On Sun, 16 Jun 2013 19:09:40 -0600, Jon wrote in message <005a01ce6af7$58b69470$0a23bd50$@net>:
> > ..my oversimplification: http://wiki.flightgear.org/YASim "guesses > > how it flies from how it looks", while > > http://wiki.flightgear.org/JSBSim "knows how it flies and tries to > > show us how that looks", e.g. "stalls are assymetrical in YASim but > > (still?) symmetrical in JSBSim." > > > > ..if I guess FG progress correctly, we need to model downwash > > correctly, and if you want assymetrical stalls in JSBSim, you need 2 > > halved JSBSim models per plane so each wing etc surface calculation > > is run independently. > > I have not tried modeling a piston aircraft in quite some time. [Hal > Engel's P-51D does stall in either direction, does it not?] ..I haven't tried the P-51Ds much, but yeah, my stalls went both ways on both FDMs AFAIR, but here I'm going on what I remember from when YASim was introduced here, and whatever I've picked up on how they differ, and on my WAG these things have changed since I last checked the P51Ds 3 or 4 years back. My big problem was always too low framerates on T/O. ;o) > In any case, it should be possible to model aerodynamic effects from > the propeller in the XML model file for any JSBSim aircraft (in the > <aerodynamics> section) - effects that would affect stalling, I > suspect. It's not that JSBSim doesn't support asymmetric stalls - > JSBSim doesn't *not* support it. ..my (flawed?) understanding of JSBSim is "both wing halves sees the same wind" because they are calculated together "as one wing", where YASim cuts up the wing and calculates the wing sections independently and adds them up together, AFAIRI from the discussion way back here. > But, I'm not sure anyone has crafted the aerodynamic/propulsion > interactions that would effect that. This isn't necessarily the fault > of users, either. We (JSBSim development community) would ideally > make available more examples and documentation. > > JB -- ..med vennlig hilsen = with Kind Regards from Arnt Karlsen ...with a number of polar bear hunters in his ancestry... Scenarios always come in sets of three: best case, worst case, and just in case. ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
