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Old June 30th 11, 04:16 AM posted to rec.aviation.soaring
Bruno[_2_]
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Posts: 114
Default I'm 4" short and need more compensation...yes this is gliding related :)

Let the jokes begin...

My Cambridge L-Nav's backup battery ran low and I switched it out.
The settings got reset to default. Now field elevation reads 4"
millibars too low. For example, 6,200 feet the awos said pressure was
29.99 and my Cambridge read 29.54 for that elevation. On start up my
LNAV showed 6,200ft at 29.54. Never had problems before the battery
switch out. Yes, have the manual and can get into config mode but
can't seem to find a way to adjust the error.

Now for compensation...
Many people thought my winglets were a desperate cry for compensation
but that is just the beginning of it. My varios seem to be working
well but act completely uncompensated. I have a TE probe in the tail
and as of this last winter the gaskets on them are nice and air
tight. I know my two flasks for the varios are air tight as well.

When I pull up in a thermal the varios both show huge increases. It
is usual for the varios to show over 10 knots in a pullup in a 3-4
knot thermal cruising at 80 knots. Yeah, no compensation. I read in
the LNAV manual that it has an electric TE compensation adjustment.
Anyone use this? Does it work pretty well?

I have no idea what is wrong with the current system. The plumbing is
all new as of last winter from the seat back forward. I divided the
vario lines back by the seat back so they are not messing with each
other. The best guess right now is the negative pressure line (TE) is
somehow not working/leaking/who knows what. I did take out the metal
probe and blow in the holes and felt airflow through the end so at
least the probe is not blocked. I am not using the ram air pressure
from the pitot but from the nose. Could this be part of the problem?

Thanks for ideas,
Bruno - B4 - maybe this should have been posted anonymously