Hawk Wind

[sr...@mindspring.com]

Has anyone any experience yet with the new Lxnav Hawk Wind program? Sounds superficially to me like it might be an alternative to the Butterfly wind solution which is no longer readily available. And this program seems to avoid some of the Butterfly installation challenges?

[krasw]

On Tuesday, 27 April 2021 at 20:27:19 UTC+3, sr...@mindspring.com wrote:
> Has anyone any experience yet with the new Lxnav Hawk Wind program? Sounds superficially to me like it might be an alternative to the Butterfly wind solution which is no longer readily available. And this program seems to avoid some of the Butterfly installation challenges?

Installation challenge = can not bother to read installation manual.

[George Haeh]

Installation challenge = can not bother to read installation manual.

Priceless!

[Sean Franke]

On Tuesday, April 27, 2021 at 7:01:34 PM UTC-6, georg...@gmail.com wrote:
> Installation challenge = can not bother to read installation manual.
> Priceless!

to read installation manual = admitting defeat?

Asking for a friend ;)

Sean

[Eric Greenwell]

It is a funny remark, but doesn't apply in this case.

Have you read the Butterfly installation manual? I have read it, I have
installed a Butterfly vario, and it was a challenge, even though I worked as an
electrical engineer for decades. It's not like the olden days, when a vario had
two wires for the battery, and one pressure port for the TE tubing.

--
Eric Greenwell - USA
- "A Guide to Self-launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Jay Campbell]

Take a look at the LXNAV user group:
LXNav Soaring Glider Equipment User Discussion Group <lxnav-us...@googlegroups.com

They have been chatting on this for a while.

[krasw]

On Wednesday, 28 April 2021 at 18:54:08 UTC+3, Eric Greenwell wrote:
> Have you read the Butterfly installation manual? I have read it, I have
> installed a Butterfly vario, and it was a challenge, even though I worked as an
> electrical engineer for decades. It's not like the olden days, when a vario had
> two wires for the battery, and one pressure port for the TE tubing.
>
> --
> Eric Greenwell - USA
> - "A Guide to Self-launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Yes I have, and I have installed that variometer to two different gliders. Both cases required fabrication of shelf for ISU to install it far away from magnetic disturbances, as warned in the manual. It worked and works beautifully in both cases.

I have heard few anecdotes of pilots complaining that vario not working. In one case I checked the installation (it was during WGC). The ISU was just thrown behind the panel with absolutely no flying f*cks given to proper installation. That pilot went on to bash it for three weeks.

Hope the LX installs itself.

[jfitch]

It does not sound like an inertial solution, but rather a more sophisticated pneumatic and magnetic calculation. It will be interesting to compare it to a Butterfly. In their paper, they erroneously claim that no instant wind calculation method existed before theirs - marketing I guess.

[2G]

The LXNAV LX8xxx and LX9xxx have all of the inertial sensors (accelerometers and rate gyros) in the unit. You can purchase the artificial horizon AHRS option as a (somewhat expensive) software key:
https://www.cumulus-soaring.com/store/manufacturers/lxnav/lxnav-ahrs-enable

Tom

[Eric Greenwell]

I don't think it uses magnetic sensing, as it does not require the optional
compass. So, it's all inertial and GPS, and I think doing it without a compass
was an important goal. 990eur for wind equal to the Butterfly, and a AHRS, is at
reasonable price for me. A separate AHRS is in the $800-$1000 range, so I'd bet
getting the Hawk features for about $200-$400 dollars with the Hawk/AHRS.

[John Galloway]

The HAWK article referenced on the LXNAV website makes it very clear that it doesn't use magnetic sensing and why:

https://gliding.lxnav.com/news/segelfliegen-magazines-eng/

Except for people with a Butterfly vario already installed that vario is now history so for the rest of us there isn't much value in comparing the two systems.

[Eric Greenwell]

There is for me: I have a new glider ordered, and I considered keeping the
Butterfly vario that's in my current glider. Now, I'm willing to let it go with
the current glider when I sell it.

It should also be a useful comparison for people that want a vario with a fast
wind update, and now know there is something that may be as good (or maybe even
better) than the now unavailable Butterfly.

[2G]

To get the Hawk option you first have to buy the AHRS option, so the total cost will be something in the neighborhood of $1,200 (the only price I have seen was about 975 euro). If you don't have an AHRS this might make sense, but I already do (a Garmin G5 PFD), so I would have to evaluate it on the wind option alone. I already get real-time wind by comparing my true airspeed to GPS ground speed (which I have displayed side-by-side in Nav boxes). And you can get a stand alone artificial horizon for as little as $335 (https://www.aircraftspruce.com/catalog/avpages/mgl-blaze-11-16581.php).

Tom

[Eric Greenwell]

On 5/1/2021 11:06 AM, 2G wrote:
> On Friday, April 30, 2021 at 7:06:28 AM UTC-7, Eric Greenwell wrote:
>> On 4/30/2021 12:43 AM, John Galloway wrote:

...

>>> The HAWK article referenced on the LXNAV website makes it very clear that it doesn't use magnetic sensing and why:
>>>
>>> https://gliding.lxnav.com/news/segelfliegen-magazines-eng/
>>>
>>> Except for people with a Butterfly vario already installed that vario is now history so for the rest of us there isn't much value in comparing the two systems.
>>>
>> There is for me: I have a new glider ordered, and I considered keeping the
>> Butterfly vario that's in my current glider. Now, I'm willing to let it go with
>> the current glider when I sell it.
>>
>> It should also be a useful comparison for people that want a vario with a fast
>> wind update, and now know there is something that may be as good (or maybe even
>> better) than the now unavailable Butterfly.
>> --
>> Eric Greenwell - USA
>> - "A Guide to Self-launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> To get the Hawk option you first have to buy the AHRS option, so the total cost will be something in the neighborhood of $1,200 (the only price I have seen was about 975 euro). If you don't have an AHRS this might make sense, but I already do (a Garmin G5 PFD), so I would have to evaluate it on the wind option alone. I already get real-time wind by comparing my true airspeed to GPS ground speed (which I have displayed side-by-side in Nav boxes). And you can get a stand alone artificial horizon for as little as $335 (https://www.aircraftspruce.com/catalog/avpages/mgl-blaze-11-16581.php).

Do you have the compass option for the LX? Does your method give real-time wind
direction, or just real-time headwind?

[2G]

No, I don't. The feedback I've been given is that the fluxgate compass doesn't work very well (it's hard to compensate). Would consider it if others gave it their stamp of approval, however.

Tom

[Andrzej Kobus]

You should read carefully before you post. This is just a display you still need a sensor.

The AHRS-2 / MAG-2 can be setup to display the following:
• Compass with optional slip indicator (requires MGL Avionics SP-6 sensor package)
• Horizon with optional slip, turn indicator & G-Force (requires MGL Avionics SP-7/9 sensor package)
• Turn and bank indicator (requires MGL Avionics SP-7/9 sensor package)
• Combined compass and horizon display with bank indicator, optional slip indicator & G-Force (requires MGL Avionics SP6 & SP-7/9 sensor packages)

[waremark]

On Friday, 30 April 2021 at 15:06:28 UTC+1, Eric Greenwell wrote:

> >
> There is for me: I have a new glider ordered, and I considered keeping the
> Butterfly vario that's in my current glider. Now, I'm willing to let it go with
> the current glider when I sell it.
>
> It should also be a useful comparison for people that want a vario with a fast
> wind update, and now know there is something that may be as good (or maybe even
> better) than the now unavailable Butterfly.
> --
> Eric Greenwell - USA
> - "A Guide to Self-launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

I would hold off making that decision until we get more positive feedback on HAWK. My friend who set up HAWK on his S10 a few days ago was disappointed on his first flight with it - a flat-land thermalling flight. On that flight at no time did it give different wind from his LX 9070, or different vario behaviour. I hope we will get better news in due course.

[Matthew Scutter]

Would you expect it to function meaningfully differently in the flatlands? Circling wind should work just fine in a homogenous atmosphere, so functioning the same would be ideal.
Similarly I would be surprised if there was improvement in variometer function from an existing well-compensated setup. All I would wish for additionally from my existing variometer is that it would read accurately in the first second of the pullup into a thermal.

[John Galloway]

According to the the articles the TEK and EKF readings should be very similar while thermal lung as long as the glider is being piloted optimally. I am hoping that it will successfully show real lift in the cruise and avoid spurious readings caused by gusts with a significant horizontal component. A huge bonus would be if it ignores excursions due to g loads during the pull-up or push-over - I am not clear from the articles published whether it can do that.

[metca...@gmail.com]

On Sunday, 2 May 2021 at 11:12:12 UTC+1, jpg...@gmail.com wrote:
> ... very similar while thermal lung as long as the glider ...
Just luuuved your spell-checker's 'thermal lung' for 'thermalling' . Mine (well, Google's) went for 'thermal ling'!
J.

[John Galloway]

Woops - didn't spot that.

[Dan Goldman]

Borglet had/has a similar (?) setup. His video shows a less nervous behavior during thermalling.
Dan

[John Galloway]

On Sunday, 2 May 2021 at 17:37:05 UTC+1, crosscou...@gmail.com wrote:
> Borglet had/has a similar (?) setup. His video shows a less nervous behavior during thermalling.
> Dan

Mike B has previously stated on RAS that the Dynamis system is not based on a filtering method, Kalman or otherwise. I understand that it uses high quality sensors. including one mounted on the rear fuselage, and a sensor fusion unit but how it works is kept confidential.

[waremark]

On Sunday, 2 May 2021 at 06:58:35 UTC+1, Matthew Scutter wrote:

> Would you expect it to function meaningfully differently in the flatlands? Circling wind should work just fine in a homogenous atmosphere, so functioning the same would be ideal.
> Similarly I would be surprised if there was improvement in variometer function from an existing well-compensated setup. All I would wish for additionally from my existing variometer is that it would read accurately in the first second of the pullup into a thermal.

Some Butterfly users reported that as you circle in a thermal you can see the wind indicators pointing in from all directions to the centre of the thermal. As to the vario, as someone else has mentioned the key aspiration is for a system which differentiates vertical gusts from horizontal gusts better than a TE vario. Again, the Butterfly was supposed to achieve this.

[2G]

The best wind indicator I have used in over 40 years of soaring is watching how my circles drift while thermaling - no special sensors, sensor fusion or Kalman filtering required. Second to that is comparing true airspeed to GPS ground speed. I would like to see LXNAV implement a Nav box that differences those two values, however (again, no additional sensors or filtering required).

Tom

[jfitch]

In fact, iGlides thermal assistant is based on that behavior. In rough, two core, or asymmetric thermals it is a better indication than other thermal assistants which just integrate climb rate around the circle. This happens in flatlands as well, but not as uniquely useful there.

On Sunday, May 2, 2021 at 3:59:20 PM UTC-7, waremark wrote:

[krasw]

On Sunday, 2 May 2021 at 08:58:35 UTC+3, Matthew Scutter wrote:
> Would you expect it to function meaningfully differently in the flatlands? Circling wind should work just fine in a homogenous atmosphere, so functioning the same would be ideal.

Matthew, this is what we thought of wind for last 100 years. Now that we can measure it accurately with 1Hz sampling rate, it has proven to anything but homogenous. Thermal does not move with wind (because lower momentum of mass flow of air from surface, millions of kg/minute). Thermal creates plume of rising air, but also a plume of slower moving air. When you measure wind while thermalling, you are measuring this. When leaving thermal, you will fly into stronger wind. Ever had that feeling on headwind final glide that glider just does not want to stay on glide path unless you find lift? You flew into stronger headwind without knowing it. When arriving under cloud, you will most likely fly into lower wind area before flying into thermal. This can be used to your advantage. No need to make those searching turns yet unless the wind calmed down first.

> Similarly I would be surprised if there was improvement in variometer function from an existing well-compensated setup. All I would wish for additionally from my existing variometer is that it would read accurately in the first second of the pullup into a thermal.

Inertial variometer does exactly this, gives a quantitative reading of the gust you feel in your seat. You need to get a used Air GlideS someday.

[Matthew Scutter]

On Monday, May 3, 2021 at 3:53:58 PM UTC+10, krasw wrote:
> On Sunday, 2 May 2021 at 08:58:35 UTC+3, Matthew Scutter wrote:
> > You need to get a used Air GlideS someday.

Actually I flew about 1000 hours with one and found it no better than my CAI302 or even my Winter.... I did not take it across to my new panel. Yes, I read the installation manual, adjusted all the calibrations, I even tried a remote install on the CG above the spars, far from any metal or electric fields, yes I read the myriad of unofficial PDF alternative operating instructions. Glad to hear it worked for you though.

[krasw]

Having heard this story from other pilot who really did everything possible to make it work, it is possible that there are just units that are not working correctly. Such a shame. I did one installation of ISU behind wings in fuselage, running pneumatic lines, can etc. there, quite an effort.

[Eric Greenwell]

I prefer an instrument that will give the vector wind without circling, because
circling is not always convenient (eg, mountain flying near/in the ridges) and
reduces my average cruise speed. Determining the instantaneous headwind with the
difference between airspeed and ground speed is useful, but it is not the vector
wind. My CN vario in the Phoenix can determine the vector wind with minor course
changes while cruising, a better solution, I think. The Butterfly/Display S can
determine it without circling or course changes, the best solution for me.

But, wind determination is not the only goal of these inertial methods, but also
improving the vario response in the presence of gusts. Circling drift and
headwind determinations can't do that. I'm hoping Hawk will equal or exceed the
Butterfly's abilities.

[Dan Marotta]

I gotta ask: If the Butterfly vario was so great, why was it discontinued?

Dan
5J

[jfitch]

I'd agree that the pneumatic variometry on the Air Glide S is not markedly better than the other offerings, this is well trodden technology. To get any advantage you need to learn to use the inertial variometry and the instantaneous wind. And I say "learn to use" because it is a new skill requiring conscious effort. Wavelets, convergence lines, and transient winds for glides can be identified from the display itself, thermal cores really require using iGlide to see the plot. The inertial variometer requires a lot of study to make use of. I think many pilots do not put this work into it, so any other variometer is as good. I have both the Air Glide and a CN variometer in the panel, for normal stuff the CN is as good - but it misses out entirely on the dynamics of wind, and in a rough or irregular thermal the usable core is better identified by iGlide and the Air.

[Nicholas Kennedy]

Like Matt Scutter said I don't think we've come real far in the wind reading dept since the CAI 302/303.
I Watch Brunos panel in his vids and IMHO opinion his varios are way too wild for me to try using.
I still fly behind the the 302/303 combo.
It gives no less than 4 wind indications and I find them all to be very accurate.
Comparing them to my Seeyou mobile in flight they often are very well matched up.
1. It gives Fast Component winds, updated every second in straight line flight.
This function has helped me find the core hundreds of times.
2. Average headwind Tailwind averaged over 30 seconds.
3.Vector wind, updated when the glider turns at least 30 degrees.
4.Relative wind direction. This is the direction of the wind relative to the gliders GPS Track over the ground.
I think the 302 was so far ahead of its time, it was digital. Never needed a software update they got it right the first time out
Totally adjustable in flight for needle and sound response and TE compensation.
Gary Kammer still has parts and services these units. I just got mine serviced and a recalibration sheet for this season.

Nick
T

[jfitch]

All those means of wind sensing use the same principle and math, so I don't doubt they would agree. They would not agree with an Air Glide S. I'm quite familiar with what the Cambridge will do, having flown with one for many years (and SeeYou mobile, Winpilot, S10, XCSoar, CN, etc). Like others using the same methods, they are pretty accurate at winds averaged over longer intervals. Short period variations they miss completely. Hopefully the Hawk is better.

[Richard Pfiffner]

On Monday, May 3, 2021 at 1:05:10 PM UTC-7, nickkennedy...@gmail.com wrote:

If you change the filter setting in the Air-Avionics Vario you can make them un wild easily. I flew with the 302 also and I believe the LXNAV Varios. and Air-Avionics vario are a huge improvement.

Richard
www.craggyaero.com

[2G]

If this were the case then I would immediately see a stronger wind, as measured by the difference between true airspeed and GPS ground speed, upon leaving the thermal. I do not see this, ever. And I am monitoring it on virtually every thermal. This way of measuring wind does only give me the headwind component, but I get it in real time. If I want to check the direction I can turn until the difference is maximized. This only takes a few seconds. Most of the time I don't need to do this.

I intend to try out Hawk for a trial and see what difference it makes.

Tom

[Jax]

In my experience the wind on the Airglide (even that it does not seem 100% accurate) provides very useful information, I mostly use the difference between the circling wind from XCSoar and the airglide wind. It is most useful flying convergences when you are not near the top part of the convection layer.

My conclusion is that the normal vario ie: the black triangle does not use the inertial platform, the blue ball on the other hand uses both the pneumatic and inertial platform.
I found the blue ball is usually a leading indicator but it is not 100% reliable, yet it can be very useful in certain circumstances.

The people that only listen to the vario (which is what we do 99% of the time) and think the Airglide vario is nothing special are perfectly correct. The sound is the black triangle, often I would prefer it to be on the blue ball but sadly we can't change it.

All in all the Airglide is my prefered vario, it is not a game changer but it is a very high quality device, very intuitive interface, it has all the info needed displayed in a simple and readable format (except for the too small wind arrow) it has a very pleasant tone with a subtle volume increase between tones rather than a harsh on/off plus it has the extra wind and inertial platform that gives the extra info when you dare bringing your eyes inside the cockpit. An Airglide with HUD focussed to horizon would be perfect :)

[Aldo Cernezzi]

I'm wondering if the Hawk upgrade will provide the same results when installed in the LX9000 series as when installed in the S10/S100 vario units. I wouldn't want to pay for an upgrade that works less effectively than intended: I'd rather upgrade the V9 vario to an S100.

My LX9000 already has the AHRS option (payed), so I'm wondering if Hawk will have lower price in this case (but I guess not, as the company says AHRS is a required function, but it may remain "hidden" to the pilot if they don't but that option).

A simpler option would be the Anemoi standalone device. It requires a power supply and simple pneumatic connections to the existing tubings. It will only calculate wind vectors (plus free AHRS), while skipping on the inertial vario functions. All based on similar sensor-fusion technology and extended Kalman filter.

When flying in the mountains, instant wind vector display is an absolute advantage. In the flatland, an averaged calculation may be satisfactory. I used to be a big Zander fan (magnetic compass interface, almost completely free from the unsolvable problems created by flux-gate compasses). Now I'm happy to see a new generation of promising devices.


Aldo Cernezzi
www.voloavela.it

[Aldo Cernezzi]

Il giorno martedì 4 maggio 2021 alle 10:13:25 UTC+2 Jax ha scritto:

> The people that only listen to the vario (which is what we do 99% of the time) and think the Airglide vario is nothing special are perfectly correct. The sound is the black triangle, often I would prefer it to be on the blue ball but sadly we can't change it.

That's a very interesting observation. Thanks!

Aldo

[Christoph Barniske]

Marc Förderer once told me that in SC mode, the audio signal reflects the airmass indicator (blue ball). He recommended to set the airmass mixer to 100% inertial, airmass filter to 3.4s and SC filter to 0.

Christoph

[Jax]

I was referring to Climb mode, it is very possible that the sound reflects the blue ball reading in cruise, I never switch always use climb mode so I can't confirm.

[Moshe Braner]

Not quite about Hawk Wind, but the same is possible with XCsoar or
Tophat: there is an infobox available that shows IAS, but it is hidden:
it is not included in the short list that appears when you tap the
settings icon for an infobox. You need to get several levels deep
inside the system settings designing the screen(s) to get the full list.
Now that I found it, I added it to my display. This allows me to
double-check the "component wind" (head or tail) by comparing the IAS
displayed there with what is displayed on my ASI. Note: yes, I wrote
IAS not TAS. This is a flight computer with no connection to the pitot
system. The estimated IAS displayed in that infobox is computed based
on the GPS ground speed, the estimated wind (resulting in TAS), and the
air density (approximated based on the altitude). If it differs from
the ASI reading, that shows that the true wind differs from the
estimated wind. E.g., if the infobox says 60 knots and the ASI says 65
knots that means there are 5 more knots of headwind (or less tailwind)
than the computer's estimate of the wind.

[krasw]

On Wednesday, 5 May 2021 at 01:35:20 UTC+3, Aldo Cernezzi wrote:
>
> When flying in the mountains, instant wind vector display is an absolute advantage. In the flatland, an averaged calculation may be satisfactory. I used to be a big Zander fan (magnetic compass interface, almost completely free from the unsolvable problems created by flux-gate compasses). Now I'm happy to see a new generation of promising devices.
>
>
> Aldo Cernezzi
> www.voloavela.it

The vector math of calculating instant wind from TAS/GS difference with corresponding flight track is pretty simple. What I don't understand is how to do this unless you have consecutive wind vectors from different directions. Thus Hawk cannot update wind reading unless glider is in circling flight. Yes there is no problems with compass, but there is no way of determining wind by flying to one direction.

[Eric Greenwell]

Have you read their paper? They are certain they can determine wind without
circling or a compass. I don't pretend to understand the paper, but this portion
from the paper describes how it might be possible:

"The mathematical system theory also answers the question under what conditions
a wind estimation is possible. In the case of a borderline case of an exact
straight flight movement and completely calm air, this is not possible. All
triangles are identical. We (Huang and Meyr) could show, however, that the
random changes in the air movement are sufficient to make the system
"observable.” "

[Andrzej Kobus]

Have you heard of "Growth mindset"? I think the appropriate thing to say would have been that you would love to learn how that was achieved, just in case you might be wrong, especially if some very smart people said that they had done it.

[krasw]

On Thursday, 6 May 2021 at 00:15:44 UTC+3, Eric Greenwell wrote:>
> "The mathematical system theory also answers the question under what conditions
> a wind estimation is possible. In the case of a borderline case of an exact
> straight flight movement and completely calm air, this is not possible. All
> triangles are identical. We (Huang and Meyr) could show, however, that the
> random changes in the air movement are sufficient to make the system
> "observable.” "
> --
> Eric Greenwell - USA
> - "A Guide to Self-launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

For wind vector you need two TAS-GS difference/track vectors. If they are identical (same direction of flight), you have no wind solution (as stated in paper). Optimum would be two vectors with 90 degrees difference, and measured in extremely short duration (this is how Oudie "live wind" tries to do it, though I haven't got it working). This would give an ok solution in circling flight, but at the same time the angular speed while circling is not very high, so sensing wind vector at different parts of thermal is rather slow (on steep turn with AIR Glide S gives you basically 20-25 separate wind measurements with 1 sec average). In straight flight Hawk is relying on miniscule differences in flight track. Instead of two wind vector components with 90 degree difference in direction they have vectors that have only few degrees difference on average. I would love to see someone comparing wind indications of Hawk and Glide S someday.

[John Galloway]

Krasw, if you study the paper you will see that your end point is the author's start question i.e. how can you possibly estimate 3D "wind" at high frequency without heading data input from a magnetometer?

[jfitch]

The paper is fairly circumspect on the details of what they are doing. Their claim that this hasn't been done before seems disingenuous, given that the Air Vario had been out for a number of years producing (or claiming to produce) a similar result. Air's efforts are described in a university published paper from some years ago. Their methods appear to be similar. But I am glad that someone has taken up the challenge that Air Avionics has now dropped. Whether it is better or worse will require installing both in the panel and flying for awhile. The advantages they expound of knowing the true wind in real time are already well known to anyone with an Air Display S who has paid attention to it.

[John Galloway]

The Air Avionics wind and blue ball netto calculations are dependent on data from an accurately reading magnetometer - and installing one of those free from EM fields is its Achilles' heel, and also the reason I never got one when they were still on sale So, to my mind the Hawk method is definitely new - although I am more interesting in finding out whether it works rather than who did what first.

I thought the paper contained a lot detail on the concept and implementation including the statement:

"Mathematical system theory also answers the question under which conditions wind estimation is possible. In the limiting case of an exactly straight-line flight motion and perfectly calm air, this is not possible. All triangles are identical. However, we could show (Huang und Meyr) that the random changes in the airmass movement are sufficient to make the system "observable"."

From this, if true, one might infer that what would be to the pilot "miniscule differences in flight track" would actually yield plenty data for the system to calculate wind.

[jfitch]

Air Avionics have been equally circumspect on exactly what they do, and how much each of the 9 axis MEMs sensors contribute to that. Using the magnetometer has some advantages, as the limiting case of straight line flight in steady flow can still produce a wind calculation, also it makes inherent an AHRS which is not possible without it. I'd agree that the result is the most important, I'd pop one in the panel and find out but they are a bit pricey as an impulse purchase - costing somewhat more than an Air Avionics did when they were still sold.

[Richard Pfiffner]

Actually the S100 with Hawk winds is about the same price as the Air-Avionics Display S + AHRS.

Richard

[jfitch]

Richard, does that include the AHRS? Or is that another $900? Hard to tell from published data, but it looks like they are separate options. The Air came with both.

[Richard Pfiffner]

I think it comes with the AHRS.

Richard

[Ramy]

LX9000 has instantaneous HW/TW box called Cwind. But to get it to work right you need to turn off units and label and ignore the number in the right. The left number is instantaneous HW/TW Calculated from HS-TAS. As important as the Hawk wind, yet free, very simple reliable calculation, and very well hidden feature. Go figure.

Ramy

On Sunday, May 2, 2021 at 9:39:57 PM UTC-7, 2G wrote:
> On Sunday, May 2, 2021 at 3:59:20 PM UTC-7, waremark wrote:

> > On Sunday, 2 May 2021 at 06:58:35 UTC+1, Matthew Scutter wrote:
> > > Would you expect it to function meaningfully differently in the flatlands? Circling wind should work just fine in a homogenous atmosphere, so functioning the same would be ideal.

> > > Similarly I would be surprised if there was improvement in variometer function from an existing well-compensated setup. All I would wish for additionally from my existing variometer is that it would read accurately in the first second of the pullup into a thermal.

> > Some Butterfly users reported that as you circle in a thermal you can see the wind indicators pointing in from all directions to the centre of the thermal. As to the vario, as someone else has mentioned the key aspiration is for a system which differentiates vertical gusts from horizontal gusts better than a TE vario. Again, the Butterfly was supposed to achieve this.

> The best wind indicator I have used in over 40 years of soaring is watching how my circles drift while thermaling - no special sensors, sensor fusion or Kalman filtering required. Second to that is comparing true airspeed to GPS ground speed. I would like to see LXNAV implement a Nav box that differences those two values, however (again, no additional sensors or filtering required).
>
> Tom

[jfitch]

So you get the magnetometer with the Hawk option? I guess probably it is in the MEMs sensor they install in every unit and just turn it on?

[2G]

The magnetometer option is a separate box, and for good reason: you need to position it somewhere free from stray magnetic fields. So, I don't think that Hawk wind uses it. It's not cheap, however:
https://wingsandwheels.com/lxnav-magnetic-compass.html

Tom

[krasw]

On Thursday, 6 May 2021 at 18:54:14 UTC+3, jfitch wrote:
> The paper is fairly circumspect on the details of what they are doing. Their claim that this hasn't been done before seems disingenuous, given that the Air Vario had been out for a number of years producing (or claiming to produce) a similar result. Air's efforts are described in a university published paper from some years ago.

Yes, they are ignoring basically everything that has been done with variometer tech during last 25 years.

[Eric Greenwell]

Not ignoring, but purposely avoiding pressure variometry and it's inherent
problems. LXNav has chosen to add Hawk to their varios, so the commercial
implementation of Hawk (currently in the S100) does not ignore conventional
pressure variometer tech. What Jon is wondering, as I am, is how different is
Hawk from the techniques used to drive the Air Vario's "Blue Ball".

[2G]

On Friday, May 7, 2021 at 6:12:20 AM UTC-7, Richard Pfiffner wrote:
> The Compass has not been available for many years from LXNAV. They don't stock it and don't ship it.
>
> Richard
> www.craggyaero.com

That's funny - your website lists it:
http://www.craggyaero.com/lxnav_accessories.htm

[2G]

...and it is also on LXNAV's website:
https://gliding.lxnav.com/products/compass/