propulsion system for star wars speeders?

[Phantasm]

I tend to use Hot Reactionless for my SW craft, actually, and a setting switch which gives the Standard and Rotary Reactionless engines some heat backwash as well. Hot is used on the small, fast ships like the Falcon and starfighters, Standard on shuttles and smaller craft, and Rotary (rear-section only) on the huge craft. Also, I tend to put up to 5 Hot Reactionless engine modules on the starfighters while only one Rotary Reactionless module on the Super Star Destroyers.

For the speeder bikes and landspeeders, I agree that a repulsorlift engine for lift and then some kind of thruster unit for propulsion is the way to go.

On the fuel issue, I tend to just handwave it as "token fuel usage".

[sir_pudding]

Originally Posted by Fred Brackin

You should note that there are things that _look_ like jet engines but they don't seem to burn jet fuel. Also, on things like X-Wings they appear to work in space. I think these things only "look" like jet engines while actually being something else probably best described as a reactionless thruster.

They could be etheric jets.

Originally Posted by Phantasm

On the fuel issue, I tend to just handwave it as "token fuel usage".

Significant plot point for a film seems more than "token" usage. It seems like capital ships have just enough fuel for one engagement.

[Fred Brackin]

Originally Posted by sir_pudding

Significant plot point for a film seems more than "token" usage. It seems like capital ships have just enough fuel for one engagement.

"Token" fuel usage can be a plot point or an economic limitation. It just can't be reaction mass or even an energy source using any science known to us. At least that's what I mean when I use the term.

[Phantasm]

Originally Posted by sir_pudding

Significant plot point for a film seems more than "token" usage. It seems like capital ships have just enough fuel for one engagement.

I don't recall it being a significant plot point in any of the movies, but then I haven't yet seen The Last Jedi.

Star Wars: We see X-Wings and Y-Wings getting something pumped into them, but it's never referred to as "fuel" on-screen; for all we know, it's coolant.

The Empire Strikes Back: Fuel is never mentioned. The line about "Bespin ... is pretty far, but I think we can make it" is in reference to the hyperdrive being blown out, indicating they'd be traveling there in realspace or using a really slow backup. Luke never has to refuel between Hoth and Bespin, even making a side trip to Dagobah.

Return of the Jedi: Again, fuel is never mentioned, nor do we see anything being fueled up.

The Phantom Menace: The only reference I can find is "the hyperdrive is leaking", and that's not necessarily leaking "fuel". A few of the Naboo fighters may have been shown having something pumped into them, but that's not necessarily fuel; I'd have to double-check. The pod-racers may or may not have fuel; a lot of the energy seems to be electricity from batteries, given some of the in-flight fixes we see.

Attack of the Clones: No mention of fuel, though something exploded on Geonosis. Lots of stuff is explosive, though, and not just fuel.

Revenge of the Sith: The first time in six movies that the word "fuel" even makes it into dialogue, and then it's Ben ... sorry, Obi-Wan asking for some for his (really small!) Jedi-issued starfighter. There's a hyperspace sled used by Ben in this and the previous movie, but that's mostly because there's no room for a hyperdrive on this generation of fighters (unlike the A-Wing of RotJ which had a hyperdrive built in).

The Force Awakens: No mention of fuel; Rey's in-flight fixes on the Falcon are for power distribution, not power generation.

Rogue One: No mention of fuel anywhere I'm aware of.

So, hardly a plot point that I'm aware of.

[sir_pudding]

Originally Posted by Phantasm

I don't recall it being a significant plot point in any of the movies, but then I haven't yet seen The Last Jedi.
...
So, hardly a plot point that I'm aware of.

The reason you aren't should therfore be self-evident.

[Culture20]

Originally Posted by sir_pudding

Significant plot point for a film seems more than "token" usage. It seems like capital ships have just enough fuel for one engagement.

This assumes the capital ships were all fully fueled at the outset. It does seem they use some sort of fuel for realspace movement that is irrelevant for hyperspace; it’s rarely mentioned in the films because they’re almost always travelling via hyperspace and using realspace more like an on-ramp to the highway.

[David Johnston2]

Originally Posted by Culture20

This assumes the capital ships were all fully fueled at the outset. It does seem they use some sort of fuel for realspace movement that is irrelevant for hyperspace;.

No. They were using the same fuel for hyperspace jumps and for driving at sublight speeds in the Last Jedi.

[Phoenix_Dragon]

It's also possible that they were going "flank speed" or the equivalent to stay out of range and therefor burning through fuel faster than if they were at cruising speed.

[a humble lich]

One issue with trying to pin down Star Wars technology is that technology (and physics for that matter) in Star Wars often isn't really consistent with itself. After 9 movies, two animated series, and a host of comic books, video games, and books there is a lot of contradictory information. Technology generally has whatever limitations the writers need it to have.

One needs to decide which sources are the most canonical and figure the technology from there. Personally, I would say spaceship engines in Star Wars use some fuel, but it is generally a small amount. Other than The Last Jedi, ships seem to be able to fly around quite a bit without mention of fuel. Also, looking at spaceship designs, there are no obvious fuel tanks on any ships I can think of. In this case I would argue that in The Last Jedi the ships were not fully fueled at the beginning of the engagement, or they were using fuel faster than normal. This could because they were running the engines hotter than normal, or perhaps they were sending more power to the shields than normal.

Alternately, you could focus on The Last Jedi, because it is the main source which explicitly refers to fuel. In this case, it is assumed that ships are routinely refueled off screen. I don't like this case as much because for a cinematic game I don't think it would be fun for the players to spend a lot of time tracking fuel usage. Time that could be spent killing storm troopers.

Other than The Last Jedi, are there any other references to a ship needing to be refueled? I have vague memories of episodes of Star Wars Rebels involving refueling, but nothing specific.

[Varyon]

Originally Posted by sir_pudding

Significant plot point for a film seems more than "token" usage. It seems like capital ships have just enough fuel for one engagement.

The primary use of fuel seems to be for hyperspace jumps. Additionally, even if fuel is needed, the realspace drives in Star Wars could easily be reactionless - in which case the fuel is the stuff you consume to generate energy to power the drive (in fact, the Wookiepedia entry on Hypermatter seems to have it as an energy source that also links the ship to hyperspace to allow for jumps to it). Token usage certainly does seem to describe every instance of it in the movies prior to The Last Jedi.

In that, fuel is still mentioned primarily in regards to hyperspace jumps. I cannot recall if the ships that lag behind during the chase scene are explicitly stated as having run out of fuel (it's possible their engines simply cut out due to redlining), although I think you are correct that "out of fuel" was the intent there. I don't think it's safe to say that capital ships generally have only enough fuel for two hyperspace jumps, however. It's possible the ships were already running low on fuel when they assisted the evacuation of the base, and it's established early in the film that the Resistance is being forced to leave some supplies behind due to the New Order arriving early, which may have included the intended fuel resupply. I can't recall if the ship suffers damage before or after it's established they only have enough fuel for one more jump, but if the damage happened first it's possible they lost a great deal of fuel during the attack. Or they could have simply forgotten to top off the tanks - that would hardly be their only tactical blunder during the film.

For what it's worth, I've always thought of Star Wars "ion" drives as being semi-reactionless - they do expel a bit of reaction mass, but nowhere near enough (and at nowhere near high enough speed) for the accelerations experienced. I think this was based on some of the mechanics and logistics of spaceships in Starships of the Galaxy, the spaceship-creation book from the old d20 Star Wars Roleplaying Game, where ships have token fuel usage (they have to refuel occasionally, but fuel isn't tracked) and IIRC do have a bit of backwash if you get too close behind one.

...

For the actual question at hand, I believe typical speeders simply use repulsorlift, and angle it to move forward. Some may supplement this with an air-breathing version of the "ion" engine in order to get higher speed - the speeder equivalents of sports cars, and actual racing speeders like pod racers, would do this. In UT, repulsorlift is an option for gravbikes and similar that gives them a very low ceiling and halves their energy consumption, but otherwise leaves their statistics (including cost) the same. A gravbike is going to use standard reactionless engines (6 of them at TL 10^, based on performance - 2 to negate gravity, 4 to get 2G acceleration), so you could say that repulsorlifts use the cost and statistics of standard reactionless engines, but have a low ceiling and each Power Point can power up to 2 such systems. A boost to price for contragravity reactionless engines may be appropriate, as such would give better maneuvering capabilities (and could be mounted anywhere on the ship, not just the Rear), but that's up to the GM. On the other hand, repulsorlift that can't be angled to produce thrust (requiring some other drive for propulsion) is probably a contragravity lifter subsystem (as a full system can negate up to 10G, one would assume a 1/3rd size system can negate up to 3G, a 1/10th size system up to 1G), and in this case I'd say the "repulsorlift" modifier should probably reduce cost.
Typical "ion" engines would be hot reactionless. An air-breathing variant would probably be less expensive, as it doesn't have to interact with the ether or whatever allows Star Wars drives to produce thrust in a vacuum.