Hi Martin, The glide polar display on xcsoar, if you have an airspeed input into xcsoar, displays an estimate of the polar based on statistical data. If you have seen the results of this, you'll see the problem with trying to have an autopolar function: the sampling of data is extremely biased by the tendencies of pilots to do the right thing and fly slower in lift, faster in sink. Because this correlation is not able to be reliably predicted, it is very difficult for any algorithm to produce reliable polar estimates.
That of course assumes you are flying in convection. If you flew in dead air, then the situation would be improved. As Tobias mentioned, the use of more advanced varios making use of inertial and attitude estimates can possibly improve this situation, though we do not have any experimental results yet. On Fri, Nov 25, 2011 at 2:24 AM, martin.kopp...@gmx.de <martin.kopp...@gmx.de> wrote: > Am 24.11.2011 um 00:00 schrieb Tobias Bieniek <tobias.bien...@gmx.de>: > >> The problem with AutoPolar is that you don't have enough measurements >> about the environment. > > That may be an issue if you want a rather immediate analysis. In the long > term, comparing prediction and logged data might be enough to narrow in on a > corrected polar of a known glider/pilot combination. > If the solver output was saved with the logged flight data, even a web based > tool could do the statisics. Think of the Flarm range check tool. Upload your > polar and a collection of recent flight logs and as a result, download a > degradation file. It wouldn't need to be 100% accurate, it would only need to > compensate for say a basic trend or noise level. > >> Once those varios like John is building or the >> Butterfly vario become available this will work better since they have >> live 3D wind calculation 20 times a second and as such the effect of >> the environment on the plane can be filtered out in a more useful way. >> But most of us don't have such systems (yet) and so this will produce >> results which are likely to be incorrect. > > Well, I'm on the edge of my seat to see one of these in flight. Very > intersting development going on there. > >> What I just remembered is a feature called "Pirker Vario" which we >> have implemented to some degree under a different name that I can't >> remember right now. It is basically the derivative of your task >> arrival altitude or a task vario. It will show you the improvement of >> your situation as a value expressed in m/s or whatever you have set as >> lift unit... This tool might also be useful to determine if the >> current thermal is actually improving your situation or not. I think >> there was a (german) PDF floating around the internet explaining the >> theory behind this. > > I guessed someone might have proposed this before, but couldn't find any info > on the net. If you have implemented something like it, where does it show up? > I usually watch estimated arrival height next WP while circling in weak lift > to see if working the thermal pays off, or if applicable, the glide bar. It > does something similar, though kinda in a low resolution with quite some time > lag. It does not tell me what averager reading would give me a good reason to > stay in that thermal or rather leave it. I could imagine this might be > helpful and speed things up. But then, I am only some guy who flies for fun. > > And, please nobody get the idea I want to criticise. I respect the work done > here, and only want to throw in some ideas. > > Best, > Martin > ------------------------------------------------------------------------------ > 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
