WINPILOT + ILEC SN-10 + VOLKSLOGGER

As an aside . . . there are two versions of WinPilot, WinPilot
'Advanced' (all purpose) and WinPilot 'Pro' that **requires** one
of the following devices to be connected to get accurate info:

a.. Cambridge 302 vario/flight recorder
b.. LX1600, LX 5000, LX7000, LX 160
c.. Westerboer VW921/922
d.. or a Borgelt B50 (with a gps-unit)
(from http://www.winpilot.com/gps.asp)

The **Pro** version is apparently able to derive wind info in
straight flight as well as the 'Advanced' version's derivision
from thermalling ability.

jk





wrote in message
oups.com...
I tend to agree with Marcel. I also fly with an ILEC SN-10 and
an IPAQ
with Winpilot. My sense is that algorith and precision from the
SN-10
is always more accurate than Winpilot. The reason I say this is
the
same as what Marcel mentioned, which is the ILEC is capable of
calculating windspeed and direction while in level flight,
whereas most
other software/computers require you to be circling.
Respectfully,

wrote:
Doug,

I'm curious to know how much variation you get between the two,
if any.

I use WinPilot Pro 6.x and an LX7000 Pro, and the two wind
indications
are usually very close.

~ted/2NO

No, the ILEC SN-10 cannot compute winds in straight/level flight. In
fact, there is a known problem when flying long straight runs in ridge
lift, where the wind speed drifts up to unreasonable values (like as
much as double the true speed). It also tends to hold on to a higher
wind speed when the wind dimishes. This can be big trouble when flying
along a ridge into a becalmed area. When you turn around and then
towards your field to land, the wind display updates, but by then it's
too late.

This is not a software bug per se, it is just a limitation of using GPS
and airspeed to measure wind without a heading sensor. Adding a
magnetic heading sensor won't really help, because the heading error is
similar to the crab angle. So without a lot of calibration, you won't
see much benefit, and you just introduce the possibility of greater
error. A two antenna GPS would be a good solution, but the current
consumer products are intended for marine applications, and are not set
up to handle high bank angles.

The problem mentioned below is not confined to the wind SPEED calculation.
Some months ago I flew a fairly straight ridge at 80 kts for many miles,
with the SN10 telling me that the wind was straight along the ridge. I knew
the calculated wind angle could not possibly be correct, because if it had
been, there would have been no ridge lift to keep me airborne, nor would I
have tracked along the ridge with the big crab angle between the ridge and
the nose of the sailplane that was clearly visible outside the canopy.
Eventually I made a couple of circles, after which the SN10 gave me a much
more sensible wind result.
Ray

"Doug Haluza" wrote in message
ups.com...
No, the ILEC SN-10 cannot compute winds in straight/level flight. In
fact, there is a known problem when flying long straight runs in ridge
lift, where the wind speed drifts up to unreasonable values (like as
much as double the true speed). It also tends to hold on to a higher
wind speed when the wind dimishes. This can be big trouble when flying
along a ridge into a becalmed area. When you turn around and then
towards your field to land, the wind display updates, but by then it's
too late.

This is not a software bug per se, it is just a limitation of using GPS
and airspeed to measure wind without a heading sensor. Adding a
magnetic heading sensor won't really help, because the heading error is
similar to the crab angle. So without a lot of calibration, you won't
see much benefit, and you just introduce the possibility of greater
error. A two antenna GPS would be a good solution, but the current
consumer products are intended for marine applications, and are not set
up to handle high bank angles.