Press both square buttons on the control panel on the left
Btw, i am not a rocket sciencist, and rocket engines in this game are not the same as ones in real life. LOXY+OIL won't be more energetic in TPT(it may have even less efficiency and thrust(less pressure in the combustion chamber)
This is a realistic one, it only uses real elements and pipes(and some electronics)
Autismrocks99: And how did you estimate the ISP?
New_man99999: This "rocket engine" design is not the most efficent engine, first of all it uses gravity to pump the fuel to the main chamber, second of all these hypergolic fuels are not very good, a better more energitic fuel would be something like lox and oil. Most rockets in this game are in seperate tanks, then portaled into the chamber, the tanks are heavly pressure then the rocket nozzle diameters need to be perfect for max efficency.
+1 for kerbal space program 2!!!