4 ms·
When I saw the title, I was hoping for a scramjet or ideally a scramjet/rocket hybrid with a railgun launch pad.
by amirhirsch 9y ago
When I saw the title, I was hoping for a scramjet or ideally a scramjet/rocket hybrid with a railgun launch pad.
- vanadium 9y agoI've been dreaming of a viable scramjet since the X-30.
- theothermkn 9y agoUgh. The X-30! What a boondoggle! Nobody had any idea how to get that done. In every aero/astro engineer's undergrad fluid dynamics class, they teach you about heat addition to subsonic and supersonic flows. The biggest takeaway is that adding heat to a moving fluid destroys total pressure (aka stagnation pressure), the measure of useful work a fluid can do. The amount of total pressure destroyed depends on the amount of heat and the flow velocity. Half the job of a diffuser and/or compressor is to raise the pressure of the incoming flow, but the other half is to slow the flow down so that heat addition can be done without destroying too much total pressure. The very idea of "supersonic combustion," the "sc" in "scramjet," is antithetical to engine efficiency. At some point,even a theoretical scramjet becomes a drag-producing device, instead of a thrust-producing device. Real scramjets will always crap out long before orbital velocity, which is around M=30. To end on an optimistic note, dream of a rocket-based combined cycle engine, instead. They may or may not ultimately be viable as SSTOs, but at least there's room to dream, there!
- jlebrech 9y agoa rail based launch pad could spin round and round around one of the poles and just let go at some point.