Hi,

I am not an expert on high altitude flying as I've done very little of it.
However, I do believe I would take the possibility of water freezing in the
wing and/or tail very seriously if I were flying above 10,000 feet for more
than a few minutes. The reason is that a while back I saw a photo of a
glider with the leading edge of the wing split open due to water freezing
and expanding in the wing. It was a dramatic photo taken in flight with the
leading edge open 4 inches or more over a split that was perhaps 3 feet
long. This is all from memory so I may not be remembering correctly. It
think it was a photo in Soaring magazine.

Good Soaring,

Paul Remde

"Bert Willing" wrote in message
...
What can happen though is that the small water content in the valve does
freeze, nad then you'll have a bloody leaking valve.

"Marc Ramsey" wrote in message
...
Francisco De Almeida wrote:
The German manufacturers would rather have their customers release the =
tail ballast at +2=BAC. I suspect solar radiation is the reason why =
people can keep their water at lower air temperatures without =
immediately being awarded a split tailplane.
So if you have both outside temperatures below 2=BAC and no sunlight ...
=
beware!

I've been assuming that solar heating is the reason that the tail ballast
doesn't end up freezing during these summer flights. At a few degrees
below 0C in shadow, it should still take something more than an hour for
a few liters of water to freeze to the extent that it would cause
structural damage. Lack of lift and cold toes would cause me to seek
warmer environs long before that point...