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 ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] Flight Instrument Accuracy
- 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 Regards John W. ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] Flight Instrument Accuracy
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
Re: [Flightgear-devel] Flight Instrument Accuracy
On Monday 02 August 2004 21:22, John Wojnaroski wrote: 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 Regards John W. FWIW, I've not attempted any 'proper' panels yet and the instruments that I've included on the panels I've done so far are more for monitoring what the a/c is doing, rather than being designed for flying the a/c. As such, many of them do not use data from the 'instrument' sub-system but show absolute readings from the property tree. I'd like to do 'proper' panels and instruments but until I have a better understanding of how they work and how they're used, in real-life, I'm holding off trying any. LeeE ___ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
