Starship flight envelopes

[Blue Ghost]

What are the performance characteristics of starships?

I understand what kind of acceleration they have (or can have), are they capable of hover, how long does it take to warm up the engine, how maneuvreable are they in an atmosphere? Things like that.

I ask because even though I don't play Traveller anymore, I would like to try my hand at attempting to write an adventure, and this is one subject that's always eluded me.

Thanks much in advance.

 

[kaladorn]

Depends on your version of Traveller I think. TNE, MT, High Gaurd LBB, FF&S, GT... they may all have differing answers. Performance envelopes definitely differed in TNE for certain.

MT covered some of what you want in the Starship Operators manual and in the procedure outlined on how to get a ship ready from start to jump point (Refs manual was it?). That covered tasks involved and times in warming up the powerplant, the drives, etc.

I have a page with a super-detailed variant of this process, that includes things for the purser and a supercargo to do, but unfortunately posting it would probably blow the 1 page Fair Use policy. Sorry...

 

[Blue Ghost]

The SOPM I have, but that may be one of those verboten quasi-canonical deals. It kind of makes me wish I hadn't gotten rid of my MT books.

Hrm... welp, I'll just have to take a crack at it, and see what the powers that be think... assuming I ever complete writing this thing.

After thinking about it I guess my real question was how much physics was behind atmospheric operations. That is to say how much "Millenium Falcon"-like performance does a starship have (assuming one that was streamlined), as opposed to any real world aerodynamic analog; i.e. it may have VTOL, but requires nozzles in the down postion. Thinking as I write this post, my guess is grav tech probably gives appreciable lift for initial takeoff, but it leaves one to wonder why some ships (presumably with grav and/or repulsor like lift systems) need streamlining, but that may be getting into detail that's best not explored.

So, again, putting my thoughts down for all to read, my guess, and it's only a guess

is that starships in Traveller are Star-Warsish for atmospheric flight operations, but once the medium is removed (a ship reaches orbit and beyond) astronautics takes over.

... OK, I can work with this.

Thanks Kaladown.

 

[Andrew Boulton]

"it leaves one to wonder why some ships (presumably with grav and/or repulsor like lift systems) need streamlining"

Grav lift will only get you so far. You still need to be streamlined enough to be able to manoeuvre without losing control or having bits ripped off.

 

[Fritz_Brown]

And, Andrew, having bits ripped off in flight is a very, very, very bad thing....

 

[Anthony]

Well, this is a long-standing flame war, but it really boils down to how fast you want to fly. If you're willing to fly down from orbit at speeds not exceeding 100mph, something with approximately the aerodynamic streamlining of your average deep sea oil rig (close structure configuration, anyone?) would be able to make it down. If you want to come down at any significant speed, however, you need at least enough streamlining to be stable in air, and if you want to move at supersonic speeds you really want to be well streamlined.

 

[batmagoo]

IMTU, the 'airframe' only provides about half of the crafts ability to 'fly'. The actual aerodynamics are provided by 'tuneable' micrometeorite screens/sheilds. I always treated it as a power function, i.e. not overwhelming the screens. They are designed to function in a vacum after all.
"Yes, your Type S will do 4000kph in this atmosphere, but, your hull will be a perfectly smooth, bare metal wedge, without a single produberance on it when your done."

Chuck

 

[kaladorn]

Think of this too... I don't have SOM tucked up my sleeve, but I think you use grav to land, but you *could* use thrusters if you didn't have grav (or rocket engines or whatever). Grav is easy, no muss no fuss. But streamlining might help if you lost your grav due to battle damage and had to land under power of a thruster/engine. Then, being streamlined would matter quite a bit. And of course, there is a difference between "I can land here, coming in reasonably slowly" and "I can swoop in like and eagle!"

 

[aramis]

Yes, the whole SL issue is one of those flame-bait subjects...

In general, though,
CT: max G rating is 6G, Typ Merchant is 1G, with a few at 2G. Streamlining is Yes or No. Thrust not defined as gravitic, but can be inferred
CT+HG: Still max 6G. Most merchants still bk2 designs... 3 levels of SL: SL, PSL, and non. SL can land; PSL can enter atmosphere and scoop GG's, but can't land. Non-SL can't enter atmosphere nor land. (Funny, the Lunar Lander was USL...) Thrust not gravitic explicitly, but thrust behavior implies that.
MT: Max 6G except when using the One Small Step (Challenge Mag or MT:HT) rules. Streamlining is Airframe, Streamlined, or Unstreamlined; landing capability not tied to it.
MT+SSOM: Gravitics can hit 400% thrust for periods up to an hour... and can provide 33% thrust at 90 degrees from primary thrust plane.... SO it basically looks much like star wars for take off. A 1G ship can thus hit 1.33G straight up when designed for "Forward" thrust, rather than upward. Oh, and the reverse thrust limit is 10%.
MT+OSS: Some designs up to 9G doable, but mostly kept down to 2-3G due to lack of compensation and AG.
TNE: No hard limit besides compensation. Compensation limits table is in FF&S. warcraft often break IC limit by 2-3 G's, and merchantmen seldom even run equal. Real-world style fuel issues. Launch/land changed severely by introduction of new technology to the Traveller architecture: Contragrav, which disconnects the ship from local gravity (or about 95-99% of it), so a ship will almost always float gently down... landings and launches very very different... since they use a reaction drive, you've got blast pads, etc, and they need to bring the mains on-thrust axis right quick. Airframe separate from streamlining; very few ships designed as AF types (Since you have to use the aircraft sequences). Multiple levels of SL.
T4: Almost identical tech to TNE, but also has grav thrust. (Contragrav +3G Gravitic thrust is 3 maneuver G's; no CG puts Maneuver G's down by local G's)
T20: Defines as a gravitic system; limits at 6G. Makes AF a better form of Streamlining, thus AF. SL, PSL, and USL. Similar limits as with HG. Non-AF hulls limited to 2G in atmosphere...

 

[Blue Ghost]

That's interesting. Which leads me to another question, though this is more of a canonical/rules question than anything else.

IIRC CT rules state that a jump takes two weeks regardless of the distance, but MT gives a variable time table within a week's time frame... or so I recall. Which is official?

 

[GypsyComet]

CT's "two weeks" is total turnaround time, not the length of the jump itself.

 

[mike wightman]

The jump itself takes one week, regardless of distace travelled. [LBB:2 page 1 1st edition, page 4 2nd edition]
The actual time for a jump is given in High Guard as 150-175 hours.

 

[Blue Ghost]

Originally posted by GypsyComet:
CT's "two weeks" is total turnaround time, not the length of the jump itself.

DOH! I should've just cracked open one of my books. Many apologiesd

 

[aramis]

All editions use the 1 week in J-space model, to varying degrees of precision.

Total turnaround for CT is 2 weeks, as it seldom takes more than 2 days in-bound nor 2 days out-bound, and that's three days for dirstside.

If you use stellar jump masking, et al, you can wind up with three week cycles.

TNE, longer runs can be up to 4 weeks for slow ships. N_space is FAR slower when you only have a few G_hours of fuel.

 

[far-trader]

Originally posted by Aramis:
All editions use the 1 week in J-space model, to varying degrees of precision.

Total turnaround for CT is 2 weeks, as it seldom takes more than 2 days in-bound nor 2 days out-bound, and that's three days for dirstside.

Presuming you don't need or want to make a fuel run to the GG in a Free-Trader, that'll add about a week

(in CT, more as noted in TNE)