I don’t know if its been mentioned in any of the previous posts, but along with alcohol engines, i’d like to see Multifuel engines in the big military trucks, maybe including the M35A2. Which has a absolutely Bad-ass 7.8 liter 6 cylinder turbocharged multi-fuel engine. you can run them on diesel, Jet fuel, alcohol (not recommended on old trucks due to rubber tubing), cooking oil, regular gasoline, USED MOTOR OIL (not even kidding), Kerosene, transmission fluid, hydraulic fluid, and just about anything flammable (I’ve heard of these things run on propane, not sure if its true)
Yea flex-fuel and multifuel wold be cool (are those different things? From your description multifuel sounds more accepting than how I understand flex-fuel to operate, which runs on arbitrary combinations of gasoline and ethanol)
Something technical that’s been holding back adding more fuels is that the game engine would only accept a limited number of fuel types, and we were already at the limit (enums 're baaad mmkkkaaaayy…?), I have a pending fix that adresses that and allows an arbitrary number of fuel types. With that out of the way, it’s a matter of adding more engine types, and probably cleaning up how different engine types are handled (right now adding a new fuel type would require updating like um… checks 17 different places in the code). I guess each fuel type would need its own tank, because a gasoline tank would only accept straight gasoline, a flex-fuel would accept gasoline, ethanol, disel, and possibly kerosene (not sure about the last one), whereas a multifuel may well accept any flammable liquid, and a potential ethanol-only engine would want pure ethanol.
For a steam engine, I think we’d want to just have a boiler unit that consumes water and whatever fuel it uses and produces power. That boils down (ha) to whether it’s desireable to have multiple fuel sources for the boiler, or multiple boilers or whatever, in which case seperating out the turbine or pistons might be called for. Probably not though.
None of this is terribly difficult, it’s mostly held up by the way engines are handled, they don’t have stats, the stats are scattered all over the code that interacts with them.
A simple steam engine could be quite interesting for running large tools.
Even just an old fashioned archimedes steam engine (the one that’s just a sphere full of water with two nozzles to shoot steam out and make it spin) would be potentially useful for powering small things.
It’d be nice if we could build small devices that could run off things like that, maybe a rudeminetary power saw or something to help with wood-based construction, or a steam powered grindstone for milling plants into flour or something.
A steam powered car would be cool though it depends how easy it is to build something that’d be useable.