Fuel Purification Plant

[boomslang]

Originally posted by Straybow:
Skimming a GG doesn't require thrust equal to gravity. An aerodynamic hull could skim without any thrust at all, although it would be a jarring ride.

Yes, but -- it's a drag issue. In order to ram that very, very thin atmo into the scoops (and presumed compressors) with enough flow to fill your tanks at any sort of time-efficient rate whilst staying above the soup, you need to be moving fast enough to generate a fair amount of pressure-driven inflow, and thus drag.

Otherwise you're just aerobraking, and that will be unhealthy for maintaining your altitude and escape velocity... especially for the extended length of time required to then tank up on mere wisps and puffs...

 

[Supplement Four]

Originally posted by boomslang:
This makes that lingering rules oversight go away with minimal hand-waving.

[snip]

A grav-propelled vessel's maximum effective ground speed is a function of atmo drag; less atmo, higher top speed in atmo. 1G is plenty to skim with; you just have to stay high and fast.

According to CT, a ship, streamlined and winged or not, cannot land on a world unless its M-Drive rating is greater than the world's G rating. A ship with a 1G M-Drive cannot reach escape velocity of a size 9 world, for example.

Many Traveller players don't realize this about CT because it's a bit hidden in the rules. And, because this type of thing is glossed over and forgotten in later editions of Traveller. But, if you look closely, you'll see CT rulings that support this.

Off the top of my head, check out pg. 11 of Striker Book 3. There, in the design sequence description of grav vehicles, it states exactly what I've said--that 1G is needed to keep the vehicle in the air and additional G thrust is needed to move the vehicle. More specifically about starships, look at pg. 41 of Striker Book 2, under the heading Naval Vessels, it states: "The movement rate of a spaceship is determined in the same way as that for a grav vehicle; the ship's maneuver drive rating is used as its G value. A ship with a G rating equal to or less than the planetary gravity may not take part in [ground] combat actions except from orbit."

This rule is often overlooked because it doesn't make a splash of an appearance in the Basic CT rules. But note that one of CT's co-creators, LKW, uses this rule when he designs CT craft. Check out his CT Supplement for the 20 ton Launch. There, LKW states plainly in the text that that the launch is rated at 2Gs but 1G is taken away to keep the vehicle in the air. Planetary speeds for the launch are rated for a 1G vessel, not one capable of 2Gs.

And, that's from LKW, designing stuff for Classic Traveller.

 

[Supplement Four]

Originally posted by boomslang:
This makes that lingering rules oversight go away with minimal hand-waving.

[snip]

A grav-propelled vessel's maximum effective ground speed is a function of atmo drag; less atmo, higher top speed in atmo. 1G is plenty to skim with; you just have to stay high and fast.

According to CT, a ship, streamlined and winged or not, cannot land on a world unless its M-Drive rating is greater than the world's G rating. A ship with a 1G M-Drive cannot reach escape velocity of a size 9 world, for example.

Many Traveller players don't realize this about CT because it's a bit hidden in the rules. And, because this type of thing is glossed over and forgotten in later editions of Traveller. But, if you look closely, you'll see CT rulings that support this.

Off the top of my head, check out pg. 11 of Striker Book 3. There, in the design sequence description of grav vehicles, it states exactly what I've said--that 1G is needed to keep the vehicle in the air and additional G thrust is needed to move the vehicle. More specifically about starships, look at pg. 41 of Striker Book 2, under the heading Naval Vessels, it states: "The movement rate of a spaceship is determined in the same way as that for a grav vehicle; the ship's maneuver drive rating is used as its G value. A ship with a G rating equal to or less than the planetary gravity may not take part in [ground] combat actions except from orbit."

This rule is often overlooked because it doesn't make a splash of an appearance in the Basic CT rules. But note that one of CT's co-creators, LKW, uses this rule when he designs CT craft. Check out his CT Supplement for the 20 ton Launch. There, LKW states plainly in the text that that the launch is rated at 2Gs but 1G is taken away to keep the vehicle in the air. Planetary speeds for the launch are rated for a 1G vessel, not one capable of 2Gs.

And, that's from LKW, designing stuff for Classic Traveller.

 

[boomslang]

Originally posted by Supplement Four:
This rule is often overlooked because it doesn't make a splash of an appearance in the Basic CT rules. But note that one of CT's co-creators, LKW, uses this rule when he designs CT craft. Check out his CT Supplement for the 20 ton Launch. There, LKW states plainly in the text that that the launch is rated at 2Gs but 1G is taken away to keep the vehicle in the air. Planetary speeds for the launch are rated for a 1G vessel, not one capable of 2Gs.

And, that's from LKW, designing stuff for Classic Traveller.

Which again only makes things worse, because now all spacecraft m-drives are consequently effectively uprated by 1G, to allow the extra G for takeoff/landing on big worlds.

If a Launch can "really" make 2Gs, then my Ship's Boat just got an upgrade to 7Gs while I'm cruisin' around out in the black.

Plus, in The Traveller Adventure, that Fat Trader must make planetfall on half a dozen Size 8+ worlds, right?

Again, hand-waving should not create more problems than it solves, I always say...

 

[boomslang]

Originally posted by Supplement Four:
This rule is often overlooked because it doesn't make a splash of an appearance in the Basic CT rules. But note that one of CT's co-creators, LKW, uses this rule when he designs CT craft. Check out his CT Supplement for the 20 ton Launch. There, LKW states plainly in the text that that the launch is rated at 2Gs but 1G is taken away to keep the vehicle in the air. Planetary speeds for the launch are rated for a 1G vessel, not one capable of 2Gs.

And, that's from LKW, designing stuff for Classic Traveller.

Which again only makes things worse, because now all spacecraft m-drives are consequently effectively uprated by 1G, to allow the extra G for takeoff/landing on big worlds.

If a Launch can "really" make 2Gs, then my Ship's Boat just got an upgrade to 7Gs while I'm cruisin' around out in the black.

Plus, in The Traveller Adventure, that Fat Trader must make planetfall on half a dozen Size 8+ worlds, right?

Again, hand-waving should not create more problems than it solves, I always say...

 

[boomslang]

Originally posted by boomslang:
Again, hand-waving should not create more problems than it solves, I always say...

[parody]For example, since a spaceship's m-drive is now actually rated 1G higher than its powerplant, I'd like to build a starship (perhaps for asteroid prospecting) with only a 1G m-drive and no powerplant (and also no fuel), please... fit in one of those Xboat j-drives, and I'm good to go...[/parody]

The canon seems to be broken in a few places, I've noticed over the years...

 

[boomslang]

Originally posted by boomslang:
Again, hand-waving should not create more problems than it solves, I always say...

[parody]For example, since a spaceship's m-drive is now actually rated 1G higher than its powerplant, I'd like to build a starship (perhaps for asteroid prospecting) with only a 1G m-drive and no powerplant (and also no fuel), please... fit in one of those Xboat j-drives, and I'm good to go...[/parody]

The canon seems to be broken in a few places, I've noticed over the years...

 

[far-trader]

I think the point being made about the launch is one I came to myself long long ago. With the CT design rules requiring a minimum of 1ton for a maneuver drive there is no point in making a 1G launch. The minimum of 1ton of maneuver drive in a 20ton hull gives you 2G. Consequently all launches have always been 2G. Loren took this fact and created an explanation for why.

So, no, your Ship's Boat is not magically 7Gs

It is still 6Gs. Though I like the idea of a powerplant free and fuel free maneuver drive

Actually I can see an alternate take of the Book 2 drives being no powerplant and just the stated fuel use, as a reaction drive for maneuver (something like... 10tons fuel per letter for 4 weeks) and flash drive for jump (10tons fuel per letter per jump). While the Book 5 drives are more efficient thruster maneuver and capacitor jump with no fuel requirement but needing a powerplant and it's fuel requirement.

Of course I don't go with the whole minus local gravity thing. First the only reference in CT seems to be in Striker*, that's hardly a convincing cite. Second it has long been glossed over in one way or another and that the maneuver drive rating is what is used for thrust, not lift, and that local gravity seems to be ignored.

* except for a strange reference to gravity altering the vector in the space combat rules in Book 2, strange because it isn't mentioned in any other CT rules, unless I'm forgetting some mention

 

[far-trader]

I think the point being made about the launch is one I came to myself long long ago. With the CT design rules requiring a minimum of 1ton for a maneuver drive there is no point in making a 1G launch. The minimum of 1ton of maneuver drive in a 20ton hull gives you 2G. Consequently all launches have always been 2G. Loren took this fact and created an explanation for why.

So, no, your Ship's Boat is not magically 7Gs

It is still 6Gs. Though I like the idea of a powerplant free and fuel free maneuver drive

Actually I can see an alternate take of the Book 2 drives being no powerplant and just the stated fuel use, as a reaction drive for maneuver (something like... 10tons fuel per letter for 4 weeks) and flash drive for jump (10tons fuel per letter per jump). While the Book 5 drives are more efficient thruster maneuver and capacitor jump with no fuel requirement but needing a powerplant and it's fuel requirement.

Of course I don't go with the whole minus local gravity thing. First the only reference in CT seems to be in Striker*, that's hardly a convincing cite. Second it has long been glossed over in one way or another and that the maneuver drive rating is what is used for thrust, not lift, and that local gravity seems to be ignored.

* except for a strange reference to gravity altering the vector in the space combat rules in Book 2, strange because it isn't mentioned in any other CT rules, unless I'm forgetting some mention

 

[far-trader]

Originally posted by boomslang:
Again, hand-waving should not create more problems than it solves, I always say...

Quite.

Which is why it has been ignored, or explained as contra-grav lifters nullify local gravity (99% or so anyway) leaving your full maneuver G for thrust.

The only problem there is some people seem to have come to the conclusion that contra-grav will allow a ship, no matter how ungainly designed it's extreme unstreamlined shape, to safely, gently, routinely, and easily, enter an atmosphere. I think it's wrong but hey, it's a game.

 

[far-trader]

Originally posted by boomslang:
Again, hand-waving should not create more problems than it solves, I always say...

Quite.

Which is why it has been ignored, or explained as contra-grav lifters nullify local gravity (99% or so anyway) leaving your full maneuver G for thrust.

The only problem there is some people seem to have come to the conclusion that contra-grav will allow a ship, no matter how ungainly designed it's extreme unstreamlined shape, to safely, gently, routinely, and easily, enter an atmosphere. I think it's wrong but hey, it's a game.

 

[Supplement Four]

Originally posted by boomslang:
Plus, in The Traveller Adventure, that Fat Trader must make planetfall on half a dozen Size 8+ worlds, right?

Actually, um, no.

Pop open your Traveller Adventure and take a look.

The HARRIER begins the campaign at Aramis Down on Aramis. Aramis is a Size 6 world. No problem there.

Next stop is Natoko, for the chapter titled In Search of Longer Legs. Natoko is a Size 5 world. Again, no problem.

Patinir is next, an asteroid belt at Size 0. No problem.

Then, on to Pysadi, a Size 4 world. No problem.

Zila is the focus of two chapters in the campaign, but its a Size 2 world. No problem.

Aramanx is Size 6. No problem there. (BTW, the HARRIER doesn't actually land on Aramanx. The ship docks at the High Port and takes a shuttle down.)

The chapter called Inselberg occurs on Lewis, a Size 4 world. No problem.

And finally, the campaign climax happens on Jesedipere, a Size 7 world. No problem there either.

If the GM takes the ship off the beaten path to one of the worlds that is Size 8+, all it means is that the HARRIER cannot land on the world. I must dock at the High Port. All business can be conducted at the High Port, and the ship can be loaded in zero-G. But if the crew is restless and wants some fresh air (given the atmo code agrees), then a shuttle ride can be purchased to take them dirtside.

But...no, no problems with the Traveller Adventure and the HARRIER's 1G drive.

I'm sure if you search long enough, though, you'll find an official GDW adventure that does break this rule.

I mean, heck, I've found characters who break the Experience Limit rule and ship deck plans that don't fit their hull displacement. I'm sure there's an adventure out there where a ship with a 1G M-Drive lands on a Size 10 world.

Not in my campaign, though. I'm sticking with the CT rule. I like it.

 

[Supplement Four]

Originally posted by boomslang:
Plus, in The Traveller Adventure, that Fat Trader must make planetfall on half a dozen Size 8+ worlds, right?

Actually, um, no.

Pop open your Traveller Adventure and take a look.

The HARRIER begins the campaign at Aramis Down on Aramis. Aramis is a Size 6 world. No problem there.

Next stop is Natoko, for the chapter titled In Search of Longer Legs. Natoko is a Size 5 world. Again, no problem.

Patinir is next, an asteroid belt at Size 0. No problem.

Then, on to Pysadi, a Size 4 world. No problem.

Zila is the focus of two chapters in the campaign, but its a Size 2 world. No problem.

Aramanx is Size 6. No problem there. (BTW, the HARRIER doesn't actually land on Aramanx. The ship docks at the High Port and takes a shuttle down.)

The chapter called Inselberg occurs on Lewis, a Size 4 world. No problem.

And finally, the campaign climax happens on Jesedipere, a Size 7 world. No problem there either.

If the GM takes the ship off the beaten path to one of the worlds that is Size 8+, all it means is that the HARRIER cannot land on the world. I must dock at the High Port. All business can be conducted at the High Port, and the ship can be loaded in zero-G. But if the crew is restless and wants some fresh air (given the atmo code agrees), then a shuttle ride can be purchased to take them dirtside.

But...no, no problems with the Traveller Adventure and the HARRIER's 1G drive.

I'm sure if you search long enough, though, you'll find an official GDW adventure that does break this rule.

I mean, heck, I've found characters who break the Experience Limit rule and ship deck plans that don't fit their hull displacement. I'm sure there's an adventure out there where a ship with a 1G M-Drive lands on a Size 10 world.

Not in my campaign, though. I'm sticking with the CT rule. I like it.

 

[Supplement Four]

Originally posted by far-trader:
Which is why it has been ignored, or explained as contra-grav lifters nullify local gravity (99% or so anyway) leaving your full maneuver G for thrust.

Or...

I wonder...

I wonder if this rule is a left-over reference from 1st edition CT. You know...back when a autopistol did 3D -3 damage and a carbine did 4D -8.

Or, the jump governor that was included in the 1st edition of Book 5. That disappeared when Book 5 went into its second edition.

It could very well be the Escape Velocity rule was removed or changed from the first edition.

Does anyone have a 1st edition LBB set to check it out?

I'm not sure if that's why it's evident in Striker's design system, though. That design system was meant to not only design vehicles for Striker, but for CT too.

I've seen a few references in CT articles in magazines to the rule, but I'd be curious if it popped up somewhere else as well.

As I'm re-reading all the CT stuff, I'll keep an eye open for it and post if I find something.




EDIT: It's not a direct reference, but in the Starship Economics chapter of The Traveller Book (and I assume this is in the LBBs too, but I haven't checked), goods taken on in orbit are delivered when placed in orbit around the destination world. Goods loaded on a planetary surface are delivered when off-loaded on the surface if the destination. The custom applies to cargo, passengers, and mail.

I think that definition can be used to support either argument, though. I'd say that the reference to the high port is in there for the 1G vessels that orbit worlds of Size 8+. You'd say that reference is in there for starports that are in asteroid belts or orbit gas giants.

It doesn't really support either arugment, but I thought I'd bring it up.

OTOH, the section on Shuttle Service mentions routine shuttles that operate between orbit and the world surface if there's a Class A, B, or C starport.

Again, not a lot of support for either argument, and some would say the High Ports are for unstreamlined ships. I'd say they're for that and ships with only 1G M-Drives around large worlds.

 

[Supplement Four]

Originally posted by far-trader:
Which is why it has been ignored, or explained as contra-grav lifters nullify local gravity (99% or so anyway) leaving your full maneuver G for thrust.

Or...

I wonder...

I wonder if this rule is a left-over reference from 1st edition CT. You know...back when a autopistol did 3D -3 damage and a carbine did 4D -8.

Or, the jump governor that was included in the 1st edition of Book 5. That disappeared when Book 5 went into its second edition.

It could very well be the Escape Velocity rule was removed or changed from the first edition.

Does anyone have a 1st edition LBB set to check it out?

I'm not sure if that's why it's evident in Striker's design system, though. That design system was meant to not only design vehicles for Striker, but for CT too.

I've seen a few references in CT articles in magazines to the rule, but I'd be curious if it popped up somewhere else as well.

As I'm re-reading all the CT stuff, I'll keep an eye open for it and post if I find something.




EDIT: It's not a direct reference, but in the Starship Economics chapter of The Traveller Book (and I assume this is in the LBBs too, but I haven't checked), goods taken on in orbit are delivered when placed in orbit around the destination world. Goods loaded on a planetary surface are delivered when off-loaded on the surface if the destination. The custom applies to cargo, passengers, and mail.

I think that definition can be used to support either argument, though. I'd say that the reference to the high port is in there for the 1G vessels that orbit worlds of Size 8+. You'd say that reference is in there for starports that are in asteroid belts or orbit gas giants.

It doesn't really support either arugment, but I thought I'd bring it up.

OTOH, the section on Shuttle Service mentions routine shuttles that operate between orbit and the world surface if there's a Class A, B, or C starport.

Again, not a lot of support for either argument, and some would say the High Ports are for unstreamlined ships. I'd say they're for that and ships with only 1G M-Drives around large worlds.

 

[Supplement Four]

Take note that, in Sup 7, the Far Trader is listed on pg. 24 as having...

Acceleration: 2G. Normal operations and crusing at 1G.

And the text says the ship has a 1G M-Drive.

I'm not sure what that's all about.




Of course, that same vessel is listed as having a 46 ton cargo hold. If you count the 1.5 meter squares of the hold (176), then divide by 2 per normal CT convention to find a displacement ton, the cargo hold should be able to store 88 tons of cargo. And that's only with a 3 meter floor-to-ceiling deck. If the hold has a high ceiling, then the cargo capacity is much more.

And, as anyone can tell you, the Type A2 is a hard ship to turn a profit with. It could sure use double the cargo space.

Then again, the vessel is supposed to be a 200 ton vessel. If you count the deckplans up, it's really a 400 ton vessel.

...And they promised me on pg. 5 of the Sup that they used Book 2 ship design and deckplan methodology...

 

[Supplement Four]

Take note that, in Sup 7, the Far Trader is listed on pg. 24 as having...

Acceleration: 2G. Normal operations and crusing at 1G.

And the text says the ship has a 1G M-Drive.

I'm not sure what that's all about.




Of course, that same vessel is listed as having a 46 ton cargo hold. If you count the 1.5 meter squares of the hold (176), then divide by 2 per normal CT convention to find a displacement ton, the cargo hold should be able to store 88 tons of cargo. And that's only with a 3 meter floor-to-ceiling deck. If the hold has a high ceiling, then the cargo capacity is much more.

And, as anyone can tell you, the Type A2 is a hard ship to turn a profit with. It could sure use double the cargo space.

Then again, the vessel is supposed to be a 200 ton vessel. If you count the deckplans up, it's really a 400 ton vessel.

...And they promised me on pg. 5 of the Sup that they used Book 2 ship design and deckplan methodology...

 

[Supplement Four]

Originally posted by boomslang:
Not necessarily; you can skim up where the air is rare (and the hydrogen is actually a higher percentage of what you encounter), if you just go fast enough.

A grav-propelled vessel's maximum effective ground speed is a function of atmo drag; less atmo, higher top speed in atmo. 1G is plenty to skim with; you just have to stay high and fast.

Just for clarification: CT rules do specify a deep dive into the atmo when skimming. Check out the Lesser Known Aspects of Space Travel section in your LBBs.

 

[Supplement Four]

Originally posted by boomslang:
Not necessarily; you can skim up where the air is rare (and the hydrogen is actually a higher percentage of what you encounter), if you just go fast enough.

A grav-propelled vessel's maximum effective ground speed is a function of atmo drag; less atmo, higher top speed in atmo. 1G is plenty to skim with; you just have to stay high and fast.

Just for clarification: CT rules do specify a deep dive into the atmo when skimming. Check out the Lesser Known Aspects of Space Travel section in your LBBs.

 

[Supplement Four]

Originally posted by far-trader:
First the only reference in CT seems to be in Striker*, that's hardly a convincing cite.

[snip]

* except for a strange reference to gravity altering the vector in the space combat rules in Book 2, strange because it isn't mentioned in any other CT rules, unless I'm forgetting some mention

Bad news, fellas. I just read that cite. This Escape Velocity rule IS mentioned in CT. In a big way. It's right where Dan just pointed...right in the middle of Book 2.

It's been there from the beginning, and I've never seen it. Heck, I think most Traveller players have just skimmed past this reference.

It's in a section that nobody reads because it has to do with rulers, milimeters, and math.

Yep, it's the Movement section of Book 2 space combat. It's the section that details a planet's gravitational effect on starships in Traveller.

That's what we're talking about, right? A ship's ability, with it's 1G M-Drive, to reach escape velocity on a Size 8 world.

I don't think this is a strange reference as Dan calls it above. Once you read it and understand it, I think it's pretty clear.

A ship with a 1G drive that begins on the surface of a Size 8 world will accelerate to a distance of 10,000 km...that is, if we do not account for the world's gravitational field.

Do the math. Look at the vector.

Once you apply the gravitational vector adjustment to the ship lifting off a Size 8 world, the ship's velocity becomes 0.

Yep. That's right. It ain't going anywhere.

It's right there in black and white. Right there in the heart of the LBBs.

THAT's where LKW is coming from when he wrote what he did in his 20 ton Launch deckplans.

THAT's what the references in the CT magazines are talking about.

THAT's why Striker's design system says what it does.

It's right there. Plot the course of the ship. It won't go anywhere. Now, if the ship had already been moving at some higher velocity, then the ship could make escape velocity through the Size 8 world's atmo. But, a ship on the ground, with a 1G drive, is starting at Velocity 0.

That's the big CT reference, right there in front of our faces.

We all missed it. But, it's there.