Re: [Flightgear-devel] FlightGear Wind and Turbulence
On Sunday 19 Jun 2005 15:22, Jon Berndt wrote: > What does FlightGear do in the way of wind and turbulence? I > assume that winds are set in FlightGear in NED coordinates and > that those change slowly? Turbulence is modeled in the FDMs, > but parameters are passed in? FlightGear does not model > turbulence itself, does it? > > I am debugging the gear jittering in JSBSim and I am seeing > windNED spike every so often and I have commented out > turbulence code in JSBSim, so I am wondering if these wind > spikes are coming from FlightGear. > > Jon It's possible that you're seeing the same problem I have here where the wind (and visibility) gets set incorrectly on an apparently random basis. I've reported it a few times now but no-one else seems to be experiencing, or perhaps noticing it. In one or two of the more recent a/c I've done I've included a simple 2d instrument to show the wind speed and direction and this makes it clearly apparent when the wind (and visibility) setting are incorrect. does anything happen if you open the weather settings dialogue and repeatedly apply the settings? (you don't need to change any of the settings for the conditions to change) LeeE ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
RE: [Flightgear-devel] FlightGear Wind and Turbulence
> I used this command line: > > fgfs [EMAIL PROTECTED] --aircraft=c172r --turbulence=0.0 > > This set up the winds as I wanted. However, even though "turbulence" was set > to zero, > there was still lots of noise present in the wind velocity coming from > FlightGear. The > wind seemed to vary +/- 5 to 10 ft/sec. Also, the variance rate of chance was > on the order > of tens of milliseconds. I was logging data at 20Hz, and at one time step the > wind > velocity would be at 10 ft/sec, the next it would be at 20, and the next it > would be back at 10. Obviously, that's physically impossible. > > Jon Never mind :-/ The spikes I was seeing were artificial, and due to the test setup I was using. Jon ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
RE: [Flightgear-devel] FlightGear Wind and Turbulence
> I am debugging the gear jittering in JSBSim and I am seeing > windNED spike every so often and I have commented out turbulence > code in JSBSim, so I am wondering if these wind spikes are > coming from FlightGear. OK, in working to fix the gear jitter I've discovered some things about the winds modeled in FlightGear. I used this command line: fgfs [EMAIL PROTECTED] --aircraft=c172r --turbulence=0.0 This set up the winds as I wanted. However, even though "turbulence" was set to zero, there was still lots of noise present in the wind velocity coming from FlightGear. The wind seemed to vary +/- 5 to 10 ft/sec. Also, the variance rate of chance was on the order of tens of milliseconds. I was logging data at 20Hz, and at one time step the wind velocity would be at 10 ft/sec, the next it would be at 20, and the next it would be back at 10. Obviously, that's physically impossible. Can someone shed some light on FlightGear's modeling of winds and turbulence? BTW, I'm using current code out of FlightGear CVS. Jon ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
RE: [Flightgear-devel] FlightGear Wind and Turbulence
> What does FlightGear do in the way of wind and turbulence? I assume that winds > are set in > FlightGear in NED coordinates and that those change slowly? Turbulence is > modeled in the > FDMs, but parameters are passed in? FlightGear does not model turbulence > itself, does it? What is WEATHER_CM? I am looking in JSBSim.cxx and wonder what the defined WEATHER_CM is set to by default. I'm determining which code is compiled in in the atmosphere code. Jon ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
