On Fri, 2002-04-26 at 09:43, Curtis L. Olson wrote: > Jon, it would also be nice if the user can directly or indirectly > control CG position as well. This can greatly affect the performance > of a plane and an instructor could throw in a tail heavy configuration > along with a few failed instruments, low visibility, and some healthy > turbulance to make things really interesting.
We would also need to specify the cg limits. > > Curt. > > > Jon S Berndt writes: > > On Fri, 26 Apr 2002 09:33:00 -0500 (CDT) > > "Curtis L. Olson" <[EMAIL PROTECTED]> wrote: > > > > >Ok, now isn't this very interesting. There is definitely some > > >confusion going on here. I agree with Jim, it's not the fault of the > > >viewer code. > > > > > >Ignoring the issue of the CG possibly moving during the simulation, > > >the assumption has always been that the FDM returns the position and > > >elevation of the CG of the vehicle. The viewer (for better or worse) > > >has always drawn the view point relative to the CG of the vehicle. > > > > > >Now we have the ability to offset the pilot view point relative to the > > >CG of the aircraft and have been doing that, but I'm not sure how that > > >is now being handled in light of the recent view manager overhaul. > > >I'm not sure where the code now resides, and I'm not sure where the > > >pilot view point offset is now configured. Jim can probably speak to > > >that. > > > > Well, I'm glad to hear (for once? :-) that this does not > > appear to be a bug with our (JSBSim) stuff. I remember > > paying lots of attention to this kind of thing when > > initially doing the landing gear model and I don't want to > > go through that again any time soon. Thanks to Curt for > > looking through this so thoroughly. > > > > I have a couple of comments: > > > > 1) We actually always return the altitude that the > > always-working radar altimeter reports. For JSBSim model > > aircraft, the radar altimeter is ALWAYS at the current CG. > > :-) So, we simply report the CG position. > > > > 2) ACHTUNG!! The CG location can change, and when the > > multi- capability within JSBSim is done we will be able to > > drop bombs and the CG will shift abruptly. There's also > > fuel burnoff that shifts the CG. We provide the pilot CG > > in JSBSim config files in structural coordinates. I can't > > remember what was decided this provided value would be > > used for, but IIRC JSBSim developers would like the > > provided value to at least be used as an initial location > > or as a strong recommendation. Remember that the pilot > > position is important to us because we add ballast for > > that location and because pilot accelerations are figured > > for that location. Anyhow, even if the CG shifts, the > > pilot viewpoint would NOT shift in the structural > > coordinate frame in which it is defined. However, it will > > shift its relative position to a "floating" CG location. > > > > Jon > > > > _______________________________________________ > > Flightgear-devel mailing list > > [EMAIL PROTECTED] > > http://mail.flightgear.org/mailman/listinfo/flightgear-devel > > -- > Curtis Olson IVLab / HumanFIRST Program FlightGear Project > Twin Cities [EMAIL PROTECTED] [EMAIL PROTECTED] > Minnesota http://www.menet.umn.edu/~curt http://www.flightgear.org > > _______________________________________________ > Flightgear-devel mailing list > [EMAIL PROTECTED] > http://mail.flightgear.org/mailman/listinfo/flightgear-devel -- Tony Peden [EMAIL PROTECTED] We all know Linux is great ... it does infinite loops in 5 seconds. -- attributed to Linus Torvalds _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
