Antigravity & Inertial Dampening

Discuss the Traveller RPG and its many settings
F33D
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Re: Antigravity & Inertial Dampening

Postby F33D » Thu Apr 23, 2015 8:26 pm

ShawnDriscoll wrote:One day, maybe we'll understand what gravity is and how it works. For now, I'm not about to say how it should work in a role-playing game.

Those of us who successfully completed Jr. High already know...
Reynard
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Re: Antigravity & Inertial Dampening

Postby Reynard » Thu Apr 23, 2015 8:50 pm

I did mean interdependent as it reads, to me, the technology of the maneuver drive and grav plate must match before they are considered usable together. Essentially, the two are part of the same engineering system and define the tech level for that level of maneuver drive. The two tech probably don't develop exactly at the same time but one needs the other to work. You really don't want ships maneuvering at one acceleration level with grav plates rated lower. Even 1G difference is going to severely toss things around.

As to Star Trek, I found the information in a recent tech guide approved by Paramount for the Enterprise of the old series. That makes it canon. They go through a detailed sidebar describing the system and it's reaction, not reactionless or inertialess. We never see a star ship on the show 'turn on a dime' or how long or how wide a turn takes even with the thrusters covering the ships to aid maneuvers. Space is really, really big so that dime can be relatively big too. Also remember the was no show bible and script writers had a lot of descriptive license.

One thing I see both Traveller and Star Trek ships doing is turning off the main propulsion briefly riding on the inertia then using control thrusters to realign the ship to a new direction then apply thrust again to the new vector. The old Mayday game did something like that. That's where the ICs come in because everything in the ship would prefer to go in the last direction.
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Re: Antigravity & Inertial Dampening

Postby F33D » Fri Apr 24, 2015 12:54 am

Reynard wrote: One thing I see both Traveller and Star Trek ships doing is turning off the main propulsion briefly riding on the inertia then using control thrusters to realign the ship to a new direction then apply thrust again to the new vector.
I've never seen trav rules where TL 10-15 grav or thrust plate M-Drive ships also use chemical thrusters to change direction. Where did you read that?
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Re: Antigravity & Inertial Dampening

Postby phavoc » Fri Apr 24, 2015 12:57 am

Well seeing them as interdependent is certainly one way to look at it, and it's just as fair as any other way since there isn't an official one that can be found. If you had the maneuver drive you could either build gimbaled decks, or align your decks in the direction of thrust. Some of the sci-fi things from the 50's had rocket ships with these ideas in them. Especially when nuclear rockets were all the rage.

I haven't seen or looked for anything regarding ST in a very long time. I suppose I could go and dig out my old SFB books, but there's not really a point. In the TV shows the ships are pretty much pigs to turn using their thrusters. Even on impulse drives they don't move very fast on the helm (remember Sulu had a hard time going hard to port/hard to starboard sometimes to avoid things incoming). The drives always had an 'ion trail' that Mr. Spock could follow - though those sneaky Romulans (and later Klingons) seemed to sometimes obscure that. So I could see how the drives might be considered reaction-based.

The rules don't really do much to accommodate vectors of thrust, which isn't necessarily a bad thing as after a turn or two trying to keep track of positive/negative thrust settings would be a royal pain in the ass. At turnover the ships do cease thrusting, rotate 180 degrees, and then resume thrusting to slow down. Technically thrusters aren't mentioned either, and the antigravity system that works so well where gravity is present has nothing to 'push' against, so thrusters make the simplest explanation - not to mention that's how things get done today. Except when you involve gyros. SOM mentions putting gyro's in ships and having to eject the warp core, err, gyro, sometimes before it destablizes and destroys the ship. :)
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Re: Antigravity & Inertial Dampening

Postby Reynard » Fri Apr 24, 2015 2:02 am

"I've never seen trav rules where TL 10-15 grav or thrust plate M-Drive ships also use chemical thrusters to change direction. Where did you read that?"

I remember seeing the depiction of the M-drive that was a gravity thruster plate sitting in a 3D cradle to move the ship in any direction. All the other editions show a thruster system with movement forward to the long plane of the vessel. Explains why the maneuver vents are always depicted stern. Every one of these systems are macro-thrust meaning they direct the vast majority of their movement power in a straight plane. Classic Traveller actually uses rotation as part of vectoring. You could turn 180 and vector facing backward or thrust to slow then move in that direction. The other systems abstract movement, including Mongoose, mostly with range bands for increasing and decreasing distance without accounting for super wide turns. That all suggests there is a way for ships to pitch, roll and yaw and that would be a system of thrusters. By the way, I never said chemical thrusters. A cluster of focused ion units at key points over the craft will easily push a vessel in a new direction. The energy is part of the power from the plant. This would be very necessary to dock with other craft or stations.
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Re: Antigravity & Inertial Dampening

Postby F33D » Fri Apr 24, 2015 2:19 am

Reynard wrote:"I've never seen trav rules where TL 10-15 grav or thrust plate M-Drive ships also use chemical thrusters to change direction. Where did you read that?"

I remember seeing the depiction of the M-drive that was a gravity thruster plate sitting in a 3D cradle
There are countless uninformed artist depictions in Trav. In MT's Starship Op manual they had huge gyro's that rotated the ship mid course in real space. It is weird that after all these decades the author hasn't pulled it together to answer these basic questions. You and I have to pick through reams of rules to find hardly anything.
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Re: Antigravity & Inertial Dampening

Postby CosmicGamer » Fri Apr 24, 2015 2:23 pm

Is there someplace in the Mongoose rules specifically detailing the M-Drive producing thrust omnidirectional? Anyplace that indicates it can it go full thrust with ship orientation reverse, up, down, sideways? Or is it the opposite where indications are thrust is somehow out the tail so a ship needs to turn around to slow down? If the later, some alternate means of rotating the ship to redirect the unidirectional thrust is needed.

In the core rules, from the combat rules, I see that the thrust needs to be "allocated". But is this just saying the omnidirectional force of the drive needs to be redirected and allocated in an alternate direction, perhaps from the rear to alternating directions to bob and weave? Or is it possible the ships orientation is somehow changed and maneuvered by secondary means and due to it's rotation/maneuvering the unidirectional thrust can not be allocated to the desired vector during evasive combat maneuvering?

Is there room for multiple interpretations?
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Re: Antigravity & Inertial Dampening

Postby F33D » Fri Apr 24, 2015 3:15 pm

CosmicGamer wrote:Is there someplace in the Mongoose rules specifically detailing the M-Drive producing thrust omnidirectional? Anyplace that indicates it can it go full thrust with ship orientation reverse, up, down, sideways? Or is it the opposite where indications are thrust is somehow out the tail so a ship needs to turn around to slow down?
Given that A) It's a Gravity M-drive. And B) Non lift producing ships can land and take off from planets. And C) Ships with lift producing bodies can land and take off from vacuum worlds, it would have to be omni-directional.
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Re: Antigravity & Inertial Dampening

Postby CosmicGamer » Fri Apr 24, 2015 5:00 pm

Where in the rules does it say the Gravity M-drive must be used rather than additional or alternative drives for fine maneuvering like docking.

If it is there (it very well may be) please provide page references to where the rules specifically say that the Gravity M-drive is used for "maneuvering" vs thrusting"?
F33D wrote:Given that A) It's a Gravity M-drive. And B) Non lift producing ships can land and take off from planets. And C) Ships with lift producing bodies can land and take off from vacuum worlds, it would have to be omni-directional.
Thank you for your interpretation.

To me, just because a) b) and c) are true does not mean "it would have to be omni-directional." Whether vacuum world or atmospheric planet, a unidirectional Gravity M-drive could be utilized to B) and C) too.

Can your vision of a omni-directional Gravity M-drive produce forces in multiple directions simultaneously? In other words, while landing on a high gravity world you produce thrust to decelerate and land "softly" but need to adjust for cross winds and "maneuver" too.
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Re: Antigravity & Inertial Dampening

Postby Reynard » Fri Apr 24, 2015 5:16 pm

"Is there room for multiple interpretations?"

Yes because the Mongoose space combat system is highly abstracted from the original vector movement of Classic Traveller and each are weak in the original description as to exactly how the maneuver drive functions. MegaTraveller, The New Era, Traveller d20 and Marc Miller's Traveller all went the abstract range band route too with little description about how ships maneuver smaller than macro-level of close/retreat. MegaTraveller and its micro-detailing mentions gravitic drives 'grab' the gravity fields of nearby bodies to move while the separate and more advanced maneuver drive reacts with nuclear forces for reactionless locomotion and thrust is 180 degrees but drops off precipitously from the +/-20 degree angle down to 10% of full thrust. This is the only example I find of the thruster plate ability spelled out and shows no need for thrust control clusters. The various reaction drive used in several editions would need TCCs.

Interpretation is almost mandatory with such abstraction. Referee's call and description of events and keep the game moving.
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Re: Antigravity & Inertial Dampening

Postby CosmicGamer » Fri Apr 24, 2015 6:40 pm

What is TCC?
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Re: Antigravity & Inertial Dampening

Postby Condottiere » Fri Apr 24, 2015 7:06 pm

Vectoring nozzles could allow for change of direction. But not necessarily VTOL.
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Re: Antigravity & Inertial Dampening

Postby phavoc » Fri Apr 24, 2015 9:02 pm

I have never regarded Traveller engines as being capable of omnidirectional thrust. Every version's depiction of travel has always been in a linear fashion.

As to thrusters existing vs. grav drives, that's always been more of a read between the lines. In a gravity well the antigrav functions fine, but without a gravity well your antigravity system is useless. Whether or not you can nimbly maneuver a 200 Dton starship using just the antigrav (while in a gravity well) or if you simply use it to nullify your mass and then thusters to do more delicate maneuvers is up for interpretation. None of the rules really go into that sort of detail. And, unfortunately, we've never had anything as detailed as SOM come out for the other versions. The T5 mega-book is chock full of information, granted it's often useless, confusing and not really detailed where it needs to be, but hey, it's a really big book! (/sarcasm off).
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Re: Antigravity & Inertial Dampening

Postby F33D » Sat Apr 25, 2015 1:03 am

phavoc wrote:I have never regarded Traveller engines as being capable of omnidirectional thrust. Every version's depiction of travel has always been in a linear fashion.
The guy who wrote the MGt rules said otherwise. That's why ship without wings can take off and land just fine on worlds. That isn't physically possible without multiple, simultaneous vectors. No opinion, just axiomatic.
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Re: Antigravity & Inertial Dampening

Postby Reynard » Sat Apr 25, 2015 1:20 am

All three configurations can be flown in an atmosphere but only the streamlined is best suited for it. (CR page 137 Atmospheric operations) Aerofins are flight enhancers to the Pilot DMs but not absolutely necessary. There is no limitation under the aerofin rules so even a displaced configuration can benefit from wings. An erector set with wings is still an accident waiting to happen.

Hmmm... The direction of this thread is definitely veering towards maneuver engines and away from AC and IC. Ladies and gentlemen and whatever that fuzzy green thing is over there, it is time to reassess the thread and head back on track.
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Re: Antigravity & Inertial Dampening

Postby Condottiere » Sat Apr 25, 2015 10:05 am

While i tend to use these terms interchangeably, thrusters would indicate one general direction at any one particular time, while an actual grav drive would create a field.
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Re: Antigravity & Inertial Dampening

Postby F33D » Sat Apr 25, 2015 5:50 pm

Condottiere wrote:while an actual grav drive would create a field.
Which is why Mgt calls them Grav M-drives...
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Re: Antigravity & Inertial Dampening

Postby Somebody » Mon Apr 27, 2015 4:10 pm

phavoc wrote:I have never regarded Traveller engines as being capable of omnidirectional thrust. Every version's depiction of travel has always been in a linear fashion.

As to thrusters existing vs. grav drives, that's always been more of a read between the lines. In a gravity well the antigrav functions fine, but without a gravity well your antigravity system is useless. Whether or not you can nimbly maneuver a 200 Dton starship using just the antigrav (while in a gravity well) or if you simply use it to nullify your mass and then thusters to do more delicate maneuvers is up for interpretation. None of the rules really go into that sort of detail. And, unfortunately, we've never had anything as detailed as SOM come out for the other versions. The T5 mega-book is chock full of information, granted it's often useless, confusing and not really detailed where it needs to be, but hey, it's a really big book! (/sarcasm off).
Looking at TNE:

The ContraGrav only provides a negation of gravity. For any kind of movement you need thrusters. In TNE they are advanced fusion engines (HEPLAR) using fuel. So even the air/raft has an extra thruster platform. GravPlates/Compensators are an extra component. Shutting down the ContraGrav when in space is quite common for older ships.

From the description in "Brilliant Lances" ships do use smaller thrusters to change their orientation and then apply thrust to change their vector. The system is not rated/does not appear as an individual sub-system but the way the text is put makes it resonable clear it is not the main drive using thrust-vectoring
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Re: Antigravity & Inertial Dampening

Postby F33D » Mon Apr 27, 2015 6:00 pm

Somebody wrote: Looking at TNE:

"In TNE they are advanced fusion engines (HEPLAR) using fuel.

...

From the description in "Brilliant Lances" ships do use smaller thrusters to change their orientation and then apply thrust to change their vector.
Yes, TNE used a completely different propulsion system than MT & Mgt. Not applicable to Mgt at all.
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Re: Antigravity & Inertial Dampening

Postby Condottiere » Mon Apr 27, 2015 10:03 pm

I think those were specialized lifters, plus thrust plates.

The grav drive field effect has to react to some form of significant gravity focus.

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