HAWK vario installed angle

[Britton Bluedorn]

Hi everyone, it’s come to my attention and probably a few others of the situation below:

For HAWK to work correctly, the vario has to be between 10deg of vertical when in the factory weighing attitude for the AHRS leveling process to work. 

For my ASW27, the panel sits around 13deg from vertical when the glider is leveled per the maintenance manual instructions. Picture below. The glider is in its level attitude, with ladder and 90deg reference angle in the background. The system states “Cannot level AHRS. Misalignment too big.”

After many emails to LXNAV, 

I finally got the following few phrases that sheds light in the situation:

“ HAWK takes into account all offsets up to the limit.”

“ For the hawk are minimum installation requirements.   We can not assure the proper operation of the hawk if installation is out of the bounds. ”

What is not in the manual is the limit is 10deg. Period. I’ve asked them to open up the tolerance to a larger value, 15, 20deg but received a no. Not sure why. 

Also was provided this link today too of someone in the same situation, take a look:

https://www.facebook.com/groups/1120553115453978?multi_permalinks=1276814546494500&hoisted_section_header_type=recently_seen

Glider is level is the picture below. Note panel angle and reference angle. 

So how many people have tried to follow the instructions and hit a snag with leveling?  I know I’m not the only one. 

The HAWK system is pretty clever using inertial vertical motion, subtracting out the circling polar sink rate to equate the final ‘potential climb rate’ for the vario. But… the assumption is that the system is aligned properly. 

I would imagine that many AS gliders are impacted 27, 29, 33, (24, 34?). 

How about you? Difficulty in performing the leveling procedure?  What glider? Let’s make a list. 

I’m very happy with the horizontal winds, just the vertical Vario reading was suspect. A 4kt day in October was showing as 8kts on the hawk vario needle. 

I’ll try to get some shims in and redo the leveling step before my next flight.  If someone has a clever idea for a bracket please post. 

Britton 

[Jim Staniforth]

That's unfortunate. Not looking forward to installing it in the ASH31 with those limits.

Might have to cancel the order on the S10 and get another used Air-Glide S for much less money.

Jim

[David Anisman]

Britton, I installed and (I believe) successfully leveled a new S100 with Hawk in my '27 (in the W&B configuration as per the manual) at the beginning of the season (May '22). No adverse messages were displayed and in flight the AHRS looks well calibrated. The Hawk climb rate does appear to read higher than true, but that has also been reported by a few others. I'm not sure it is related to the leveling step.

What device did you install? What F/W version? I'm on 9.05

I cannot find the hawk minimum installation requirements or any bounds specified anywhere in the manual for the S100. Only the leveling and calibration procedure. Is there another reference?

To be clear, I leveled by raising the tail boom to 3 degrees down from level at a point ~2500 mm back from the wing's leading edge at the root.

David

[Tom Serkowski]

Any chance of lengthening the upper panel stiffeners to force it more vertical?   You can also shim the vario to be more vertical. 

Tom

Sent from my iPhone

On Oct 31, 2022, at 21:29, David Anisman <david....@gmail.com> wrote:



--
You received this message because you are subscribed to the Google Groups "LXNav Soaring Glider Equipment User Discussion Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email to lxnav-user-gro...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/lxnav-user-group/18bca394-ccf1-4476-b724-660d73b92f1en%40googlegroups.com.

[Steve Koerner]

I had the same reaction as Mr Anisman. My hawk 9070 is reading high by something like 25%.  Many other folks have reported the same. So I think it's a bug in the code that still needs fixing.  It seems unlikely to me that it would have anything to do with leveling.

Steve Koerner

[Morgan Hall]

Regarding the over indication of thermal strength by Hawk, I seem to recall from either a Hawk presentation or possibly a post by Adam Wooley that Hawk is indicating what *should* be possible for climb rate.  Like a super netto pointer.  But if you have any sideslip or anything that might degrade your climb to less than the circling polar would assume, you'll see lower average climb rates than the pointer would suggest.

When I was in Ely and flying with Hawk on my non-compatible GPS in my 9070, I felt like I was achieving climb rates that were lower than the pointer or the audio would suggest I should have been getting.  These were my first flights with the new panel and with Hawk, so I was very much trying to dial in a lot of new information. But it certainly contributed to me wasting time in thermals that I thought were stronger than they turned out to be.  

Morgan

To view this discussion on the web visit https://groups.google.com/d/msgid/lxnav-user-group/CAJGEj%3DBBgrDYUKr7ic8cZqFoRh52EqetMWXyZMZW_a2gK_EyFA%40mail.gmail.com.

[John Mclaughlin]

I have experimented in smooth wave lift. It seems to agree with TEK in wings level climbs but often (though not always) over reads in turning flight. 

I don't believe that poor piloting is the cause of the problem - I've had Hawk sideslip angle displayed on my S100 and tried varying the sideslip angle around the suggested values - nothing changes very much. I wonder if the increased g in turning flight is upsetting the sensors? Surely they'd have considered that right at the beginning of design, but there's something about turning flight which upsets it. I'd say that poor piloting is not likely to cost me more than a knot or .5m/s climb rate, but we're seeing much bigger discrepancies, such that they're unlikely to relate to incorrect sideslip angle or speed.

John

To view this discussion on the web visit https://groups.google.com/d/msgid/lxnav-user-group/CAPaUW1RQnyPurXskcUvC__SCqd99yuti_N%2BCjqfpUuT0D-Q42g%40mail.gmail.com.

[Aldo Cernezzi]

Today a new video has been posted on YouTube, about "Hawk: lessons
learned" .

https://youtu.be/_j4xHq1wwEQ

It's in German language, but it seems that an English version will be
coming soon.


Aldo Cernezzi

www.voloavela.it

[Paul Remde]

Hi Aldo,

The English language webinar will be hosted by myself on November 26th at 10 AM U.S. Central Time (16 UTC).  Details are below.

HAWK Update Webinar

Title: “The blue needle shows a larger value than the red TEK needle: It’s not a bug”

Presenter: Heinrich Meyr

Hosts: Paul Remde of Cumulus Soaring, Inc. and Toni Šibanc of LXNAV

Abstract:
By far the most frequently asked questions by users has been why the potential climb rate is often   substantially larger than the climb rate of the TEK vario. We will explain that the algorithm is working perfectly well. The aerodynamical reason for the difference between the two needles is caused by the so-called plateau effect of modern profiles. The plateau effect produces a much larger sink rate in turbulent thermals than is predicted by the theoretical circular polar.  We show experimental results of the effect based on analyzing the data of a large number of flighty by different pilots flying different gliders.

To optimally exploit the structure of thermals we propose the dual instrument approach : in circling the TEK - and the HAWK vario are complementary.

Date: Saturday, November 26, 2022

Time: 10 AM U.S. Central Time (16 UTC)

Join Zoom Meeting
https://us02web.zoom.us/j/7773320198

The webinar will be recorded and made available for anyone to view on my Patron page a few days after the webinar.
https://www.patreon.com/cumulussoaring 

I hope you can join us.  

Best Regards,

Paul Remde

Cumulus Soaring, Inc.

[Jim Staniforth]

The mounting angle adjustment should account for all sailplane manufacturers. AS gliders have had a tilted panel longer than LXNAV has existed.

Similar to TE adjustments in electronic varios, shouldn''t there be a a software update allowing owners the option to adjust these functions in HAWK?

Perhaps add a step before the adjustment page with a warning that you're screwing it up.

Pilots could then select "hold my beer and watch this" or "continue with recommended settings".

Jim

[Ramy Yanetz]

If I understand correct the hawk vario will show correct climb rate only in wide smooth thermals when we can easily keep constant angle and speed. TEK varios also work very well in these situations. But in most thermals when we keep making speed and bank adjustments while slipping and skidding to stay in the core it will read much higher values, in fact the less coordinated you are the better the hawk climb rate. Sounds like at least the audio should automatically switch to TEK vario when circling. 

Ramy

--

You received this message because you are subscribed to the Google Groups "LXNav Soaring Glider Equipment User Discussion Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email to lxnav-user-gro...@googlegroups.com.
To view this discussion on the web visit

https://groups.google.com/d/msgid/lxnav-user-group/3af66c75-ff0e-48fc-9405-ff9e22f07c82n%40googlegroups.com

.

[Paul Remde]

Hi,

LXNAV has just confirmed that tolerances will be extended so installation will be easier for some types of the gliders.

It may ore may not be included in the next firmware release, but in one of next releases as they need to do some software mods.

Paul Remde

Cumulus Soaring, Inc.

[Ian Molesworth]

My Lak 17At panel slopes at more than 20 degrees. Strangely enough I did not get a calibration error when setting it up!

I 3D printed a wedge to put between the panel and the instrument that tilts it much closer to the vertical and relevelled it all. No problems again.

It is however far more accurate in the climb now.

[skypic...@gmail.com]

Take into consideration the angle of attack when cruising and you are probably fine.

Sent from my iPhone

On Nov 3, 2022, at 12:18 PM, Paul Remde <pa...@remde.us> wrote:

Hi Aldo,

--

You received this message because you are subscribed to the Google Groups "LXNav Soaring Glider Equipment User Discussion Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email to lxnav-user-gro...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/lxnav-user-group/9d6d31e0-d15b-442e-9b1b-6c2db7ef179dn%40googlegroups.com.