LX7007 speed-to-fly problem, revisited ...

I had a pair of seemingly disjoint flight data problems through Saturday and I’m curious whether their absence on Sunday had them connected in some way.

My setup: LX7007 Pro IGC (ver 2.01) providing NMEA and LXWP* sentences to an Oudie (SeeYou Mobile, latest version). I use the LX for general task and flight direction including speed commanding, and the Oudie for birds-eye situational awareness (landing options) and second opinion on final glide data. (The Oudie is new this year, replacing my old hx4705 that also ran SYM.)

Problem One: the LX’s speed commander hadn’t worked in a long time. (Hard to pinpoint when since I’ve flown so little since summer 2010.) I recently had the LX’s firmware upgraded from 1.2 to 2.01 hoping that would fix the problem. It didn’t. The speed director would always tell me to fly slower, no matter how slow I was flying. It would only suggest faster (err, less slower) speeds if I upped the McCready to high settings ( 4).

Problem Two: the Oudie’s altitude display was way off, even though I set it to the field elevation in the Settings page before launch. During the flight it would read up to several thousand feet different than the analog instrument or the LX’s. This was giving me incorrect arrival altitudes on the Oudie, thus rendering it nearly useless as a situational awareness tool.

Saturday evening while discussing the problem with N7, he suggested, wrt Problem One, it might be a polar data problem in the LX. This reminded me that sometime in the last two years I switched from using my own calculated polar coefficients (for ASG-29/15) to simply using the ASW-27 selection in the LX’s polar list. So Sunday morning I reinstated the polar data numbers I used from 2008 to ~2011, and made the same change to the Oudie’s polar setting.

Sunday’s flight saw BOTH problems disappear.

Coincidence? I’m concerned about Problem Two happening again, and how it might be fixed in flight.

Regardless … sure was nice to finish my first AST in nearly two years, even if I was slower than N7’s tortoise (http://www.youtube.com/watch?v=fTpgqgfJs4w).

~ted/2NO

ps I suppose if Problem Two happens again I can tell it to use internal GPS instead of LX data, but I hate to lose the air data in SYM ...