JBlyth
Aquilotto
  
Australia
238 Posts |
Posted - 13/08/2024 : 12:20:35
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[EDIT] This problem only seems to occur when an AAT Task is set in LK8000 - see next post as well....
I have noticed a few times that the LK8000 Final Glide seems to be inaccurate where there is a CIRCULAR Finish Line. This is particularly telling when flying an AAT task, as the calculated finish time is also inaccurate.
This seems to be because LK is measuring to the centre of the circle, rather than the closest point to the outer edge. I believe XCSoar users have reported that they also suffer from the issue too.
In the image below, which I took while flying Condor in VR, you can see that the Distance to the Finish Point at the EDGE of the finishing circle in Condor and CoMoMap is 18.8km, while it is 21.8km in LK8000 to the CENTRE of the finish circle.
Likewise, the height above/below the 0 feet finish is -79 feet in Condor Vs an inaccurate -271 (plus the 200 ft safety margin) or -471 feet as shown. (Sorry - I was striving to get the perfect picture, rather that getting the "glider" perfectly on 0 feet final glide ;-) Also, ignore the +537 feet in CoMoMap as that is the Total Energy finish height calculation.
I have noticed this problem numerous times in years past. It must cause issues in real life flying as well, I would imagine...
Cheers John in Sunny Carnarvon, Western Australia
The "1" red numerals point to the Condor/CoMoMap data, and the "2" to the LK8000. NOTE:- their is no problem if the Finish Line is a line.
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Edited by - JBlyth on 16/08/2024 02:58:38 |
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