Todd Pattist wrote:

"David Starer" wrote:


a quick calculation shows that if you glide at 70
knots in a 35 knot 90 degree crosswind, you will experience the equivalent
of about 8 kts headwind component. This is the figure you would have to feed
into the calculation to find the height needed to complete your final glide.


1) It's not at all unusual for me to be high enough to final
glide to a TP, then turn and glide home. I need more than a
component of the wind to figure out if I can make it to the
TP and then home.

If the wind is changing along your course, knowing it accurately right
at the moment probably won't help much. You'll still be guessing about
the wind along the rest of the course, 10-20-30 minutes later. I suggest
using the headwind component for the entire final glide.


2) To figure out which of five potential airports in the
area you can safely get to with maximum remaining altitude
needs more than the wind component along your current glide
path.

Since you can easily make the turnpoint, this won't be an issue until
you reach it. When you make the turn at the turnpoint, the computer
will update the vector wind. This should improve the glide calculations
to your safety airports. If you have head for one, you can go back the
headwind value to improve the calculations.


3) I'm gliding down to the ridge from thermals and expect to
arrive low over relatively poor landability terrain. I'd
really like that real time wind speed and direction to
comfort my fearful heart as I dump off precious altitude and
descend to the ridge.

I think this is the kind of short term (a minute or two) situation -
getting close to the ridge where you either need to turn away or
continue - that wind updates every 10-20 seconds would be useful. The
other situations involved long (30-40 minutes) glides during which the
wind could change several times.

--
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Eric Greenwell
Washington State
USA