Replacing Thruster Plates

[Alexander Cecil]

I want to replace thruster plates in my Traveller campaign, because I just don't like the idea of a reactionless thrust system. I have decided to keep contragrav technology in order to eliminate gravity and allow air/rafts and whatnot. What do you think is the best replacement for thrust in both spaceships and air/rafts?

In spaceships, I was going to go with plasma-fired thrust when near the planet surface or any other ship, and fusion rockets once deeper into space. Both ideas are taken from FFS.

I am unsure what to do for air/raft. I want to keep them very easy to drive, but I am unsure how to rectify this with the low friction of being in the air and basic physics (objects in motion tend to. . ., etc.).

I would highly appreciate input on both air/rafts and spaceships, as well as any other ideas you might have.

 

[far-trader]

...What do you think is the best replacement for thrust in ...air/rafts?

Vectored jet engine(s). Probably two for balance and backup redundancy. So the contra-grav negates the bulk of the influence of gravity and the vectored thrust provides the remaining required lift and directional thrust including steering. Use a ducted rocket (also available in FF&S) and you can even retain the classic climb to orbit capability, though at a much faster rate (and just as well since the fuel duration will be much less as well).

 

[Lee Torres]

You could take a step back technologically and go with something like this:

http://www.moller.com/

I believe that there are several science fiction rpg settings that make use of "aerodynes" (Cyberpunk 2.0.2.0) and ducted fan-driven lift.

http://en.wikipedia.org/wiki/Avrocar

Hope that helps!

 

[EDG]

HEPLaR should work fine I guess... for air rafts there's always the hover type stuff (ducted fans or maglev, pg 75/76 in FF&S) - I don't think you even need to resort to contragrav for that.

 

[Ishmael]

I use HePlar for ships.
For grav stuff like air/rafts, I make them power hungry by making them use up power equal to the change in potential energy of the vehicle and where tech level affects its efficiency.

power needed = mass*altitude*grav (m/sec^2)/eff%

altitude is the change in altitude from the time the machine is turned on.
if you start on a mountaintop and drop into a ravine, you'll bleed off the extra energy as heat.

heavy stuff needs more power to reach a height
gain more altitude by throwing bad guys off the raft. ( okay, not so much, but maybe enough to clear the edge of the dam..)

This is completely seperate from power needed for thrust in different directions...ducted fans work nice for that.

 

[Infojunky]

I am unsure what to do for air/raft. I want to keep them very easy to drive, but I am unsure how to rectify this with the low friction of being in the air and basic physics (objects in motion tend to. . ., etc.).

If this helps, I have always treated air/rafts as rotor-less helos. Aircraft in effect.

 

[simonh]

I don't think you can get away from contragrav of some sort, otherwise you can't sensibly have artificial gravity or thrust compensation on starships.

I generaly stick to thruster plates because then I don't have to worry about getting the players from A to B and generaly my players have been happy to just conveniently ignore the weapons potential. I see it as being just an inconvenient side-effect in the same way that breaking relativity and potential time travel is just an inconvenient side-effect of FTL. To me, HePLAR has just as much weapons potential, and in fact at close range a HePLAR drive exhaust should be able to cut through spaceship hulls like a hot knife through butter. It's just a matter of taste.

Simon Hibbs

 

[aspqrz]

I am unsure what to do for air/raft. I want to keep them very easy to drive, but I am unsure how to rectify this with the low friction of being in the air and basic physics (objects in motion tend to. . ., etc.).

If this helps, I have always treated air/rafts as rotor-less helos. Aircraft in effect.

There's presumably a lot of Helium from those Fusion generators, so why not aerofoil dirigibles with vectored fans :shock:

A lot lower tech and easier to maintain :lol:

Phil

 

[Rikki Tikki Traveller]

I don't think you can get away from contragrav of some sort, otherwise you can't sensibly have artificial gravity or thrust compensation on starships.

I generaly stick to thruster plates because then I don't have to worry about getting the players from A to B and generaly my players have been happy to just conveniently ignore the weapons potential. I see it as being just an inconvenient side-effect in the same way that breaking relativity and potential time travel is just an inconvenient side-effect of FTL. To me, HePLAR has just as much weapons potential, and in fact at close range a HePLAR drive exhaust should be able to cut through spaceship hulls like a hot knife through butter. It's just a matter of taste.

Simon Hibbs

Not using Contr-Grav might explain the 6G limit to acceleration though. A typical passenger/cargo ship will only go to 1g. Paramilitary might do 2gs and anything above that will require dedicated acceleration couches, which puts it into the military realm. 6Gs would be for combat maneuvers and emergency thrust. Build your ships like skyscrapers with the engines at the bottom and you don't need CG. Of course, you would still need some kind of atmospheric maneuvering system, since fusion/plasma drives are not very nice in atmo...

 

[simonh]

Build your ships like skyscrapers with the engines at the bottom and you don't need CG. Of course, you would still need some kind of atmospheric maneuvering system, since fusion/plasma drives are not very nice in atmo...

Sure, but even so your players are goign to spend most of their game-time in space in Zero-G, e.g. any time they are in orbit, any time they are docking and most of the time they are docked to anything. You can also forget going anywhere near a gas giant's atmosphere.

That's all fine if that's what you want, but for me running in-game scenes in zero-g is far enough outside my personal experience and comfort zone that I would rather have it the exception rather than an everyday (or rather every game session) occurrence.