Bill Daniels wrote:

By "enroute" I think RD meant straight flight. To solve for accurate winds
without turning, you need four pieces of data: Ground Track, Groundspeed,
True Airspeed and Heading.

The first two are available now from GPS. True Airspeed can be obtained
with a differential pressure sensor and air temperature. A good heading
sensor is the tough nut. I notice that marine navigation vendors are
beginning to sell GPS based heading sensors using two antennas and receivers
in one box. They're expensive but, being pure electronics, the price will
likely come down

I'm already carrying two gps units, but they don't talk to each other!
Maybe mounting a Garmin Geko on each wing tip, then combining their
output would give us a heading. Mike B ought to be able to do that with
his RS232 combiner box and a small mod to his flight computer software.


I know that reasonably accurate wind data can be computed if the glider
makes slight turns while gliding between thermals. However, after decades
of powered flight, I habitually make very straight glides and the accuracy
of the wind data becomes highly suspect. Super accurate wind info while in
a straight glider would be very helpful finding convergence zones.

Glide Navigator II and probably other software can display the error
between measured headwind (using IAS and ground speed) and headwind
calculated from the vector wind in use. An error over +/- 2 knots is a
good indication the vector wind in use isn't valid anymore. If I care
about the wind, I'll update the vector wind calculation by deviating
from a straight course, or even making one circle.

It's not as good as a system using headings, but it works well most of
the time.

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA