302 wind calculation

Hi Evan,

Your feedback is so different from all other Cambridge 302 user feedback
I've received that it makes me wonder whether your 302 is out of calibration
in some way. Does it show accurate airspeed while in flight?

Best Regards,

Paul Remde

"T8" wrote in message
...
Today was an interesting day to test instruments. Winds varied from
about 15 kts at 2600 to 26 kts at 3600 and favored a local ridge which
added its own influence. It wasn't anywhere near good enough to go
anywhere, so (unusually) I flew local, tested out XCSoar for the first
time in flight and played with vector wind on the 302.

I stand by my assessment of the 302 being inferior to the latest
versions of the LNav+GPSNav. That older system would get good vector
winds under normal thermal soaring cruise conditions as long as you
were not flying in an arrow straight line. It would also frequently
get useful updates on a meandering ridge. The 302 requires GPS track
changes of close to 90 degrees to get a decent vector wind. Lesser
changes will sometimes get updates, but frequently the updates will be
a little funny -- definitely at odds with other recordings in the same
airmass and therefore suspect. I think it's probably quicker, faster
and more efficient to do a 360 turn if you really need a wind update.
I've only ever been willing to do that once on a racing task, but it
does work.

XCSoar, happily, does vector wind in cruise quite nicely using the
302s GPS and TAS output. Nothing bad to say about this at all. It
seems likely that it will out perform the 302. I'll be interested to
see how this works in normal XC soaring.

Darryl: my apologies for jumping down your throat. I *don't* think
the 302 works as well as you say it does. In fact I think the vector
wind in cruise capability it has is next to useless for performance XC
and racing (my main interest) but clearly it does work in a limited
sort of way that I can see *would* be useful for exploring a
convergence, perhaps also wave, etc. Different strokes.

-Evan Ludeman / T8