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Old May 25th 18, 05:05 PM posted to rec.aviation.soaring
Martin Gregorie[_6_]
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Default Birds do it too...

On Fri, 25 May 2018 07:48:16 -0700, Tom BravoMike wrote:

BTW, between the lines, maybe the secret to so many successful Polish
pilots in the history of soaring: Poland has the world's largest
population of white storks (ca. 25% of the world's count), virtually all
of them migrating every year back and forth between Europe and Africa.
Flying with them in a thermal is a common experience in Central Europe
(including around Leszno), although they are a little bit timid and
probably not as good in centering upwinds as soaring birds of prey.

I'm not so sure of that: from personal observation the best soaring birds
are storks and kites - both have an amazing ability to centre and climb
in thermals. During a Free flight event in Portugal in 1998 the field was
covered with small groups of storks. Very wary: they'd fly off if we got
within 50m of them and when they did I never saw them flap higher than
10-15m before snagging lift and cruising away - and remember that we were
making them fly rather than them picking their moment. Similarly, I've
seen kites regularly climb away from 5-7 m without any flapping. The only
US bird I've watched that comes near to this was brown pelicans ridge
soaring along ridiculously small ripples.

The other noticeable differentiator is that gulls, storks, vultures and
kites generally have good traffic management in thermals - they all tend
to circle the same way. Gulls in particular have always turned the same
way I'm turning when they've joined me, but hawks and buzzards haven't
any such manners: the only hawks I've met in thermals have been turning
the wrong way and not looking ahead: when they do see me, they've all
immediately closed wings and plummeted out of the pattern.

However, bigger raptors may be better behaved: one one flight out of
Boulder we were joined by a bald-headed eagle who sat well above and
inboard of our Grob's inner tip in a thermal while he looked us over for
some minutes before moving on.


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