John Wojnaroski said: > > ----- Original Message ----- > From: "Jim Wilson" <[EMAIL PROTECTED]> > To: "FlightGear developers discussions" <[EMAIL PROTECTED]> > Sent: Monday, August 02, 2004 2:58 PM > Subject: Re: [Flightgear-devel] Flight Instrument Accuracy > > > > John Wojnaroski said: > > > > > Jim Wilson writes: > > > > > > > > If it wasn't for the great work on JSBsim and YASim we'd have very few > > > > aircraft. But I think those config files, along with the "source > code" > > > that > > > > ends up interpreting and processing them, both make up the FDMs. > There is > > > > considerable skill and effort involved in producing accurate flight > models > > > for > > > > new aircraft isn't there? > > > > > > > Hmmm, speaking of accuracy. Do all the new aircraft use the output of > the > > > Instrumentation model to drive the flight instruments? If that is the > case, > > > then the 747, YF-23, T-38, 737, etc, etc are using data based on a light > > > aircraft pitot-static ssytem and vacuum driven gauges and the associated > > > lags and delays. For my 747 project I've decided to dig into JSBSim to > get > > > the "raw data" and pass that through an INS/ADC model to drive the glass > > > displays. > > > > > > Depending on your purpose and application it might be a don't care, but > it > > > would have an impact on things like autopilots and error > > > tracking/man-machine interface research. Just a thought.... > > > > The 747-400 3D models of displays and instruments do not use the cooked > > "instrumentation" outputs. Off the top of my head the backup AI might be > an > > exception...not sure. In any case I've assumed the modern airliner > displays > > to be quite accurate and responsive and just run directly off the FDM > output. > > > > Best, > > > > Jim > > > > > Have you looked at the .xml files in the base package? I'm not all that > conversant in xml or how the properties work, but it appears that some of > the pressure instrument readings are drawn from the instrumentation property > node and some for the /orientation node and in the case of the 737 some from > the /fdm/jsbsim nodes. > > Perhaps someone could prove me wrong, but I can't find another altimeter > model in the source except for the one in the /Instrumentation directory. > The steam.cxx has been removed ( was it 0.9.1 or 0.9.2 ) > > Some other excerpts from instruments-3D > > > <property>/instrumentation/airspeed-indicator/indicated-speed-kt</property> > > <property>/instrumentation/altimeter/indicated-altitude-ft</property> > > > <property>/instrumentation/vertical-speed-indicator/indicated-speed-fpm</pro > perty> > > > <property>/instrumentation/magnetic-compass/indicated-heading-deg</property> >
The 747 xml files myself and they are stored in the Aircraft/747/Models directory. It looks like that analog backup altimeter and backup airspeed indicator are using the cooked values. The glass displays and the attitude indicator do not. FWIW it is somewhat better to work with the standard FDM interface properties rather than the fdm/JSBSim properties. If there is something you need that isn't already published (in the standard: position/ orientation/ velocities/ engine/ gear/ surface-positions/ paths) then maybe it needs to be added somewhere. Best, Jim _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
