On Thursday 24 May 2012 01:26:35 Burin Sungketkit wrote: > I've checked the Total Aero Moment from /fdm/jsbsim/moments/m-aero-lbsft > and compared with the summation of all Cm from aerodynamics section. > > Do these two properties have to be equal or not? (I think it should be > equal). > > This happended with FG V.2.0.0 and 2.4.0 but never test with FGv.2.6.0 and > with all aircraft. > > Please help me about this.
They are equal only if, and only if, the center of gravity (CG) is equal to the aerodynamic reference (aerorp) point. Otherwise, when AeroRP != CG you get sum(aero/moments) + sum(aero forces)*(AeroRP-CG). In other words, the aerodynamic forces set up moments as well. Those are visible in the main property "moments/m-aero-lbsft" but aren't created by the moment axises in the FDM file so they don't appear in your Cm properties. Ron ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
