Ninzoris

This is perfect, thank you everyone.

Having tried to launch from Eve with a lander than can easily reach orbit from kerbin only to see it apogee at 20km was a bit disappointing. So this time I would like to actually calculate how much fuel I need to reach orbit with out getting at that number with trail and error. If I know the dry mass of my lander, twr, engine thrust and specific impulse, surface gravity and atmospheric drag. What formula would I use to calculate how much fuel I need to lift the craft to 120km orbit? Thank you

Thank you! It was a fuel line loop.

I'm working on a SSTO and after many, many failures from a mysterious pulling of the plane to the right starting at 30km I finally discovered what was at fault. One of the two fuel tanks hanging under the wings (right one) was draining before the other tank was. Even though I had symmetrical fuel transfer lines running from each tank to the engines. I thought it could be a bug from the order in which the plane was assembled, so I unclipped the tanks and clipped them back in using symmetry and put in new fuel transfer lines. Now the problem persists but this time with the left tank draining first. Any help would be appreciated.