From: Hal V. E. <hv...@gm...> - 2010-12-09 16:10:51
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On Thursday, December 09, 2010 12:30:39 am Erik Hofman wrote: > On Wed, 2010-12-08 at 17:13 -0800, Hal V. Engel wrote: > > I used 120Hz (this is the same as the freq. of the FDM) and it almost > > works. But the problem is that on each run there is enough variation in > > the behavior of the model that the control inputs eventually get out of > > sync with the state of the flight test and it ends up crashing. In fact > > it appears that things like what view is being used affect how the > > aircraft behaves. > > > > I am doing spins during the flight and the exit state of the spin > > (direction, roll angle, speed and so on) appears to vary in each run and > > that is where I run into the issue since the control inputs don't match > > the state of the aircraft at that point. > > Hm, you probably should make sure that you use the same weather settings > for every run. At the moment the GIT version of FlightGear always > enables METAR fetching for example. This occurred to me but I have not tested it yet. This is likely the single biggest factor in the variability. For example a difference in the wind direction or strength has a big influence on the take off roll and the control inputs needed. > > Thinking about it there can also be some influence from attached > joysticks and perhaps the mouse.. > > Erik Yes this is possible but I have not set the --control=... parm in the script I am using to launch the playback so the joystick should not be a factor although the mouse may be a factor. I am going to try using the autopilot between spins and during climb outs to get things in a know state (wings level and so on) as things progress through the flight. This should allow for the state of the flight and the control inputs to sync up enough to get a reliable playback. Hal |