On 6 Jun 2005 07:27:50 -0700, "Paul kgyy" wrote
in .com::

never once a tailwind.

Most winds have a head wind component; in fact, only winds directly
from directly behind have no head wind component. Quartering winds at
90 degrees to the intended course act to reduce on-course ground
speed, and those quartering winds of up to 60 degrees aft of course
can have a significant head wind component.

The point I'm making is, that of the 360 degrees available for winds
to intersect the intended course, only about 15% are able to result in
a net ground speed increase.

This is from memory, so I'm sure someone will correct me with a more
detailed analysis.