Form follows function.

Discuss the Traveller RPG and its many settings
steve98052
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Form follows function.

Postby steve98052 » Tue Oct 23, 2018 6:07 pm

It seems to me that most Traveller art that has been published tries to follow the "rule of cool" more than anything else. But each artist seems to have his or her own ideas about what is cool. That makes the collection of designsas a whole pretty haphazard.

I lean more toward "form follows function". Different types of ships have different function, which drives different forms. One way to break down designs is by whether they enter atmospheres, land, or both.

1. Ships that are designed to land on worlds with gravity greater than their maneuver drive ratings must have a shape that allows them to supplement their maneuver drive lift or tyrust with aerodynamic lift. That pretty much forces them to look like an airliner, the Space Shuttle shuttle, or some sort of lifting body. Because aerodynamic lift is largely proportional to the area of the lifting surface, the square/cube relationship will tend to drive larger aerodynamic lift starships toward thin, sprawling flying-wing shapes. They also need to consider landing gear; they must be able to land without crushing their own landing gear or cracking runways.

2. Ships that are designed to land only on worlds with gravity lighter than their own maneuver drive ratings (whether because they visit only lower gravity worlds or because they have sufficiently powerful drives) should still aim for streamlined designs. However, because they do not depend on aerodynamic lift, they can be any shape that is practical for its design purpose, as long as it is reasonably streamlined. They are under similar landinf gear constraints to type 1, except that they don't need runways; landing pads are sufficient.

3. Ships designed to land, but only on airless or trace-atmosphere worlds, do not need to be streamlined. They do, however, need to have a shape that allows it to land without tipping over. Because they cannot rely on aerodynamic lift, their maneuver drive ratings must exceed the gravity of any world they will land on, but since worlds with greater than 1 G gravity are almost certain to have atmospheres Maneuver-1 should be sufficient.

4. Ships that venture into atmosphere only for gas giant refueling can ignore considerations related to landing gear and ground pressure, but they are otherwise under similar design constraints to types 1 and 2.

5. Ships that never venture into atmosphere and never land on any world (even airless worlds) will be designed entirely on the basis of function.

So what about function? There are a lot of considerations there.

- How much of the ship is dedicated to each of its components (fuel, engineering, control, crew, passengers, cargo, weaponry, etc.)?

- How do surface features (turrets, bays, spinal mounts, engineering features, docking features, cargo and vehicle doors, airlocks, sensors, windows, fuel scoops, etc.) affect the ship's exterior?

- Is the ship a military combatant, military but noncombatant (carrier, transport, support, spy, etc.), armed private, or unarmed private?

- How important are cargo handling, vehicle (space or surface) handling, passenger handling, troops, and special facilities (research, medical, repair, spin gravity sections, etc.)?

- Does the ship need to fit inside another ship, contain another ship, or attach to another ship?

- Do passengers or crew have special requirements (communal space, open spaces, recreation, etc.)?

- What deck alignment (parallel to planetary surface when landed, perpendicular to typical movement axis, etc.) and plan fit the function of the ship best?

- Do internal or external esthetics matter, and if yes, what are the customer's preferences like?

Finally, how does the functionality of the ship's super-science components affect design?

- Should jump drives be near the center of the jump bubble, be close to the power plant or fuel tanks, have access to ship's surface, etc.?

- Do power plants or the ship as a whole need to radiate waste heat?

- Do maneuver drives need to reach the surface of the ship, align with the main axis of movement, etc.? Do they need attitude control appendages, and if yes is it advantageous to mount them far from the ship's center of mass?

- How do micrometeoroid armor, military armor, and radiation shielding affect the design of the ship's surface?

- How do artificial gravity and inertial compensation affect design?

The answers to the super-science questions and the atmosphere and landing categories should affect all ships, regardless of who built the ship or what its service role may be. A new set of ship designs built around a specific vision of the super-science constraints would give ships a more self-consistent feel.

(I thought about adding this to the "ugly ships" thread, but I thought it might get lost in a ten-page thread that's mostly from two years ago.)
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Re: Form follows function.

Postby Saladman » Tue Oct 23, 2018 7:38 pm

steve98052 wrote:
Tue Oct 23, 2018 6:07 pm
It seems to me that most Traveller art that has been published tries to follow the "rule of cool" more than anything else.
I question this premise. Most Traveller art I've seen tries to depict the classic published deck plans. Which pushes your later considerations onto ship builders, not just artists.
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Re: Form follows function.

Postby AnotherDilbert » Tue Oct 23, 2018 8:43 pm

steve98052 wrote: It seems to me that most Traveller art that has been published tries to follow the "rule of cool" more than anything else. But each artist seems to have his or her own ideas about what is cool. That makes the collection of designsas a whole pretty haphazard.
While I agree completely, I fear it is a few decades too late to try to impose any standardised design pattern on Traveller.
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Re: Form follows function.

Postby AnotherDilbert » Tue Oct 23, 2018 8:49 pm

Saladman wrote:
steve98052 wrote: It seems to me that most Traveller art that has been published tries to follow the "rule of cool" more than anything else.
I question this premise. Most Traveller art I've seen tries to depict the classic published deck plans. Which pushes your later considerations onto ship builders, not just artists.
In order to make deck plans, you generally have to make at least a superficial exterior design first in order to have proximate limits for the deck plans. Most deck plans come with an exterior view. And most deck plans seems to follow from the exterior "cool" form, rather than functional requirements.
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Re: Form follows function.

Postby ShawnDriscoll » Tue Oct 23, 2018 10:43 pm

I think it's funny when people assume what the deck plans are for my various exterior ship art. If I modeled their insides, it would look nothing like the blocky decks from the '70s.
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Re: Form follows function.

Postby paltrysum » Wed Oct 24, 2018 5:32 pm

While Traveller tries to at least pay homage to hard sci-fi, we can't forget its influences: books like Tubbs' Dumarest of Terra series, the Ensign Flandry series, Laumer's Retief. Cool-looking ships that look more like stealth fighters than actual spacecraft were the norm. While I wouldn't want to stray too far from hard sci fi, I also really like emphasizing the "cool factor."

Thanks for the detailed post. Lots of inspiring ideas there.
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Re: Form follows function.

Postby NOLATrav » Thu Oct 25, 2018 2:50 pm

T5 has made some basic gestures along this line of thinking. A T5 Ship Sheet includes a 1D-1D hit location table, giving a range of -5 to +5 with 0 being the average result. So a Free Trader might look something like this:

-5: J Drive
-4: Power
-3: M Drive
-2: Fuel
-1: Sensors
0: Hull
+1: Turret
+2: Hull
+3: Cargo
+4: Stateroom
+5: Bridge

It basically compartmentalizes the various ship components so you can arrange them in blocks. Space combat rules allow big hits to spread damage into adjacent areas (Up or down one slot on the table. It also references J Drive location based on jump paradigm (centrally located for jump bubbles for instance). This could be used as a basis for redesigning ship layouts to be more “realistic” or logical at least.

Doesn’t address the core concerns of the OP but is a step in that direction.
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Re: Form follows function.

Postby steve98052 » Thu Oct 25, 2018 5:20 pm

My point in starting this topic was pretty much to ask what design patterns would make ships that look like they're all built under the same rules of physics, both real physics (such as aerodynamic laws for ships thatare atmosphere capable, and things like ground pressure for ships that land) and invented physics (jump drives and reactionless maneuver drives).

So if we were to disregard the decades of published ship art (both exterior and deck plans), what would ships look like? Would jump drives be centrally located, and if so how would that work with crew access? Do maneuver drives need contact with the ship's surface? Do ships need to radiate waste heat, either through maneuver drives or dedicated radiators? How does artificial gravity affect ship layout? Is there a maximum practical size for ships that need to supplement their maneuver drives with aerodynamic lift to reach space?
Saladman wrote:
Tue Oct 23, 2018 7:38 pm
I question this premise. Most Traveller art I've seen tries to depict the classic published deck plans. Which pushes your later considerations onto ship builders, not just artists.
The classic published material is what I meant; it was largely designed after each artist's rule of cool, and deck plans fitted into the drawings. In some cases, I suppose, deck plans came first, but in any case my point was that the artists of way back weren't working from a common vision of what designs would be functional.
AnotherDilbert wrote:
Tue Oct 23, 2018 8:43 pm
While I agree completely, I fear it is a few decades too late to try to impose any standardised design pattern on Traveller.
Obviously the idea of design patterns is not going to solve the haphazard ships of the past. This bulletin board is full of discussions of how to update classic published designs to newer rules, and how to make them more suitable for their stated purpose, particularly in the case of combat ships.

My point is that one could lay out a few design constraints and create new ships that are consistent with them, and use the published designs only to the extent that they agree with the chosen design constraints.
ShawnDriscoll wrote:
Tue Oct 23, 2018 10:43 pm
I think it's funny when people assume what the deck plans are for my various exterior ship art. If I modeled their insides, it would look nothing like the blocky decks from the '70s.
I have a hard time remembering whose art was whose. Are your exterior designs originals rather than your versions of classic published materials? And do you have any example interiors to show off?
paltrysum wrote:
Wed Oct 24, 2018 5:32 pm
Thanks for the detailed post. Lots of inspiring ideas there.
You're welcome, and thanks.
NOLATrav wrote:
Thu Oct 25, 2018 2:50 pm
T5 has made some basic gestures along this line of thinking. . . . It also references J Drive location based on jump paradigm (centrally located for jump bubbles for instance). This could be used as a basis for redesigning ship layouts to be more “realistic” or logical at least.

Doesn’t address the core concerns of the OP but is a step in that direction.
The central location of a jump drive is a hint that could point toward a common design vision. Thanks for the peek into an edition I haven't seen.
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Re: Form follows function.

Postby Old School » Thu Oct 25, 2018 7:02 pm

Is there a point to the 1d-1d approach? Isnt it the same distribution as 2D?
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Re: Form follows function.

Postby AnotherDilbert » Thu Oct 25, 2018 9:02 pm

Old School wrote: Is there a point to the 1d-1d approach?
It's a general mechanism in T5 called Flux. It's e.g. used to generate a random variation.

Old School wrote: Isnt it the same distribution as 2D?
It's the same distribution as 2D - 7, yes.
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Re: Form follows function.

Postby Condottiere » Fri Oct 26, 2018 10:50 pm

I'm inclined to think atmospheric resistance weighs larger in a streamline requirement than gravity.
steve98052
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Re: Form follows function.

Postby steve98052 » Sun Oct 28, 2018 4:23 pm

I think the combination of atmosphere and gravity balance against the combination of streamlining and maneuver drive power.

The case of vacuum worlds is simplest. If maneuver drive power exceeds surface gravity, no problem. If surface gravity exceeds maneuver drive power, takeoff and non-crash landing are impossible without a tugboat. Streamlining is immaterial in either case.

When atmosphere is present, it's more complicated. If maneuver drive power exceeds surface gravity, streamlining is useful, but not absolutely necessary; one can still fly an unstreamlined ship like an elevator. At 50 km/h, it's two hours to space from the Earth's surface. If surface gravity exceeds maneuver drive power, not only is streamlining mandatory, the streamlined hull must have a shape that generates enough aerodynamic lift to make up the difference between gravity and maneuver drive power. The streamlining should also be capable of withstanding the heat of high velocity atmospheric friction during the highest speed parts of the atmospheric transit, particularly reentry.

The difference between gravity and maneuver drive power also matters. With a 1 G drive, only a small amount of aerodynamic lift is needed to escape a 1.05 G world. But a 2 G world will require a lot of lift and really heavy duty heat shielding.

I'm not sure how much gravity a gas giant has at an altitude where scoops would be able to function. It may be that wilderness refueling means cracking ice on icy moonlets, rather than diving into gas giants, unless one has pretty powerful maneuver drives.
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Re: Form follows function.

Postby phavoc » Mon Oct 29, 2018 1:27 pm

Flight (non anti-grav at least) has four factors - drag, thrust, lift, and weight. And then things get more complicated. :)

Basically most Traveller starships don't have a chance in hell of flying using their hulls as lifting surfaces. Why? Because they are way too heavy. Starship hulls are made out of crystalline steel, or in some cases collapsed matter. Even the Serpent-class scout, with it's wings, should not be able to generate enough lift through wings. Now, using anti-grav to offset it's mass, it could potentially use wings to generate lift, and then using the wings to maneuver. It would still have mass, so it would fly like a brick, but it could maneuver with wings and it's control surfaces.
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Re: Form follows function.

Postby locarno24 » Mon Oct 29, 2018 3:18 pm

M-Drive:

Does the most recent traveller go into any more detail about the function of an M-drive.
That is; when you power it up, it accelerates you at X g in a direction of your choice.

I was under the impression that the M-drive was gravetic.
Where, relative to the ship, 'is' the perceived centre of mass of the gravity well the ship is now 'freefalling' into?
Because that could cause some weird turbulence patterns close in to the ship.

What's needed to 'project' the gravity well is the decider - there's no specific need to be on the surface of the ship (since if you can manoeuvre in any direction you can obviously 'fire' the drive through the mass of the ship).

J-Drive:
Since the jump drive creates/slices off an artificial 'bubble' universe and floats off in it to your destination point (okay, that's a simpliciation).

It's my understanding the bubble forms around you rather than opening a hole you fly into, which means logically you want to pack the most starship into the minimum bubble size (as it requires less hydrogen and a smaller drive), so theoretically spherical ships should be preferable.
Understand that I'm not advocating violence.
I'm just saying that it's highly effective and I strongly recommend using it.
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Re: Form follows function.

Postby AnotherDilbert » Mon Oct 29, 2018 3:49 pm

locarno24 wrote: M-Drive:

I was under the impression that the M-drive was gravetic.
Where, relative to the ship, 'is' the perceived centre of mass of the gravity well the ship is now 'freefalling' into?
Because that could cause some weird turbulence patterns close in to the ship.
It's "gravitic", as in somehow based on gravitic (anti-grav) technology.

The M-Drive does not generate a grav field that the ship falls into. It generates a force that pushes the M-drive itself.

MT RM wrote:The fourth significant development came from the search for a starship maneuver drive that did not lose efficiency when away from a strong gravity well. Artificial gravity and damper technology led to yet another sub-atomic force-based technology. This new, artificially generated force pushes against a vessel's "thrust plates" themselves, which make true reactionless thrusters a reality for starship sized vessels.
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Re: Form follows function.

Postby Sigtrygg » Mon Oct 29, 2018 6:08 pm

There is so much wrong with the MT definition of how the m-drive works that it is not worth referencing.

It's not so much handwavium as completebollixium. The folks at DGP never got ships right - the travesty that was ship combat in MT is also one of those things that is best never to mention.
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Re: Form follows function.

Postby steve98052 » Mon Oct 29, 2018 6:35 pm

I did some (very rough) calculations about real world vehicles for comparison. The short story is that Traveller ships are really big.
  • The fastest airliner, the Concorde, is under 40 dtons.
  • The fastest air-breathing aircraft, the SR-71, is just over half the length of the Concorde, so it's quite a bit smaller.
  • The largest airliner, the Airbus 380, is about 50 dtons.
  • The largest aircraft, the C-5, is about 70 dtons.
  • The Space Shuttle seems to be between 100 and 160 dtons, which makes me question my calculations, because it could ride on the back of a 747.
  • The second largest warship, the Nimitz-class aircraft carrier, is (very roughly) around 25k dtons. (The largest, the Gerald Ford class, isn't much larger, but measurements were even more vague than for the Nimitz class. But the coolest thing about them isn't size, it's that they replace steam catapults with electromagnetic mass drivers for aircraft launches.)
phavoc wrote:
Mon Oct 29, 2018 1:27 pm
. . . most Traveller starships don't have a chance in hell of flying using their hulls as lifting surfaces. Why? Because they are way too heavy. Starship hulls are made out of crystalline steel, or in some cases collapsed matter. . . .
I see a range of thrust/weight of under 25% (modern airliners) to about 37% (SR-71). Given the square/cube problem (area is proportional to the square of length, but volume and presumably mass are proportional to the cube of length), how large can a spacecraft be, while still generating a useful amount of aerodynamic lift? Lift is (very roughly) proportional to area, and the square/cube problem can be reduced by making ships thinner (in terms of height relative to area), but eventually there's a point where a ship becomes impractically thin.

Or would we just have to rule that aerodynamic lift just doesn't help enough to offset gravity in any but the smallest ships? That would mean all ships that land (or refuel from gas giants) need need maneuver drives more powerful than the maximum gravity the the worlds they visit?

Does anyone know how much gravity a gas giant has at the altitude where the atmosphere is dense enough to use for refueling?
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Re: Form follows function.

Postby AnotherDilbert » Mon Oct 29, 2018 8:21 pm

Sigtrygg wrote: There is so much wrong with the MT definition of how the m-drive works that it is not worth referencing.
That is the only description of how M-drives work we have.

T5.09 wrote:How Maneuver Works
Elementary instruction systems explain:
Maneuver drives interact with gravity to move spaceships. Parts of the drive reach out and grab the gravity of a world or a star and push against it to make the ship move.
This is hardly better or clearer.

It might imply that the drive push against the local gravity field, and hence as a reaction the grav field pushes on the drive?


Or do you reject canon out of hand?
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Re: Form follows function.

Postby phavoc » Mon Oct 29, 2018 8:33 pm

steve98052 wrote:
Mon Oct 29, 2018 6:35 pm
I see a range of thrust/weight of under 25% (modern airliners) to about 37% (SR-71). Given the square/cube problem (area is proportional to the square of length, but volume and presumably mass are proportional to the cube of length), how large can a spacecraft be, while still generating a useful amount of aerodynamic lift? Lift is (very roughly) proportional to area, and the square/cube problem can be reduced by making ships thinner (in terms of height relative to area), but eventually there's a point where a ship becomes impractically thin.

Or would we just have to rule that aerodynamic lift just doesn't help enough to offset gravity in any but the smallest ships? That would mean all ships that land (or refuel from gas giants) need need maneuver drives more powerful than the maximum gravity the the worlds they visit?

Does anyone know how much gravity a gas giant has at the altitude where the atmosphere is dense enough to use for refueling?
You also get into the actual shape of the starship. Aerodynamics and drag are a real bitch when it comes to lift - regardless of your thrust. Then you can get it even more complicated by adding in atmospheric density and gravity... Smaller ships with lifting surfaces can use their 'wings' to fall towards the surface and land (that's how the shuttle does it. The shuttle was originally designed to return to earth from orbit with cargo, about 16 tons worth. The shuttle itself weighs about 82 tons empty. So assuming an empty shuttle and cargo, we are talking 98 tons. Residual fuel and crew and other stuff would probably push it over 100 tons. In comparison a 747-800 freighter can take off with 154 tons of cargo.

The design of each craft is widely different because of their operational needs. And both are built to minimize the weight of their components, and both are completely helpless when it comes to damage resistance. Antigravity turns this whole discussion on it's ear because you have not eliminated issues like lift, thrust and drag (the latter two affecting how FAST you may lift off from the ground). Some of the rulesets stated that your anti-grav rating was equivalent to your G-drive rating, though that never took into account craft mass (loaded vs full, armored vs. not). So we are still left with a mish-mash of hand-wavium.
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Re: Form follows function.

Postby Sigtrygg » Mon Oct 29, 2018 8:37 pm

AnotherDilbert wrote:
Mon Oct 29, 2018 8:21 pm

That is the only description of how M-drives work we have.
No it's not. HG79 fusion rockets, TNE HEPlaR, T4 reactionless with wording closer to T5 rather than MT.
This is hardly better or clearer.
I disagree - the MT totalboloxium explanation requires damper tech, gravitics and something that reads a lot like perpetual motion - not to mention it is much higher TL than CT and other Traveller versions m-drives. Handwaving 'gravitics' is a lot better than armshaking 'dampers, gravitics, brand new subatomic forces'
It might imply that the drive push against the local gravity field, and hence as a reaction the grav field pushes on the drive?
I can live with that :)
Or do you reject canon out of hand?
Only the 'canon' that contradicts all other canon and is needlessly complicated.

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