I'm working on a kinda-sorta confidential device. I would like to know how much psi is required to lift approx. 400 pounds 120m (about 393ft and 8 13/32 inches) into the air. The thing I'm working on is still in the designing stage, so don't worry about the specifics of individual thrusters and stuff since I'll work it out. P.S. This is just something I hope to complete as something to add to my college résumé.