On 29 Jan 2007 16:54:27 -0800, wrote:

Sounds like it would be a usefull instrument for a hot air baloon.
After all, you need to know which way the wind is blowing.

Balloons do use something similar to a yaw string. They hang a piece
of rope from the periphery of the bag down to a point level with the
basket, with a piece of yarn at the end. It serves as a measure of
horizontal wind shear, which tells you which way your path will
deviate if you change altitude.

rj