Yes, subcooled propane looks surprisingly doable.
Given the unusual overlap in temperature ranges, I woulder if you could
even use *both* propellants to regen the engine. There's more heat
capacity, and they would both end up hotter, and easier to burn.
On 16 February 2018 at 13:54, <Nels.Anderson@xxxxxxx> wrote:
Gesendet: Donnerstag, 15. Februar 2018 um 17:41 Uhr
Von: "Ian Woollard" <ian.woollard@xxxxxxxxx>
Google suggests
you have to subcool propane to around 0F to get reasonable tankage
pressure. IRC someone (John Carmack?) suggested it becomes awkwardly
viscous at low temps
NIST's Chemistry Webbook (webbook.chemistry.gov) provides lots useful
information at no charge.
At 0 degF, propane is relatively inviscid (about 0.2 centipoise). Cool it
to lox temperatures, though, and it becomes syrupy: about 10 cP.
In comparison, RP-1 at room temperature is something like 2 cP. Cooled to
20 degF (about what SpaceX does), it's about 3.3 cP.