On Thursday, October 9, 2014 9:36:20 AM UTC-7, jfitch wrote:
On Thursday, October 9, 2014 7:31:08 AM UTC-7, Richard wrote:

On Wednesday, October 8, 2014 7:47:11 PM UTC-7, wrote:



On Wednesday, October 8, 2014 9:24:51 PM UTC-4, wrote:







There has been soooooooo much time from the initial announcement of the S80 and the now just released manual that they may have changed the design perameters of the unit.































I want to hear from LX how the winds are computed.















Reading through the manual, there is no mention of wind at all. Also no mention of being able to connect a compass module, which is referenced on their S80 page in the second to last line of the paragraph directly below the picture of the unit. It states: "fast wind calculation with external compass"















http://www.lxnav.com/products/lxnav-varios/s80.html















The same web page mentions under "Hardware": integrated synthesized speech output. Yet in the manual, it states on page 45 under "stall speed", that the voice module is _not_ integrated in the S80. Confusing.















Interesting feature is ability to set the battery chemistry and battery warnings.







I heard from LXNAV







Compass can be connected via can bus. In the moment compass is not available.



Maybe some sounds are not implemented , but will be in future releases.







Concerning Winds: I have both the PowerFlarm-V7-Ultimate Le system and the Butterfly Vario in my glider. I do not see a significant difference in the wind calculation between the systems. Approx 400 hours of flying comparing the systems.







Richard



www.craggyaero.com



Richard, how do the winds compare in instantaneous changes? Also what to you have the wind filter set to?



I don't have a V7 (never seen one) but it appears to calculate winds by the traditional schemes: either thermal drift or GPS track velocity compared to heading and airspeed. On my Butterfly, in steady state conditions the inertial wind compares with the traditionally derived schemes as seen on PDA, Cambridge, etc. However the Butterfly reports momentary abrupt changes in wind in and around thermals, and sometimes during glides, that these traditional methods miss entirely. Based on other available data, I believe the Butterfly is correct.



If you fly with iGlide, Butterfly uses the rapid instantaneous wind changes in thermals for their thermalling assistant, which presents a wind direction arrow in each lift dot each second. At least in well organized thermals, the instantaneous wind reliably points towards the center of lift, and can be used to center.



At other times (notably on final glides over the Carson valley heading back to Truckee) there will be a sudden increase in wind that lasts for many minutes (or perhaps an altitude band, or geographic location) before reverting the the prevailing wind. For example it will go from 8 knots southwest to 28 knots south for 5 minutes, then back - as reported by the Butterfly. This can be confirmed by comparing GPS to TAS. After some time, the traditional methods will agree. When the strong wind is cross, the traditional method may never show it, while the Butterfly does.



My conclusion is that in steady state, and particularly for headwind/tailwind components, averaged over some time, the traditional and inertial methods agree well. But the traditional methods miss a lot of rapid changes and there are times when this is significant.



One problem with observing every change in wind is that if final glide calculations are based on them, you see it varying rapidly as wind gradients are encountered. As far as I know, the Butterfly itself has no way to set the averaging filters differently for final glide calcs, which would be desirable.



A curiosity (but proof of Butterfly's method) is that while the engine in my ASH26e is running, traditional wind calculation is off by a huge amount since the tail pneumatics are in the prop wash. However the Butterfly correctly calculates the wind during engine runs.

I usually fly with my wind filter in the Butterfly at 20 sec. I agree with you for the traditional and inertial for final glide. Also the V7 uses some inertial assist. I have it set to 4 of 4 . I also have the butterfly set to 50% for vertical airmass filter Inerital vs TE.
If you want to set the wind filter at l or 2 sec you can see rapid wind changes with the butterfly but I am more concerned with the final glide winds..

I don't see a way to change the butterfly filter just for final glide. That is a question for Marc at Butterfly.

Richard
www.craggyaero.com