On 25 Aug 2008, at 03:25, Curtis Olson wrote: > Hi James, > > I think this was all done intentionally because it's quite common to > want to start a flight simulator on a 5 or 7 or 10 mile approach so > you can practice ILS landing. > > The start-offset-m value I believe was added later to account for > the difference in aircraft size. A starting position that works > well to place the C172 at the end of the runway, might put the back > half of the 747 off the end of the runway.
Understood on both counts, but that means I think there is a bug in the glideslope code: > > On Sun, Aug 24, 2008 at 3:53 PM, James Turner wrote: > > Anyway, what makes me wonder if there's a bug here is the glideslope > logic. In the case where a glideslope angle is specified, and also a > preset altitude, we encounter the code at line 976 of fg_init.cxx. > Now, the crucial observation is that this code does multiply the final > distance by -1. As a result, the calculated offset-distance-nm would > place the start position well down the runway - possibly some way > beyond it, in fact. Hence my feeling that something isn't quite right - I understand why the 'polarity' of start-offset-m and offset-distance-nm are they way there are, but then it does seem as if the glideslope calculation will place the point in a silly place. From testing with the code, that does indeed seem to be the case. The fix would be as trivial as removing the '-1' term from that line, of course. James ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
