Jim Wilson writes: > Norman Vine <[EMAIL PROTECTED]> said: > > > > > > IMHO You need two (2) CG's. > > > > 1) the 'reference' < static > CG usually determined from manufacturer > > specs or something similar for use in FGFS for reference purposes. > > > > 2) The 'actual' < dynamic > CG of the aircraft, as determined by vehicle > > loading for use in the FDM > > > > Think of (1) above as the 'local origin' of the aircraft frame and think > > geometry not gravity. > > Yes that is correct. If the positon and orientation data as published by the > FDM's are based on a center of gravity that moves, then the models would move > with it since the model origin is being positioned at the lon/lat/alt reported > by the FDM. That said, I would suspect that movement in the center of gravity > for a given aircraft would not affect the altitude reference very much (during > flight and on the runway) and the tiny shift in lon/lat position would be > hardly noticable.
It may be that in most cases the CG doesn't move enough from frame to frame to have a noticable visual effect. However, it seems like in the long run we would be a lot better off using some fixed reference point on the airframe, rather than the CG. In some cases the CG could move far enough to produce a noticable visual jump/glitch. Why make ourselves subject to that when we don't have to? Regards, Curt. -- Curtis Olson IVLab / HumanFIRST Program FlightGear Project Twin Cities [EMAIL PROTECTED] [EMAIL PROTECTED] Minnesota http://www.menet.umn.edu/~curt http://www.flightgear.org _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
