Where is the LX S80?

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.

Excellent questions and observations.
I am focused on the S80 and Butterfly primarily because they have an artificial horizon but also would like a unit that can filter out horizontal gusts that cause me/us to think we have entered a strong thermal. It also would seem that the instantaneous wind readings would be very helpful when flying convergence lines.

On Friday, October 10, 2014 3:50:54 AM UTC+11, wrote:
Excellent questions and observations.

I am focused on the S80 and Butterfly primarily because they have an artificial horizon but also would like a unit that can filter out horizontal gusts that cause me/us to think we have entered a strong thermal. It also would seem that the instantaneous wind readings would be very helpful when flying convergence lines.

You have a built in filter that can eliminate false readings due to gusts. It's called your backside. If you can't feel the acceleration, it's not there.

Now that was a very sensitive, insightful, and constructive comment for this thread. Thank you.

On Monday, October 20, 2014 4:24:46 PM UTC-7, wrote:
On Friday, October 10, 2014 3:50:54 AM UTC+11, wrote:

Excellent questions and observations.



I am focused on the S80 and Butterfly primarily because they have an artificial horizon but also would like a unit that can filter out horizontal gusts that cause me/us to think we have entered a strong thermal. It also would seem that the instantaneous wind readings would be very helpful when flying convergence lines.



You have a built in filter that can eliminate false readings due to gusts.. It's called your backside. If you can't feel the acceleration, it's not there.

Acceleration due to a a vertical or horizontal gust are not discernible by the human backside. Both result in an increase in lift: the former due to an increase in the angle of attack and the latter due to an increase in air speed. Both can be used to gain energy, but you will find circling in the latter a pointless exercise. Which is why every variometer manufacturer is trying to differentiate them.

Thank you for such a clear explanation for why vario manufacturers are working so hard on these issues. It also makes me feel better about getting fooled by "my backside" and my vario when flying cross-country.

On Tuesday, October 21, 2014 11:03:48 AM UTC-4, jfitch wrote:
On Monday, October 20, 2014 4:24:46 PM UTC-7, wrote:

On Friday, October 10, 2014 3:50:54 AM UTC+11, wrote:



Excellent questions and observations.







I am focused on the S80 and Butterfly primarily because they have an artificial horizon but also would like a unit that can filter out horizontal gusts that cause me/us to think we have entered a strong thermal. It also would seem that the instantaneous wind readings would be very helpful when flying convergence lines.







You have a built in filter that can eliminate false readings due to gusts. It's called your backside. If you can't feel the acceleration, it's not there.



Acceleration due to a a vertical or horizontal gust are not discernible by the human backside. Both result in an increase in lift: the former due to an increase in the angle of attack and the latter due to an increase in air speed. Both can be used to gain energy, but you will find circling in the latter a pointless exercise. Which is why every variometer manufacturer is trying to differentiate them.

I do not agree. The scream on the vario not associated with the seat feel "true" lift is obvious when you practice enough. All these instruments are trying to do is make the vario agree with what we should feel in the seat.
This could help the less experienced or less active pilot but likely will have little benefit to the pilot that flies a lot.
UH

On Tuesday, October 21, 2014 12:59:31 PM UTC-7, wrote:
On Tuesday, October 21, 2014 11:03:48 AM UTC-4, jfitch wrote:

On Monday, October 20, 2014 4:24:46 PM UTC-7, wrote:



On Friday, October 10, 2014 3:50:54 AM UTC+11, wrote:







Excellent questions and observations.















I am focused on the S80 and Butterfly primarily because they have an artificial horizon but also would like a unit that can filter out horizontal gusts that cause me/us to think we have entered a strong thermal. It also would seem that the instantaneous wind readings would be very helpful when flying convergence lines.















You have a built in filter that can eliminate false readings due to gusts. It's called your backside. If you can't feel the acceleration, it's not there.







Acceleration due to a a vertical or horizontal gust are not discernible by the human backside. Both result in an increase in lift: the former due to an increase in the angle of attack and the latter due to an increase in air speed. Both can be used to gain energy, but you will find circling in the latter a pointless exercise. Which is why every variometer manufacturer is trying to differentiate them.



I do not agree. The scream on the vario not associated with the seat feel "true" lift is obvious when you practice enough. All these instruments are trying to do is make the vario agree with what we should feel in the seat.

This could help the less experienced or less active pilot but likely will have little benefit to the pilot that flies a lot.

UH

Do not agree with what?

The aerodynamics is accepted by pretty much everyone. The seat of the pants feel is simply vertical acceleration (and sometimes a little lateral mixed in). This could be displayed on a very inexpensive accelerometer. If what you say is true, then you don't need a variometer at all. I hope the vario manufacturers are trying to do more (and they are). Specifically, concisely present information allowing maximum extraction of energy from the surrounding air. There are many reasons why a barometric variometer does not (and cannot) duplicate the accelerations you feel.

On Tuesday, October 21, 2014 2:21:38 PM UTC-7, jfitch wrote:
On Tuesday, October 21, 2014 12:59:31 PM UTC-7, wrote:

On Tuesday, October 21, 2014 11:03:48 AM UTC-4, jfitch wrote:



On Monday, October 20, 2014 4:24:46 PM UTC-7, wrote:







On Friday, October 10, 2014 3:50:54 AM UTC+11, wrote:















Excellent questions and observations.































I am focused on the S80 and Butterfly primarily because they have an artificial horizon but also would like a unit that can filter out horizontal gusts that cause me/us to think we have entered a strong thermal. It also would seem that the instantaneous wind readings would be very helpful when flying convergence lines.































You have a built in filter that can eliminate false readings due to gusts. It's called your backside. If you can't feel the acceleration, it's not there.















Acceleration due to a a vertical or horizontal gust are not discernible by the human backside. Both result in an increase in lift: the former due to an increase in the angle of attack and the latter due to an increase in air speed. Both can be used to gain energy, but you will find circling in the latter a pointless exercise. Which is why every variometer manufacturer is trying to differentiate them.







I do not agree. The scream on the vario not associated with the seat feel "true" lift is obvious when you practice enough. All these instruments are trying to do is make the vario agree with what we should feel in the seat.

On Wednesday, October 22, 2014 2:03:48 AM UTC+11, jfitch wrote:
On Monday, October 20, 2014 4:24:46 PM UTC-7, wrote:
On Friday, October 10, 2014 3:50:54 AM UTC+11, wrote:

Excellent questions and observations.



I am focused on the S80 and Butterfly primarily because they have an artificial horizon but also would like a unit that can filter out horizontal gusts that cause me/us to think we have entered a strong thermal. It also would seem that the instantaneous wind readings would be very helpful when flying convergence lines.



You have a built in filter that can eliminate false readings due to gusts. It's called your backside. If you can't feel the acceleration, it's not there.

Acceleration due to a a vertical or horizontal gust are not discernible by the human backside. Both result in an increase in lift: the former due to an increase in the angle of attack and the latter due to an increase in air speed. Both can be used to gain energy, but you will find circling in the latter a pointless exercise. Which is why every variometer manufacturer is trying to differentiate them.

A horizontal gust does NOT produce acceleration. That's why you can't feel it. If you cannot sense vertical acceleration it's not there, despite what your instruments are telling you.
To put it another way: if your vario is telling you that you are accelerating upwards at 5 knots (500 fpm or over 8 feet per second) and you cannot feel it, then you can ignore it as a gust. Why look for a complex technological solution to something so simple?
A vertical gust is a different matter. I presume by vertical gust you are referring to a vertical movement of air. What distinguishes a vertical gust from lift?