[theunchosen]

Their power-to-weight is not great. its actually terrible. Gas engines can get 1.0+ and diesels can come in at 1.2 and Gas turbines come in very nicely at 1.5 and higher. Scramjet engines do. . .like 50:1.
But in this situation(low power) Stirling comes in better because it does not have ti withstand detonation and the ICE does. Stirling just has to be able to withstand heat differences and high temperatures(400-800). can make them out of very thin aluminum or very thin pretty much anything heat conducive and resilient.

<edit> scramjets are just gas turbines. . .sort of. . .more like pulse engines. . .but anyway they only work at the sound barrier and faster because they ramscoop air into the manifold to achieve ridiculous intake pressure blast lots of fuel in ignite and the really high pressure acts as a barrier to keep it travelling backwards while the exhaust manifold is just a wide open cone(the pressure against the cone wall causes the acceleration). its like two big traffic cones put together with the small ends together and the fuel is ignited at the junction. vessel goes rocketing on at mach 15 or so.
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