That is what I was planning on doing. To add upthrust, you push "Fly" on the main menu but don't take off. Go to "File" and click on "Edit aircraft." To change the CG, click on the fuse and down in the right corner there will be a icon of a plane with a balance point. Click on this and then change the first cg on the bottom corner (The one farthest left). Negative CG moves make it farther back. To change upthrust, select the engine and add negative downthrust (There is no upthrust option)