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2300AD & 2320 Discussion of the original 2300AD from GDW, the revised 2300 from Mongoose Publishing, or QLI's 2320AD.

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Old September 9th, 2007, 07:18 PM
PFVA63 PFVA63 is offline
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Default Some Questions on 2300 AD Era Ships

Hi,

I have a couple questions about 2300 AD era ship's that have confused me for a while that maybe some one here can help me with.

First off, with spin habitats, if you are rotating them in one direction, what prevents the rest of the ship from rotating in the opposite direction? If I am understanding correctly, on craft like helicopters, many of them use tail rotors, or two separate sets of rotors, or even a single set of contra-rotating blades to conter act the tendancy of the craft to want to spin in the opposite direction of the rotors. Is this an issue with starships in 2300 AD, and if so how do they account for this?

Second, from college physics, if I am understanding correctly things like a two-bladed propeller (and I'm assuming a two arm spin habitat) are concidered dynamically not fully stable because their cross-moments of inertia don't cancel out, but on some aircraft this is compensated for by the use of small balancing weights near the hub. As such, on 2300 era ships are similar things necessary for ships with two arm spin habitats?

Third, if I am understanding correctly the stutterwarp drive is supposed to be a reactionless drive, what are the bright shiny things at the back end of some of the ships like shown on the cover of the "Mission Arcturus" ( http://rpg.drivethrustuff.com/produc...ts_id=433&it=1 ) or on alot of the ship's shown on the Etranger website ( http://www.users.globalnet.co.uk/~dh...min/Index5.htm )? Are these some of secondary drives for operating in gravity wells?

If anyone has any thoughts I'd be happy to hear from them. Thanks.

Regards

PF
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Old September 9th, 2007, 07:43 PM
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perhaps gyros could be used?
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Old September 9th, 2007, 07:57 PM
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Oh-oh. It looks like somebody has discovered the wrench in the works. ;-)

1) Yes, spin habitats need a counter-rotational device of some sort. The easiest way to deal with this is to assume that there's some sort of flywheel gyro included in the mechanics of the habitats (thus there wouldn't be any extra costs involved). Ships with two spin habitats will rotate in opposite directions and won't have that problem.

2) Your idea sounds good and doesn't involve any extra rules. Thus, it's perfect.

3)And you've noted another little wrench in the works. I've always assumed that those were used to make orbital adjustments. It's noted that stuuterwarp drive efficiency drops below that of rockets in gravity fields greater than .1G. They don't provide any additional movement and are included in the cost of the drive systems.
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Old September 10th, 2007, 03:48 AM
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The Bayern's Spin sections counter-spin each other.
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Old September 16th, 2007, 01:10 PM
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Quote:
Originally Posted by PFVA63 View Post
Hi,

I have a couple questions about 2300 AD era ship's that have confused me for a while that maybe some one here can help me with.

First off, with spin habitats, if you are rotating them in one direction, what prevents the rest of the ship from rotating in the opposite direction? If I am understanding correctly, on craft like helicopters, many of them use tail rotors, or two separate sets of rotors, or even a single set of contra-rotating blades to conter act the tendancy of the craft to want to spin in the opposite direction of the rotors. Is this an issue with starships in 2300 AD, and if so how do they account for this?

Second, from college physics, if I am understanding correctly things like a two-bladed propeller (and I'm assuming a two arm spin habitat) are concidered dynamically not fully stable because their cross-moments of inertia don't cancel out, but on some aircraft this is compensated for by the use of small balancing weights near the hub. As such, on 2300 era ships are similar things necessary for ships with two arm spin habitats?

If anyone has any thoughts I'd be happy to hear from them. Thanks.

Regards

PF
To offset the P-factor, I've always thought there was some sort of internal counter balance in the hub itself. Like a superdense counter-weight 90 degrees off from each support arm that spins in the opposite direction in some sort of "Jeffereies Tube" using superconducting technology (i.e. the counter weights of prop hubs that you mentioned above). This would still be true for ships that have multiple rotating habs. And in those cases, the habs would spin in opposite direction for better direction stablility. So in this example: Spin ring Alpha rotate clockwise around the ship axis, while spin ring Beta spins counter-clockwise.

Last edited by shanksow; September 16th, 2007 at 01:13 PM.. Reason: spelling
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Old September 16th, 2007, 01:20 PM
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Quote:
Originally Posted by PFVA63 View Post
Hi,

I have a couple questions about 2300 AD era ship's that have confused me for a while that maybe some one here can help me with.

Third, if I am understanding correctly the stutterwarp drive is supposed to be a reactionless drive, what are the bright shiny things at the back end of some of the ships like shown on the cover of the "Mission Arcturus" Are these some of secondary drives for operating in gravity wells?

PF
In a word - yes. I don't think the Star Cruiser rules really covered this (in hindsight now) like they should have. There was always fuel for control thrusters. But the artists that were drawing ships needed something else to convey speed. A glowing blue thruster bell on the backside of a ship does just that. Like in regular Traveller, one must have a means of getting 1 planetary diameter away from a planet before jumping can take place. I'm just trusting my memory on this since its been years since I had a chance to play Star Cruiser or Traveller.
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Old September 24th, 2007, 01:40 AM
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Re:this thread
As I recall, the Stutterwarp drive is completely useless as a means of propulsion at the 0.1G gravity gradient of a planet....
While a civilian ship may have the equivalent of navigation thrusters for stationkeeping or for heading at low speed for a orbitial facility, military vessels need fairly hefty M-drives, for changing their delta-V in combat situations.....
There's a nice illustration of a spin habitat equipped vessel, (the "Wagon Wheel") at Classic Battletech.com's download section...
(They allow you to down PDF "tasters" of their technical readouts, & the "Wagon Wheel" is one of their tasters....)
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Old September 30th, 2007, 06:08 PM
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In Artur C Clarkes 2001 the Discovery had an internal spin hab, a horizontal disc running above the pod bay and below the bridge. In the novel it mentions having a flywheel and a gearing system to counteract the torque, and having to keep supplying power as the bearings induced friction and slowdown.

In 2010 the derelict discovery is found to be rotating end over end, as the angular momentum of the spin hab has been transferred to the ship itself. I can't get my head around the physics in this, but Clarke is suaually pretty sound.

G.
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Old October 1st, 2007, 02:42 AM
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I suspect Mr. Clarke forgot he had counterrotatng weights...

It should have simply come to a stop, perhaps with a very slow spin.

Now, if the net spin between the two was for some reason imballanced, gyroscopic precession would take over, and slowly impart a wobble...
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Old October 1st, 2007, 06:15 PM
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Hi PF!

Quote:
Originally Posted by PFVA63 View Post
First off, with spin habitats, if you are rotating them in one direction, what prevents the rest of the ship from rotating in the opposite direction? If I am understanding correctly, on craft like helicopters, many of them use tail rotors, or two separate sets of rotors, or even a single set of contra-rotating blades to conter act the tendancy of the craft to want to spin in the opposite direction of the rotors. Is this an issue with starships in 2300 AD, and if so how do they account for this?
As has already been said: Counterwheels/Flywheels. If there is a counter-flywheel in the hub of the spin habitat, it's have to be both massive and spin fast to counter the longer movement arms of the habitat sections. Some ships, like the American luxury liner that appeared in Ships of the French Arm, don't bother with counterspin: the entire ship spins (there may be a small center section that counterspins, I don't remember). Someone with more Physics-wise can tell me if I'm right on this: Wouldn't counter-spinning spin habitats have to be on the opposite ends of the center of mass, in order to correctly counter the torgue of each other?

Quote:
Originally Posted by PFVA63 View Post
Third, if I am understanding correctly the stutterwarp drive is supposed to be a reactionless drive, what are the bright shiny things at the back end of some of the ships like shown on the cover of the "Mission Arcturus" ( http://rpg.drivethrustuff.com/produc...ts_id=433&it=1 ) or on alot of the ship's shown on the Etranger website ( http://www.users.globalnet.co.uk/~dh...min/Index5.htm )? Are these some of secondary drives for operating in gravity wells?
It's already been mentioned that they could be maneuver drives, but the vast majority of ship-to-ship combat is at stutterwarp speeds. Instead, I think of them as exhausts for their powerplants. One thing 2300AD (in its original incarnation) didn't address very much was the issue of heat and thermal-radiation. Craft with Fusion powerplants and MHD drives need a way to dump lots of heat, and the original design process didn't detail any kind of radiators or heat sinks. For a very good resource for "Real Physics" check out: http://www.projectrho.com/rocket/index.html

As for the "Tumbling Discovery" discussion: remember she'd been without human or computer control for nearly nine years before the US/USSR team caught up with her in 2010. She was without power most of that time, and thus her spin section (and counterweight) eventually stopped from friction. Finally, consider she was inbetween the gravity wells of IO and Jupiter, so any forces could send her wobbling. Even if she had the gyroscopic stabilizing force of a spin section, the gravitational forces pulling on her could easily have over come that.

Anyway, my 0.02lv...
-Andrew
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