/sci/ - Science & Math

>>12281101
>I assumed he meant a single F-1B lower with 2 SSMEs on the upper stage
Well that would be silly, the size ratio of the first stage to the second stage would be completely off base. For a decently performance optimized first-to-second-stage mass ratio look at the Falcon 9. The first stage has roughly 9x the thrust and roughly 3.5 times the mass of the second stage (the second stage gets away with a much lower thrust to weight ratio).
Following this rule of thumb, if your second stage has one RS-25 producing ~2300 kN of thrust, you should have a first stage producing ~20,000 kN of thrust, which is about 3 F-1 engines. You want the entire rocket to start off with a TWR of ~1.3 and you want the second stage to start off with a TWR of ~0.8. I'd do it but I don't have realism overhaul installed because I'm a poopy dum dum who can't computer.