USA AAT scored distance issue on LX9xxx series

[Tango Eight]

Is there any way to get the 9070 to calculate distance/speed correctly on AAT task using the USA 5 mile radius start cylinder?  "Start out the top" -- which I think is the correct option for USA rules -- seems to calculate distance from the center of the cylinder, which can add up to 5 miles to the scored distance.  

best regards,

Evan Ludeman / T8

[Andy Blackburn]

M glider is in the box but I recall on the start configuration page there is at least one option to “shorten leg distance” or something like that. I think it’s the same page where you select start out of the top.

Andy

Sent from my iPhone

On Dec 23, 2025, at 8:25 AM, Tango Eight <tango...@gmail.com> wrote:



Is there any way to get the 9070 to calculate distance/speed correctly on AAT task using the USA 5 mile radius start cylinder?  "Start out the top" -- which I think is the correct option for USA rules -- seems to calculate distance from the center of the cylinder, which can add up to 5 miles to the scored distance.  

best regards,

Evan Ludeman / T8

--
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 visit https://groups.google.com/d/msgid/lxnav-user-group/f6ac11a2-805e-425e-b8f1-2bb4a725be6bn%40googlegroups.com.

[Tango Eight]

Thanks, Andy.

This seems to solve the scored distance/speed problem on the first task leg in the sim (9.0.20).  However, as soon as one enters the first turn area the scored distance changes abruptly to scoring from the start center.  With any luck, this bug is confined to the sim...

best regards,

Evan

[Andy Blackburn]

Word! I never noticed that. But then I haven’t done a start cylinder in a few years. Maybe this year.

Switching the measurement system on the fly is almost certainly a bug.

I believe you an also make the selection for the finish ring. Might make a difference on that marginal final glide to have two miles added.

IIRC the elections are something like:

- Shortern leg distance

- Navigate to closest point

Happy Holidays!

Andy

[Andrzej Kobus]

Evan, it has always been like that. I inquired about it probably 10 years ago. LXNAV responded it was as designed, so no joy.

[Uroš Krašovic]

Please try to check "navigate to nearest point" under task options.

Best regards, Uros 

V V tor., 23. dec. 2025 ob 21:06 je oseba Andrzej Kobus <soa...@gmail.com> napisala:

To view this discussion visit https://groups.google.com/d/msgid/lxnav-user-group/CABhEzgzyrOntEdwSc6Gyynm8o0Z5jakEjX2_%3D7NuHE%2By%2Bgy2QA%40mail.gmail.com.

[Tango Eight]

Hi Uros:

yes, I have been using "navigate to nearest".

I recorded a 4 minute desktop video that shows this issue in sim.  

This is a contest flight played back in the PC Sim.  At the beginning, I show you the task setup including options, waypoints, observation zones, MC.  Start occurs near 1314 by the clock displayed on 9070sim, at the edge of the start cylinder (5 mile radius).  I show that on the first leg, task stats are correct for distance and speed.  When the first turn area is entered, I show that as soon as I select "next", the distance on task jumps by 5 miles and the speed on task jumps accordingly.  It looks like after this time that the program scores from the center of the start cylinder (like FAI rules), though this isn't correct for start out the top.

https://youtu.be/hRpMDAhCgJs

best regards,

Evan

[Tango Eight]

There's another issue that arises when both observation zone distance correction and navigate to nearest are selected, also visible in that video: The delta time databox shows bad numbers.  Not sure what is going on here.  The delta T isolines seem correct.

-Evan

[Morgan Hall]

Evan,  one thing to consider is that the Sim hasn't been updated in over a year and doesn't track the software releases of the 90X0 devices.  The behavior of the sim, may not align with the current software on your device. It's great for training on the basic functions, but I don't trust that it will give me exact behaviors of the actual unit. 

Morgan

To view this discussion visit https://groups.google.com/d/msgid/lxnav-user-group/47de246d-4eea-42cc-aacf-9cb5b5de9cebn%40googlegroups.com.

[Tango Eight]

Hi Morgan,

Understood, good point.

It's well understood by USA competition pilots that the 9xxx computers have -never- (see Andrzej's comment) scored speed and distance correctly for USA rules.  The start cylinder is the obvious primary suspect here. 

best,

Evan

[Andy Blackburn]

Important info here for the US Rules process. We pay a price for having rules that aren’t compatible with the global infrastructure for creating, distributing, loading, flying, downloading scoring and tracking competition flights - in order to support a few hundred pilots. This isn’t the only example.

Food for thought.

Andy

Sent from my iPhone

On Dec 28, 2025, at 10:51 AM, Tango Eight <tango...@gmail.com> wrote:



To view this discussion visit https://groups.google.com/d/msgid/lxnav-user-group/CALtO1AVZOCDWdjyp%3Ds6_A11hwy6etHhiQ73rRwd%3DNdMapD8Rew%40mail.gmail.com.