In my case the reason has normally been 1. "too clean" a glider (the polar may be overly optimistic with regular glider of type - I normally use clean value .97 or so) 2. Changing wind (depending altitude or time, both has happened e.g. when coming closer to a frontier the thermal estimation may be wrong) 3. and most often - wrong route ;) If the air is sinking it adds to polar sink and surely the estimation overshoots
hannu On 14.5.2011 21:13, Roman Stoklasa wrote: > Hi all, > > does XCSoar 6.1 calculate correctly how the wind affects overall glide > performance of the glider, when it calculates required altitude to finish the > task? > > Why'm asking.... because about 2 weeks ago, I have been flying my final glide > with the headwind and I noticed, that the Final Glide reserve altitude was > decreasing during the cruise. > So it seemed that XCSoar compute the required altitude for the "normal" > polar, but due to the headwind my L/D was smaller so I was loosing my > altitude faster than XCSoar estimated and because of that the altitude > reserve was decreasing. I have set MC value on approx. 2 - 2.5. > > Did anybody noticed similar behavior? > Any idea, what was wrong? > > Thanks, > > R. > > ------------------------------------------------------------------------------ > Achieve unprecedented app performance and reliability > What every C/C++ and Fortran developer should know. > Learn how Intel has extended the reach of its next-generation tools > to help boost performance applications - inlcuding clusters. > http://p.sf.net/sfu/intel-dev2devmay > _______________________________________________ > Xcsoar-user mailing list > Xcsoar-user@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/xcsoar-user ------------------------------------------------------------------------------ Achieve unprecedented app performance and reliability What every C/C++ and Fortran developer should know. Learn how Intel has extended the reach of its next-generation tools to help boost performance applications - inlcuding clusters. http://p.sf.net/sfu/intel-dev2devmay _______________________________________________ Xcsoar-user mailing list Xcsoar-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xcsoar-user
