So, I was testing a large space plane which was to heavy to get off the runway just by using winglets so I added some small rockets to the side to help get it up. After a few seconds they suddenly stopped working and made the flame-out noise which was odd, so i looked at the fuel tanks and it said that only the oxidiser was gone. I then realised that it had used liquid fuel from the planes fuselage . I could make the rockets last longer if i had tanks with only oxidiser in them, it would also be useful in other situations as well. Who agrees?