On Thu, 08 Jan 2004 21:34:44 +0100 Erik Hofman <[EMAIL PROTECTED]> wrote:
Paul Surgeon wrote:
Shucks ... I must be tired or something because this is getting more and more confusing by the minute.
What is this "arbitrary point" you are referring to?
It is a location which you can choose. You can use the CG, the nose of the aircraft, the center location of the front of the nozzle, anything.
Paul:
Within the FDM our math model really doesn't care about the specific locations of anything. We really only care about the relative distances from the aircraft CG of things like the wheels, the wings, the aerodynamic reference point, the pilot eyepoint, etc. Also, the FDM always reports the latitude, longitude, and altitude of the center of gravity. One more point (to complicate things further): the CG moves as fuel burns off.
So, you may ask: What's a modeler to do? The answer is that we have to agree on a common reference point to report to FlightGear. I mean: the flight model can report to flightgear the position of any point since we have intimate knowledge of the position of the CG and the orientation of the aircraft, and the relative location of the reference point relative to the CG (i.e. the vector from the CG to the reference point). We (FDM) simply report the location of the reference point (I think we agreed it would be the forward-most position of the aircraft, like the prop hub tip, or nose tip) and FlightGear places the reference point (tip of nose, for example) at that point in "world space".
I have still not delivered on my promise to provide the reference point to FlightGear. I don't know what we do for the C-172, in order to place it correctly.
Jon
_______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
