguing now is about the interpretation of how MGT drives actually work. Some people seem to have latched on to the erroneous idea that "artificial gravity" literally means "by creating gravity wells", which is not the case at all.

According to you that is not the case, the rules don't explain, so we just don't know the exact details but we do know the in game effects.

Your explanation is to use a very flawed explanation taken from another game that was over-written two editions back.

 

[F33D]

Do you understand that AndrewW is a moderator here, and he's already asked people not to use personal attacks?

I would rather not see this thread locked because you are incapable of being civil.

You DO understand that your backhanded attacks ARE recognize for what they are?

I'd rather not have this thread locked because you are incapable of playing nice.

WHY do you refuse to read the MT rules & understand that load affects performance for ships using the Thruster plates? Once you admit it you have to know that the items in the 2 additions don't mechanically work the same... :roll: :lol:

 

[phavoc]

Thanks for the feedback. I think I'll be changing a few things.

Based on what others have said, Traveller M-drives work more along the lines of push/pulling power rather than pure brute force. A 1G M-drive will have a maximum speed of 1G until it reaches its upper Dton limit, and then it's capabilities will be reduced. I guess real-world analogies would be things like tug boats or say large cargo ships whose propulsion systems are optimized for moving mass efficiently instead of speed. An unloaded VLCC still is a pig in the water no matter what.

Ok, back to the grav sniping!

 

[Ishmael]

WHY do you refuse to read the MT rules & understand that load affects performance for ships using the Thruster plates? Once you admit it you have to know that the items in the 2 additions don't mechanically work the same... :roll: :lol:

Because in MT, mass and any changes in mass do NOT affect a ship's acceleration.
Mass as a factor of ship's performance is used ONLY for calculating agility for use in a CT High Guard like system.
Go read the rules. :roll:

---------------------------------------

Just assume a ship's mass is 10 tonnes per dton with a half load of cargo and fuel. It won't change much from that for common Trav ships. any changes would be small in relation to the ship's overall mass anyways.
Tracking ship's mass would really be an issue during construction mostly for adjusting performance with extra armor. As it is, there is no performance gains for building light-weight craft even though that would allow for better economy ( less power for a given performance level ) and handling ( low moments of inertia ).

For example, a 10,000 ton tanker that has set aside 9,500 tons for fuel. To get 1G fully loaded the Mdrive is 100 tons and the PP is 150 tons. But if it's running empty then it's quite over-powered.

In this case, the ship might be estimated to mass ~100,000 tonnes loaded, and removing 9,500 dtons of fuel @ 1 tonne per dton would still leave a ship massing ~ 90,500 tonnes... a reduction of ~10% of mass. Thus the revised acceleration might end up being 1.1 g's. Naturally dropping off 9,500 dtons of something more dense than liquid hydrogen would affect things more, but then the full ship would need a larger drive and power plant in such a case anyways.
In-game play won't be affected so much that it becomes a constant issue.

There is still no explanations given by people here concerning why mass does not affect reaction drives as per RAW.
THAT should be a hoot.
But then again, see above comments about 1 dton ~ 10 tonnes.

 

[phavoc]

I've never had issue with mass NOT being calculated. i'm fine with this particular hand-wavium since it speeds up the gaming by not having to take it into affect. I don't think including it makes the game more fun, just more burdensome.

In this particular instance the removal of 90% of the displacement is a huge amount. But after the discussions on list, and some real-world research, I'm okay with the one-way affect Dtons has on movement ratings.

 

[Wil Mireu]

It states it uses artificial gravity and uses the term thruster plates. But the thruster plates of MgT are not the same as the MT or TNE ones - same name different pseudo-physics.

What you don't seem to understand is that you're just asserting that. There is no evidence to support your assertion at all.

MT an TNE explanation has been overwritten by T4 and T5.

T4's explanation isn't really that different to MT/TNE's in practical terms. It's still plates that push the ship forwards, not a gravity well. I don't know what T5's explanation is unless you'd care to quote it.

 

[F33D]

It states it uses artificial gravity and uses the term thruster plates. But the thruster plates of MgT are not the same as the MT or TNE ones - same name different pseudo-physics.

What you don't seem to understand is that you're just asserting that. There is no evidence to support your assertion at all.

Except rules regarding loading and performance are different. That is 100% proof that they operate differently. If the rules aren't evidence what is? Please explain why rules aren't evidence. This should good.

 

[Wil Mireu]

What we're really arguing now is about the interpretation of how MGT drives actually work. Some people seem to have latched on to the erroneous idea that "artificial gravity" literally means "by creating gravity wells", which is not the case at all.

According to you that is not the case, the rules don't explain, so we just don't know the exact details but we do know the in game effects.

Your explanation is to use a very flawed explanation taken from another game that was over-written two editions back.

Your opinion on whether it's flawed or not isn't irrelevant - there are a lot of things in Traveller that are flawed but people still use them. Fact is, it's the official explanation.

Like I said, I use previous editions to fill in the gaps in current editions with official answers. You just seem to want to leave the gap there and make up your own explanation - which is great for you, but don't go around pretending that your explanation is the official answer, or that it's any more valid than using what was in previous editions.

 

[F33D]

Your opinion on whether it's flawed or not isn't irrelevant - there are a lot of things in Traveller that are flawed but people still use them. Fact is, it's the official explanation.

Nope. WRONG. It is an explanation for THAT specific version. ONLY.

 

[Wil Mireu]

A 1G M-drive will have a maximum speed of 1G until it reaches its upper Dton limit, and then it's capabilities will be reduced.

It will have a maximum acceleration of 1G. It won't have a maximum speed (beyond the speed of light).

I think what Sig was saying (he confused issues by referring to 't' (tons), not 'dt' (displacement tons)) is that if you have a 100dt ship and add 500dt of external modules to it (the actual mass of which is irrelevant), then the drive performance will change because the volume of the ship has changed from 100dt to 600dt.

If you have a 600dt ship with a 500dt cargo bay, its drive performance will always be the same whether you completely fill that 500dt completely with osmium, feathers, or air because the total volume of the ship hasn't changed.

Which is utterly ridiculous, but that's Traveller.