[Spaceships] Non-TL^ Power Plants and air propulsion below TL7?

[johndallman]

Originally Posted by Flyndaran

How efficient could such a thing(s) be? That water consumption really limits airship endurance.

Well, it can be really quite efficient. Once you're well into TL6, or better, TL7. Condensers for steam sea-ships seem to be really a TL6 thing. They cost space and weight, but they are worth it, because they allow the engine to have a near-vacuum to exhaust into, which helps efficiency usefully. The extra weight would be a real pain for an airship, pushing up the required size.