Details on how M-Drives work

[Proneutron]

I am customizing the Cepheus Engine for my Trav game. Since how an M-drive works can have mechanical effects in game I decided to codify for my players.

The standard M-Drive is a gravity based system. It doesn't "push" against anything but it creates an external artificial 2D gravity well. 2D meaning it only causes a "pull" from one direction. So the ship "falls" in the direction the well is created. This also explains why a ship that fills its hold with gold accelerates the same as if its hold were filled with feathers.

Looking at a craft like this cutter the M-drive would be in the front hemisphere. There are articulating stalks with the graviton creation emitters that can point in various directions to achieve what the pilot wants. Take off from belly, point them up and slightly aft maybe. Take off like a rocket, point straight ahead (up). The crew do not feel any acceleration for obvious reasons. That means the crew needs artificial grav inside.

 

[Werner]

I am customizing the Cepheus Engine for my Trav game. Since how an M-drive works can have mechanical effects in game I decided to codify for my players.

The standard M-Drive is a gravity based system. It doesn't "push" against anything but it creates an external artificial 2D gravity well. 2D meaning it only causes a "pull" from one direction. So the ship "falls" in the direction the well is created. This also explains why a ship that fills its hold with gold accelerates the same as if its hold were filled with feathers.

Looking at a craft like this cutter the M-drive would be in the front hemisphere. There are articulating stalks with the graviton creation emitters that can point in various directions to achieve what the pilot wants. Take off from belly, point them up and slightly aft maybe. Take off like a rocket, point straight ahead (up). The crew do not feel any acceleration for obvious reasons. That means the crew needs artificial grav inside.

In other words it's a warp drive. If you have an M-drive like that, you don't need a Jump drive.

 

[coliver988]

In other words it's a warp drive. If you have an M-drive like that, you don't need a Jump drive.

Wasn't that basically Alan Dean Foster's technique in the Flinx books?

 

[vegas]

In other words it's a warp drive. If you have an M-drive like that, you don't need a Jump drive.

It's a warp drive that only accelerates to a handful of Gs. (And perhaps cuts out too many D from a gravity source; looks sideways at T5). Not going to visit too many star systems like that.

 

[Proneutron]

In other words it's a warp drive. If you have an M-drive like that, you don't need a Jump drive.

Nope. That isn't how a warp drive is envisioned to work. Warp drives don't create or use gravity

 

[Proneutron]

It's a warp drive that only accelerates to a handful of Gs. (And perhaps cuts out too many D from a gravity source; looks sideways at T5). Not going to visit too many star systems like that.

Nope. A warp drive WARPS space AROUND the vessel and the vessel moves WITHIN the warped space. That isn't how the grav drive works. The ship falls TOWARDS a grav well. Which is always AHEAD of the ship.

 

[mike wightman]

Warped spacetime is gravity - that's pretty much the whole point of general relativity.

If you are warping spacetime ahead of you to fall into it it is still a warp drive...

 

[Proneutron]

If you are warping spacetime ahead of you to fall into it it is still a warp drive...

Nope. And this.

 

[aramis]

Nope. A warp drive WARPS space AROUND the vessel and the vessel moves WITHIN the warped space. That isn't how the grav drive works. The ship falls TOWARDS a grav well. Which is always AHEAD of the ship.

That's from A.D. Foster, not the OTU. Flinx of the Commonwealth series.

Traveller T-Platers grab onto the local curvature and produce a finite thrust, not a contantly moving hole.

 

[Proneutron]

That's from A.D. Foster, not the OTU. Flinx of the Commonwealth series.

No idea about Flinx, never read it. I just made it up a few days ago.

Traveller T-Platers grab onto the local curvature and produce a finite thrust, not a contantly moving hole.

Right which is why I an writing this description. Because it IS different than anything in any OTU. I posted in the IMTU to avoid just that confusion.

 

[atpollard]

I thought it was like a microwave oven ... a magic black box that you plug in, press a few buttons and it somehow “just works”.

 

[Timerover51]

May someone add his own view of how Maneuver Drives work, or should I either start another thread or add it to My Heretical Traveller Universe?

 

[Proneutron]

May someone add his own view of how Maneuver Drives work, or should I either start another thread or add it to My Heretical Traveller Universe?

Go for for it! And if anyone knows all the different Cannon data from the carious versions of Trav that would be cool. Aramis already added the thruster plate data from MT?

 

[aramis]

Go for for it! And if anyone knows all the different Cannon data from the carious versions of Trav that would be cool. Aramis already added the thruster plate data from MT?

MT, T4, T5 all have thruster-plates.
CT has gravitic thrusters in Striker as a suspension system at TL8, MD's are TL9. (Bk2-81 A-D drives are TL 9 per the Tech Table b3 p14-15; HG has some form of unspecified thruster at TL7.)

K. Grav Generators: A grav vehicle requires grav generators installed in its chassis. Each .02 m3 of grav generators produces 1 ton of thrust and requires .l megawatts of power from the power plant. They weigh 2 tons and cost Cr100,OOO per m3.

One cautionary element in diving through the corpus of CT: the focus of the game rules changed between 1977 and 1981. Popular demand for a ready setting was pressuring GDW to create the OTU; corporate intent shifts following the 1979 creation of the OTU as a concept. This also results in some other changes happening.

 

[Proneutron]

MT, T4, T5 all have thruster-plates.
CT has gravitic thrusters ...

Thanks for the overview!

 

[mike wightman]

Nope. And this.

Nice pictures but I think we are talking past each other with regards to general relativity.

If you warp spacetime then that warp is perceived as gravity. It doesn't matter if you are wrapping yourself in a warped spacetime bubble or projecting said warp in front of you to fall into it, the warping of spacetime is what we perceive as gravity.

A warp bubble drive will have 'interesting' effects on anything external to the ship that interacts with the warped spacetime, in a similar way the gravitic projection spacetime warp that you propose will also have 'interesting' effects on stuff external to the ship. How safe would such a drive be to use in a planetary atmosphere or in a crowded starport?

 

[mike wightman]

Fire, Fusion and Steel for TNE and the T4 version has several variations on the maneuver drive for referees to experiment with in their own settings. Similarly MgT has a few variant technologies too.

In CT the m-drive was intended to be a reaction drive, this changed as the rules were revised and rules were modified. By High Guard 1980 edition the reference to the m-drive being a fusion rocket was removed and how the m-drive functions was never explained again until MT reactionless thrusters. A late MT supplement Hard Times included rules for building low TL spacecraft within the MT design system which included chamical rockets all the way to fusion rockets.

TNE had the plasma rocket - HEPlaR - but ships could also be equipped with grav lifters to aid with maneuvering within a gravity well.

The Third Imperium standard m-drive in MgT is described as gravitic, yet all the ship illustrations continue to show drive plumes

I should state that I agree that the CT fusion drive and the TNE HEPlaR defy the laws of physics.

My personal solution is to have the m-drive reduce the inertial mass of the ship as well as its gravitic mass, so that a much lower powered ion engine or plasma/fusion rocket can achieve the g rating performance.

 

[Proneutron]

Nice pictures but I think we are talking past each other with regards to general relativity.

No, you are talking about a DIFFERENT usage of gravity. What NASA describes as a warp drive. Which is ENCASING the ship is a bubble of space time that is then moved. That is not how a gravity well works. Two different uses for gravity altogether.

 

[BRover]

My vision (rather fuzzy) of maneuver drives is that of creating a gravity "ramp" (bubble?) so the ship falls down it--higher Gs having a steeper "hill"--with the ship floors/ceilings having (flat) grav-modules for internal gravity. Hence the limit is volume (or length?) rather than mass, since all the stuff in the field fall at the same acceleration.

So, yeah, a "warp" drive, but limited--max 6G (or thereabouts. Seems...odd that they go 1G to 6G in tech 8-10, IIRC, but then hit a firm limit forevermore...) as well as, likely, some sort of velocity limit . . . not sure if I can justify it, but that's life in the slow lane.

 

[whartung]

The standard M-Drive is a gravity based system. It doesn't "push" against anything but it creates an external artificial 2D gravity well. 2D meaning it only causes a "pull" from one direction.

What are the external effects of the drive? What happens to someone standing next to the ship when they fire it up?