AIR Glide S

[krasw]

I recently found some interesting articles concerning AIR Glide S and it's inertial platform in particular. Enjoy:

http://www.how2soar.de/index.php/584-butterfly-without-frustration

http://www.how2soar.de/images/H2S_media/02_pdf/Butterfly%20Vario%20englisch%20V2.1.pdf

http://www.asl.ethz.ch/people/lestefan/personal/icra2012.pdf

Latter one has some heavy math in it, but worth reading anyway (incl. references for further study). They measured AIR Glide ISU accuracy with GPS signal switched off. Position error was 600 meter after 30 mins flight. Not bad.

[Bruce Hoult]

On Tuesday, October 20, 2015 at 6:12:13 PM UTC+3, krasw wrote:
> I recently found some interesting articles concerning AIR Glide S and it's inertial platform in particular. Enjoy:
>
> http://www.how2soar.de/index.php/584-butterfly-without-frustration
>
> http://www.how2soar.de/images/H2S_media/02_pdf/Butterfly%20Vario%20englisch%20V2.1.pdf
>
> http://www.asl.ethz.ch/people/lestefan/personal/icra2012.pdf
>
> Latter one has some heavy math in it, but worth reading anyway (incl. references for further study). They measured AIR Glide ISU accuracy with GPS signal switched off. Position error was 600 meter after 30 mins flight. Not bad.

Without (yet) reading those documents, that is amazing. It suggests that the accuracy of the accelerometers is on average within 0.00004 of a G.

[Andrzej Kobus]

A question to anyone who uses AirGlide S. Is there a nav box available in the software that displays compass reading?

Regards, Andrzej

[JS]

Not as far as I can tell, but some options are abbreviated and without pop-up explanation. There is GPS track like any other instrument.
Perhaps heading is reserved for the Display M and L?
Jim

On Tuesday, October 20, 2015 at 11:21:19 AM UTC-7, Andrzej Kobus wrote:
> A question to anyone who uses AirGlide S. Is there a nav box available in the software that displays compass reading?
>
> Regards, Andrzej

[krasw]

On Tuesday, 20 October 2015 21:21:19 UTC+3, Andrzej Kobus wrote:
> A question to anyone who uses AirGlide S. Is there a nav box available in the software that displays compass reading?
>
> Regards, Andrzej

Not as navbox, but magnetic compass reading is visible on horizon page.

[John Carlyle]

Thanks for posting those links. I'd be interested in trying some of the settings described in the second link - if I could just read the instrument settings.

Any chance that someone could translate the words on the screens?

-John, Q3

On Tuesday, October 20, 2015 at 11:12:13 AM UTC-4, krasw wrote:
> I recently found some interesting articles concerning AIR Glide S and it's inertial platform in particular. Enjoy:
>
> http://www.how2soar.de/index.php/584-butterfly-without-frustration
>
> http://www.how2soar.de/images/H2S_media/02_pdf/Butterfly%20Vario%20englisch%20V2.1.pdf
>
> http://www.asl.ethz.ch/people/lestefan/personal/icra2012.pdf
>
> Latter one has some heavy math in it, but worth reading anyway (incl. references for further study). They measured AIR Glide ISU accuracy with GPS signal switched off. Position error was 600 meter after 30 mins flight. Not bad.

[George Haeh]

At 21:16 20 October 2015, John Carlyle
wrote:
>Thanks for posting those links. I'd be
interested in trying some of the
>settings described in the second link - if I
could just read the instrument
>settings.
>
>Any chance that someone could
translate the words on the screens?
>
>-John, Q3

Just enter the setup menus in English.
The boxes should be in the same order.

[jfitch]

On Tuesday, October 20, 2015 at 8:12:13 AM UTC-7, krasw wrote:
> I recently found some interesting articles concerning AIR Glide S and it's inertial platform in particular. Enjoy:
>
> http://www.how2soar.de/index.php/584-butterfly-without-frustration
>
> http://www.how2soar.de/images/H2S_media/02_pdf/Butterfly%20Vario%20englisch%20V2.1.pdf
>
> http://www.asl.ethz.ch/people/lestefan/personal/icra2012.pdf
>
> Latter one has some heavy math in it, but worth reading anyway (incl. references for further study). They measured AIR Glide ISU accuracy with GPS signal switched off. Position error was 600 meter after 30 mins flight. Not bad.

Regarding the description of wind accuracy in the first link: This was my impression also: that the instantaneous wind indication could not be accurate, as it was so dynamic. However after two years of use I have come to believe it is accurate, and the wind field really is that dynamic, you just had no way to measure it before. This instrument is really in a class of its own.

[krasw]

On Wednesday, 21 October 2015 03:32:11 UTC+3, jfitch wrote:
>
> Regarding the description of wind accuracy in the first link: This was my impression also: that the instantaneous wind indication could not be accurate, as it was so dynamic. However after two years of use I have come to believe it is accurate, and the wind field really is that dynamic, you just had no way to measure it before. This instrument is really in a class of its own.

I agree, I started noticing noise in wind measurement when going to under 2 sec time constant. Wind measurement is basically as fast as the variometer.. Now who would do a software where I could record 3D airmass movement with AIR Glide to a file and visualize it later with Seeyou or similar?

[Dan Marotta]

Of what use is instantaneous wind? Can you react to it without flapping
control surfaces all over the place? Do you use it for planning your
next turn in a thermal?

Not knocking it, I just don't get it why it would be important. Please
enlighten me.

On 10/21/2015 3:06 AM, krasw wrote:
> On Wednesday, 21 October 2015 03:32:11 UTC+3, jfitch wrote:
>> Regarding the description of wind accuracy in the first link: This was my impression also: that the instantaneous wind indication could not be accurate, as it was so dynamic. However after two years of use I have come to believe it is accurate, and the wind field really is that dynamic, you just had no way to measure it before. This instrument is really in a class of its own.
> I agree, I started noticing noise in wind measurement when going to under 2 sec time constant. Wind measurement is basically as fast as the variometer. Now who would do a software where I could record 3D airmass movement with AIR Glide to a file and visualize it later with Seeyou or similar?

--
Dan, 5J

[Alex[_6_]]

Comparing instantaneous wind to average wind will show you any local wind deviations as they occur near thermals. Can't find the thermal under a cloud? Just follow the diverging local wind. Need to find the best line along a cloud street or convergance? Watch the local wind. Feel that blue thermal nearby, but not sure where to turn? The wind will tell you.



Am Mittwoch, 21. Oktober 2015 16:01:38 UTC+2 schrieb Dan Marotta:
> Of what use is instantaneous wind?* Can you react to it without
> flapping control surfaces all over the place?* Do you use it for
> planning your next turn in a thermal?
>
>
>
> Not knocking it, I just don't get it why it would be important.*
> Please enlighten me.

[Richard[_9_]]

On Tuesday, October 20, 2015 at 2:16:29 PM UTC-7, John Carlyle wrote:
> Thanks for posting those links. I'd be interested in trying some of the settings described in the second link - if I could just read the instrument settings.
>
> Any chance that someone could translate the words on the screens?
>
> -John, Q3
>
> On Tuesday, October 20, 2015 at 11:12:13 AM UTC-4, krasw wrote:
> > I recently found some interesting articles concerning AIR Glide S and it's inertial platform in particular. Enjoy:
> >
> > http://www.how2soar.de/index.php/584-butterfly-without-frustration
> >
> > http://www.how2soar.de/images/H2S_media/02_pdf/Butterfly%20Vario%20englisch%20V2.1.pdf
> >
> > http://www.asl.ethz.ch/people/lestefan/personal/icra2012.pdf
> >
> > Latter one has some heavy math in it, but worth reading anyway (incl. references for further study). They measured AIR Glide ISU accuracy with GPS signal switched off. Position error was 600 meter after 30 mins flight. Not bad.

John,

Google translator

Richard
www.craggyaero.com

[jfitch]

On Wednesday, October 21, 2015 at 7:01:38 AM UTC-7, Dan Marotta wrote:
> Of what use is instantaneous wind?* Can you react to it without
> flapping control surfaces all over the place?* Do you use it for
> planning your next turn in a thermal?
>
>
>
> Not knocking it, I just don't get it why it would be important.*
> Please enlighten me.
>
>
>
>
> On 10/21/2015 3:06 AM, krasw wrote:
>
>
>
> On Wednesday, 21 October 2015 03:32:11 UTC+3, jfitch wrote:
>
>
> Regarding the description of wind accuracy in the first link: This was my impression also: that the instantaneous wind indication could not be accurate, as it was so dynamic. However after two years of use I have come to believe it is accurate, and the wind field really is that dynamic, you just had no way to measure it before. This instrument is really in a class of its own.
>
>
> I agree, I started noticing noise in wind measurement when going to under 2 sec time constant. Wind measurement is basically as fast as the variometer. Now who would do a software where I could record 3D airmass movement with AIR Glide to a file and visualize it later with Seeyou or similar?
>
>
>
>
>
> --
>
> Dan, 5J

The companion software iGlide uses it as a thermal centering tool. Each lift dot displayed each second while thermaling has in it an instantaneous wind vector. These point towards the center of the thermal with pretty good reliability. I have experimented with using the instantaneous wind deviation to judge which way to turn, however iGlide does not display the vectors until you have already turned about 270 or you zoom in to an otherwise unusable level. Something I would like them to work on.

There are other uses: flying out of Truckee and returning from the south we have long known that the glide over the Carson valley is usually better than fair at the end of the day. I thought this was due to delayed sink, buoyant air, or something. But now I know that there is very frequently a strong tailwind blowing up the middle of the valley above about 12,000 ft. Like 22 - 28 knots from the south on an otherwise 10 knots from the west day. So rather than crossing directly to Lake Tahoe, I now fly up the middle of the valley until I lose that tailwind, then turn. Never knew that before and most people still don't. This kind of tailwind will eventually show up on computers using traditional wind calculation methods, but the time constants are so long you will lose most of the benefit. The shift in velocity does not show up on CU or XCSoar until you are just about out of it.

I also now notice serious wind shears with increasing altitude. The headwind may increase from 12 knots to 22 knots in 500 ft of climb. Usually near the top of the thermal band, but worth exploiting in some instances.

[Dan Marotta]

That's great for telling me what does, but not how to use it. Are you
saying to always turn downwind in the local micro wind to get to the
center of the thermal?

Maybe my CNvXC vario has this capability, maybe not. I'll have to do
some research on that. In the mean time, I've had good luck with
finding thermals at the upwind edge of cumulus clouds. That's not
always the case but true more often than not.

On 10/21/2015 8:34 AM, Alex wrote:
> Comparing instantaneous wind to average wind will show you any local wind deviations as they occur near thermals. Can't find the thermal under a cloud? Just follow the diverging local wind. Need to find the best line along a cloud street or convergance? Watch the local wind. Feel that blue thermal nearby, but not sure where to turn? The wind will tell you.
>
>
>
> Am Mittwoch, 21. Oktober 2015 16:01:38 UTC+2 schrieb Dan Marotta:
>> Of what use is instantaneous wind? Can you react to it without
>> flapping control surfaces all over the place? Do you use it for
>> planning your next turn in a thermal?
>>
>>
>>
>> Not knocking it, I just don't get it why it would be important.
>> Please enlighten me.

--
Dan, 5J

[JS]

Dan et al,
Flying in convergence, the Air-Glide informs you of approaching shear line conditions. The wind changes from a ~10Kt tailwind through 9, 6, 4, 3, to "Still", at which point your vario is going up. If you fly through the shear, there will be a similar indicated headwind.
Running along the shear, if the wind is from your right, move left. If it is from your left, move right. Simple. Accurate. Just as you imagine this shear stuff works.
No other vario I have personally flown with that will do that.
Jim


On Wednesday, October 21, 2015 at 2:33:02 PM UTC-7, Dan Marotta wrote:
> That's great for telling me what does, but not how to use it.* Are
> you saying to always turn downwind in the local micro wind to get to
> the center of the thermal?
>
>
>
> Maybe my CNvXC vario has this capability, maybe not.* I'll have to
> do some research on that.* In the mean time, I've had good luck with
> finding thermals at the upwind edge of cumulus clouds.* That's not
> always the case but true more often than not.
>
>
>
>
> On 10/21/2015 8:34 AM, Alex wrote:
>
>
>
> Comparing instantaneous wind to average wind will show you any local wind deviations as they occur near thermals. Can't find the thermal under a cloud? Just follow the diverging local wind. Need to find the best line along a cloud street or convergance? Watch the local wind. Feel that blue thermal nearby, but not sure where to turn? The wind will tell you.
>
>
>
> Am Mittwoch, 21. Oktober 2015 16:01:38 UTC+2 schrieb Dan Marotta:
>
>
> Of what use is instantaneous wind?* Can you react to it without
> flapping control surfaces all over the place?* Do you use it for
> planning your next turn in a thermal?
>
> Not knocking it, I just don't get it why it would be important.*
> Please enlighten me.
>
> Dan, 5J

[Jonathan St. Cloud]

Does the LX 9070 or similar with the compass option provide the same information?

On Wednesday, October 21, 2015 at 8:09:54 PM UTC-7, JS wrote:
> Dan et al,
> Flying in convergence, the Air-Glide informs you of approaching shear line conditions. The wind changes from a ~10Kt tailwind through 9, 6, 4, 3, to "Still", at which point your vario is going up. If you fly through the shear, there will be a similar indicated headwind.
> Running along the shear, if the wind is from your right, move left. If it is from your left, move right. Simple. Accurate. Just as you imagine this shear stuff works.
> No other vario I have personally flown with that will do that.
> Jim
>
>
>

[krasw]

On Thursday, 22 October 2015 08:19:48 UTC+3, Jonathan St. Cloud wrote:
> Does the LX 9070 or similar with the compass option provide the same information?

At similar rate and accuracy? Absolutely not.

Several legacy variometers have had electric compass options since 90's. Instant wind speed can be calculated with TAS, GS, track and compass reading. Electric compass placement was absolutely critical then, as it is today. Comparing wind display of these old computers to full blown AIR Glide ISU is day and night difference. Since variometer manufacturers are shy of revealing the science behind their products, one can only quess what technology goes into LX.

[[email protected]]

How do you know the LX 9000 series with compass doesn't perform as well for winds? The new LX Nav compass module with 3 axis accelerometers and 3 axis magnetometers has only recently become available and I, for one, am waiting to hear how it is performing.

John Galloway

[Bruce Hoult]

On Thursday, October 22, 2015 at 10:00:09 AM UTC+3, krasw wrote:
> Several legacy variometers have had electric compass options since 90's. Instant wind speed can be calculated with TAS, GS, track and compass reading.

Instant headwind/tailwind component, yes.

Side gusts are unknown until either the glider equalizes with them, or the pilot uses the rudder to bring the yawstring into the middle (which will change the compass reading and TAS).

Now, if the yawstring angle was an input to the computer...

(or, better, a weather vane in the free flow .. maybe a nice addition to the TE probe? Or use multiple suction holes at different angles, with individual pressure metering)

[Rhubarb[_2_]]

My current setup is: redbox Flarm IGC - LX V7 - GliderGuider - XCSoar

From XCSoar I can
- declare tasks and download flights to/from the redbox
- sync V7 settings such as MC,ballast,bugs,QNH
- IIRC V7 gets goal info for final glide etc from XCSoar
- display Flarm info

I am wondering if I can replace the V7 and redbox with an AirGlide. I realise that it is not so well supported by XCSoar but is it still compatible or will I lose functionality.

setup would then be (I guess) something like

AirGlide sensor box IGC - AirGlide S - AIR Glide NMEA Interface Box - GG - XCsoar

Obviously I am especially interested in the wind info. Is it shown (well) on the AirGlide S or do I need one of the bigger displays to gain full advantage.

Is wind only shown *after* I start circling as mentioned in the linked document which would be a shame

Does the AirGlide send out this tasty wind (and inertial) info on the serial cable (at a fast rate) so that XCSoar could displayed it (maybe with some additional programming).

Peter

[[email protected]]

Hi,

I've flown both, CNv XC and Air Glide S (aka Butterfly Vario). In terms of wind indication, Air Glide S has far superior capabilities. I don't know any instrument in gliding that has the same speed and resolution of wind vector and speed.

However, the sensor unit needs to be correctly placed and well compensated. This may require quite some effort, especially in motorgliders with a lot of cables and metal in the fuselage. But probably the same applies to other AHRS units.

Best,
Christoph

[krasw]

torstai 22. lokakuuta 2015 10.31.21 UTC+3 kirjoitti:
> How do you know the LX 9000 series with compass doesn't perform as well for winds? The new LX Nav compass module with 3 axis accelerometers and 3 axis magnetometers has only recently become available and I, for one, am waiting to hear how it is performing.
>
> John Galloway

I had the impression that they have been running inertial platform (with wind output) for years as they advertise their variometers have mems gyros and accelerometers already. Compass reading is essential part of inertial platform. For clarification, I have not flown with latest compass module.


torstai 22. lokakuuta 2015 10.51.09 UTC+3 Bruce Hoult kirjoitti:
> Instant headwind/tailwind component, yes.
>
> Side gusts are unknown until either the glider equalizes with them, or the pilot uses the rudder to bring the yawstring into the middle (which will change the compass reading and TAS).

Gusts were out of reach for these systems, that's true. But Zander for example shows wind vector as numerical info line. Sure it is harder to interpret when seeing only direction and speed in number rather than animated arrow, but it is "instant wind vector" nontheless.

[krasw]

torstai 22. lokakuuta 2015 10.51.29 UTC+3 Rhubarb kirjoitti:
> setup would then be (I guess) something like
>
> AirGlide sensor box IGC - AirGlide S - AIR Glide NMEA Interface Box - GG - XCsoar

You would probably want to keep your Redbox Flarm as AIR Glide doesn't have flarm integrated.

>
> Obviously I am especially interested in the wind info. Is it shown (well) on the AirGlide S or do I need one of the bigger displays to gain full advantage.
>

The wind arrow is in the middle of the variometer screen, hard to think more prominent way to display it.

> Is wind only shown *after* I start circling as mentioned in the linked document which would be a shame

No, wind vector is visible all the time.

>
> Does the AirGlide send out this tasty wind (and inertial) info on the serial cable (at a fast rate) so that XCSoar could displayed it (maybe with some additional programming).
>
> Peter

AIR Glide parses flarm traffic, gps position, altitude and variometer reading together and send them to CU/XCSoar. You can choose the format, AIR Glide can emulate LX or CAI data lines. I use CAI emulation, so my Seeyou Mobile thinks that it is connected to CAI302. AFAIK it does NOT send instant wind data out. For a long final glide I like to use averaged wind from longer time, instant wind gives you a lot of variation to arrival height. When close to airport I tend to follow more AIR Glide final glide calculation. It's nice to have both opinions.

[Bruce Hoult]

On Thursday, October 22, 2015 at 11:14:37 AM UTC+3, krasw wrote:
> I had the impression that they have been running inertial platform (with wind output) for years as they advertise their variometers have mems gyros and accelerometers already. Compass reading is essential part of inertial platform. For clarification, I have not flown with latest compass module.

MEMS devices are cheap and rugged, but they are not necessarily very high precision.

The ones I've played with, in the single digit to very low double digit dollar price range -- which is what you find in smartphones -- are fine for deciding when to switch your screen from portrait to landscape, and can function as an acceptable inertial platform for up to maybe 30 seconds or so.

I've never come across one that could -- purely inertially -- have only 600m position error after half an hour. That implies that the speed is still accurate to better than about 3 knots after that time.

To do that, I think you're going to need at *least* 18 bits of useful precision in each axis. I'd expect that to cost quite a few hundred or even a thousand dollars for the chip alone, unless these things have really come along in the last year or two.

[Dan Marotta]

Nice description, thanks!

Most of my experience with shear in New Mexico has involved a long line
of clouds with bases considerably higher on one side of the line. It's
a simple matter to find and use the lift. Next time I get the chance to
fly in shear I'll try to watch the wind indication on my ClearNav
vario. It's pretty quick to update, but I don't think it will be as
useful as you described.

On 10/21/2015 9:09 PM, JS wrote:
> Dan et al,
> Flying in convergence, the Air-Glide informs you of approaching shear line conditions. The wind changes from a ~10Kt tailwind through 9, 6, 4, 3, to "Still", at which point your vario is going up. If you fly through the shear, there will be a similar indicated headwind.
> Running along the shear, if the wind is from your right, move left. If it is from your left, move right. Simple. Accurate. Just as you imagine this shear stuff works.
> No other vario I have personally flown with that will do that.
> Jim
>
>
> On Wednesday, October 21, 2015 at 2:33:02 PM UTC-7, Dan Marotta wrote:
>> That's great for telling me what does, but not how to use it. Are
>> you saying to always turn downwind in the local micro wind to get to
>> the center of the thermal?
>>
>>
>>
>> Maybe my CNvXC vario has this capability, maybe not. I'll have to
>> do some research on that. In the mean time, I've had good luck with
>> finding thermals at the upwind edge of cumulus clouds. That's not
>> always the case but true more often than not.
>>
>>
>>
>>
>> On 10/21/2015 8:34 AM, Alex wrote:
>>
>>
>>
>> Comparing instantaneous wind to average wind will show you any local wind deviations as they occur near thermals. Can't find the thermal under a cloud? Just follow the diverging local wind. Need to find the best line along a cloud street or convergance? Watch the local wind. Feel that blue thermal nearby, but not sure where to turn? The wind will tell you.
>>
>>
>>
>> Am Mittwoch, 21. Oktober 2015 16:01:38 UTC+2 schrieb Dan Marotta:
>>
>>
>> Of what use is instantaneous wind? Can you react to it without
>> flapping control surfaces all over the place? Do you use it for
>> planning your next turn in a thermal?
>>
>> Not knocking it, I just don't get it why it would be important.
>> Please enlighten me.
>>
>> Dan, 5J

--
Dan, 5J

[jfitch]

I have used XCSoar with the Air Avionics ISU. The serial stream mimics either LX or CAI protocol, and either can be used with XCSoar. Wind data is transmitted in both procotols, but in a time filtered form. However XCSoar does not seem to use that data, rather it calculates wind using its own traditional methods.

While others have claimed to have and use inertial sensors going back to the first CAI 302, it appears as though no one except Air is actually using them to a meaningful result even today.

[krasw]

On Friday, 23 October 2015 00:27:41 UTC+3, wrote:
>
> bruce, i think you might be assuming the butterfly is merely doing dead reckoning, but what it's doing is more complex than that. it uses an extended kalman filter (EKF), which is a type of software algorithm that is good for estimating the state of something that cannot be directly measured (the motion of the glider, in this case). the EKF takes various data steams as input: accelerometer, gyroscope, static pressure, pitot pressure, magnetometer (compass), and time. what it outputs is an estimate of the motion of the glider.
>
> now, if the EKF only had acceleration and time as inputs, it would need an extremely accurate accelerometer and clock, as you have surmised. acceleration is relative, so even small errors in acceleration will snowball over time into large errors when doing dead reckoning this way.
>
> fortunately, the EKF has much more data to work with. since it also has access to measurements that are absolute (heading, altitude, airspeed), it can integrate all the data in a way that makes the accelerometer error much less significant. since acceleration is only one piece of the puzzle, it has less influence on the overall motion estimate, and therefore the drift you would expect with dead reckoning is diminished.
>
> thanks to the power of the EKF, an extremely accurate IMU (accelerometer, gyro) is not necessary. i wouldn't be surprised if the butterfly has an IMU of similar quality as that of a smartphone.

Kalman (and EKF) is a process that you run into pretty much everywhere. It's quite elementary way of correct predicted state of something on basis of comparing previous predicted state to current observations. It doesn't do theh inertial navigation itself, it's just way of polishing things numerically. For example, if airspeed measurement is systematically too small, Kalman filter corrects that error (this is maybe too elementary example, reality is more complex for sure). I think important part of achieving this state of inertial navigation (without GPS) is by using measured TAS.

[[email protected]]

On Friday, October 23, 2015 at 12:57:08 AM UTC-7, krasw wrote:
> Kalman (and EKF) is a process that you run into pretty much everywhere. It's quite elementary way of correct predicted state of something on basis of comparing previous predicted state to current observations. It doesn't do theh inertial navigation itself, it's just way of polishing things numerically. For example, if airspeed measurement is systematically too small, Kalman filter corrects that error (this is maybe too elementary example, reality is more complex for sure). I think important part of achieving this state of inertial navigation (without GPS) is by using measured TAS.

TAS (calculated, not measured) is probably the most important input to the algorithm, but navigation without GPS cannot be done without heading information as well. interestingly, accurate heading cannot be computed without at least a rough idea of where you are on the planet due to magnetic declination. so this system would not work as well (in most places) without an initial GPS fix. this purely academic though because any navigation system would be useless without at least knowing the starting point.

also interesting is that having a rough idea of where you are also improves the accuracy of the accelerometer because the force of gravity differs depending on where you are on the planet. remember that at rest, an accelerometer will always show roughly 9.8m/s^2 in the downward direction.

[Fox Two[_2_]]

I would assume that the two most common mounting locations of the ISU would be forward of the instrument panel, or behind the pilot's seat. I'm leaning towards installing mine forward of the instrument panel, but the nearby radio concerns me. Behind the pilot's seat would be a less convenient installation, and its proximity to the speaker and the steel spar pin present interference issues as well.

Any installation advice from people with either setup?

Thanks!
Chris Fleming

[Mike Oliver]

Mine, in an ASW20, is mounted forward of the instrument panel on the
opposite side from the radio. I've had no interference issues. Love the
instrument.






At 09:01 05 July 2016, Fox Two wrote:
>I would assume that the two most common mounting locations of the ISU
>would=
> be forward of the instrument panel, or behind the pilot's seat. I'm
>leanin=
>g towards installing mine forward of the instrument panel, but the nearby
>r=
>adio concerns me. Behind the pilot's seat would be a less convenient
>instal=
>lation, and its proximity to the speaker and the steel spar pin present
>int=
>erference issues as well.=20
>
>Any installation advice from people with either setup?
>
>Thanks!
>Chris Fleming
>

[Fox Two[_2_]]

It's not on the longitudinal axis (you installed it off-center)? Does that cause any roll issues on the artificial horizon?

[jfitch]

On Tuesday, July 5, 2016 at 2:01:15 AM UTC-7, Fox Two wrote:
> I would assume that the two most common mounting locations of the ISU would be forward of the instrument panel, or behind the pilot's seat. I'm leaning towards installing mine forward of the instrument panel, but the nearby radio concerns me. Behind the pilot's seat would be a less convenient installation, and its proximity to the speaker and the steel spar pin present interference issues as well.
>
> Any installation advice from people with either setup?
>
> Thanks!
> Chris Fleming

I mounted mine on CL forward of the instrument panel under the glare shield as far from anything else as I could. No problems due to mounting location..

[JS]

On Tuesday, July 5, 2016 at 8:31:23 AM UTC-7, Fox Two wrote:
> It's not on the longitudinal axis (you installed it off-center)? Does that cause any roll issues on the artificial horizon?

Mine is forward of the instrument panel, essentially over the right knee. Transponder and radio "guts" are not on that side. It appears to work fine there. Have not flown much IFR with it but appears the AHRS is fully functional.

A note that closing the canopy (if the instrument panel tilts with it) immediately after power up helps the Air S calibrate. Look for the three dots in the upper R of the AHRS display prior to launch. Without at least one (prefer two) dots, you won't get the sort of wind reporting the Air is famous for.

At the moment (could be fixed with software) if you're at a contest that demands disabling the AHRS the entire funtionality of the ISU is lost, seriously compromising the vario.
Had originally thought the AHRS screen would be the only loss.
I will send an e-mail to Air support about this.
Jim

[Mike Oliver]

If it does I haven't noticed but there again have done little IFR but have
flown with the horizon on without noting any issues.



At 15:31 05 July 2016, Fox Two wrote:
>It's not on the longitudinal axis (you installed it off-center)? Does
that
>cause any roll issues on the artificial horizon?
>

[krasw]

Ahrs lock affects only horizon. Everything else works as usual. It might be distracting that you get red cross over wind indication while on ground, but cross disappears right after take off.

[George Haeh]

The ISU contains compass sensors; so
the same precautions as mounting a
compass apply as far as magnetic fields
are concerned. The Installation manual
does a thorough job in specifying
minimum distances from magnetic
sources such as battery wires, speakers
and compasses.

I relocated my battery selector and wires
to the bottom of my panel. Happily the
fuses were already there. The radio was
also moved down into a hole vacated by a
Cambridge. The boat compass on the
glareshield was tossed - the hole now
accommodates PowerFLARM antennae.
In Canada the Air Glide qualifies as a
magnetic direction indicator.

Then there's the geometric requirements. I
leveled my glider according to the
Maintenance Manual directions for CG
measurement. Don't expect the panel to
be 90° off the level flight attitude. Most
likely it will be something else. Those with
a tilting panel with access behind the
panel accomplished by removing the
canopy and glareshield need to support
the panel with canopy removed in the
same position as when the canopy is in.

I cut a basswood plank from a hobby shop
for the ISU platform with bevels to fit the
panel and other side of the instrument
binnacle. A foam block raises the ISU to
just below the glareshield.

Once you have the ISU on the platform
and hooked up to the vario with the glider
leveled, you can use the info boxes to
show pitch and roll angles. Shim to get to
zero.

Nothing better to keep a glider
owner occupied over the winter.