How do Gravity drives work??

[Captain Brann]

HI
I have been thinking and it came to me that a lot of Sci-fi has energy coming out of the back of a ships drive system.
Would this be true for a gravity drive as I gather the idea is that you move by using attraction/repulsion of gravity.

However as someone new to Traveller I might have this totally wrong.

So how does a gravity drive work?
Is there any exhaust blast?
Does this mean that the drive unit is just a power plant for the grav plates?


Thanks

 

[dmccoy1693]

Would this be true for a gravity drive as I gather the idea is that you move by using attraction/repulsion of gravity.

Sounds as good a short-hand explaination as any other I've heard.

30 years ago, if you asked someone how you could get someone to move a mouse cursor with their mind, they'd be able to give you a basic answer, but they'd be clueless about the specifickes. Ask someone 50 years ago about how a computer operates and they'll give you an answer that involves vacuum tubes and punch cards.

IMO, we might have the basic idea how a propulsion drive might work 1000-5000 years from now, but my guess we don't even know that that branch of science exists yet.

 

[rust]

Here is what the Traveller Wiki has:
http://traveller.wikia.com/wiki/Maneuver_Drive

Different versions of Traveller added different bits of "fluff", so in the
end you are free to imagine and describe the details as you please.

 

[EDG]

HI
I have been thinking and it came to me that a lot of Sci-fi has energy coming out of the back of a ships drive system.
Would this be true for a gravity drive as I gather the idea is that you move by using attraction/repulsion of gravity.

The traditional explanation has been that the default M-drives (thruster plates) in Traveller are reactionless drives. You put energy into them from the power plant, and they move the ship. They may or may not glow, but there's usually no visible "rocket plume" or anything like that, but I guess it depends on how you think the drive interacts with the environment (e.g. do they ionise atmosphere near the plate somehow? Do they emit heat as well?).

 

[alex_greene]

HI
I have been thinking and it came to me that a lot of Sci-fi has energy coming out of the back of a ships drive system.
Would this be true for a gravity drive as I gather the idea is that you move by using attraction/repulsion of gravity.

The traditional explanation has been that the default M-drives (thruster plates) in Traveller are reactionless drives. You put energy into them from the power plant, and they move the ship. They may or may not glow, but there's usually no visible "rocket plume" or anything like that, but I guess it depends on how you think the drive interacts with the environment (e.g. do they ionise atmosphere near the plate somehow? Do they emit heat as well?).

I generally rationalise the function of gravitics as something like "A grav plate, deckplate or reactionless M-drive unit functions in the same way: by generating a focused field of gravitons which simulates a gravity field.

"When an M-drive operates, it generates a concentration of gravitons in the direction designated "forward" and the ship freefalls into the artificial gravity well, which is projected a constant distance from the ship; this propels the vessel along its designated vector.

"Propulsion grav plates function in much the same way, by generating a smaller field of focused gravitons, but their principle of operation is to generate a field of suspended gravity around the vehicle, permitting it to appear to defy local gravity and to hover in place above the ground.

"Deck plates provide two distinct functions: gravitational attraction to the deck in a microgravity environment, permitting a definite and distinct sense of "up" and "down," and inertial damping, permitting the ship to manoeuvre at high accelerations of 1G or more without requiring that the crew strap themselves in to acceleration couches.

"In every case, the directed graviton field produces a stream of neutrinos visible to any SIN detector as an integral part of its design."

And if anyone else asks me how do grav plates work, I'll simply reply "Very efficiently, thank you."

 

[Gee4orce]

Weirdly, I had an extremely vivid dream about Star Trek last night - part of which involved being in the engineering section (this was nothing like Star Trek you've ever seen on TV).

There was a grid of red pyramidal 'coils' each about 10ft tall, which were somehow related to the M drive. It was critical that the coils remained cool - but stressing the drives meant that coils started to overheat, and had to be shut down individually before they exploded.

I woke up thinking that this would be pretty cool for a Traveller game - giving the players something that they have to take good care of, and something that has consequences if it's worked too hard. At the moment M drive in traveller is just a black box - push a button to go faster. Not very exciting....

As for your question - I figured that the M drive somehow pushes against space/time itself....

 

[Mithras]

I suppose there are many ways.

A gravity 'wave' could be ridden.
A gravity incline could be created at the bow, the ship is falling forward.
Gravitons spat out the back pushing against the mass of the universe.

My favourite mixes dream-tech with hard-tech: an emitter reduces the mass of the vessel to zero within a gravity field, then an efficient plasma drive uses that 10xPn hydrogen fuel to move the virtually massless ship forward at very efficient Gee ratings. I like reaction drives Keeping it plasma means the reaction mass will not be radioactive (I've heard).

 

[d(sqrt(-1))]

A gravity incline could be created at the bow, the ship is falling forward.

I like to call this the "Escher Drive" - no matter where you are, you're always at the top of a slope.

Mark

 

[Rikki Tikki Traveller]

One of the big problems I have with the explanations of the M-Drive is that if it creates a field around the ship, or in front of the ship, then why are the drives ALWAYS in the back of the ship?

If the M-Drive creates a Zero-Mass field around the ship, then the M-Drive should be in the middle of the ship and the ships would tend to be spherical.

Same for the Jump Drive. If it creates a field around the ship, the drive should be in the middle of a sphere to minimize the output (which is huge)...

Personally, I am leaning more and more to making the M-Drive a very efficient reaction drive using the PP fuel as 24hrs of thrust for every 2 weeks of fuel provided. PP fuel is now free.

 

[rust]

Personally, I am leaning more and more to making the M-Drive a very efficient reaction drive using the PP fuel as 24hrs of thrust for every 2 weeks of fuel provided. PP fuel is now free.

The more I think about it, the more I like the idea - perhaps with the
modification that gravitic thruster plates are used to accelerate the re-
action mass (since I have already introduced the M-Drive as gravitic
technology into my setting).

This could leave me with the problem how to determine the fuel con-
sumption of stationary reactors, but currently the setting uses fission
reactors for most such purposes, so there is time to come up with an
explanation ...

Yep, thank you very much - another good idea, borrowed.

 

[Mithras]

Which is as it should be with fusion powerplants. If a nuclear submarine does not need refuellling throughout its intended life - how come a 5000 AD fusion powerplant needs refuelling every 2 weeks?

PP fuel is now free.

 

[Mithras]

I like that. Differing concepts make for good alien alternatives, no better or worse than the 3i maneuver drive - just ... different. I think my Golorons will use an 'Escher Drive'.

I like to call this the "Escher Drive" - no matter where you are, you're always at the top of a slope.
Mark

 

[EDG]

A gravity incline could be created at the bow, the ship is falling forward.

I like to call this the "Escher Drive" - no matter where you are, you're always at the top of a slope.

Mark

Sounds more like an Alcubierre Drive to me.

 

[Rikki Tikki Traveller]

Which is as it should be with fusion powerplants. If a nuclear submarine does not need refuellling throughout its intended life - how come a 5000 AD fusion powerplant needs refuelling every 2 weeks?

PP fuel is now free.

Not to derail the thread, but nuclear submarines (fission powered) DO refuel during their lifetimes. Typically twice.

Each core lasts about a decade, depending on how much power they actually pull out of it based on missions.

 

[Mithras]

I stand corrected!

 

[Gaidheal]

"There is no free lunch"

 

[Tobias]

gravitic thruster plates are used to accelerate the re-
action mass

That's exactly how I would do gravitic drives. Also reduces some of the hassle resulting from reactionless drives.

 

[Thlaylie]

Particle Accelerator on high speed acceleration produces a perpendicular gravity sheer. Gimbled drives would have no problems, stationary mountings would produce Bright photon emissions and EMP type interference as well as heat discharge when vectored against the plane of emission. This is why UFO's display this phenomina.

 

[rust]

Thlaylie, I hate to admit it, but I simply do not comprehend what you
have written. It sounds like something that could be very interesting
for me, but I fail to understand "perpendicular gravity sheer", "gim-
bled" and "vectored against the plain of emission".

Could you perhaps explain it with a few more words ? - Thank you.

 

[Thlaylie]

Perpendicular Gravity sheer is a Gravity "Force" directed at a 90 degree angle to the plane of rotation.

Visual aid: stick a pencil through a donut, the donut is your Particle Accellerator, the pencil would be the Gravity Sheer. "Thrust" along that line.

Gimbled means mounting the engine in a ball turret type thing so it can rotate freely and direct it's thrust. Without the gimble mount, you will have to vector or shift the thrust away from it's prefered direction, this causes molecular bombardment in an atmosphere producing light and heat. EMP effects come from the magnetic fields used to vector the thrust. Gimbled is better.