On Tue, 16 Nov 2010 03:26:01 -0800, Wiktor Moskwa wrote:


I would avoid White Storks, especially on weak days - they're great
soarers but they're low wing loading let's them use thermals
that would just reduce glider's descent rate a bit.

According to Henk Tennekes ("The simple science of flight") a bird can't
make a living unless its min.sink speed is 1 m/s or less. I'd think that
land birds are unlikely to be much better than that sinply because the
amount of wing they'd need would make life awkward in trees, etc.

Our gliders can certainly outperform some soaring birds. Some years ago
on an almost flat calm evening I was sitting in a very weak thermal,
flying an SZD 51-1 Junior slowly in fairly wide circles and climbing at
half a knot or less, but hey, it was a nice evening and the drift wasn't
taking me anywhere, so I was just enjoying my last flight of the day.
After a while I was joined by a pair of black-backed gulls. They flew
several turns without gaining on me and then left, coming back 5 minutes
later and somewhat lower. This time they flew one turn and exited, not to
be seen again. I could almost hear one of them saying as they flew off
"See, I told you that thermal was too weak last time".


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martin@ | Martin Gregorie
gregorie. | Essex, UK
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