Making Engines

This is less about my post on Ethanol/Lox engines and more on how to make replica engines for rockets. For example:

Model 39a
Thiel LOx/Alcohol rocket engine. Single chamber engine for V-2 series C, A9. Tested 1942-45. Never went into production in Germany, but formed the basis for successful post-war American and French rocket engines.
AKA: A-9. Status: Tested 1942-45. Thrust: 288.70 kN (64,902 lbf). Specific impulse: 255 s. Specific impulse sea level: 220 s. Burn time: 115 s. Diameter: 1.65 m (5.41 ft).

288.7kN for 115 seconds?! There seriously isn’t an engine in game that can be this powerful without being compact. Really. Gas Generator II and Staged are too big, Electric and Pressure engines aren’t powerful enough, which only leaves Gas Generator I. I ran different sizes on increments of +-5% and increased combustion pressure to nozzle size, and there really isn’t any combination of kerolox that can get close to Ethelox, unless Methalox is a better try.