Max, What you say is clear, but would seem to be applicable to manually set MC settings. Thanks for the explanation.
However, nobody has yet described what happens if MC is left on Auto. Presumably during thermal flight some sort of averaging algorithm is applied depending on each actual thermal climb, but: - is the input to this just the climb rate as measured during circling flight? - does straight line climbing, e.g. running a convergence line, affect the auto setting? - what happens to the Auto setting as the day dies, thermals stop, and the pilot does fewer and weaker thermal climbs, IOW does thermal climb frequency affect the Auto setting? - is the Auto setting adjusted in any way as you round the last turnpoint and head home and, if so, how? Martin On Tue, 2011-11-22 at 21:08 +0100, Max Kellermann wrote: > This is the "I repeat myself over and over" thread! > > On 2011/11/22 20:51, David Reitter <david.reit...@gmail.com> wrote: > > In my view, the problem at hand is that XCSoar seems to assume that > > height is always gained by way of thermaling. That is obviously not > > correct. > > No, you are wrong. XCSoar only assumes that height is gained by way > of thermaling if you tell XCSoar to do so. If you don't tell XCSoar > to do so, XCSoar will not assume it. > > If you set a positive MacCready value, you tell XCSoar that you want > to gain height by circling thermals. If you don't plan to do that, > don't set a positive MacCready value, because the whole point/basis of > the MacCready theory is the assumption of future lift. > > All other reasons to set a positive MacCready value are kludges that > don't fit into the theory, but XCSoar might need additional features > to account for some of that. For example, head wind is already being > considered, and you don't need to adjust the MacCready setting for > that. You may use the "bugs" setting to degrade your polar, but don't > tweak MacCready for that. > > > XCSoar 6.x does not make assumptions about finding a thermal or other lift > > source if MC>0, for purposes of reachability calculations, right? I would > > be very confused if it did. Please clarify. Recall that reaching some > > outlanding field is already "plan B", i.e., it's the plan in place for when > > the thermals die. > > If the outlanding field is reachable, no lift is assumed, because no > lift is needed. > > If the outlanding field is not reachable, and you have a positive > MacCready setting, then XCSoar will need to assume that you will be > thermaling to ever reach that field, and it will include the wind > drift while thermaling in its calculations. > > If you don't want XCSoar to assume you'll ever be thermalling, don't > set a positive MacCready value. (Have I repeated this statement often > enough in this email?) > > Max > > ------------------------------------------------------------------------------ > All the data continuously generated in your IT infrastructure > contains a definitive record of customers, application performance, > security threats, fraudulent activity, and more. Splunk takes this > data and makes sense of it. IT sense. And common sense. > http://p.sf.net/sfu/splunk-novd2d > _______________________________________________ > Xcsoar-user mailing list > Xcsoar-user@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/xcsoar-user ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ Xcsoar-user mailing list Xcsoar-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xcsoar-user
