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Old February 8th 17, 06:44 PM posted to rec.aviation.soaring
jfitch
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Default Reachable landing sites in iGlide

On Wednesday, February 8, 2017 at 8:38:56 AM UTC-8, JS wrote:
On Tuesday, February 7, 2017 at 10:36:24 PM UTC-8, jfitch wrote:

When connected to the Air Vario, the thermal assistant in iGlide gets much more interesting due to the use of instantaneous wind.


Jon, I'm interested in that point of interest!
Do the reachable landing points in iGlide keep changing with the fast wind?
Won't mention what I'm thinking of connecting the Air-Glide to, not part of this thread.
Jim


Yes, the landing points change based on wind. The wind is embedded in the LX1600 serial stream that iGlide and Air seem to use, once per second. The Air Vario calculates the true wind about 20 times a second. There are some averaging constants and it is not completely clear to me what applies to the landing site arrivals. It changes pretty quickly, but not instantly so I *think* it is using the time averaged wind (if I recall the default is 20 seconds). Wind can make quite a large difference in landing site reachability or arrival altitude as you know. In iGlide you can also fix the wind for calculation, if that is appropriate.

The thermal assistant shows an instantaneous wind vector in each lift dot, each second (not averaged). This adds quite a lot of information to the thermal assistant, as the wind is quite dynamic in and around thermals, generally pointing towards the center of the thermal or greatly deflected towards the center of the thermal.