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Old August 15th 07, 08:08 PM posted to rec.aviation.soaring
Bill Daniels
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Posts: 687
Default Question about preparing a x-country plan with decision (go/no go) points...

Dave, you'll get a lot of good advice about using "Glideplan" technique.
However, I'm going to give an unconventional answer that may help someone.

When I started, like everyone else, I drew circles around airports where I
knew I could land showing the altitude required to get there. That resulted
in a lot of circles around a lot of airports - most of which I didn't get
near. One of many problems with this approach is that circles don't
accurately show the actual heights required - wind and changing terrain
elevation make a big difference.

Now, I look at it differently. I just want to know my 'glide footprint' or
how far I can glide from right here, right now, taking everything into
consideration. That tells me which 'known-safe' landing areas are within
range at, say, 1/2 best L/D. I always keep two within range in case one
gets blocked by a downburst or thunderstorm. If I start to get low, I move
toward one of them while still looking for lift. If I don't find lift, I'll
still be in a good position to land.

Only on a dead calm day over a perfectly flat plain with the 'glide
footprint' be a circle. The 'glide footprint' in mountainous areas is
usually a really bizzare shape looking like a butterfly if you are over a
ridge or a star over a group of peaks. There are two PDA software programs
that display 'glide footprints'. One is XC Soar and the other is GPS_LOG
WinCE. I use GPS_LOG Win CE.

Bill Daniels

wrote in message
ups.com...
I've seen mention of this quite a bit, but have not been able to find
examples of the different ways to do this. Anyone care to elaborate on
what you do?

By the way, I have a flight computer with GPS (302/303) and also have
the GlidePlan software for printing areas of sectionals with altitude
rings along any flight routes/tasks. I'm really just curious about
what folks would be doing without the nicer tools.


Thanks,
Dave