The problem is that you usually only have ONE MC value set, and getting all those values requires you to cycle through the possible values like Alex did. This is not practical. Much better would be something like Morgan suggested that shows you that in this case you would need thermals of at least 0.7 m/s if you want to improve your situation by circling.
And your comment on the Final Glide AutoMC leads me to believe that you didn't really understand how to use it. Let me paste (for the others) what I already tried to explain on IRC: (23:59:37) staylo: The Auto MC manipulation on final glide is a very early XCSoar feature and it's definitely worth reevaluating. (23.11.2011 00:05:12) _Turbo_: staylo: I'm open to proof that this feature is wrong but from the evidence I've found so far some people have thought about this and figured it to be a good way of getting to the goal as fast as possible (00:07:54) staylo: _Turbo_: But the mechanism is: Look at the polar, determine what speed causes a sink rate which will cause the aircraft glideslope to coincide with arrival altitude. *Then* find the MacCready value which would command this speed-to-fly. (00:09:05) staylo: The speed to fly is found in the first step, the second is entirely superfluous. (00:09:06) _Turbo_: isn't that just the same thing in reverse?! (00:09:39) _Turbo_: it still results in the same thing if I'm not mistaken (00:09:53) _Turbo_: and that MC value that gets calculated from the STF is needed (00:10:05) staylo: needed for..? (00:10:11) _Turbo_: otherwise you wouldn't know when to leave the thermal and that would defeat it's purpose (00:10:28) _Turbo_: you should leave as soon as the AutoMC reaches the current lift of the thermal (00:11:23) _Turbo_: because climbing higher would cause you to loose time climbing and climbing less would loose time because you would fly a lower speed on final glide (00:11:58) _Turbo_: all that assuming that you don't hit any other thermals anymore Turbo 2011/11/23 Andreas Pfaller <pfal...@gmail.com>: > On Tuesday, November 22, 2011, Alexander Swagemakers wrote: >> I just set up a scenario in condor with my streak running xcsoar connected >> to experiment with the glide bar behavior. The setup is as follows: >> >> LS8, final Glide St. Croix to Puimoisson due north 10.2km distance with >> 50km/h headwind, 1352m MSL. >> >> >> Switching MC values in XCSoar gives following results. >> >> >> MC 0 = +11m above final glide >> >> MC 0.1 = +8m >> >> MC 0.2 = +3m >> >> MC 0.3 – 0.6 = no glide bar >> >> MC 0.7 = -596m (glide bar reappears) >> >> MC 0.8 = -266m >> >> MC 0.9 = -212m >> >> MC 1 = -195m >> >> >> I’m sure these calculations are technically correct but from a practical >> point of view this is madness! > > Why? > 0.0 - 0.2 Reachable by direct glide (no thermalling -> no drift while > thermalling). > 0.3 - 0.6 You need to thermal to gain height but drift while thermalling > is too large due too slow height gain with big drift. > 0.7 - Thermalling needed, the stronger the lift the shorter the time > needed > to reach the required height -> reduced drift distance > > That is exactly the kind of helpful assistance a traditional device does not > give > you. If you expect thermals <= 0.6 don't even try, you will landout. Fly with > speeds given for 0.0 - 0.2. > > > Andreas > > ------------------------------------------------------------------------------ > 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
