2nd Ed Ship Design

[allanimal]

The new High Guard looks nice.
I wish there was more consistency in the ship stats pages, but I'm sure that will all be fixed in the pdf updates... (I hope!)

Anyway, started looking at the ship design rules. I think most of my new designs will be close structures - -10% cost, +10% hull and partially streamlined? Seems like a great deal. What's the downside?

Any other interesting quirks to be found in the new design rules?

 

[wbnc]

The new High Guard looks nice.
I wish there was more consistency in the ship stats pages, but I'm sure that will all be fixed in the pdf updates... (I hope!)

Anyway, started looking at the ship design rules. I think most of my new designs will be close structures - -10% cost, +10% hull and partially streamlined? Seems like a great deal. What's the downside?

Any other interesting quirks to be found in the new design rules?

partially streamlined ships cn skim fuel but I don't expect them to be very good in atmosphere...basically, they would be one of those ships that can land, but it probably voids the insurance policy.

 

[Spartan159]

I allow the 800 dTon Merc Cruiser to land but it handles like a pig in atmosphere. I think a sphere is a strong structure whereas I think a close structure should only be allowed to land in special gravitically controlled bays or very low gravity worlds. IIRC the 1800 dTon Leviathan was a close structure. Edit: I checked the stats in HG2e, they say standard structure for the Leviathan.

 

[wbnc]

I allow the 800 dTon Merc Cruiser to land but it handles like a pig in atmosphere. I think a sphere is a strong structure whereas I think a close structure should only be allowed to land in special gravitically controlled bays or very low gravity worlds. IIRC the 1800 dTon Leviathan was a close structure. Edit: I checked the stats in HG2e, they say standard structure for the Leviathan.

I wouldn't take the Leviathan anywhere near a strong crosswind...it would be pushing it just to stay on course without crabbing ( moving sideways as it moves forward)

It looks like they addressed the leviathans aerodynamics in the descriptive text...

. The vessels are semi streamlined, allowing skimming refuelling manoeuvres as well as landings in types 0 and 1 atmospheres. Atmospheric landings are otherwise impossible, hence the large complement of ship’s boat

 

[AndrewW]

IIRC the 1800 dTon Leviathan was a close structure. Edit: I checked the stats in HG2e, they say standard structure for the Leviathan.

Classic Traveller A4 Leviathan:

Tonnage: 1800 (standard).

 

[phavoc]

An unstreamlined ship should be able to maneuver in an atmosphere, but it should be limited in it's speed (say 200-300kph?). Semi-streamlined should be faster (double), and streamlined should top out around 1,000kph. Purpose-built aircraft like hypersonic craft should run rings around spaceships, and that's fine because they are specifically designed for it.

A in-atmo speed chart would be nice.

 

[fusor]

partially streamlined ships cn skim fuel but I don't expect them to be very good in atmosphere...basically, they would be one of those ships that can land, but it probably voids the insurance policy.

Right, but from the HG preview doc it seems that "Close Structures" are the same as "Standard" but 10% more hull points and 10% cheaper, and they're both partially streamlined. So what is "Standard" and why would anyone use it?

Also, the meaning of "partial" vs "full" streamlinining isn't explained at all there.

And the "Double Hull" description doesn't make sense to me. Why would you spin the outer hull and not the inner hull? Wouldn't you want to spin the inner hull because that's where people would be?

 

[rust2]

Why would you spin the outer hull and not the inner hull? Wouldn't you want to spin the inner hull because that's where people would be?

Most designs I have seen with spinning hulls have a zero-g core and a spinning habitat around it, mostly because one needs a minimum diameter of the spinning hull habitat to avoid serious medical problems for the inhabitants.

 

[wbnc]

partially streamlined ships cn skim fuel but I don't expect them to be very good in atmosphere...basically, they would be one of those ships that can land, but it probably voids the insurance policy.

Right, but from the HG preview doc it seems that "Close Structures" are the same as "Standard" but 10% more hull points and 10% cheaper, and they're both partially streamlined. So what is "Standard" and why would anyone use it?

Also, the meaning of "partial" vs "full" streamlinining isn't explained at all there.

And the "Double Hull" description doesn't make sense to me. Why would you spin the outer hull and not the inner hull? Wouldn't you want to spin the inner hull because that's where people would be?

The added this section to the descriptive text of the Leviathan which is partially streamlined.
Pg: 154 Highguard

The vessels are semi streamlined, allowing skimming refuelling manoeuvres as well as landings in types 0 and 1 atmospheres. Atmospheric landings are otherwise impossible, hence the large complement of ship’s boat

and under atmospheric operations they listed
Pg: 143 Corebook

Partial streamlining allows a ship to skim gas giants and enter Atmosphere codes of 3 or less, acting in the same way as streamlined ships. In other atmospheres, the ship will be ponderous and unresponsive, reliant on its thrusters to keep it aloft. All Pilot checks will be made with DM-2.

changing the close structure to Semi streamlined , and adding the Semi streamlined modifier to the atmospheric operations section would adjust things a bit. A close structure ship would be one that had to steer clear of any appreciable atmosphere, and a standard hull can make slow deliberate landings on most worlds. the mechanics are there they just need a bit of shuffling to be more obvious.

So in atmo it boils down to...
Streamlined: no effect, go for it...
Standard: Don't try this without adult supervision
Closed Structure: dont try this at home kids...
Dispersed: Ya know there are easier ways to commit suicide...
Asteroid hull: Aint this how the dinosaurs bought it?

 

[fusor]

The added this section to the descriptive text of the Leviathan which is partially streamlined.
Pg: 154 Highguard

The vessels are semi streamlined, allowing skimming refuelling manoeuvres as well as landings in types 0 and 1 atmospheres. Atmospheric landings are otherwise impossible, hence the large complement of ship’s boat

and under atmospheric operations they listed
Pg: 143 Corebook

Partial streamlining allows a ship to skim gas giants and enter Atmosphere codes of 3 or less, acting in the same way as streamlined ships. In other atmospheres, the ship will be ponderous and unresponsive, reliant on its thrusters to keep it aloft. All Pilot checks will be made with DM-2.

changing the close structure to Semi streamlined , and adding the Semi streamlined modifier to the atmospheric operations section would adjust things a bit. A close structure ship would be one that had to steer clear of any appreciable atmosphere, and a standard hull can make slow deliberate landings on most worlds. the mechanics are there they just need a bit of shuffling to be more obvious.

So in atmo it boils down to...
Streamlined: no effect, go for it...
Standard: Don't try this without adult supervision
Closed Structure: dont try this at home kids...
Dispersed: Ya know there are easier ways to commit suicide...
Asteroid hull: Aint this how the dinosaurs bought it?

So they added a new (totally unnecessary) streamlining classification? And they still don't actually explain what a "Standard" hull configuration vs a "Close Structure" is. I always thought Close Structure was "anything that wasn't Cylinder,Sphere, Needle, Wedge, etc".

 

[phavoc]

The problem with the books explanation is that it negates the entire concept of anti-gravity. Your ship could be a flying brick and it still can land and maneuver in an atmosphere. It just handles like a flying brick. The fact is, the miracle of anti-gravity enables all kinds of things that the rules totally toss out the door.

Where you are going to have issue is when you try to land your craft that has a rotating habitat - umm, unless you have REALLY long landing struts or the rotating habitat is built for it, it's not going to happen. But that doesn't mean you can't fly into an atmosphere. The rules posit no such thing as material stress factors. It's all just arbitrarily lumped together, which is sad because I would have hoped this would have been addressed by now.

You don't need streamlining to enter an atmosphere. What it does is allow you to enter it faster, and maneuver better. Anti-gravity doesn't overcome atmospheric resistance, it just means you can float (and in some cases propel yourself, aka grav vehicles). Starships use it to offset gravity, then they can either float all the way to orbit, albeit very slowly, or they can engage their drives to push them faster and even ascend vertically on their tail (the benefits of having an internal gravity field!).

So take the lowly Mercenary Cruiser. The spherical structure, even with the engines/legs, would allow it to land on Earth with no issue. But it wouldn't be able to do it as quickly as a Free Trader with it's semi-streamlined hull. With wind resistance, and assuming a controlled landing, you shouldn't expect more than a few hundred KPH flight speed. This would be based on hull type and thruster capability. Though even with 6G engines physics says that sort of hull structure would still have huge aerodynamic issues to overcome, as well as control issues (and heat.. but that kind of magically isn't an issue).

 

[AnotherDilbert]

And they still don't actually explain what a "Standard" hull configuration vs a "Close Structure" is. I always thought Close Structure was "anything that wasn't Cylinder,Sphere, Needle, Wedge, etc".

Standard = boring box?
Close = a few geometric shapes close together?

 

[fusor]

Standard = boring box?
Close = a few geometric shapes close together?

Except that "Standard" looks no different to "Close Structure" in the image they've used.

Why would you spin the outer hull and not the inner hull? Wouldn't you want to spin the inner hull because that's where people would be?

Most designs I have seen with spinning hulls have a zero-g core and a spinning habitat around it, mostly because one needs a minimum diameter of the spinning hull habitat to avoid serious medical problems for the inhabitants.

Maybe I'm just not envisioning this right then. What does a double-hull look like?

I mean, a hamster cage would be like the Leonov from the movie "2010" (or earthforce ships from Babylon 5), or a ship from Jovian Chronicles or 2300AD. I thought a double-hull would be like the Discovery in 2001 - the spinning part is a ring inside the ship, the outer sphere at the front doesn't spin. It's not something like the Babylon 5 station with a spinning spherical section at the front (that wouldn't be a "double hull" then), and it's not like the space station in 2001 because the whole thing is spinning then.

I thought maybe the Traveller Lab Ship would be a double hull - the inside of the ring spins, the outside doesn't?

 

[fusor]

The problem with the books explanation is that it negates the entire concept of anti-gravity. Your ship could be a flying brick and it still can land and maneuver in an atmosphere. It just handles like a flying brick. The fact is, the miracle of anti-gravity enables all kinds of things that the rules totally toss out the door.

Where you are going to have issue is when you try to land your craft that has a rotating habitat - umm, unless you have REALLY long landing struts or the rotating habitat is built for it, it's not going to happen. But that doesn't mean you can't fly into an atmosphere. The rules posit no such thing as material stress factors. It's all just arbitrarily lumped together, which is sad because I would have hoped this would have been addressed by now.

You don't need streamlining to enter an atmosphere. What it does is allow you to enter it faster, and maneuver better. Anti-gravity doesn't overcome atmospheric resistance, it just means you can float (and in some cases propel yourself, aka grav vehicles). Starships use it to offset gravity, then they can either float all the way to orbit, albeit very slowly, or they can engage their drives to push them faster and even ascend vertically on their tail (the benefits of having an internal gravity field!).

So take the lowly Mercenary Cruiser. The spherical structure, even with the engines/legs, would allow it to land on Earth with no issue. But it wouldn't be able to do it as quickly as a Free Trader with it's semi-streamlined hull. With wind resistance, and assuming a controlled landing, you shouldn't expect more than a few hundred KPH flight speed. This would be based on hull type and thruster capability. Though even with 6G engines physics says that sort of hull structure would still have huge aerodynamic issues to overcome, as well as control issues (and heat.. but that kind of magically isn't an issue).

It depends how antigravity works. If the ship can negate the vast majority of its mass then it effectively becomes buoyant in an atmosphere and would as you say "float" like a balloon - with all the control issues that would entail as well. But I agree that streamlining becomes less important if you can just slowly drift into the atmosphere rather than hurtle in at several km/s.

 

[wbnc]

The problem with the books explanation is that it negates the entire concept of anti-gravity. Your ship could be a flying brick and it still can land and maneuver in an atmosphere. It just handles like a flying brick. The fact is, the miracle of anti-gravity enables all kinds of things that the rules totally toss out the door.

Where you are going to have issue is when you try to land your craft that has a rotating habitat - umm, unless you have REALLY long landing struts or the rotating habitat is built for it, it's not going to happen. But that doesn't mean you can't fly into an atmosphere. The rules posit no such thing as material stress factors. It's all just arbitrarily lumped together, which is sad because I would have hoped this would have been addressed by now.

You don't need streamlining to enter an atmosphere. What it does is allow you to enter it faster, and maneuver better. Anti-gravity doesn't overcome atmospheric resistance, it just means you can float (and in some cases propel yourself, aka grav vehicles). Starships use it to offset gravity, then they can either float all the way to orbit, albeit very slowly, or they can engage their drives to push them faster and even ascend vertically on their tail (the benefits of having an internal gravity field!).

So take the lowly Mercenary Cruiser. The spherical structure, even with the engines/legs, would allow it to land on Earth with no issue. But it wouldn't be able to do it as quickly as a Free Trader with it's semi-streamlined hull. With wind resistance, and assuming a controlled landing, you shouldn't expect more than a few hundred KPH flight speed. This would be based on hull type and thruster capability. Though even with 6G engines physics says that sort of hull structure would still have huge aerodynamic issues to overcome, as well as control issues (and heat.. but that kind of magically isn't an issue).

Anti-grav can negate a lot of issues but it's far from a fix-all for atmospheric operation.

Wind can do a lot ore than slow a ship down if it's going the wrong way...it can actually cause entire skyscrapers to wobble and weave like a drunk, or tear apart a state of the art suspension bridge if the structure give the wind a lot of surface area to work on, and is not stressed to allow it to deal with the forces applied.

I have made landings with my nose t 20 degrees away from my flight path due to wind forces in a well-streamlined aircraft.something slab sided, or with lots of open spaces in the hull structure for the wind to get into and the ship would have to turn into the wind and use its drives to compensate.( and nope I don't subscribe to the magi-omni-directional drives) it would only be able to crab walk using it's lateral dives to edge it along if it is not approaching directly downwind of a landing zone.

A ship like the leviathan is a large flat surface for the wind to work on..they call those sails by the way as long as it is headed into the wind, or working in thin atmosphere it is stable enough to be safe. add a 20mph cross wind, or a wind that is kicking around and changing directions and it would be a rough ride at best...at worst sudden 30 Mph gust kicks up as it is a few meters away from the landing area and is sidles to the left a few hundred meters. or gets pushed into a hillside/small town before it's drives can compensate.

I will just mention in passing how a ship would have to be engineered to allow for the varying stress loads caused by thrusters, and drive plates, in both cruise, and landing configuration. or that long narrow shapes tend to want to sag in the middle, and need to be reinforced. As well as a structure with widely varying lateral cross sections and front cross section will try to twist or rotate to an angle that has the least wind resistance...like a weather vane.


It would be a pretty involved subject to cover een 1/10th the variable in a ship that could operate in atmo..The term streamlining was used but it's a bit more complex than just having low wind resistance......Streamlining is a bit of shorthand in this case....it is a simple catch-all for "designed for atmospheric operation"

 

[rust2]

Maybe I'm just not envisioning this right then. What does a double-hull look like?

The design I am aware of you could imagine like a macaroni around a spaghetti, where the sphaghetti is the zero-g core and the macaroni is the rotating habitat.

 

[Condottiere]

Inertia, how much does a starship weigh?

It would take a lot of wind energy to move that ship.

 

[fusor]

Maybe I'm just not envisioning this right then. What does a double-hull look like?

The design I am aware of you could imagine like a macaroni around a spaghetti, where the sphaghetti is the zero-g core and the macaroni is the rotating habitat.

What's the point of that though? In a spinning ship the central core is always going to be zero-G anyway. The Lab Ship can either spin in its entirety (which means the central core where the cutter attaches is 0g, with gravity increasing down the connecting spine to a maximum at the outer ring), or it can have a double hull where the whole ship doesn't spin, but a ring inside the outer ring does.

Thing is, in nautical terms a "double hull" is "one hull inside the other". Ships and submarines often have this and they put ballast and stuff like that there. That's why I think it's more like "a rotating ring inside a stationary outer hull".

 

[phavoc]

It depends how antigravity works. If the ship can negate the vast majority of its mass then it effectively becomes buoyant in an atmosphere and would as you say "float" like a balloon - with all the control issues that would entail as well. But I agree that streamlining becomes less important if you can just slowly drift into the atmosphere rather than hurtle in at several km/s.

Agreed. It allows you do all kinds of things, though you are still subject to the laws of aerodynamics.

Anti-grav can negate a lot of issues but it's far from a fix-all for atmospheric operation.

Wind can do a lot ore than slow a ship down if it's going the wrong way...it can actually cause entire skyscrapers to wobble and weave like a drunk, or tear apart a state of the art suspension bridge if the structure give the wind a lot of surface area to work on, and is not stressed to allow it to deal with the forces applied.

I have made landings with my nose t 20 degrees away from my flight path due to wind forces in a well-streamlined aircraft.something slab sided, or with lots of open spaces in the hull structure for the wind to get into and the ship would have to turn into the wind and use its drives to compensate.( and nope I don't subscribe to the magi-omni-directional drives) it would only be able to crab walk using it's lateral dives to edge it along if it is not approaching directly downwind of a landing zone.

A ship like the leviathan is a large flat surface for the wind to work on..they call those sails by the way as long as it is headed into the wind, or working in thin atmosphere it is stable enough to be safe. add a 20mph cross wind, or a wind that is kicking around and changing directions and it would be a rough ride at best...at worst sudden 30 Mph gust kicks up as it is a few meters away from the landing area and is sidles to the left a few hundred meters. or gets pushed into a hillside/small town before it's drives can compensate.

I will just mention in passing how a ship would have to be engineered to allow for the varying stress loads caused by thrusters, and drive plates, in both cruise, and landing configuration. or that long narrow shapes tend to want to sag in the middle, and need to be reinforced. As well as a structure with widely varying lateral cross sections and front cross section will try to twist or rotate to an angle that has the least wind resistance...like a weather vane.

It would be a pretty involved subject to cover een 1/10th the variable in a ship that could operate in atmo..The term streamlining was used but it's a bit more complex than just having low wind resistance......Streamlining is a bit of shorthand in this case....it is a simple catch-all for "designed for atmospheric operation"

Yes, That's all true. "Galloping Gertie", i.e. the first Tacoma Narrows bridge, vividly illustrates that you must account for wind in structures. So do skyscrapers. Most people don't realize the tops of the higher buildings sway back and forth, and only very cleverly engineered counterweights make it so the structures don't fall down.

However, the difference there is that these are structures tied to the earth. Once you lose your connection you float, and are much more subject to the vagaries of the wind. However, even the shuttle, which weighs in at a mere 165,000lbs, isn't going to be in the same class as a Traveller starships. These craft have no need to worry about weight, and they are built of magical materials that ignore micro-meteroids (and that's just crystal iron, now get into the ships using collapsed matter plating and their mass shoots up). A craft that has no need for lift can easily change its heading so that it's flying into, or with, or laterally to the wind shear. With more mass comes more protection against lower wind factors. And even these ships would be hard-pressed to maneuver safely in a 250kph gale (I can't remember which supplement had a planetary colony that you could only access in shuttles flown by local pilots because of the vicious wind conditions).

I'm not saying at all they aren't affected by it - a bad storm should close a downport just like it would an airport. All I'm saying is that the rules as written don't relate well to how this stuff should be working if it was real. Spherical ships can land anywhere a streamlined ship can, just not as fast. Instead of "flying" to the ground you more or less drop down from orbit. It's more akin to taking an elevator down than what you see the space shuttle do (or to keep the analogies similar, it's what a space capsule does vs. a space plane).

All the other engineering work is just assumed to be there. Kind of like how the underlying engineering is present in a ship with a Armor Factor of 15 - the rules don't require you to set aside additional mass to structural support to make it possible for that massive slab of armor to not crumple when it's hit with a lot of damage. I'm okay with delving a little bit into things so they better match what really is, but if you take that too far, the game becomes a chore, and it's supposed to be fun. It's always a challenge to find the right mix.

 

[fusor]

Inertia, how much does a starship weigh?

It would take a lot of wind energy to move that ship.

Actually... hm. If antigravity negates the MASS of the ship, then the density decreases (density of the ship = mass/volume, mass decreases, volume remains the same) and you essentially get something that has buoyancy in at atmosphere (with no atmosphere it'd just affect how much thrust is required to move it, since there's nothing to be buoyant in). The ship could literally have a mass of 1 kg (and 1 kg worth of inertia to go with it) - a 1G thruster could accelerate it to ridiculous speeds if it had inertial mass that low.

If antigravity negates the WEIGHT of the ship (which depends on the external gravity - the mass and therefore density would remain the same), then density stays the same and it's not buoyant at all!

You'd get all sorts of weird counter-intuitive effects if you could separate inertial mass from gravitational mass.