mike wightman
SOC-14 10K
If you could refill the fuel tank of a rocket it could return to Earth without aerobraking - no heat shield required just like you don't need a heat shield going up.
Question about Streamlined warships
- Thread starter Badenov
- Start date
WizWom
SOC-7
Since this is in General, rather than in Mongoose, I'm going to give you the CT stuff.
CT HGB5 2ed pg 22 Streamlining refers to theability of the ship to enter atmosphere (partial streamlining allows fuel skimmingbut prohibits entry into world atmospheres for the purpose of landing).
So, a config 5, spheroid ship has partial, and may get fuel from a gas giant, or an icy asteroid.
CT TCSA5 pg 39 Any ship may be refueled at a starport. Only streamlined and partially streamlined ships may refuel from gas giants. Only streamlined ships may refuel from planetary oceans and ice caps.
Interestingly, this is a passage giving a time to refuel in CT, 7 "battle turns" - whatever that is in HG combat; AHL says 3 hours.
It then gives a rule that to refuel in a week (the standard TCS game turn) the task force must have 10% of its fuel tankage in appropriate ships.
CT LCCS5 pg 42 goes into a difficult procedure for refueling as a special rule for those "close" configuration vessels, a bit of a downgrade from the normal, automatic refueling the configuration should enjoy. It includes pilot checks, "buffeting incidents" and possible damage to the ship.
As for a Broadsword (type C) being able to land on Garda-Vilis, I'd say it clearly is a streamlined version, paying the extra MCr8. The rules are clear you can add streamlining to any standard design at construction.
So sphere's sreamlining, or lack thereof, is the same in both versions. That much is good. I assume 'Any ship may be refueled at a starport' refers specifically to a Highport?
In Mongoose, 'Close' is similar to sphere, snugly built rather that sprawling, but not actually rounded. A Borg Cube might be 'Close' structure, if I understand correctly.
I don't know about the broadsword other than what I've read here. https://wiki.travellerrpg.com/Type_C_class_Mercenary_Cruiser seems to be a Broadsword-like ship, but it specifically says 'The hull is unstreamlined,' not even claiming the partial streamlining it might be entitled to a spherical hull. That site lists Broadsword as unstreamlined also despite the art being spherical. Adding Streamlining to a standard design seems to me like it makes it into a whole new design. Its physical configuration would have to be very different. Not spherical, for one. But if it says you can, I guess there is, along with the book spherical standard, a standard streamlined version of it. AFAIK, the only difference would be price and capability, as the differences would not be pertinent at the ship design level, other than blueprint revisions?
Spinward Flow
SOC-14 5K
Close Structure is anything "box-like" that doesn't have a particularly aerodynamic exterior.
Battlestar Galactica, for example, would be a Close Structure configuration.
As the title in this thread specifies warships, I'm going to make some assumptions here that warships have > 1g of thrust, unless it's an Imperium missile boat. 
To get around the thrust damaging the land, a streamlined but not heat shielded warship can use thrust to bring the craft to subsonic speeds before entering atmosphere then use it's atmospheric lift and control surfaces to bring it down to the surface. As I tend to design my warships in T4, I seldom use grav drives in warships due to the "Here I am" fields on the grav drives, besides the whole "magic happens here" thing.
To get around the thrust damaging the land, a streamlined but not heat shielded warship can use thrust to bring the craft to subsonic speeds before entering atmosphere then use it's atmospheric lift and control surfaces to bring it down to the surface. As I tend to design my warships in T4, I seldom use grav drives in warships due to the "Here I am" fields on the grav drives, besides the whole "magic happens here" thing.
And this is fully against what AnotherDilbert quoted about being only able to land on vacuum wourds, but having it landed was a script need...
(risking to open another can of worms)
If the ship was not landed, the Zhodani comandos could not have telproted to it, as per rules of energy and momentum conservation that apply to teleporting
If the ship was not landed, the Zhodani comandos could not have telproted to it, as per rules of energy and momentum conservation that apply to teleporting
mike wightman
SOC-14 10K
Maybe it was put there by an Imperial 2000t landing craft to serve as a fortress/base.
What's more difficult to explain is how it can leave the planet to take part in the Escort scenario.
What's more difficult to explain is how it can leave the planet to take part in the Escort scenario.
AnotherDilbert
SOC-14 1K
If it landed itself, but wasn't transported by a bigger streamlined ship...
It says grounded, not landed.
AnotherDilbert
SOC-14 1K
Or a ground-port with enough shuttles, so no not only highports.
Note the limited amount of fuel available at starports: TCS, p39.
Spinward Flow
SOC-14 5K
Where's my facepalm emote?
Garda-Vilis has a type B starport.
That means that surface to orbit transfer shuttles are available.
Just pay for 800*1.1=880 tons of transfer shuttle cargo capacity to load the Broadsword into an orbital shuttle and bring it down to the surface of Garda-Vilis inside another craft (an orbital transfer shuttle) that is streamlined.
Price for bringing 880 tons of (big craft) "cargo" down from orbit to a world surface ... Cr10 per ton (LBB2.81, p9).
So pay a "starport contractor" Cr8800 to shuttle your Mercenary Cruiser down from orbit to the planetary surface where it can be unloaded and "GROUNDED" without needing to deal with atmospheric entry streamlining.
Basically, you "outsource" the streamlined hull issue to a third party (more or less).
The Broadsword would be perfectly capable of launching from the surface of Garda-Vilis ... through atmosphere ... out towards orbit, because Mercenary Cruisers have 3G acceleration (plenty for launching from terrestrial surfaces).
In other words, a partially streamlined hull can go UP (to orbit) from a surface through atmosphere, but cannot come DOWN (atmospheric entry) to a surface through atmosphere (2+) without assistance.
THAT'S the missing puzzle piece there.
No "rule breaking" needed to make it happen, but the details were almost certainly glossed over and therefore poorly explained.
My first thought upon reading that was the the Broadsword had done a Lithobraking maneuver ... which any craft can do ... ONCE ...
Tends to prevent the craft from being "spaceworthy" afterwards though ...
At 366 tons of fuel (according to https://wiki.travellerrpg.com/Broadsword_class_Mercenary_Cruiser), that's a lot of shuttles. Clearly timliness isn't on anyone's mind, and no one is being paid by the hour. Typical government work.
Hum, consider this, maybe "streamlining" is the ability for a ship to support itself in angles other than the direction of main thrust...
Think along the lines of ocean going ships, they don't ground very well, i.e. running up on a sandbar at low speed can cause sever structural damage.
Or Aircraft, landing gear to land on unimproved fields and the like require significant strengthening of the airframe.
Think along the lines of ocean going ships, they don't ground very well, i.e. running up on a sandbar at low speed can cause sever structural damage.
Or Aircraft, landing gear to land on unimproved fields and the like require significant strengthening of the airframe.
AnotherDilbert
SOC-14 1K
About five standard Shuttle (70 Dt payload) trips, or 6 trips with two cutters (30 Dt payload each).
Should be doable well inside a day without distractions.
I suppose I was thinking of much larger non-streamlined ships or much smaller cargo ships. At Thrust 4 for the cutters, that's just under 17 minutes up and 17 minutes back, No idea how much time to load fuel, or offload it, but that's still 3 runs in 2 hours, plus coffee breaks. 4 hours to fuel up is competitive with scooping, so that's pretty good time.
Don't threaten me with a good time!
Oh, right. Nevermind.
Anyhow. Consider the time needed to get to the gas giant to do the scoop run in the first place....
Condottiere
SOC-14 5K
Autopilot?
I was assuming they were just transferring processed fuel from groundside, not scooping themselves. You're on a planet, oceans are right there, if they didn't have processed fuel available (as A and B starports do, I think) they could scoop from oceans, no need to go to a gas giant, though in either case, it does add the 1d6 hours per run. (The ecological harm done to a planet by a few hundred years of scooping ocean water by the ton probably belongs in a separate thread.) Also unrelated to the thread, I do assume that any A or B starport on a world with suitable oceans can drain water from the ocean directly and run groundside processors to make fuel. Having to scoop it yourself instead of sucking it in through a pipeline seems like an extra step. If you'd used your last fuel to fill up a previous ship, you'd still need the 1d6 hours to refill your station's tank and process that into liquid hydrogen, but I assume groundside space stations can have as much storage as they like, so that would happen rarely.
My only issue with TCS refueling is it treats ice worlds the same as liquid water worlds. That's kind of unavoidable without adding complexity, but ice is everywhere, especially hydrogen-flavored ices. If you can refuel just by prospecting for an ice body, then warships will carry whatever equipment they need to draw fuel from whatever ices they find and anyone in the outer system can refuel at their leisure.
Have to roll for presence of Oort clouds and ice density is likely not good enough for a week refueling.
