Jim Wilson wrote: > Ok, so are you saying that the lon/lat/alt values that the fdm outputs > are at the origin already adjusted for cg? If so then how would that > affect the axis of say pitch rotation on the c172 model? It's origin > is at the firewall and the pitch rotation is always on the access that > intersects there. Should we be doing something different?
OK, now I'm confused. :) To the first part: yes. If you take an aircraft with zero velocity and spin it, the output lat/lon/alt values from the FDM will be moving in a circle around the center of gravity, even though the c.g. is stationary. All of this math is done for you by the FDM. The second answer, if I understand the question, is "it doesn't matter". Orientations and positions have nothing to do with each other. The lat/lon/alt values tell you where the firewall point of the aircraft is, but they don't say anything about where the aircraft is pointing. The hdg/pitch/roll numbers tell you how the aircraft is oriented, but not where the firewall is. Andy -- Andrew J. Ross NextBus Information Systems Senior Software Engineer Emeryville, CA [EMAIL PROTECTED] http://www.nextbus.com "Men go crazy in conflagrations. They only get better one by one." - Sting (misquoted) _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel