AA Butterfly versus CNv LCD wind calculation

[[email protected]]

The Air Avionics Butterfly has developed an outstanding reputation as having a competitive advantage for its ability to "instantaneously" calculate wind direction.

Does the CNv (with latest 3.3.3899 or beta 3.4.4089) calculate wind as quickly as the Butterfly?

T8, what is the wind direction update rate of the CNv?

If anyone has experience using both varios at the same time, please share your opinions.

[waremark]

On Friday, 16 September 2016 21:23:48 UTC+1, wrote:
> The Air Avionics Butterfly has developed an outstanding reputation as having a competitive advantage for its ability to "instantaneously" calculate wind direction.
>
> Does the CNv (with latest 3.3.3899 or beta 3.4.4089) calculate wind as quickly as the Butterfly?
>
> T8, what is the wind direction update rate of the CNv?
>
> If anyone has experience using both varios at the same time, please share your opinions.

And how do the LX Nav varios compare? I have LX9000/V9. I am impressed by the way it shows me wind changing with height as I climb in wave etc.

[2G]

On Friday, September 16, 2016 at 4:36:01 PM UTC-7, waremark wrote:
> On Friday, 16 September 2016 21:23:48 UTC+1, wrote:
> > The Air Avionics Butterfly has developed an outstanding reputation as having a competitive advantage for its ability to "instantaneously" calculate wind direction.
> >
> > Does the CNv (with latest 3.3.3899 or beta 3.4.4089) calculate wind as quickly as the Butterfly?
> >
> > T8, what is the wind direction update rate of the CNv?
> >
> > If anyone has experience using both varios at the same time, please share your opinions.
>
> And how do the LX Nav varios compare? I have LX9000/V9. I am impressed by the way it shows me wind changing with height as I climb in wave etc.

Unfortunately that tells us nothing about how accurate the real time wind calculation is. I have flown with the Butterfly vario for 2 seasons now and can say that the wind accuracy is good, but sometimes goes bonkers (off by 10 kt or more). I monitor while circling and can compare it to my track over the ground. I have also set up the Butterfly to display both true airspeed and GPS ground speed. The difference is the head/tailwind component. I can compare that to the real time wind vector for a sensibility measure.

Tom

[[email protected]]

Respectfully, please keep comments focused to OP. The question does not address the LX products which are outstanding IMHO.


> And how do the LX Nav varios compare? I have LX9000/V9. I am impressed by the way it shows me wind changing with height as I climb in wave etc.

[[email protected]]

I own a CNv and installed the latest software updates. I also have experience with an Air Avionics Butterfly. But I did not use both varios at the same time.

CNv wind calculations became quicker during the various releases. But in my opinion, it is still slower and less reliable compared to a well compensated Butterfly vario. You will notice the difference especially when flying straight.

The Air Avionics system has a much higher resolution of small wind changes compared to the CNv and it does not need changes in direction for wind updates. But you need to spend some time in setting up the Butterfly sensor unit until it works well. If you did so, it can be very helpful to find lines of lift. I find CNv wind speed calculations sometimes to be inconclusive (too high), but perhaps this is related to my setup.

[[email protected]]

On Saturday, September 17, 2016 at 5:12:54 PM UTC-4, wrote:
> I own a CNv and installed the latest software updates. I also have experience with an Air Avionics Butterfly. But I did not use both varios at the same time.
>
> CNv wind calculations became quicker during the various releases. But in my opinion, it is still slower and less reliable compared to a well compensated Butterfly vario. You will notice the difference especially when flying straight.
>
> The Air Avionics system has a much higher resolution of small wind changes compared to the CNv and it does not need changes in direction for wind updates. But you need to spend some time in setting up the Butterfly sensor unit until it works well. If you did so, it can be very helpful to find lines of lift. I find CNv wind speed calculations sometimes to be inconclusive (too high), but perhaps this is related to my setup.

Great opinions...thanks for contributing. Keep them coming.

[JS]

On Saturday, September 17, 2016 at 4:38:17 PM UTC-7, wrote:
> On Saturday, September 17, 2016 at 5:12:54 PM UTC-4, wrote:
> > I own a CNv and installed the latest software updates. I also have experience with an Air Avionics Butterfly. But I did not use both varios at the same time.
> >
> > CNv wind calculations became quicker during the various releases. But in my opinion, it is still slower and less reliable compared to a well compensated Butterfly vario. You will notice the difference especially when flying straight.
> >
> > The Air Avionics system has a much higher resolution of small wind changes compared to the CNv and it does not need changes in direction for wind updates. But you need to spend some time in setting up the Butterfly sensor unit until it works well. If you did so, it can be very helpful to find lines of lift. I find CNv wind speed calculations sometimes to be inconclusive (too high), but perhaps this is related to my setup.
>
> Great opinions...thanks for contributing. Keep them coming.

I've had both Air and CNv for a year or so now.
The wind display from the Air is amazingly fast. Yes, it changes a lot but so do conditions. The most incredible display of wind is while flying lines of convergence.
While the CNv wind display refreshes much faster in the latest version, the wind itself does not update. Attributed to the difference between using the inertial sensors or not.
But the CNv does an excellent job in choppy thermals.
Jim

[Tango Eight]

On Friday, September 16, 2016 at 4:23:48 PM UTC-4, wrote:

> Does the CNv (with latest 3.3.3899 or beta 3.4.4089) calculate wind as quickly as the Butterfly?

No.

> T8, what is the wind direction update rate of the CNv?

I don't have a quantitative answer here. Mostly it depends on your flight path. CNv depends on some GPS track variation for vector wind calculation, but it doesn't take a great deal (20 degrees total track seems to do it in most cases). Given sufficient GPS track variation, the fast wind seems to update in just a few seconds (< 10). The auto wind is slower, gives a more stable number. It seems to take a few tens of seconds to update. Either mode is noticeably faster than previous generation flight computers (302, SN-10B). I haven't flown the Butterfly vario. The component head/tail wind is updated very fast (less than a second).

The only difference between "auto" and "fast" winds in CNvXC is the time constant. I see no downside to the fast wind, so I've been lobbying to make this the default. The fast wind is excellent for close in mountain flying.

best,
Evan / T8

[jfitch]

On Friday, September 16, 2016 at 1:23:48 PM UTC-7, wrote:
> The Air Avionics Butterfly has developed an outstanding reputation as having a competitive advantage for its ability to "instantaneously" calculate wind direction.
>
> Does the CNv (with latest 3.3.3899 or beta 3.4.4089) calculate wind as quickly as the Butterfly?
>
> T8, what is the wind direction update rate of the CNv?
>
> If anyone has experience using both varios at the same time, please share your opinions.

The Air Vario updates the wind once a second and calculates it much more often than that.

When I first began using it, I was skeptical, but have come to pretty much believe what it says. Every time I thought it had a surprising value, in any situation I could confirm, it was correct. I have discovered convergence lines, shear lines, and wave using it. I have also discovered some local weather patterns which can be exploited, no one else seems to know they are there nor did I, until the Air Vario.

[Sean[_2_]]

I thought accurate straight line glide computer wind accuracy required a fixed compass (aka LXNAv) for the best not thermaling wind detection sensitivity. My S10 is going to have a compass module shortly. But I really can't imagine a need that that much wind accuracy. The wind where you are now isn't the problem. It's accurate anticipation of what the wind is 1, 5 10 and 20 miles ahead, just like sailing, but much less critical.

Am I right or wrong on the compass module?

I believe the butterfly an fixed compass built in, and this is the reason that it is more energetic on updates? Correct?

[[email protected]]

On Sunday, September 18, 2016 at 5:24:31 PM UTC-4, Tango Eight wrote:
> On Friday, September 16, 2016 at 4:23:48 PM UTC-4, wrote:
>
> > Does the CNv (with latest 3.3.3899 or beta 3.4.4089) calculate wind as quickly as the Butterfly?
>
> No.
>
> > T8, what is the wind direction update rate of the CNv?
>
> I don't have a quantitative answer here. Mostly it depends on your flight path. CNv depends on some GPS track variation for vector wind calculation, but it doesn't take a great deal (20 degrees total track seems to do it in most cases). Given sufficient GPS track variation, the fast wind seems to update in just a few seconds (< 10). The auto wind is slower, gives a more stable number. It seems to take a few tens of seconds to update. Either mode is noticeably faster than previous generation flight computers (302, SN-10B). I haven't flown the Butterfly vario. The component head/tail wind is updated very fast (less than a second).
>
> The only difference between "auto" and "fast" winds in CNvXC is the time constant. I see no downside to the fast wind, so I've been lobbying to make this the default. The fast wind is excellent for close in mountain flying.
>
> best,
> Evan / T8

Thanks T8.

[[email protected]]

On Friday, September 16, 2016 at 4:23:48 PM UTC-4, wrote:
> If anyone has experience using both varios at the same time, please share your opinions.

When you have 2 or more systems how can you possibly know which wind reading is more accurate?
Without flying in a giant laboratory with controlled winds how do you know what the truth is to compare each system to?
I would imagine each system needs to average the data over some time period, so unless you can set them to be the same how can you tell?
If you make note of the in flight wind indications then reviewed that part of the flight in SeeYou would that be useful?

Chris

[Tim Taylor]

Actually in some conditions it is very easy. Stop and circle. I find in mountains and along shear lines that the wind can change 30 to 180 degrees in a very short distance. Many traditional varios and computers will take 10 to 15 minutes to adjust.

[Per Carlin]

On Monday, September 19, 2016 at 2:42:36 AM UTC+2, Sean wrote:
> I thought accurate straight line glide computer wind accuracy required a fixed compass (aka LXNAv) for the best not thermaling wind detection sensitivity. My S10 is going to have a compass module shortly. But I really can't imagine a need that that much wind accuracy. The wind where you are now isn't the problem. It's accurate anticipation of what the wind is 1, 5 10 and 20 miles ahead, just like sailing, but much less critical.
>
> Am I right or wrong on the compass module?
>
> I believe the butterfly an fixed compass built in, and this is the reason that it is more energetic on updates? Correct?

There is no need for a compass module with S8x/S10x, the wind calculating system is doing a fine job in straight flight.
I have flown about 150h with the S80 this year, and I’m still surprised every time I take off that the wind calculation is accurate already in the tow. I measure this by comparing the wind vector before and after the first thermal after release and they are more or less the same in most situations.

[krasw]

On Monday, 19 September 2016 03:42:36 UTC+3, Sean wrote:
> I thought accurate straight line glide computer wind accuracy required a fixed compass (aka LXNAv) for the best not thermaling wind detection sensitivity. My S10 is going to have a compass module shortly. But I really can't imagine a need that that much wind accuracy. The wind where you are now isn't the problem. It's accurate anticipation of what the wind is 1, 5 10 and 20 miles ahead, just like sailing, but much less critical.
>
> Am I right or wrong on the compass module?
>
> I believe the butterfly an fixed compass built in, and this is the reason that it is more energetic on updates? Correct?

There are ways to calculate wind vector on straight flight without compass module, Oudie claims to do it by comparing track/gs to different straight paths (did not get it to work, though), so it is possible at least theoretically.

But bottom line is: you either have full inertial platform with 3D acceleration, rate gyros and compass data, or you don't. Former gives you instant airmass data in all directions instantly, if implemented correctly. That's big IF.

It is not enough to throw in electric compass if the system is not up to it.. Many variometer systems have compass option that manufacturers do not use for any meaningful data. Representative of one company told me of pilot who was very happy after installing optional compass module. He didn't have the heart to tell pilot that variometer firmware version couldn't use compass data at all. I always take pilot reports with a grain of salt.

And no, we do not *need* anything, you can fly perfectly well with seat-of-pants feeling. It just nice to have all that data.

[Dave Nadler]

On Sunday, September 18, 2016 at 5:24:31 PM UTC-4, Tango Eight wrote:
> ...CNv depends on some GPS track variation for vector wind calculation

You're saying that, unlike for example Butterfly, CNv does not use compass?
And therefore cannot do instantaneous winds?

Sounds like the same algorithm SN10 introduced two decades ago (GPS track and airspeed)?

[Dan Marotta]

Whichever one you like better "must" be the most accurate.

On 9/18/2016 9:39 PM, wrote:
> On Friday, September 16, 2016 at 4:23:48 PM UTC-4, wrote:
>> If anyone has experience using both varios at the same time, please share your opinions.
> When you have 2 or more systems how can you possibly know which wind reading is more accurate?
> Without flying in a giant laboratory with controlled winds how do you know what the truth is to compare each system to?
> I would imagine each system needs to average the data over some time period, so unless you can set them to be the same how can you tell?
> If you make note of the in flight wind indications then reviewed that part of the flight in SeeYou would that be useful?
>
> Chris

--
Dan, 5J

[Dan Marotta]

Do you really fly a perfect circle of constant radius? I certainly
don't. I think without that, the wind calculation is really a best
guess based on the assumption that you're flying a circle. One could
argue that an accurate wind calculation is necessary to fly the correct
drift angle to your target, but this is soaring. Who flies in a
straight line?

On 9/18/2016 10:05 PM, Tim Taylor wrote:
> Actually in some conditions it is very easy. Stop and circle. I find in mountains and along shear lines that the wind can change 30 to 180 degrees in a very short distance. Many traditional varios and computers will take 10 to 15 minutes to adjust.

--
Dan, 5J

[jfitch]

On Sunday, September 18, 2016 at 5:42:36 PM UTC-7, Sean wrote:
> I thought accurate straight line glide computer wind accuracy required a fixed compass (aka LXNAv) for the best not thermaling wind detection sensitivity. My S10 is going to have a compass module shortly. But I really can't imagine a need that that much wind accuracy. The wind where you are now isn't the problem. It's accurate anticipation of what the wind is 1, 5 10 and 20 miles ahead, just like sailing, but much less critical.
>
> Am I right or wrong on the compass module?
>
> I believe the butterfly an fixed compass built in, and this is the reason that it is more energetic on updates? Correct?

The Butterfly (Air) vario wind is inertially derived and calculated many times a second. As far as I know they are the only ones really doing this. I'm pretty sure they use air speed, GPS speed, etc for long term calibration, but the instantaneous wind is derived from the MEMS sensors. For example I will get an accurate instantaneous wind in my motorglider with the engine running. The tail pitot is in the prop wash and indicates about 45 knots over the actual speed. The Oudie or XCSoar will say I have a 45 knot headwind whenever it is running. The Air vario gives accurate wind, even with it running.

It is pretty difficult to get an independent verification of the wind vector. Headwind and tailwind component not that hard in stable conditions. Circling, unless very close to the ground, will only give you a vague notion. In the western mountains at least, the wind is quite dynamic in and around thermals, a fact that iGlide uses as a thermal centering device.

The instantaneous wind IS of immediate interest at least some times. I have found many days (in western mountains again) when there is a rather abrupt shear at say 14,500 ft. The cloud bases are 15,500. But you are heading upwind. When you hit the shear you leave the thermal. Going downwind, obviously carry it right to the cloud. This information is verifiable by checking TAS agains GPS speed. But most soaring instruments determine this too late to be of much use. There are other times when wave was dipping into the boundary layer again producing a sudden change of instantaneous wind. When I saw this I knew to look around for wave. I have discovered there is often a strong south wind blowing up the Minden valley late in the afternoon above about 12,000 ft. Never saw that before on other instruments, I'm not in it long enough for their filters to figure it out. Yet it can be exploited by flying down the middle of the valley rather than cutting straight across which seems otherwise more logical. Again these readings can be verified by observing TAS and GPS speeds.

[Dave Nadler]

On Monday, September 19, 2016 at 10:57:42 AM UTC-4, Dan Marotta wrote:
> I think without that, the wind calculation is really a best
> guess based on the assumption that you're flying a circle.

That is incorrect for any decent wind calculation algorithm;
certainly precise circles are not required. With SN10 you will
often have estimated wind before you are off of tow...

[George Haeh]

TAS and GPS are sufficient to determine
headwind / tailwind component flying in a
straight line.

To get crosswind component, you need a
compass to supply heading, then apply
that to the GPS track.

[Dave Nadler]

On Monday, September 19, 2016 at 12:45:13 PM UTC-4, George Haeh wrote:
> To get crosswind component, you need a
> compass to supply heading, then apply
> that to the GPS track.

That is incorrect.
Multiple observations on different headings allow wind calculation.

[Craig Funston]

On Monday, September 19, 2016 at 10:15:18 AM UTC-7, Dave Nadler wrote:
> On Monday, September 19, 2016 at 12:45:13 PM UTC-4, George Haeh wrote:
> > To get crosswind component, you need a
> > compass to supply heading, then apply
> > that to the GPS track.
>
> That is incorrect.
> Multiple observations on different headings allow wind calculation.

George, not sure how up you are on Dave Nadler's background. He developed the software for the SN-10 which for many years was the gold standard for providing in-flight wind values. I was thrilled & impressed when I heard him describe his very elegant solution for computing winds with a limited information set.

Cheers,
Craig

[Jonathan St. Cloud]

Reminds me of my Father, 'it isn't what it is, it is what I call it, that matters". Found out this meant a pipe can be a hammer :(

So the "best Vario" is the one you think is the best.


On Monday, September 19, 2016 at 7:50:48 AM UTC-7, Dan Marotta wrote:
> Whichever one you like better "must" be the most accurate.
>

[George Haeh]

Dave Nadler is quite correct in his
assertion that "Multiple observations on
different headings allow wind calculation",
but that methodology necessarily requires
more time than AA's wind updates at 20
Hz, for which you need a heading source
when flying a straight line.

At 17:34 19 September 2016, Craig
Funston wrote:
>On Monday, September 19, 2016 at
10:15:18 AM UTC-7, Dave Nadler wrote:
>> On Monday, September 19, 2016 at
12:45:13 PM UTC-4, George Haeh wrote:
>> > To get crosswind component, you
need a=20
>> > compass to supply heading, then
apply=20.
>> > that to the GPS track.
>>=20
>> That is incorrect.
>> Multiple observations on different
headings allow wind calculation.
>
>George, not sure how up you are on Dave
Nadler's background. He developed
>t=
>he software for the SN-10 which for
many years was the gold standard for
>pr=
>oviding in-flight wind values. I was
thrilled & impressed when I heard
>him=
> describe his very elegant solution for
computing winds with a limited
>info=
>rmation set.
>
>Cheers,
>Craig
>

[Dave Nadler]

On Monday, September 19, 2016 at 4:30:20 PM UTC-4, George Haeh wrote:
> Dave Nadler is quite correct in his
> assertion that "Multiple observations on
> different headings allow wind calculation",
> but that methodology necessarily requires
> more time than AA's wind updates at 20
> Hz, for which you need a heading source
> when flying a straight line.

Of course. But Evan has said get wind the CNv requires
flying on different headings and takes some time,
which means it is not incorporating a heading source.

[JS]

Without a doubt, the SN10 when introduced was the best at wind. Believe Dave would like to produce something more modern, but Ilec is no longer interested in building varios.

Probably paid too much attention to the panel today, watching winds.
After a change in wind eventually the two varios agree, but the change is displayed immediately on the Air-Glide. Sometimes it was several minutes before the CN caught up.

I have installed and configured but no flight time with the LX90x0/V8 system a few in this thread have asked about.

Looking at flight logs in SeeYou PC isn't the determining factor of which wind is accurate. When SeeYou PC shows 7Kts and a thermal's 360 degree turns don't overlap at all, it's time to say "********". At that point Air indicated 23Kts, way more believable.
Jim

[[email protected]]

Memory is cheap, advanced instruments that generate IGC files should log all air data for later analysis. Then programs such as SeeYou could use this to not only preset flight traces but a picture of the airmass the glider(s) flew through.

We often experience some phenomena that these logs might help explain.

On Monday, September 19, 2016 at 6:57:20 PM UTC-7, JS wrote:
> Looking at flight logs in SeeYou PC isn't the determining factor of which wind is accurate. When
> SeeYou PC shows 7Kts and a thermal's 360 degree turns don't overlap at all, it's time to say
> "********". At that point Air indicated 23Kts, way more believable.

[[email protected]]

If I have understood the workings of AA Vario correctly, the wind is simply the difference between the GPS observations (fixed axis system compared to earth) and the inertial axis system (drifts with the wind).

[Per Carlin]

A thought regarding usage of IAS, TAS and GS for wind calculations: I have been a long term abuser of this, when flying with the Zander GP940 who only calculate the wind during circling. The wind component calculation is of great information on final glide to detect any changes of wind when getting closer to the ground. But I just got a second thought about this.

When reading this tread and putting 1+1 together do I realize that using the difference between TAS and GS is not an useful approach to calculate the wind. Read any of the Johnsson reports and figure out why he is so keen on calibrating the IAS readings!
It is not uncommon that the IAS differs from TAS(at ground level) with more than 5%, it is individual both between types of gliders and most likely also within gliders of the same type depending on which static probe you are using.
This error in reading the IAS in the glide computer is not calibrated, therefore can it not use the difference TAS / GS to calculate the wind. The error would be of dignity 5-15 km/h.

[Dave Nadler]

On Tuesday, September 20, 2016 at 5:52:15 AM UTC-4, Per Carlin wrote:
> This error in reading the IAS in the glide computer is not calibrated...
Plenty of instruments provide calibration (ie, SN10).
So, CAS is available.

> therefore can it not use the difference TAS / GS to calculate the wind.

Just plain Wrong. In addition to input IAS-CAS calibration,
wind algorithm can (should be) be designed to self-calibrate and
be relatively intolerant of airspeed errors.

We did all this 2 decades ago, and now you're saying it is not possible???

Really now.

[krasw]

On Tuesday, 20 September 2016 12:52:15 UTC+3, Per Carlin wrote:
> A thought regarding usage of IAS, TAS and GS for wind calculations: I have been a long term abuser of this, when flying with the Zander GP940 who only calculate the wind during circling. The wind component calculation is of great information on final glide to detect any changes of wind when getting closer to the ground. But I just got a second thought about this.
>
> When reading this tread and putting 1+1 together do I realize that using the difference between TAS and GS is not an useful approach to calculate the wind. Read any of the Johnsson reports and figure out why he is so keen on calibrating the IAS readings!
> It is not uncommon that the IAS differs from TAS(at ground level) with more than 5%, it is individual both between types of gliders and most likely also within gliders of the same type depending on which static probe you are using.
> This error in reading the IAS in the glide computer is not calibrated, therefore can it not use the difference TAS / GS to calculate the wind. The error would be of dignity 5-15 km/h.

You are correct but all of this can be taken into consideration. TAS can be calculated with the help of pressure and temperature, computers (Zander incl.) can be calibrated for pitot-static errors. At least GlideS does this, I would think that it is same with other systems.

[Per Carlin]

>
> You are correct but all of this can be taken into consideration. TAS can be calculated with the help of pressure and temperature, computers (Zander incl.) can be calibrated for pitot-static errors. At least GlideS does this, I would think that it is same with other systems.

Yes I did the Zander TAS calibration, but how good was it? The IAS has the same error in reading as it uses the same static port.

[Tango Eight]

To clarify/confirm a few things about CNv...

CNv has hardware on board for inertial sensing and magnetic compass. These are not used at the present time. The goal was to build the best possible pneumatic + GPS vario first.

Wind is determined by an algorithm that compares computed TAS to GPS ground track many times per second. So a determined effort to fly a constant ground track can inhibit wind updates. In real life, on all but the straightest ridges, it updates automatically, also shows the time elapsed since last update. As well, one can force the wind to reset at any time.

If you don't get vector wind on tow with CNv, then you need to check your installation.

Some features, including the thermal assistant and quick wind are available only with the XC license. The thermal assistant graphics just don't fit on the LCD included with the mechanical pointer display, which is why that feature is NAV display only.

Best,
Evan Ludeman for CNi

[krasw]

tiistai 20. syyskuuta 2016 15.40.52 UTC+3 Per Carlin kirjoitti:
> >
> > You are correct but all of this can be taken into consideration. TAS can be calculated with the help of pressure and temperature, computers (Zander incl.) can be calibrated for pitot-static errors. At least GlideS does this, I would think that it is same with other systems.
>
> Yes I did the Zander TAS calibration, but how good was it? The IAS has the same error in reading as it uses the same static port.

I guess IAS-CAS difference is pretty linear in most glider pitot-static systems, at least with normal flying speeds. I cannot remember Zander calibration procedure anymore, but Air Glide S let you correct IAS for several speeds and probably does linear interpolation between. Maybe some computers let you do only one point of correction? TAS is result of CAS + temp + pressure, that cannot be calibrated.

[K m]

On Monday, September 19, 2016 at 11:15:18 AM UTC-6, Dave Nadler wrote:

That is incorrect.
Multiple observations on different headings allow wind calculation.

Dave,
Can you explain a little more how this works?

[krasw]

On Wednesday, 21 September 2016 19:02:11 UTC+3, K m wrote:
> On Monday, September 19, 2016 at 11:15:18 AM UTC-6, Dave Nadler wrote:
>
> That is incorrect.
> Multiple observations on different headings allow wind calculation.
>
> Dave,
> Can you explain a little more how this works?

You get windspeed component in flight track direction comparing TAS and GS. Doing this to different bearings gives you several wind component vectors, after that it is basic vector math. Optimal vectors would be to widely different bearings, and flying only straight line gives you nothing.

[K m]

On Wednesday, September 21, 2016 at 10:24:25 AM UTC-6,

> You get windspeed component in flight track direction comparing TAS and GS. Doing this to different bearings gives you several wind component vectors, after that it is basic vector math. Optimal vectors would be to widely different bearings, and flying only straight line gives you nothing.

Thanks, This is as I understand. I was confused when Dave posted that you can not use track and heading. Seems that these (Along with TAS and GS) would make instantaneous cross wind calculations possible.

[krasw]

keskiviikko 21. syyskuuta 2016 19.48.27 UTC+3 K m kirjoitti:
> On Wednesday, September 21, 2016 at 10:24:25 AM UTC-6,
>
> > You get windspeed component in flight track direction comparing TAS and GS. Doing this to different bearings gives you several wind component vectors, after that it is basic vector math. Optimal vectors would be to widely different bearings, and flying only straight line gives you nothing.
>
> Thanks, This is as I understand. I was confused when Dave posted that you can not use track and heading. Seems that these (Along with TAS and GS) would make instantaneous cross wind calculations possible.

Yes, with compass you get the bearing that is not available from any other source. Using bearing, track vector, TAS & GS gives you instant wind vector in straight flight.

[[email protected]]

I think you mean Heading- a compass shows your heading.
On Wednesday, September 21, 2016 at 2:09:50 PM UTC-4, krasw wrote:
> keskiviikko 21. syyskuuta 2016 19.48.27 UTC+3 K m kirjoitti:
> > On Wednesday, September 21, 2016 at 10:24:25 AM UTC-6,
> >
> > > You get windspeed component in flight track direction comparing TAS and GS. Doing this to different bearings gives you several wind component vectors, after that it is basic vector math. Optimal vectors would be to widely different bearings, and flying only straight line gives you nothing.
> >
> > Thanks, This is as I understand. I was confused when Dave posted that you can not use track and heading. Seems that these (Along with TAS and GS) would make instantaneous cross wind calculations possible.
>
> Yes, with compass you get the bearing that is not available from any other source. Using bearing, track vector, TAS & GS gives you instant wind vector in straight flight.

[Sean[_2_]]

Thanks for confirming my question that a fixed magnetic compass provides the fastest and best wind speed/direction calculation. It is also impressive how much others have done (even 20 years ago) to build algorithms which calculate great wind info without the fixed compass.

Racing sailboat instrumentation today (and for the past 20 years or so) is also extremely advanced at calculating "true wind speed" and "true wind direction." Imagine how important it is for a sailing team to understand what the "TRUE" wind direction and speed actually is! The funny thing is that on a moving sailboat (especially a fast moving sailboat) "true" wind direction and speed is actually very difficult to calculate accurately. Modern boats are accelerating and decelerating rapidly and make almost constant course adjustments. Modern sailboats are very high performance, especially downwind, especially multihulls or foiling boats. This performance (huge advanced sailplans, lightweight and powerful and efficient hull shapes) create racing sailboats which develop significant "apparent wind." Apparent wind essentially "bends" the true wind forward as the boat builds speed as much as 120 degrees from the "true" direction as the boats forward speed creates considerable additional wind energy. This energy fluctuates greatly as the boat changes speed and direction to maximize its speed as the true wind changes. Accurate true wind speed and direction data is extremely important for calculating what polar speed is optimum and (equally important) for what tack is favored towards the next mark (SMG, speed made good and SMGT, speed made good (optimum) other tack). The sailors are constantly referencing key instruments for optimum heading (apparent wind angle) and boatspeed in order to stay on the optimum polar heading and speed. This is exactly the same as when a glider references "speed to fly" and changes pitch (1 dimension vs 2 on a sailboat) to stay at the optimum polar speed for the current lift shown on the speed to fly vario. Sailing teams spend many, many thousands of dollars buying and countless hours optimizing these instruments (just as glider pilots do) but sailors actually have a much more critical tactical need for the instantaneous and accuarate true wind data.

For whatever it is worth.

Sean

[[email protected]]

On Thursday, September 22, 2016 at 10:25:34 AM UTC-4, Sean wrote:
> Thanks for confirming my question that a fixed magnetic compass provides the fastest and best wind speed/direction calculation. It is also impressive how much others have done (even 20 years ago) to build algorithms which calculate great wind info without the fixed compass.
>
> Racing sailboat instrumentation today (and for the past 20 years or so) is also extremely advanced at calculating "true wind speed" and "true wind direction." Imagine how important it is for a sailing team to understand what the "TRUE" wind direction and speed actually is! The funny thing is that on a moving sailboat (especially a fast moving sailboat) "true" wind direction and speed is actually very difficult to calculate accurately. Modern boats are accelerating and decelerating rapidly and make almost constant course adjustments. Modern sailboats are very high performance, especially downwind, especially multihulls or foiling boats. This performance (huge advanced sailplans, lightweight and powerful and efficient hull shapes) create racing sailboats which develop significant "apparent wind." Apparent wind essentially "bends" the true wind forward as the boat builds speed as much as 120 degrees from the "true" direction as the boats forward speed creates considerable additional wind energy. This energy fluctuates greatly as the boat changes speed and direction to maximize its speed as the true wind changes. Accurate true wind speed and direction data is extremely important for calculating what polar speed is optimum and (equally important) for what tack is favored towards the next mark (SMG, speed made good and SMGT, speed made good (optimum) other tack). The sailors are constantly referencing key instruments for optimum heading (apparent wind angle) and boatspeed in order to stay on the optimum polar heading and speed. This is exactly the same as when a glider references "speed to fly" and changes pitch (1 dimension vs 2 on a sailboat) to stay at the optimum polar speed for the current lift shown on the speed to fly vario. Sailing teams spend many, many thousands of dollars buying and countless hours optimizing these instruments (just as glider pilots do) but sailors actually have a much more critical tactical need for the instantaneous and accuarate true wind data.
>
> For whatever it is worth.
>
> Sean

Makes huge sense in sailing where every shift matters.
I'm still trying to understand why fast response wing information is as important as this thread seems to imply.
FWIW
UH

[[email protected]]

I suspect the Butterfly has a large bias for the ASI input, but for sure things would be improved with calibration.

I believe there is only one yacht processor that does it to a similar level as the Butterfly. Mostly, people just use simple trigonometry and damp inputs and results.

[Sean[_2_]]

I agree UH. I dont think real time wind data is all that critical in a glider.

Sure its nice to have, but as I see it, little advantage can be gained by having slightly better wind accuracy than another guy.

Maybe I just dont live on the ridge enough.

[Jonathan St. Cloud]

Realtime wind sure is useful flying shear lift.

On Thursday, September 22, 2016 at 6:07:56 PM UTC-7, Sean wrote:
> I agree UH. I dont think real time wind data is all that critical in a glider.
>
> Sure its nice to have, but as I see it, little advantage can be gained by having slightly better wind accuracy than another guy.
>
> Maybe I just dont live on the ridge enough.

[xcnick]

I did meet a pilot I respect with both installed. He mentioned the fast accurate wind of the butterfly helped him decide which way to turn when entering a thermal. He liked the wind indicator for many other reasons as well.
> I'm still trying to understand why fast response wing information is as important as this thread seems to imply.
> FWIW
> UH

[krasw]

On Thursday, 22 September 2016 23:47:15 UTC+3, wrote:
> I'm still trying to understand why fast response wing information is as important as this thread seems to imply.
> FWIW
> UH

It is hard to explain to pilots who have never seen how wind changes around thermals and especially cloudstreets. We have had very accurate variometers for decades so we are used to look at clues from variometer when approaching thermal. Those same clues are visible also with horizontal flow around thermal. There cannot be vertical disturbance without corresponding horizontal disturbance in flow. Think which is easier to measure when you are 100m from thermal, you cannot measure lift (yet), but wind tells you that something is happening nearby.

[waremark]

How do you use this instant wind info?

[Jonathan St. Cloud]

Sean, while I enjoyed the sailing tangental as I too am a sailor (year around) I think you have made a logic jump in "confirming my question" at the same time using non-standard phrasing :)

From this discussion I had gleaned that the Butterfly is the only instrument that actually has all the goodies to be an inertial nav unit. The Butterfly inertial nav, with it's 3D accelerometers, gyros on a multiple chips... is the most accurate way to measure wind.


On Thursday, September 22, 2016 at 7:25:34 AM UTC-7, Sean wrote:
> Thanks for confirming my question that a fixed magnetic compass provides the fastest and best wind speed/direction calculation. It is also impressive how much others have done (even 20 years ago) to build algorithms which calculate great wind info without the fixed compass.
>

[Dan Daly[_2_]]

On Friday, September 23, 2016 at 10:26:40 AM UTC-4, Jonathan St. Cloud wrote:
> Sean, while I enjoyed the sailing tangental as I too am a sailor (year around) I think you have made a logic jump in "confirming my question" at the same time using non-standard phrasing :)
>
> From this discussion I had gleaned that the Butterfly is the only instrument that actually has all the goodies to be an inertial nav unit. The Butterfly inertial nav, with it's 3D accelerometers, gyros on a multiple chips.... is the most accurate way to measure wind.
>
>
> On Thursday, September 22, 2016 at 7:25:34 AM UTC-7, Sean wrote:
> > Thanks for confirming my question that a fixed magnetic compass provides the fastest and best wind speed/direction calculation. It is also impressive how much others have done (even 20 years ago) to build algorithms which calculate great wind info without the fixed compass.
> >

@Jonathan - CNv too - see T8's post. Just not currently used.
@xcnick - I don't want to be in thermal with your friend who's looking at his vario to see what the wind is joining in... or joining the same thermal from another direction.

I've not flown with the Butterfly, but I'm very happy with the wind the CNv-XC gives me.

Dan

[[email protected]]

I have flown with the Butterfly for three seasons. It was difficult to install as its sensor unit needs to be mostly well clear of any magnets or any moving ferrous control rods. It turns out that most of our gliders have been magnetized a bit in their lifetime. Dave Nadler told me that they tried to incorporate some sort of compass data in the SN10 but were unable to overcome that obstacle. After moving all speakers behind my head and getting the inertial sensor unit away from moving metal I finally got it working. It has some built in compensation which works for some weak standing magnetic fields but not moving ones, such as a control rod or speaker magnet. That took most of a year to sort out. It does work as advertised, giving real time wind information. The question is, does that help in finding and centering lift?
Years ago Al Leffler helped me learn to fly the Mojave shear line on blue days. He said that when, in doubt, the lift is probably downwind. That was and is good advice. In the west most of our flying utilizes some form of convergence. Over the years the phenomenon has been called, DEW line, shear line, convergence, and most recently "energy lines. I mostly fly from Siskiyou County airport in Montague, CA, We have a convergence that routinely sets up east of mount Shasta and extends easterly for about 50 miles. It appears to be a combination of converging anabatic thermals from the two sides of a wide mountain ridge, and meeting of northerly valley winds from north with the prevailing southwesterly winds from the south. The Butterfly real time winds do reliably steer you to the convergence and have helped me choose which side of the clouds to cruise. Of course experienced pilots will figure that out anyway but every little advantage helps.
There may be information displayed that would help centering thermals. Do horizontal gusts converge from all sides in a thermal?
The little wind arrow is easy to interpret and quickly becomes part of your scan and need not become a safety issue. According to Richard (Craggy Aero), the Lx Varios. (S8,S80,V7) have similar sensors and should be capable of producing similar information. I have an S80 in another glider and I do not think the wind calculations are as "real time" as the Butterfly. As a side note, after years of flying with the Ilec. SN10 I think it is still the best at computing and displaying average winds.
DLB

[jfitch]

On Friday, September 23, 2016 at 11:56:58 AM UTC-7, wrote:
> I have flown with the Butterfly for three seasons. It was difficult to install as its sensor unit needs to be mostly well clear of any magnets or any moving ferrous control rods. It turns out that most of our gliders have been magnetized a bit in their lifetime. Dave Nadler told me that they tried to incorporate some sort of compass data in the SN10 but were unable to overcome that obstacle. After moving all speakers behind my head and getting the inertial sensor unit away from moving metal I finally got it working.. It has some built in compensation which works for some weak standing magnetic fields but not moving ones, such as a control rod or speaker magnet. That took most of a year to sort out. It does work as advertised, giving real time wind information. The question is, does that help in finding and centering lift?
> Years ago Al Leffler helped me learn to fly the Mojave shear line on blue days. He said that when, in doubt, the lift is probably downwind. That was and is good advice. In the west most of our flying utilizes some form of convergence. Over the years the phenomenon has been called, DEW line, shear line, convergence, and most recently "energy lines. I mostly fly from Siskiyou County airport in Montague, CA, We have a convergence that routinely sets up east of mount Shasta and extends easterly for about 50 miles. It appears to be a combination of converging anabatic thermals from the two sides of a wide mountain ridge, and meeting of northerly valley winds from north with the prevailing southwesterly winds from the south. The Butterfly real time winds do reliably steer you to the convergence and have helped me choose which side of the clouds to cruise. Of course experienced pilots will figure that out anyway but every little advantage helps.
> There may be information displayed that would help centering thermals. Do horizontal gusts converge from all sides in a thermal?
> The little wind arrow is easy to interpret and quickly becomes part of your scan and need not become a safety issue. According to Richard (Craggy Aero), the Lx Varios. (S8,S80,V7) have similar sensors and should be capable of producing similar information. I have an S80 in another glider and I do not think the wind calculations are as "real time" as the Butterfly. As a side note, after years of flying with the Ilec. SN10 I think it is still the best at computing and displaying average winds.
> DLB

Yes the horizontal gusts converge on all sides towards the thermal. This is nicely shown on the iGlide display, when using Air vario wind data. In the thermal display, a green dot is painted each second showing lift as is typical of other thermal assistants. In iGlide, each dot also has an instantaneous wind vector. In nice soft, round flatland thermals it is quite symmetrical and pointing to the thermal center. In rough mountain thermals it is more chaotic, but still points towards the best lift reliably. You can recognize two core thermals easily on the display, verified by vario and seat of pants. I think this would be very difficult to interpret using just the instantaneous arrow on the S display, but can be seen at a glance on iGlide.

All the other varios have inertial sensors, even the CAI 302 was claimed to have them - after all the MEMS parts are only a dollar or so and are in practically every consumer electronic device these days. The trick is not the installing of them, but doing something with them. To my knowledge only Air has done so with any meaningful result, including the inertially derived vertical air mass movement.

[Dan Daly[_2_]]

On Friday, September 16, 2016 at 4:23:48 PM UTC-4, wrote:
> The Air Avionics Butterfly has developed an outstanding reputation as having a competitive advantage for its ability to "instantaneously" calculate wind direction.
>
> Does the CNv (with latest 3.3.3899 or beta 3.4.4089) calculate wind as quickly as the Butterfly?
>
> T8, what is the wind direction update rate of the CNv?
>
> If anyone has experience using both varios at the same time, please share your opinions.

Thread hijacking: Does anyone have experience with the CNv in wave? What settings do you use? What screen?

[Dan Marotta]

On 9/23/2016 1:56 PM, Dan Daly wrote:
> Thread hijacking: Does anyone have experience with the CNv in wave? What settings do you use? What screen?

I have used my CNvXC in wave and I set it exactly as I do for thermal
soaring. It's my Streak/XCSoar that gets set up differently. On the
Streak, I zoom in way in, maybe 2 mile or less range and then I can see
the line of best lift and navigate quickly to it following an upwind
reversal turn. As altitude increases the leg length also (generally)
increases.

Wave will be upon us soon!

--
Dan, 5J

[Dan Daly[_2_]]

On Friday, September 23, 2016 at 6:42:17 PM UTC-4, Dan Marotta wrote:
> On 9/23/2016 1:56 PM, Dan Daly wrote:
> > Thread hijacking: Does anyone have experience with the CNv in wave? What settings do you use? What screen?
>
> I have used my CNvXC in wave and I set it exactly as I do for thermal
> soaring. It's my Streak/XCSoar that gets set up differently. On the
> Streak, I zoom in way in, maybe 2 mile or less range and then I can see
> the line of best lift and navigate quickly to it following an upwind
> reversal turn. As altitude increases the leg length also (generally)
> increases.
>
> Wave will be upon us soon!
>
> --
> Dan, 5J

Thanks! I do that with XCSoar on my Oudie Lite. On the CNv, I assume you don't use Thermal Assistant, just the snail trail?

The club Pawnee goes to Lake Placid today.

Dan, 2D

[Dan Marotta]

I've got the mechanical CNv so no snail trail or thermal assistant. Had
the LCD version been available at the time, I likely would have gotten one.

On 9/24/2016 5:41 AM, Dan Daly wrote:
> On Friday, September 23, 2016 at 6:42:17 PM UTC-4, Dan Marotta wrote:
>> On 9/23/2016 1:56 PM, Dan Daly wrote:
>>> Thread hijacking: Does anyone have experience with the CNv in wave? What settings do you use? What screen?
>> I have used my CNvXC in wave and I set it exactly as I do for thermal
>> soaring. It's my Streak/XCSoar that gets set up differently. On the
>> Streak, I zoom in way in, maybe 2 mile or less range and then I can see
>> the line of best lift and navigate quickly to it following an upwind
>> reversal turn. As altitude increases the leg length also (generally)
>> increases.
>>
>> Wave will be upon us soon!
>>
>> --
>> Dan, 5J
> Thanks! I do that with XCSoar on my Oudie Lite. On the CNv, I assume you don't use Thermal Assistant, just the snail trail?
>
> The club Pawnee goes to Lake Placid today.
>
> Dan, 2D

--
Dan, 5J

[Jonathan St. Cloud]

On Friday, September 23, 2016 at 10:27:23 AM UTC-7, Dan Daly wrote:
> @Jonathan - CNv too - see T8's post. Just not currently used.

Dan - CNv Not Used.

[Sean[_2_]]

I agree with you that the Butterfly is the best "all in one" on wind from the marketing on the product and the reports from the pilots. I was ageeing that my question was "indirectly" answered in terms of concensus that a fixed compass integrated with a vario is going to be faster, better, more accurate in a straight line...

I hope that clears me.

I'm just not sold yet on the importance of the hyper accurate wind data. Im way to busy looking out the window and usually only listen to the speed to fly. Maybe a special been for significant wind change would be useful to hint to the pilot that therre is something of value to check? Cross referencing for wind changes in a thermal, street, sheer line or wave or something like that is interesting, but I certainly am not doing it often at current.

I like to try and feel with my rear as much as possible while cross referencing with my ears and the vario. I also generally have not flown with the Butterly. I only played with one for 1 week at a contest. Not enough time to master it and ultimately chose a ClearNav Vario and a LXNav S10 backup this spring for my new panel. I do not think the butterfly is worth the price...

SMF
7T

[Jonathan St. Cloud]

oh, you are bringing sensibility into the equation, this is a new concept.

On Sunday, September 25, 2016 at 6:25:15 PM UTC-7, Sean wrote:
.... I do not think the butterfly is worth the price...
>
> SMF
> 7T

[krasw]

On Monday, 26 September 2016 04:25:15 UTC+3, Sean wrote:
LXNav S10 backup this spring for my new panel. I do not think the butterfly is worth the price...
>
> SMF
> 7T

What are you backing up with S10? Don't you have mechanical vario?

[Richard[_9_]]

On Sunday, September 25, 2016 at 11:15:12 PM UTC-7, krasw wrote:
> On Monday, 26 September 2016 04:25:15 UTC+3, Sean wrote:
> LXNav S10 backup this spring for my new panel. I do not think the butterfly is worth the price...
> >
> > SMF
> > 7T
>
> What are you backing up with S10? Don't you have mechanical vario?

No need for a mechanical backup the S10 has an internal backup battery for 3 hrs of use.

Richard
www.craggyaero.com

[krasw]

On Monday, 26 September 2016 17:24:02 UTC+3, Richard wrote:
> On Sunday, September 25, 2016 at 11:15:12 PM UTC-7, krasw wrote:
> > On Monday, 26 September 2016 04:25:15 UTC+3, Sean wrote:
> > LXNav S10 backup this spring for my new panel. I do not think the butterfly is worth the price...
> > >
> > > SMF
> > > 7T
> >
> > What are you backing up with S10? Don't you have mechanical vario?
>
> No need for a mechanical backup the S10 has an internal backup battery for 3 hrs of use.
>
> Richard
> www.craggyaero.com

Never heard of anyone not having a mechanical vario in glider.

[jfitch]

On Sunday, September 25, 2016 at 6:25:15 PM UTC-7, Sean wrote:
> I agree with you that the Butterfly is the best "all in one" on wind from the marketing on the product and the reports from the pilots. I was ageeing that my question was "indirectly" answered in terms of concensus that a fixed compass integrated with a vario is going to be faster, better, more accurate in a straight line...
>
> I hope that clears me.
>
> I'm just not sold yet on the importance of the hyper accurate wind data. Im way to busy looking out the window and usually only listen to the speed to fly. Maybe a special been for significant wind change would be useful to hint to the pilot that therre is something of value to check? Cross referencing for wind changes in a thermal, street, sheer line or wave or something like that is interesting, but I certainly am not doing it often at current.
>
> I like to try and feel with my rear as much as possible while cross referencing with my ears and the vario. I also generally have not flown with the Butterly. I only played with one for 1 week at a contest. Not enough time to master it and ultimately chose a ClearNav Vario and a LXNav S10 backup this spring for my new panel. I do not think the butterfly is worth the price...
>
> SMF
> 7T

Once you have (and use) the instantaneous wind information, you begin to understand how useful it is. The Butterfly seems to be about the same price as the LX product, similarly configured. S100 + compass module + AHRS to get to the Butterfly spec., and still no inertial wind or VAM.

[jfitch]

On Monday, September 26, 2016 at 8:35:58 AM UTC-7, krasw wrote:
> On Monday, 26 September 2016 17:24:02 UTC+3, Richard wrote:
> > On Sunday, September 25, 2016 at 11:15:12 PM UTC-7, krasw wrote:
> > > On Monday, 26 September 2016 04:25:15 UTC+3, Sean wrote:
> > > LXNav S10 backup this spring for my new panel. I do not think the butterfly is worth the price...
> > > >
> > > > SMF
> > > > 7T
> > >
> > > What are you backing up with S10? Don't you have mechanical vario?
> >
> > No need for a mechanical backup the S10 has an internal backup battery for 3 hrs of use.
> >
> > Richard
> > www.craggyaero.com
>
> Never heard of anyone not having a mechanical vario in glider.

I don't.

[JS]

On Monday, September 26, 2016 at 8:35:58 AM UTC-7, krasw wrote:
> On Monday, 26 September 2016 17:24:02 UTC+3, Richard wrote:
> > On Sunday, September 25, 2016 at 11:15:12 PM UTC-7, krasw wrote:
> > > On Monday, 26 September 2016 04:25:15 UTC+3, Sean wrote:
> > > LXNav S10 backup this spring for my new panel. I do not think the butterfly is worth the price...
> > > >
> > > > SMF
> > > > 7T
> > >
> > > What are you backing up with S10? Don't you have mechanical vario?
> >
> > No need for a mechanical backup the S10 has an internal backup battery for 3 hrs of use.
> >
> > Richard
> > www.craggyaero.com
>
> Never heard of anyone not having a mechanical vario in glider.

The two varios mentioned in the OP are all I have. The mechanical vario went away a long time ago, as did the mechanical compass.
Jim

[Dan Daly[_2_]]

I have a CNv-XC-digital as primary, LX S3 secondary. If they fail, I have the seat of my pants...

[Tango Eight]

On Monday, September 26, 2016 at 11:35:58 AM UTC-4, krasw wrote:

> Never heard of anyone not having a mechanical vario in glider.

I haven't had a mechanical in years. I have a B400 for backup (with AA back up battery pack) but it hasn't been switched on for more than a functional check in about 4 years (the last time I got out to the airport and discovered my batteries hadn't come with me).

Mechanical varios don't play well with modern pressure transducer type varios and should not share TE sources with them.

Evan Ludeman / T8

[kirk.stant]

On Monday, September 26, 2016 at 10:35:58 AM UTC-5, krasw wrote:

> Never heard of anyone not having a mechanical vario in glider.

Really? I havn't had a mechanical vario in my glider (LS6) since 2001. Gave the Sage that came with it to a good friend (who likes mechanicals) and have used an SN10 and a Westerboer since then.

Carefully designed electrical system with two independent batteries. Never had a complete failure.

I have lost one vario due to a leak in my TE probe - nice that my backup has electronic TE, so I still had a fully functions system, with audio, netto, etc..

Now, tell me again why I would want a mechanical vario?

Kirk
66

[[email protected]]

>
> Mechanical varios don't play well with modern pressure transducer type varios and should not share TE sources with them.
>
> Evan Ludeman / T8

A practice many seem to ignore. Do you think there is any advantage to using a fin mounted Prandtl tube versus fuselage pitot/static ports? Do you prefer mechanical or electronic TE? How do you "plumb" your CNvXC and B400?

[Dan Marotta]

On 9/26/2016 10:15 AM, Tango Eight wrote:
> <snip>
> Mechanical varios don't play well with modern pressure transducer type varios and should not share TE sources with them.
>
> Evan Ludeman / T8

I have a 57 mm Winter mechanical and a CNvXC connected to the triple
probe in my Stemme. The needles on each track perfectly with each
other. The Winter is in my line of sight and I moved the CNvXC to the
right side of the panel for my wife to use. I still use the CN's audio
and occasionally glance at the averager and STF displays. BTW, the
speed ring on the Winter and the STF on the CN also track quite
closely. Some day, if/when I upgrade my panel, I'll probably replace
the Winter with one of the fine new electronic varios but, for now, what
I have works just great.

--
Dan, 5J

[krasw]

Wow, it hasn't even crossed my mind that someone would omit mechanical vario. That is the basis of glider instrumentation. Walking trough grid of last wgc most gliders had mechanical vario at prominent location in panel, I did not remember seeing one without.

I have two TE probes in my glider and have tried both mechanical and electric varios with same and separate probes. I did not find any differences plumbing them to same TE source.

[Tango Eight]

On Monday, September 26, 2016 at 1:19:46 PM UTC-4, Dan Marotta wrote:
> On 9/26/2016 10:15 AM, Tango Eight wrote:
> > <snip>
> > Mechanical varios don't play well with modern pressure transducer type varios and should not share TE sources with them.
> >
> > Evan Ludeman / T8
>
> I have a 57 mm Winter mechanical and a CNvXC connected to the triple
> probe in my Stemme. The needles on each track perfectly with each
> other.

Which illustrates what goes wrong :-).

The effect of the mechanical vario is to slow the whole system down to its own speed.

If you are using the triple probe pitot and static for CNv's pitot and static inputs, and the static source is not shared with any mechanical instrument (pitot source may be shared with an ASI since the pitot aneroid volume is small), try setting CNv to "no probe" and see if you don't like the response of the instrument better. I suggest setting the audio & pointer time constants to 0.5 sec.

best,
Evan for CNi

[Renny[_2_]]

On Monday, September 26, 2016 at 9:41:21 AM UTC-6, jfitch wrote:
> On Monday, September 26, 2016 at 8:35:58 AM UTC-7, krasw wrote:
> > On Monday, 26 September 2016 17:24:02 UTC+3, Richard wrote:
> > > On Sunday, September 25, 2016 at 11:15:12 PM UTC-7, krasw wrote:
> > > > On Monday, 26 September 2016 04:25:15 UTC+3, Sean wrote:
> > > > LXNav S10 backup this spring for my new panel. I do not think the butterfly is worth the price...
> > > > >
> > > > > SMF
> > > > > 7T
> > > >
> > > > What are you backing up with S10? Don't you have mechanical vario?
> > >
> > > No need for a mechanical backup the S10 has an internal backup battery for 3 hrs of use.
> > >
> > > Richard
> > > www.craggyaero.com
> >
> > Never heard of anyone not having a mechanical vario in glider.
>
> I don't.

I also do not have a mechanical vario...No need (at least for me) at all....In fact I am somewhat amazed folks are still buying them. Perhaps some clubs still buy them for simplicity or for some other reason, but I haven't had one in many years...

[Tango Eight]

On Monday, September 26, 2016 at 1:05:36 PM UTC-4, wrote:
> >
> > Mechanical varios don't play well with modern pressure transducer type varios and should not share TE sources with them.
> >
> > Evan Ludeman / T8
>
> A practice many seem to ignore. Do you think there is any advantage to using a fin mounted Prandtl tube versus fuselage pitot/static ports? Do you prefer mechanical or electronic TE? How do you "plumb" your CNvXC and B400?

CNv works great on electronic compensation *provided* the pitot/static system is essentially perfect. The only practical, reliable way to get that is with a triple probe set up on the fin. Don't share the static with mechanical instruments.

I have a triple probe set up plus fuselage static ports.

I plumb all three triple probe sources to CNv, the TE also goes to B400. ASI uses triple probe pitot and fuselage static. CNv works well on the probe (an old venturi style probe) but even better on the pitot/static.

best,
Evan

[Jonathan St. Cloud]

I do not have a mechanical vario. I have a computer with vario, a Butterfly and I have a LX V3 with battery backup, which I think is much better than a mechanical vario. I usually just leave the V3 off, but if I lose my main bus, I still have an electric vario with audio good for 8 hours of flight time. The V3 can be run off main power or battery backup. This V3 vario has it's own speaker so it is a compact install. I believe a few other manufacturers off the same type of functionality.



On Monday, September 26, 2016 at 8:35:58 AM UTC-7, krasw wrote:
>
> Never heard of anyone not having a mechanical vario in glider.

[Dan Marotta]

Thanks Evan, I was gonna try that. I already have the TCs set at 0.5
sec. I'll report back if I see any difference.

Dan

On 9/26/2016 12:14 PM, Tango Eight wrote:
> On Monday, September 26, 2016 at 1:19:46 PM UTC-4, Dan Marotta wrote:
>> On 9/26/2016 10:15 AM, Tango Eight wrote:
>>> <snip>
>>> Mechanical varios don't play well with modern pressure transducer type varios and should not share TE sources with them.
>>>
>>> Evan Ludeman / T8
>> I have a 57 mm Winter mechanical and a CNvXC connected to the triple
>> probe in my Stemme. The needles on each track perfectly with each
>> other.
> Which illustrates what goes wrong :-).
>
> The effect of the mechanical vario is to slow the whole system down to its own speed.
>
> If you are using the triple probe pitot and static for CNv's pitot and static inputs, and the static source is not shared with any mechanical instrument (pitot source may be shared with an ASI since the pitot aneroid volume is small), try setting CNv to "no probe" and see if you don't like the response of the instrument better. I suggest setting the audio & pointer time constants to 0.5 sec.
>
> best,
> Evan for CNi
>
>

--
Dan, 5J

[Dan Marotta]

The triple probe on the Stemme extends to about 3 feet in front of the
nose. That should be in pretty much undisturbed air.

On 9/26/2016 12:20 PM, Tango Eight wrote:
> On Monday, September 26, 2016 at 1:05:36 PM UTC-4, wrote:
>>> Mechanical varios don't play well with modern pressure transducer type varios and should not share TE sources with them.
>>>
>>> Evan Ludeman / T8
>> A practice many seem to ignore. Do you think there is any advantage to using a fin mounted Prandtl tube versus fuselage pitot/static ports? Do you prefer mechanical or electronic TE? How do you "plumb" your CNvXC and B400?
> CNv works great on electronic compensation *provided* the pitot/static system is essentially perfect. The only practical, reliable way to get that is with a triple probe set up on the fin. Don't share the static with mechanical instruments.
>
> I have a triple probe set up plus fuselage static ports.
>
> I plumb all three triple probe sources to CNv, the TE also goes to B400. ASI uses triple probe pitot and fuselage static. CNv works well on the probe (an old venturi style probe) but even better on the pitot/static.
>
> best,
> Evan

--
Dan, 5J

[[email protected]]

The mechanical vario and compass may have disappeared from your consciousness, but I bet they are still on the required equipment list from your glider's manufacturer. Something to remember at your next annual inspection. Just sayin'

[Jonathan St. Cloud]

In the ASG-29 a vario is minimum equipment for France, but does not specify electric or mechanical. USA required ASI, ALT, Compass 9which I am not sure why i need as I have two gyro compasses.


On Monday, September 26, 2016 at 6:17:06 PM UTC-7, wrote:
> The mechanical vario and compass may have disappeared from your consciousness, but I bet they are still on the required equipment list from your glider's manufacturer. Something to remember at your next annual inspection. Just sayin'

[kirk.stant]

On Monday, September 26, 2016 at 8:17:06 PM UTC-5, wrote:
> The mechanical vario and compass may have disappeared from your consciousness, but I bet they are still on the required equipment list from your glider's manufacturer. Something to remember at your next annual inspection. Just sayin'

Compass, yes, unfortunately (so I have a small PZL hidden behind my Oudie). Vario - not at all.

I feel safer with an all-glass cockpit (with suitable power supplies) than with any mechanical instrument. ASIs, altimeters, varios - the mechanical ones have all failed much more frequently than any of my electronic instruments.

And if all the blue smoke escapes, then it's back to basic airmanship. Look out the window, fly pitch attitude, feel the air... BTDT (due to mechanical instrument failures).

YMMV, of course ;^) A glass cockpit in a 2-33 would be a bit weird!

Kirk
66

[Sean[_2_]]

No mechanical vario for me.

I have 2 separate battery circuits (tail & main, both supported by solar) and the LXNav S10/100 has an internal battery backup for all functions (up to 4 hours).

I felt like a mechanical vario was a waste of panel as a total power loss results no audio vario or navigation (or logging). I also use a nano for a logger backup. And of course mechanical varios require a bottle (PITA).

Sean

[krasw]

I use mechanical vario to get more info from airmass, not as a backup. I have never experienced electrical variometer failure (nor heard of one), and if I did, that would not even remotely be classified as a problem, more like a minor inconvenience. Only backup I have is second battery.

[bumper[_4_]]

It's not undisturbed air. On my ex Stemmes , serial 11-18, the nose TERRY was severely under compensatedevelopment due to the bow wave. I increased the TE "washer" size to 3/4" IIRC and that helped a lot. Other Stemmed owners followed suit and agreed. Stemmes did not come stock with fin mounted probes then, some owners got them when the issue became known.

[Tango Whisky]

Le mardi 27 septembre 2016 08:11:20 UTC+2, krasw a écritÂ*:
> I use mechanical vario to get more info from airmass, not as a backup. I have never experienced electrical variometer failure (nor heard of one), and if I did, that would not even remotely be classified as a problem, more like a minor inconvenience. Only backup I have is second battery.

Why would a mechanical vario give you more information on airmass?

[krasw]

On Tuesday, 27 September 2016 11:15:02 UTC+3, Tango Whisky wrote:
> Why would a mechanical vario give you more information on airmass?

That is interesting question. If it would give identical information, the varios should read exactly the same. They obviously are not, so they are either measuring TE pressure differently, or one of them is measuring same thing but poorly (which I don't agree with, in some gusting thermals my Bohli reacts more realistically than electric vario). I feel getting two "opinions" from same thing is advantage (three actually if you count inertial variometer). Heck, I would gladly install fourth variometer if that tells me something new, instead of duplicating something I already have.

[[email protected]]

Only compass that works as a data source for wind vector calculations, to my knowledge, is the Zander's. Of course, it is part of the Zander system (can't add the Zander compass interface to instruments by other manufacturers).

I would discourage anyone from adding an electronic compass module to their existing computers, as it's just not working properly. Probably due to extreme sensibility to pitch changes, and software unable to correct that.
If on a low budget, buy a working, used Zander set.
If on a higher budget, try the newer inertial varios.

I agree that accurate and real-time wind calculation is of very high interest to soaring techniques. I used it for years and I just can't adapt to fly woithout it.

all IMVHO, of course!

Aldo Cernezzi




> It is not enough to throw in electric compass if the system is not up to it. Many variometer systems have compass option that manufacturers do not use for any meaningful data. Representative of one company told me of pilot who was very happy after installing optional compass module. He didn't have the heart to tell pilot that variometer firmware version couldn't use compass data at all. I always take pilot reports with a grain of salt.

[[email protected]]

In the past I flew an old Stemme S10V for many hours. Loved it, but vario was very undercompensated.
Would love you to expand on the "washer" mod. I just can't figure what you mean.

thanks!

Aldo Cernezzi




Il giorno martedì 27 settembre 2016 10:13:43 UTC+2, bumper ha scritto:
> It's not undisturbed air. On my ex Stemmes , serial 11-18, the nose TERRY was severely under compensatedevelopment due to the bow wave. I increased the TE "washer" size to 3/4" IIRC and that helped a lot.

[[email protected]]

On Monday, September 26, 2016 at 10:35:58 AM UTC-5, krasw wrote:
> On Monday, 26 September 2016 17:24:02 UTC+3, Richard wrote:
> > On Sunday, September 25, 2016 at 11:15:12 PM UTC-7, krasw wrote:
> > > On Monday, 26 September 2016 04:25:15 UTC+3, Sean wrote:
> > > LXNav S10 backup this spring for my new panel. I do not think the butterfly is worth the price...
> > > >
> > > > SMF
> > > > 7T
> > >
> > > What are you backing up with S10? Don't you have mechanical vario?
> >
> > No need for a mechanical backup the S10 has an internal backup battery for 3 hrs of use.
> >
> > Richard
> > www.craggyaero.com
>
> Never heard of anyone not having a mechanical vario in glider.

No mechanical vario for me over the last 15 years. Never missed it. My standby is a Westerboer with pressure sensors, compensated on the same line as my 302. I also have an A-B battery switch.
Herb J7

[Dave Nadler]

On Friday, September 23, 2016 at 2:56:58 PM UTC-4, wrote:
> ... sensor unit needs to be mostly well clear of any magnets or any
> moving ferrous control rods. It turns out that most of our gliders
> have been magnetized a bit in their lifetime. Dave Nadler told me
> that they tried to incorporate some sort of compass data in the
> SN10 but were unable to overcome that obstacle.

We researched this long time ago. One test placed a sensor inside canopy
on top of pilot to minimize magnetic distractions during testing. The
pilot was shocked when, after releasing from tow, he retracted the gear
and the compass swung 15 degrees! IIRC ILEC's LS-8 had very highly
magnetized gear linkage components.

Ultimately we decided then current technology would not give enough
benefit over our no-compass algorithm, and wouldn't be glider-pilot-proof
for installation... so did not bring the compass to market...

> ...As a side note, after years of flying with the Ilec SN10 I think
> it is still the best at computing and displaying average winds.

Thanks, you are not alone ;-)

[krasw]

tiistai 27. syyskuuta 2016 16.50.57 UTC+3 kirjoitti:
> Only compass that works as a data source for wind vector calculations, to my knowledge, is the Zander's. Of course, it is part of the Zander system (can't add the Zander compass interface to instruments by other manufacturers).
>
> I would discourage anyone from adding an electronic compass module to their existing computers, as it's just not working properly. Probably due to extreme sensibility to pitch changes, and software unable to correct that.
> If on a low budget, buy a working, used Zander set.
> If on a higher budget, try the newer inertial varios.
>
> I agree that accurate and real-time wind calculation is of very high interest to soaring techniques. I used it for years and I just can't adapt to fly woithout it.
>
> all IMVHO, of course!
>
> Aldo Cernezzi
>
>

Even Zander compass was very sensitive to installation. I installed one Zander system to a LS8 for WGC years ago and calibrated it with factory calibration compass. It worked fantastically giving very accurate readings. After that my club bought similar system to D2 and it didn't work at all, even after many calibration attempts. I have flown third glider with similar setup, and that also did not work. We never understood why. With current knowledge of compass sensor installation problems, there might have been speaker or something too close to compass.

[Dan Marotta]

Interesting, would you mind sending me more detailed information? In the
mean time, I'll be sure my CNv is electronically compensated and see how
that works.

On 9/27/2016 2:13 AM, bumper wrote:
> It's not undisturbed air. On my ex Stemmes , serial 11-18, the nose TERRY was severely under compensatedevelopment due to the bow wave. I increased the TE "washer" size to 3/4" IIRC and that helped a lot. Other Stemmed owners followed suit and agreed. Stemmes did not come stock with fin mounted probes then, some owners got them when the issue became known.

--
Dan, 5J

[bumper[_4_]]

On Tuesday, September 27, 2016 at 6:52:44 AM UTC-7, wrote:
> In the past I flew an old Stemme S10V for many hours. Loved it, but vario was very undercompensated.
> Would love you to expand on the "washer" mod. I just can't figure what you mean.
>
> thanks!
>
> Aldo Cernezzi
>

Also (and Dan),

As mentioned, the Stemme TE probe is adversely affected by the nose bow wave. You can see this with the classic stick pull push as the vario needle follows showing lift or sink - "stick thermal".

The TE probe is the "top hat" style with the brim of the hat creating a low pressure area directly behind the probe - the negative pressure is reduced by the bow wave. Increasing the top hat diameter compensates (mostly) for the bow wave and dramatically reduces stick thermal indication.

To increase diameter, I used a 3/4" OD nylon washer with an ID to closely match the horizontal barrel of probe. The washer is cut from OD to ID at an angle to allow the washer to be "threaded" onto the probe just ahead of he top hat flange - thus effectively increasing it's diameter and further reducing the pressure behind the probe in flight.

I did a bunch of ground testing too, using a leaf blower and various means to smooth the airflow to the probe while using a manometer to monitor pressure in an attempt to increase compensation further still. Larger washer did not work. Going to a cone shape instead of a washer to further smooth flow also made no improvement. Best I could come up with was that washer . . . and it works!

IIRC, I found the washers at West Marine years ago, I'm sure they can be found on-line.

bumper

[[email protected]]

Den tirsdag den 27. september 2016 kl. 15.19.03 UTC+2 skrev krasw:
> On Tuesday, 27 September 2016 11:15:02 UTC+3, Tango Whisky wrote:
> > Why would a mechanical vario give you more information on airmass?
>
> That is interesting question. If it would give identical information, the varios should read exactly the same. They obviously are not, so they are either measuring TE pressure differently, or one of them is measuring same thing but poorly (which I don't agree with, in some gusting thermals my Bohli reacts more realistically than electric vario). I feel getting two "opinions" from same thing is advantage (three actually if you count inertial variometer). Heck, I would gladly install fourth variometer if that tells me something new, instead of duplicating something I already have.

I think the mechanical vario and the electrical transducer based vario should have different responses simply due to physics.

Consider a sudden small pressure drop in the TE line (like hitting very sudden lift). The mechanical vario measures the flow rate from the flask to the TE line. This flow is proportional to the pressure difference between the flask and the TE pressure. The pressure difference, and hence the vario reading, is largest right after the pressure drop and then decays exponentially back to zero. That explanation is consistent with a simple experiment done a few years ago with a 57 mm Winter vario, a syringe and a video camera. The vario reading peaked after just 0.3 s. The subsequent decay fitted perfectly with an exponential decay with a time constant of 3 s.

The electrical vario indicates the time derivative of the measured TE pressure after some low pass filtering. The response depends on the actual filtering, but the response to a sudden small pressure drop will peak after some time given by the filter type and time constant. The lab experiment with a syringe and a video camera showed that a late generation LX5000 on minimum time constant (0.5 s) would peak after 2.5 s. On the other hand, the following decay to zero was much faster than for the Winter vario.

The tests were repeated with both the Winter and the LX5000 on the same TE line in order to evaluate the influence of the mechanical vario and flask on the LX5000 response. Surprisingly, the LX5000 response to a sudden small pressure drop was essentially unchanged, and if anything it measured a bit faster.

Another test with an LX7007 showed similar results, except now the Winter on the same TE line did seem to slow the LX7007 a bit when operated on the shortest possible time constant of 0.2 s (peak after 2.0 s without Winther, peak after 2.5 s with Winther on TE line).

I prefer the electrical vario, but I know one regular WGC pilot who keeps a mechanical vario claiming that it has a faster response to sudden changes in the air mass. He doesn’t know why – and I don’t know if the considerations above are relevant at all in the real world…

-J

[Jonathan St. Cloud]

That is why, if it is in the budget, buy the latest generation instruments. I have compass module on LX 90XX, compass on Butterfly, and Bolhi compass, They all work within two degrees of each other. The LX90XX and butterfly always agree.

On Tuesday, September 27, 2016 at 8:21:44 AM UTC-7, krasw wrote:

> Even Zander compass was very sensitive to installation. I installed one Zander system to a LS8 for WGC years ago and calibrated it with factory calibration compass. It worked fantastically giving very accurate readings. After that my club bought similar system to D2 and it didn't work at all, even after many calibration attempts. I have flown third glider with similar setup, and that also did not work. We never understood why. With current knowledge of compass sensor installation problems, there might have been speaker or something too close to compass.

[[email protected]]

Capito!
thanks!
aldo

> The TE probe is the "top hat" style with the brim of the hat creating a low pressure area directly behind the probe - the negative pressure is reduced by the bow wave. Increasing the top hat diameter compensates (mostly) for the bow wave and dramatically reduces stick thermal indication.

[Dan Marotta]

We tried for wave today and all we got was high on the engine. Since I
was in smooth air, I tried pushing over and pulling up and found the
Winter mechanical vario in my Stemme to be very well compensated.
Likewise the CNv was well compensated. Checking its setup, I found that
it is set for electronic compensation, I did not look at the percentage.

On 9/26/2016 4:43 PM, Dan Marotta wrote:
> Thanks Evan, I was gonna try that. I already have the TCs set at 0.5
> sec. I'll report back if I see any difference.
>
> Dan
>
> On 9/26/2016 12:14 PM, Tango Eight wrote:
>> On Monday, September 26, 2016 at 1:19:46 PM UTC-4, Dan Marotta wrote:
>>> On 9/26/2016 10:15 AM, Tango Eight wrote:
>>>> <snip>
>>>> Mechanical varios don't play well with modern pressure transducer
>>>> type varios and should not share TE sources with them.
>>>>
>>>> Evan Ludeman / T8
>>> I have a 57 mm Winter mechanical and a CNvXC connected to the triple
>>> probe in my Stemme. The needles on each track perfectly with each
>>> other.
>> Which illustrates what goes wrong :-).
>>
>> The effect of the mechanical vario is to slow the whole system down
>> to its own speed.
>>
>> If you are using the triple probe pitot and static for CNv's pitot
>> and static inputs, and the static source is not shared with any
>> mechanical instrument (pitot source may be shared with an ASI since
>> the pitot aneroid volume is small), try setting CNv to "no probe" and
>> see if you don't like the response of the instrument better. I
>> suggest setting the audio & pointer time constants to 0.5 sec.
>>
>> best,
>> Evan for CNi
>>
>>
>

--
Dan, 5J

[krasw]

tiistai 27. syyskuuta 2016 22.23.28 UTC+3 kirjoitti:
> Den tirsdag den 27. september 2016 kl. 15.19.03 UTC+2 skrev krasw:
> > On Tuesday, 27 September 2016 11:15:02 UTC+3, Tango Whisky wrote:
> > > Why would a mechanical vario give you more information on airmass?
> >
> > That is interesting question. If it would give identical information, the varios should read exactly the same. They obviously are not, so they are either measuring TE pressure differently, or one of them is measuring same thing but poorly (which I don't agree with, in some gusting thermals my Bohli reacts more realistically than electric vario). I feel getting two "opinions" from same thing is advantage (three actually if you count inertial variometer). Heck, I would gladly install fourth variometer if that tells me something new, instead of duplicating something I already have.
>
> I think the mechanical vario and the electrical transducer based vario should have different responses simply due to physics.
>
> Consider a sudden small pressure drop in the TE line (like hitting very sudden lift). The mechanical vario measures the flow rate from the flask to the TE line. This flow is proportional to the pressure difference between the flask and the TE pressure. The pressure difference, and hence the vario reading, is largest right after the pressure drop and then decays exponentially back to zero. That explanation is consistent with a simple experiment done a few years ago with a 57 mm Winter vario, a syringe and a video camera. The vario reading peaked after just 0.3 s. The subsequent decay fitted perfectly with an exponential decay with a time constant of 3 s.
>
> The electrical vario indicates the time derivative of the measured TE pressure after some low pass filtering. The response depends on the actual filtering, but the response to a sudden small pressure drop will peak after some time given by the filter type and time constant. The lab experiment with a syringe and a video camera showed that a late generation LX5000 on minimum time constant (0.5 s) would peak after 2.5 s. On the other hand, the following decay to zero was much faster than for the Winter vario.
>
> The tests were repeated with both the Winter and the LX5000 on the same TE line in order to evaluate the influence of the mechanical vario and flask on the LX5000 response. Surprisingly, the LX5000 response to a sudden small pressure drop was essentially unchanged, and if anything it measured a bit faster.
>
> Another test with an LX7007 showed similar results, except now the Winter on the same TE line did seem to slow the LX7007 a bit when operated on the shortest possible time constant of 0.2 s (peak after 2.0 s without Winther, peak after 2.5 s with Winther on TE line).
>
> I prefer the electrical vario, but I know one regular WGC pilot who keeps a mechanical vario claiming that it has a faster response to sudden changes in the air mass. He doesn’t know why – and I don’t know if the considerations above are relevant at all in the real world…
>
> -J

That is very interesting, thanks. I think many pilots recognize good mechanical variometers fast peaking / slow decay behaviour vs. electricals somewhat opposite response. I've often considered would it be possible to build a vario that has adjustable, separate time constants/filters for peak and decay. Cannot think any reason why not.

[JS]

Sorry, but comparing the two varios mentioned in the original post:

When flying through turbulence that nets neither up nor down and not worth circling in, ever wonder what it is? A mechanical or old school vario won't soon display anything useful about the change in airmass horizontal vector..
Correction, a mechanical vario will never tell you about it.

Today's flight was in wind from SE then NW then SW then SE then NW then SW then S then SW then SE then SW then NW. When approaching convergence lines the wind change was indicated on the Air-Glide S before the airmasses converged, by showing velocity reduction then change of direction then - on both mentioned varios - up indication.
Jim

[[email protected]]

On Thursday, September 29, 2016 at 9:29:18 PM UTC-4, JS wrote:
> Sorry, but comparing the two varios mentioned in the original post:
>
> When flying through turbulence that nets neither up nor down and not worth circling in, ever wonder what it is? A mechanical or old school vario won't soon display anything useful about the change in airmass horizontal vector.
> Correction, a mechanical vario will never tell you about it.
>
> Today's flight was in wind from SE then NW then SW then SE then NW then SW then S then SW then SE then SW then NW. When approaching convergence lines the wind change was indicated on the Air-Glide S before the airmasses converged, by showing velocity reduction then change of direction then - on both mentioned varios - up indication.
> Jim

JS...do you use electronic compensation on both varios?

[JS]

On Thursday, September 29, 2016 at 7:35:50 PM UTC-7, wrote:
> On Thursday, September 29, 2016 at 9:29:18 PM UTC-4, JS wrote:
> > Sorry, but comparing the two varios mentioned in the original post:
> >
> > When flying through turbulence that nets neither up nor down and not worth circling in, ever wonder what it is? A mechanical or old school vario won't soon display anything useful about the change in airmass horizontal vector.
> > Correction, a mechanical vario will never tell you about it.
> >
> > Today's flight was in wind from SE then NW then SW then SE then NW then SW then S then SW then SE then SW then NW. When approaching convergence lines the wind change was indicated on the Air-Glide S before the airmasses converged, by showing velocity reduction then change of direction then - on both mentioned varios - up indication.
> > Jim
>
> JS...do you use electronic compensation on both varios?

Using electronic on the CNv, a (50/50?) mix in the Air-Glide.
Jim

[Dan Marotta]

On 9/29/2016 7:29 PM, JS wrote:
> <snip>
>
> Today's flight was in wind from SE then NW then SW then SE then NW then SW then S then SW then SE then SW then NW. When approaching convergence lines the wind change was indicated on the Air-Glide S before the airmasses converged, by showing velocity reduction then change of direction then - on both mentioned varios - up indication.
> Jim
How much head down time did that take? Were there other aircraft nearby?
--
Dan, 5J

[JS]

On Friday, September 30, 2016 at 8:37:21 AM UTC-7, Dan Marotta wrote:
> On 9/29/2016 7:29 PM, JS wrote:
> > <snip>
> >
> > Today's flight was in wind from SE then NW then SW then SE then NW then SW then S then SW then SE then SW then NW. When approaching convergence lines the wind change was indicated on the Air-Glide S before the airmasses converged, by showing velocity reduction then change of direction then - on both mentioned varios - up indication.
> > Jim
> How much head down time did that take? Were there other aircraft nearby?
> --
> Dan, 5J

Well mum, there was no more heads down than checking airspeed, etc. The Air is next to the ASI in the top row of the panel.
Some of that wind direction crap was remembered from post-flight analysis.
As for the train spotting bit:
Saw Cezzna, MD80, 727, bizjet, condor, hawk, raven, vulture, various F-things.
Didn't steal any thermals from any of the inorganic ones.
Jim

[Dan Marotta]

Cool. Thanks for the reply! That's a lot of aircraft.

My wife and I flew 2.2 hours yesterday and, during that time I saw one
airliner up in the 30s and got one PCAS alert at 5 miles. Never saw
him. I love flying in the desert! Oh, yeah... We were the only glider up.

Dan

On 9/30/2016 12:18 PM, JS wrote:
> On Friday, September 30, 2016 at 8:37:21 AM UTC-7, Dan Marotta wrote:
>> On 9/29/2016 7:29 PM, JS wrote:
>>> <snip>
>>>
>>> Today's flight was in wind from SE then NW then SW then SE then NW then SW then S then SW then SE then SW then NW. When approaching convergence lines the wind change was indicated on the Air-Glide S before the airmasses converged, by showing velocity reduction then change of direction then - on both mentioned varios - up indication.
>>> Jim
>> How much head down time did that take? Were there other aircraft nearby?
>> --
>> Dan, 5J
> Well mum, there was no more heads down than checking airspeed, etc. The Air is next to the ASI in the top row of the panel.
> Some of that wind direction crap was remembered from post-flight analysis.
> As for the train spotting bit:
> Saw Cezzna, MD80, 727, bizjet, condor, hawk, raven, vulture, various F-things.
> Didn't steal any thermals from any of the inorganic ones.
> Jim

--
Dan, 5J

[[email protected]]

Will slipping or skidding influence the instantanei0us wind reading ? The compass shows your heading which changes when slipping/skidding.
Dan
On Saturday, October 1, 2016 at 10:04:48 AM UTC-4, Dan Marotta wrote:
> Cool. Thanks for the reply! That's a lot of aircraft.
>
> My wife and I flew 2.2 hours yesterday and, during that time I saw one
> airliner up in the 30s and got one PCAS alert at 5 miles. Never saw
> him. I love flying in the desert! Oh, yeah... We were the only glider up.
>
> Dan
>
> On 9/30/2016 12:18 PM, JS wrote:
> > On Friday, September 30, 2016 at 8:37:21 AM UTC-7, Dan Marotta wrote:
> >> On 9/29/2016 7:29 PM, JS wrote:
> >>> <snip>
> >>>
> >>> Today's flight was in wind from SE then NW then SW then SE then NW then SW then S then SW then SE then SW then NW. When approaching convergence lines the wind change was indicated on the Air-Glide S before the airmasses converged, by showing velocity reduction then change of direction then - on both mentioned varios - up indication.
> >>> Jim
> >> How much head down time did that take? Were there other aircraft nearby?
> >> --
> >> Dan, 5J
> > Well mum, there was no more heads down than checking airspeed, etc. The Air is next to the ASI in the top row of the panel.
> > Some of that wind direction crap was remembered from post-flight analysis.
> > As for the train spotting bit:
> > Saw Cezzna, MD80, 727, bizjet, condor, hawk, raven, vulture, various F-things.
> > Didn't steal any thermals from any of the inorganic ones.
> > Jim
>
> --
> Dan, 5J