"Roger Long" om wrote in
message ...
But there can't be a relative wind unless some other force is acting on
the
plane.

"Some other force". You mean, like the lift vector being tilted to one side
or the other, dragging the airplane sideways?

An airplane is not a weathervane.

No, you're right. An airplane is an airplane and a weathervane is a
weathervane. However, the airplane can behave a lot like a weathervane in a
variety of situations, including while in flight. All it takes is for the
relative wind to not be coming directly from the nose.

Pete