Spin

Robert John wrote in message ...
Hi Karel,
I do not follow your explanation.
If I carry out the same 180 degree manouver at 5000
feet, even in a 50kt wind, both I and the glider are
quite unaware of groundspeed. No change in attitude
is required or made.
The only difference in doing it at 100 feet is surely
the close view of the ground and the APPEARANCE of
changing speed which may cause me to lower or raise
the nose when I should not.
Regards
Robert

Hi Robert,

You are right Robert. The glider is unaware of groundspeed.
Looked several times at the short film of the crash where it is
obvious that the DG500 is flying to slow relative to the fast moving
air rather then to slow relative to the ground while having a lot of
tailwind (which is not very fast either).
During standard circling no accelleration forces in the longitudinal
direction of the glider are required to keep the IAS constant when the
glider makes perfect circles relative to the moving layer of air. From
the ground this looks quite different of course. But that is indeed
irrelevant.

Regards and thanks for your comment,
Karel