On Fri, 2010-02-19 at 08:37 -0700, Ron Jensen wrote: > On Fri, 2010-02-19 at 10:20 +0100, andrea...@gmx.net wrote: > > Hi everyone! > > > > I think I found a little bug in a couple of JSBSim-aircraft: > > The property > > /fdm/jsbsim/aero/coefficient/CDde (Drag_due_to_Elevator_Deflection) > > > > takes negative values when the elevator moves up, so the elevator face > > is accelerating the plane. > > The wrong code is found in the <model>.xml file: > > > > <product> > > <property>aero/qbar-psf</property> > > <property>metrics/Sw-sqft</property> > > <property>fcs/elevator-pos-norm</property> > > <value>0.059</value> > > </product> > > > > "fcs/elevator-pos-norm" should be turned to an absolute value by > > <abs> .. </abs> > > Yes, you are correct. >
One thing I forgot to note is, just a "quick" fix like this can break an aircraft if it was "tweaked" to fly correctly with this bug. After all, you're changing a moderate amount of thrust for an equivalent drag force. I tried a quick flight in the L-1049 after doing this change and it would barely take off... So each aircraft at a minimum needs a flight test and possibly some tuning for the fix. Ron ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
