On 5/2/2021 9:39 PM, 2G wrote:
On Sunday, May 2, 2021 at 3:59:20 PM UTC-7, waremark wrote:
On Sunday, 2 May 2021 at 06:58:35 UTC+1, Matthew Scutter wrote:
Would you expect it to function meaningfully differently in the flatlands? Circling wind should work just fine in a homogenous atmosphere, so functioning the same would be ideal.
Similarly I would be surprised if there was improvement in variometer function from an existing well-compensated setup. All I would wish for additionally from my existing variometer is that it would read accurately in the first second of the pullup into a thermal.
Some Butterfly users reported that as you circle in a thermal you can see the wind indicators pointing in from all directions to the centre of the thermal. As to the vario, as someone else has mentioned the key aspiration is for a system which differentiates vertical gusts from horizontal gusts better than a TE vario. Again, the Butterfly was supposed to achieve this.
The best wind indicator I have used in over 40 years of soaring is watching how my circles drift while thermaling - no special sensors, sensor fusion or Kalman filtering required. Second to that is comparing true airspeed to GPS ground speed. I would like to see LXNAV implement a Nav box that differences those two values, however (again, no additional sensors or filtering required).
I prefer an instrument that will give the vector wind without circling, because
circling is not always convenient (eg, mountain flying near/in the ridges) and
reduces my average cruise speed. Determining the instantaneous headwind with the
difference between airspeed and ground speed is useful, but it is not the vector
wind. My CN vario in the Phoenix can determine the vector wind with minor course
changes while cruising, a better solution, I think. The Butterfly/Display S can
determine it without circling or course changes, the best solution for me.
But, wind determination is not the only goal of these inertial methods, but also
improving the vario response in the presence of gusts. Circling drift and
headwind determinations can't do that. I'm hoping Hawk will equal or exceed the
Butterfly's abilities.
--
Eric Greenwell - USA
- "A Guide to Self-launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1