Agility and the CT manuever drive

[robject]

Originally posted by Fritz88:
Actually, robject, by your statement, SoD IS your book. ...

For gearheads, that's sometimes too many in one pot.
...

I see what you mean, and I guess you're right. I'm more Space Opera.

And I agree with Sigg and Ditzie - I think gravitics can be the single factor in contragrav and thrust plates -- although I'm also in favor of throwing out inertial compensation. I seem to recall that the spirit of Proto-Traveller is a bit more wargamey and less Space Operatic in at least this way.

After all, people use shotguns and cutlasses in PT.

 

[Tobias]

Originally posted by Fritz88:
There's also the bit about how agility is measured, and very few craft (with the thrusters) have an agility anywhere near 6G, and none at 9G - where the F16 is.

Traveller ships can accelerate at 6Gs (while an armed F-16 can accelerate at less than 1G.) We do not know what kind of G-Forces Traveller space fighters can withstand, but my answer (somewhat influenced by my preference for supertech, naturally) is: A lot.
If one wants to eliminate inertial compensators from his TU, realistic acceleration limits for longer times (very relevant for space combat, seeing as how battles last several hours) are probably in the neighbourhood of 2-3 Gs. Even that would be extremely taxing for the crew. If higher accelerations are technically possible, robotic ships would probably dominate such a TU.

Regards,

Tobias

 

[robject]

...which makes me think of that neat-o grav fighter from T4. 4 tons, and can pull eighteen G's. Simply amazing.

 

[Tobias]

Originally posted by robject:
...which makes me think of that neat-o grav fighter from T4. 4 tons, and can pull eighteen G's. Simply amazing.

If one infers from Canon that inertial compensators work at a maximum of 6Gs negated, that had better be a robot pilot in that fighter...

Regards,

Tobias

 

[robject]

Yeah, I guess inertial compensation has to be pretty major. Greg Porter designed that craft, too, using Yet Another Version of FFS2 (the version found in Central Supply Catalog).

 

[Tobias]

Am I by the way the only one to feel that the Traveller acceleration ratings for spaceships are pretty tame? I, personally, wouldn't mind ratings in the 10-30g range for high tech vessels.

Regards,

Tobias

 

[Fritz_Brown]

Well, Tobias, w/out my books in front of me, I seem to recall Agility being power leftover after acceleration (maxed at 6G). I don't seem to recall it being that high - but I could definitely be wrong.

If you take the rubber sheet model of gravity (Welcome, Ditzie), when you pushed or pulled the sheet, it would seem to affect other things than just your craft. That's where you get into problems - as canon certainly doesn't imply that as a consideration. Admittedly, if you assume the point affected is fairly close - say, 1m from the thruster plates - you don't get much effect (diminishes as the square of the distance). But, that isn't the same as none. Highports would constantly have to be firing manuevering thrusters to counter all the ships coming and going. (This makes a definite case for using mass v volume, though....)

Along those lines, how do you possibly run inertial compensators on a non-spherical ship? If you set the grav point in the middle of the ship, it will extend out of the sides in places. Would you pick up a cloud of debris within that field? Stuff that followed along with you until jump or you turned off the M-drive? And, of course, the inertial compensators would not be as efficient the further from them you were....

So, I can see pushing against the local grav field (which wouldn't work well very far up the sides of the gravity well), and generating a grav point (lots of little ones for grav floor plates in your passageways, etc.), but thrusters is really tough to swallow.

 

[parmasson]

Am I by the way the only one to feel that the Traveller acceleration ratings for spaceships are pretty tame? I, personally, wouldn't mind ratings in the 10-30g range for high tech vessels.

Wow 10Gs?! I always though a 6G acceleration was really something.
You can go from earth to the moon in something like an hour IIRC.

 

[parmasson]

By Fritz88

. . . but thrusters is really tough to swallow.

But wouldn’t a reaction drive require so much fuel than an average Traveller ship could not hold it? A 100 ton scout/courier only holds 40 tons of fuel (hydrogen right?). From what I have been able to glean the thrust is a combination of the amount of reaction mass and how fast it is moving when it exists the engine. Isn’t it just as much handwaving to create an engine that produces that kind of hyper velocity thrust? (no mocking intended, an honest question here)

 

[mike wightman]

Originally posted by Tobias:
Am I by the way the only one to feel that the Traveller acceleration ratings for spaceships are pretty tame? I, personally, wouldn't mind ratings in the 10-30g range for high tech vessels.

Regards,

Tobias

You're not alone with that wish Tobias, and there are a couple of ways to do it.

Using fusion rockets in MT/HT you can make your ship thrust at over 10G IIRC - it just means having a really big rocket and a small ship.

T4's Central Supply Catalogue and FF&S2 allow acceleration compensators to be stacked, so that even at TL12 you can use two 3G commpensators to cope with 6G, or six of them to thrust at 18G.

GT Starships introduces the "megathruster" to Traveller ship building. This is a late-GTL13/TTL17-18? version of the reactionless drive that has three and a half times the thrust of a lower TL drive.

 

[Fritz_Brown]

Well, Parmasson, you are right about the fuel requirements. However, I would rather extrapolate some future outrageous level of efficiency (after all, you could always use the computer tonnage for fuel, right? ) than something I just can't see within the realm of physics.

And, BTW, a fighter jet can do more than 1G accel - it's not 6Gs, but it ain't no paltry 1G, neither. And, the shuttle (w/ boosters, etc.) does something approaching 2Gs - remember that 1G is negated by the Earth's gravity, but it still has to be there.

 

[Tobias]

Originally posted by Parmasson:But wouldn’t a reaction drive require so much fuel than an average Traveller ship could not hold it? A 100 ton scout/courier only holds 40 tons of fuel (hydrogen right?). From what I have been able to glean the thrust is a combination of the amount of reaction mass and how fast it is moving when it exists the engine.

That's correct AFAIK. 1 ton of fuel from a ship with a mass of 1000 metric tons (corresponding roughly to a 100-dton ship), pumped out at a crazy speed of 100,000,000 m/s (that's 0.33c!) would mean 10,000 G-seconds for that ship, or about 3 G-Hours.

Regards,

Tobias

 

[Tobias]

Originally posted by Fritz88:
And, BTW, a fighter jet can do more than 1G accel - it's not 6Gs, but it ain't no paltry 1G, neither.

It is often even less than 1G, but 1G is the general ballpark. Simply compare weight to thrust. An F-16, for example, has a takeoff mass of 12-16 tons, so we have ~120-160 kN of weight. Compare to its 129 kN of afterburner thrust, and you arrive in the neighbourhood of 1G, without even taking drag into account.

Regards,

Tobias

 

[Tobias]

Originally posted by Sigg Oddra:
You're not alone with that wish Tobias, and there are a couple of ways to do it.

A sample suggestion for High Guard. It seemed always kinda odd to me that a TL 15 drive is just as good as a TL 9 one.

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">Percentage ---------- Tech Level ----------
required 8-9 10-11 12-13 14-15
for m-drive m 4m-1 3m-1 2m-1 m-1
Energy req 4/3 1 2/3 1/3
Price (MCr) per ton 0.25 0.5 1.5 4.5

TL 8 Max. 2 Gs
TL 9 Max. 5 Gs
TL 10 Max. 8 Gs
TL 11 Max. 11 Gs
TL 12 Max. 14 Gs
TL 13 Max. 17 Gs
TL 14 Max. 20 Gs
TL 15 Max. 23 Gs
etc.</pre>[/QUOTE]To convert existing ships, simply multiply existing G-Rating by 3 for TL 14-15 vessels, by 1.5 for TL 12-13 vessels and by 0.75 for TL 7-9 vessels. Divide power plant requirement by the same. Adjust the total vessel price according to the table.
Now, what to do about agility? Should it go up in the same way as the Power plant numbers? In this case, the combat rules need some reworking (They do, anyway, though.)

Regards,

Tobias

 

[robject]

Or you can borrow Ken Pick's "Book 2" solution by "stacking" maneuver drives.

But that's a good point about M-drives not having a TL granularity. I'm not sure how I'd want to approach that problem. Perhaps by lowering power requirements every 2 or 3 (or 4 or 5) TLs.

Tending to be more of a gamer than a techie, I'd carefully stagger the improvements in ship components by tech level, say between M-drive and Power plant.

...and the combat rules will never not need reworking.

Anyone know where the latest thread on ship combat is?

 

[robject]

Originally posted by Fritz88:

If you take the rubber sheet model of gravity (Welcome, Ditzie), when you pushed or pulled the sheet, it would seem to affect other things than just your craft.

[...]

Along those lines, how do you possibly run inertial compensators on a non-spherical ship?

[...]

That sounds right -- if gravity is like a flexible wall, then the wall hits everything. After all, gravity does affect everything the same way.

That sounds like how gravity pullers work -- if you line the floors of your ships with fake grav, then it induces an acceleration. I wonder how the range of those things are controlled -- for surely they have to only extend to the top of the affected deck. Maybe it has something to do with being a closed environment? And at what TL does artificial gravity kick in? Is it related to inertial compensation?

But it seems that, at the distances we deal with, gravity is significant only when one of the objects is massive. Maybe that's how gravity pushers work -- it's much easier for a "lifter" to push against a massive object than a small object. That's sort of counter-intuitive, though. You'd think contragrav would make a great mass driver, wouldn't you? Surface bombardment via M-Drives... the near-C rock problem...

But actually, that's what happens at very high tech levels, according to MT: you finally get pressor beams. So there's a progression and refinement going on. There's also a progression leading to tractor beams as well.

Then there's the TL11 breakthrough of somehow being able to push against a piece of the Universe itself -- the most massive thing we know of.

My thinking is probably muddled in this area.

Some of this is worth working through, because it has playable consequences. But I bet that inertial compensation is not meant to be over-analyzed.

 

[rhoneycutt]

it seems to me that 'juking' around, like a UFO is suppose to do, requires inertia-less drives. Otherwise, the ship must turn using its acceleration in place of aero-lift. For thruster based ships, thats a maximum of 6g's. An f-16 can pull 9g's or more. Acrobatic show planes are routinely stressed to handle +-12g's. Juking around at very high speeds ( hypersonic) would probably cause a ship depart controlled flight. 1G or 6G thrusters....airspeed is limited by atmospheric heating.

most ships/shuttles are not stressed for hi g combat anyways...and are horribly massive. Inertia will hurt them.

 

[rhoneycutt]

dammit..hit the send button too quick

My opinion is that ships will beat fighters in the vertical and with better energy management, but planes will beat them in turning battles.

 

[Fritz_Brown]

Tobias, a F-15E will accelerate going straight up - so I know some have a >1G accel. (Course, that's slick....) Further materials advancements should make more capable engines.

With some further thought, here is my take on grav-drive. Grav generators generate a point (fairly closeby - though being able to project it would give all kinds of cool "weapons" - one of which might be a tractor beam) which can cause a + or - grav gradient (pushing or pulling the einsteinian rubber sheet). If you allow it within .25m of the aft of the ship, it will be calibrated to push at 1g (given a 1g drive!) at .25m. This means it will be 1/16g at 1m (inside the ship). Yes, the front of the ship doesn't experience the actual grav gradient (the nose of a scout gets .00005g), but it gets pushed by the fact it's connected to the stern of the ship. I would actually put it inside the ship to prevent any problems with external interactions. This also makes it easier to use it for vectoring.

The real problem with this scenario is gravity is omnidirectional (in einsteinian rubber sheet land). This means problems like putting the g-gradient point inside the ship pushes the back end opposite your intended direction, or your grav plates (in the flooring) pulling up all the wiring underneath them. So, you go one more step and allow for a directional field to be created. This means your floorplates only generate a field that goes up through the floor and the drive only pushes one direction at a time.

An inertial compensator would have to create some kind of field that would remove the ship from the universe in which the drive (of whatever type) is operating. If you accept that, then the drive has to actually go outside the field in order to push the ship without pushing everything inside it.

As far as the range of your floor grav plates? If your projector is (for S&G) .15m "thick", the floor plate is another .05m and you desire 1g at the floor interface, at 1m => .04g, and at 2m => .01g. So, you could actually carry things rather easily since there would be moon gravity or less above your knees. Of course, someone could hurt themselves lifting something planetside if they were really use to doing it shipboard.... (I see safety posters galore on the bulkheads of ships that land planetside - "Lift with your knees!"

)

 

[far-trader]

Originally posted by Fritz88:
Tobias, a F-15E will accelerate going straight up - so I know some have a >1G accel. (Course, that's slick....)

That's more speed and lift. They don't launch vertically, they burn down the runway generating speed and lift before they can go vertical and as they lose lift they have to go horizontal again or stall, so I don't think they have true full 1G+ thrust the same way a rocket does.