I am designing my own vessel and am having a problem understanding the real and orbiter configured Centre of Gravity. I understand the parallelogram of forces acting on an airframe, with its lift, drag, G and the like. I also have a passing understanding of good old Newton
Here is a very simple drawing of my craft. It is for use on and around the Moon, i.e. a vacuum and low to nil gravity. It has a single lift off / hover engine, a single retro braking engine and 3 main engines. The main body is mounted on 4 legs. The actual CoG is nowhere near the middle in any axis and would change with cargo and fuel. If I was a Loadmaster on a C130 I would tell you where to stick your boxes, a Flight Eng on Concorde would pump fuel around. I don't have those options. Not all UCGO cargoes are the same Mass and the weight will change from lunar surface to low orbit and above.
I have the RCS thrust to make changes (well the autopilot would) but where would the main engines force act, both in and out of gravity? Around which point would the roll occur. I get I need to have two jets acting together, like the tracks on a turning tank, but where is the CoG in a zero grav setup. Each time I reason it in my head I end up with a different answer.
Please understand this is from some who does not believe Bees, 747s and Harriers can fly!!!:facepalm:
Here is a very simple drawing of my craft. It is for use on and around the Moon, i.e. a vacuum and low to nil gravity. It has a single lift off / hover engine, a single retro braking engine and 3 main engines. The main body is mounted on 4 legs. The actual CoG is nowhere near the middle in any axis and would change with cargo and fuel. If I was a Loadmaster on a C130 I would tell you where to stick your boxes, a Flight Eng on Concorde would pump fuel around. I don't have those options. Not all UCGO cargoes are the same Mass and the weight will change from lunar surface to low orbit and above.
I have the RCS thrust to make changes (well the autopilot would) but where would the main engines force act, both in and out of gravity? Around which point would the roll occur. I get I need to have two jets acting together, like the tracks on a turning tank, but where is the CoG in a zero grav setup. Each time I reason it in my head I end up with a different answer.
Please understand this is from some who does not believe Bees, 747s and Harriers can fly!!!:facepalm: